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Vorshlag S550 & S650 Mustang Development + 2018 GT, 2024 Darkhorse & #Trigger

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  • Vorshlag S550 & S650 Mustang Development + 2018 GT, 2024 Darkhorse & #Trigger

    Vorshlag S550 & S650 Mustang Development Thread + 3 Shop Cars - October 23rd, 2014: This thread is where we talk about our testing, shop work, parts development, and racing with S550 Mustangs (and later S650 Mustangs). We will use this thread to share weights, pictures, and tech of various S550 Mustang parts and cars we work on. I started this thread in 2014 when this chassis was just arriving, and in February 2018 our shop bought a 2018 Mustang GT, which we are now using for more hands-on testing. We will use this shop car for development instead of just relying on outside testers' cars, and I have re-written this intro to reflect the change in direction for this thread.

    This forum thread was started in 2014 just on our little forum, but when I revived it in 2018 we cross-posted it to some other forums we sponsor (or that allow us to post there), after we bought our red 2018 GT. Getting this car after the '18 major sheet metal facelift and new Direct Injected 5.0L engine made it seem more relevant now, and I'm glad we waited. Automotive forums are declining, but we feel these are much better places to share data and a better long-term repository for tech than social media (where everything posted is wiped out in about 48 hours), so that's why we go to the effort. We will be updating this thread on the following forums:
    We will try to answer every question in this thread on all forums we have cross-posted on, so feel free to ask or comment about anything you see. Please keep your comments to S550 related things that "we would know" (we are not a basic repair shop, body shop, EFI tuner, or stereo/bling shop - we specialize in suspension, wheels/tires, brakes, safety gear, aero, and chassis work). You can always call or email us at Vorshlag, too.

    Autocrossing and tracking this car on the skinny stock 235mm all season tires was hilarious!

    We did both a track test and autocross (above) in the first week of ownership, in bone stock form, and it was pretty terrible. The next week we upgrade the base model GT with 11" wide wheels/tires, aftermarket monotube adjustable coilovers, plus our front camber/caster plates and spherical Rear Shock Mounts.

    That's more like how a Mustang should look...! 19x11" Forgestars and 305 Bridgestones

    As always, any picture you see can be clicked for higher resolution versions. Videos are almost always linked to our YouTube channel, for best results there. As you might know we weigh everything - and that is what prompted the start of this thread in October 2018, when we started weighing these S550 cars.

    Stay tuned as we add more S550 content to this thread, from work we have done over the last 4 years as well as new development we tackle using our shop 2018 GT and other testers' and customers' cars.


    At long last an S550 Performance Pack 6-speed GT finally arrived in Dallas. Not the one we ordered, but a stocking order GT with similar performance equipment. This one has power leather seats (not the leather Recarcos) with Sat Nav, 12 speaker stereo, the bigger 15" 6-piston brakes, the 19x9/19x9.5" wheels, the works. All the goodies, probably the heaviest way to get an S550 other than convertible automatic GT (yuck!)

    You have all seen the "magazine" weights thrown around, and like usual, the numbers are bunk. I swear these writers don't know how to work a set of scales. We see this every time a new model comes out - either they weigh a car with a full tank of fuel, or two people inside, or lead weights in the trunk, or just parrot the marketing materials they were given. Can they just plain dyno and weigh a car for us gearheads, PLEASE??

    Corey White of Five Star Ford of Plano gave me a heads up that their very first 2015 Mustang had arrived earlier today. It was the FIRST GT 5.0 Performance Package car he knows of in Dallas, as there was a production delay on these cars due to some changes to the placement of the catalysts.

    This 2013 GT is caged and has all the W2W safety gear. With one seat it is almost 3300 even

    After finishing up with a customer's delivery of his race-prepped 2013 GT (built for NASA ST3, see above on the scales) we loaded up our brand new wireless Intercomp digital scales and rushed over to Five Star Ford to get that pony weighed. Why? Because I'm always a skeptic about almost ALL data on cars, and only believe what I can measure on real scales, first hand.

    Turns out this thing is about 100 pounds lighter than all of the numbers the magazines had been throwing around. 3718 pounds with low fuel - low fuel levels are easier to compare between cars and is often how we race these cars in Autocross or Time Trial (depending on fuel tank/pick-up). This weight is with the "Trunk Junk" (TM) removed, which includes the floor mats, trunk mat, and the emergency tire inflation kit (no optional spare tire).

    Trunk junk came to 13 pounds, and there's likely another 15-20 pounds in the trunk mounted sub-woofer. It is removable but they asked me NOT to take it out, since this car is their very first 2015 and going right on the showroom today. After we weighed the car, Corey White (the salesman in the pics, and a real gear head) told me to hop in and we drove to their fuel pumps to put a splash of 93 in the tank. Then he hopped out and said, "You're driving!" How could I say no?

    We went on about a 15 minute test drive, re-striping the streets of Plano in Pirelli rubber. The car drives REALLY well, rides very similarly to a CTS-V... good compression damping, firm but supple ride on the choppy concrete roads, and hauls ass when you give it the Go pedal. Motor feels strong for a zero mile car with similar acceleration to the 2011-14 GT or Boss 302. The PP cars all have the 3.73 gears and Torsen axle. The sticker price is shown below.

    As always you can click any picture for a larger rez version

    The ergonomics are spot on. I've sat in a couple of these but driving it was amazing. 6'7" Corey fits in here well, and my 6'3" frame was swallowed up with ease as well. The shifter feels GREAT and the lever is right where my arm wanted it. The steering wheel has a big FAT rim and gauges that were easy to read. The seats were good, but the Recaros are better - that option worth the extra coin, if you never plan on installing real racing seats.

    Loved the switch gear, and the materials + leathers were top notch. Pedal spacing was perfect for heel-toe downshifts. Just a quick street drive but I really liked it.

    Left: 2014 Camaro Z/28 with A/C and 3/4 tank, sans trunk junk = 3835 lbs. Right: 2011 GT Brembo Premium 6-spd, sans trunk junk = 3563 lbs

    Closing thoughts: this car will be a hot seller. We happened to weigh a 2014 Camaro Z/28 today (equipped with A/C, see above) and it was 3835 pounds with 3/4 tank of fuel. So the S550 is considerably lighter, which is good news. I was pretty upset after hearing the (bogus) 3850+ pound numbers being thrown all over the internet for the S550, and had essentially given up on these cars before they even arrived. That was probably a bit rash, and now I am back on the Pro-S550 bandwagon.

    Since we introduced them in 2014, our S550 camber/caster plates have been a huge seller

    Look for products for this chassis coming from Vorshlag soon - and don't worry, we're going to keep supporting the S197 Mustang even after our 2011 GT is sold (edit: it was sold in 2015). The dyno numbers for the S550 look promising, and the exhaust gains seem pretty big for simple work. The wheel/tire packages on these cars are SUPER heavy - we have a Forgestar CF5 18x10 that fits this car, plus 18x11" wheels in the works, and there's even more "extra weight" in the exhaust and wheels. We will try to get some weight out where we can...

    Thanks for reading,
    Last edited by Fair!; 11-16-2023, 10:15 AM.
    Terry Fair -
    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

  • #2
    Re: Vorshlag S550 Mustang Development

    Thread Update for September 12th, 2016: Long time no update here, but we have been busy with S550 development. In this update we will show two camber plate designs we made for this chassis, plus wheels/tires and MCS coilovers we developed in early 2015.


    Aaron's 2015 GT PP was weighed in stock form, with the trunk junk removed, at 3678 lbs (1/4 tank)

    Shortly after Aaron Sockwell got his 2015 Mustang GT PP (May 2015), we borrowed it and took a number of measurements. He worked at a shop across town that competed at the same Optima events as us, and he had the first S550 locally that would be competitively run in their autocross and time trial events.

    Above: The factory "Performance Pack" wheels are 19x9" front and 19x9.5" rear, but they can fit more...

    We measured for wheels, MCS coilover shocks, and more. To measure for wheels we started with the stock GT Performance Pack 1 parts he had - pulled them off and of course weighed the wheels and tires (above). We used some other wheels we had on hand to help determine what we thought could fit this S550.

    As always we were going for MAXIMUM width under stock fenders without significant modifications. We found out after years of testing on our similar weight/power/sized S197 Mustang GT that the more tire width you can run, the better. How wide? "As wide as they make!" - but on this car, he didn't want to cut the fenders, at first. So 315mm width tires was our goal, front and rear. That tire width needs a 11" wide wheel, but many of our customers want a "rotatable" set so we use a 10" wide wheel, which fits front and rear (shown above at right). The S550 needs different offsets for both the 10" and 11" wide wheels than the S197 chassis, and it also uses a different lug stud size (M14) than the older model.

    The Forgestar CF5 wheels above are what we ended up with, in 18x11" size. These fit the S550 under the stock fenders with a 315/30/18 tire (he started with Falkens and moved to BFG Rivals) as shown, with some added camber up front. Its a tricky setup, and there is VERY little room for error. Some wheel makers just "get it close enough" and tell you to run a spacer for this width on these cars, but we have it down to the millimeter. The front and rear offsets are VERY different to fit this car, but that is what it takes to fit it.

    Our shop took apart the suspension then Shannon and Jason measured the stock shocks, mounting locations, and made a bunch of drawings for MCS out of Georgia. Those drawings were fired off to them and we put Aaron's car back together for the day.

    A couple of weeks later the shocks and wheels arrived, so then it was time for a camber plate design. We had the car for 2 days and in that 48 hours we measured, designed, programmed, machined, assembled and installed these camber-caster plates. It was a short deadline but Jason stepped up and got it done.

    The prototype camber plates were installed onto the prototype MCS TT2 struts, shown above. These were installed along with a rear spring and MCS shock onto our tester's Aaron's Mustang, then it was on track 48 hours later and racing in the Optima/USCA series. He has run these prototype plates for 2 seasons and the parts are still working perfectly on the 2nd owners' car.

    These S550 camber plates were initially only available for "coilover spring" sizes, which the market wasn't ready for. It would take another tester to prompt us to make that version, the following year.


    At the time in early 2015, MCS had the first "serious" monotube adjustable on the market, after working with Vorshlag to get this set on our tester's car. We didn't have a good rear spring solution at the time (we do now) but with the Eibach lowering spring in the stock location, and a stiffer 60mm spring up front, the car was fast.

    Since then we have moved to a coilover-rear spring, but I will show that in a future post. For certain racing classes where you have to use the spring in the stock location we have a ride height adjuster in the works for this car.

    We had the TT2 set dyno'd and the shock dyno charts for the front struts and rear shocks are shown below. The red curves are at the least rebound or compression valving. The green is about mid-way up and the blue is at full stiff. Of course rebound and compression are independently adjustable on these 2 way non-remote MCS dampers. MCS makes S550 shocks in single adjustable (TT1: low speed rebound), 2 way non-remote (TT2:, low speed rebound, low speed compression), 2 way with remotes (RR2), and 3 way with remotes (RR3:, low speed rebound, low speed compression, and high speed compression).

    We tend to avoid the 3 way option unless a customer is building a race car -and- they are very familiar with 3 way dampers. You can tune yourself into a bad place with too many adjustments. The dyno above shows the MCS TT2 fronts struts with damping force curves that can accommodate a large range of of spring rates without re-valving. Both rebound and compression curves are digressive - which allows for both aggressive track use and, when turned down, good ride for street use.

    The MCS TT2 rear shocks are similar in their dyno shapes, ranges of damper forces, and adjustability. We tend to recommend these TT2 doubles for folks who are more serious about competition in autocross or track environments, that understand adjustable dampers, and don't want to spend the extra money on remote reservoirs. Remotes move the compression stack + the floating piston and Nitrogen chamber into the reservoir. This allows for more total damper travel in the same length shock as well as more heat shedding area and more total fluid. We recommend MCS remotes for dedicated race cars and Pro level teams.

    The dampers and spring rates we picked for Aaron's 2015 GT really helped control the roll/dive/squat/heave of the very soft factory S550 chassis setup. Aaron raced his S550 for two years on the Optima Ultimate Street Car Circuit, with wins in the GT class and invites to the OUSCI shootout after SEMA. He moved to another shock brand sometime in his second year of competition, as well as wider 335mm tires, 18x12" wheels, and flares. Then he added a supercharger. Aaron sold the car soon after that so we lost our local S550 tester.


    Shortly after the prototype set was built we made a production version of our S550 camber plate, shown below. This was still only compatible with the common coilover spring sizes: 2.25", 60mm, or 2.5". We make perches to fit any of those. But the problem was - the car was so new, people weren't ready for coilovers. They wanted to keep the stock shocks...

    Adding negative camber is one of the FIRST modifications racers do to their cars, and the S550 chassis needs it just like so many others. Brian Matteucci was an old friend from college and he bought a used 2015 GT PP 6-speed Mustang in 2016. We used his car to develop a new version of our S550 camber plate for use with the OEM style springs. Like a lot of you out there Brian didn't want coilovers - he had three other road race cars and the Mustang was only supposed to be a stop-gap car, a quick build. Brian just wanted to do a handful of changes to make the S550 autocross and track worthy, without spending a lot of money.

    The 2015 GT above was the test mule for a new design of our S550 camber plate made to use the OEM style springs and stock shocks. He ended up running our 18x11" Forgestar wheel and a 315/30/18 BFGoodrich Rival-S tire. These cars need front camber to help fit that massive tire under the stock fenders, but it also needed the camber to keep from excessively wearing the tire's outer shoulder.

    The S550 camber plate for use with OEM springs (shown below) was a bit trickier to design, and we tackled this in early 2016. The OEM top mount / upper spring perch (above) made for a very short stack-up height, so we had to design some new parts and use a new bearing to make our parts match the factory height. Again, we want to neither raise nor lower a car with our camber plate + perch assembly when the stock springs are used.

    Similar to the S197 design, the S550 camber plate has variable camber adjustment that "slides" for another 2.5° of negative camber travel, as well as 2 fixed caster settings (stock and +1.0°). These plates also have more travel built into them than the stock strut tower will allow, but like the S197 design you can modify the tower opening for more usable range. We found that with OEM springs and stock ride heights you can still get to -2.5 to -2.8° camber on an S550 without touching the towers or going to coilovers - which is ideal for the weekend warrior, dual purpose track rat.

    We rated factory springs from the Shelby GT350 (left) and GT350R (right) in the charts above. We rated these at 1/2" increments on our digital spring rater. Many spring makers take the springs to coil bind, back them off a hair, and divide this load by the travel they reached - which leads to artificially high spring rates. We see this on almost every lowering spring on the market when we rate them what we consider "the right way", to get actually useful information.

    Brian installed the GT350R springs, our prototype camber plates made for OEM style springs, and the 11" wide wheels and some stick 200 treadwear tires. He then immediately took this otherwise stock Mustang and beat 19 CAM-C cars at its first National level autocross event, then won the CAM ProSolo class a few weeks later. Negative camber helps even more on a road course.

    This has been our best selling camber plate since it was introduced in late 2016. It seems to be the first mod S550 owners do if they autocross or track their cars.


    Just like the 2015-up Mustang GT V8 and turbo 4 Ecoboost cars, the Shelby GT350 is a great car to use on track - and with more cooling, better brakes, and bigger tires and wheels from the factory they are that much further ahead. These Shelbys are still just as heavy as the GT, and likewise suffer from the same "lack of camber adjustments" problems. If you run these cars in bone stock trim on track be prepared to replace the front tires often...

    In 2016 we started to get our hands on more and more of these GT350 Mustangs. We used the installation of a production set of Vorshlag S550 camber plates on the 2016 Shelby above to make this installation instruction gallery, which has been viewed hundreds of times since.

    Take a look at that gallery to see step-by-step instructions and tips to help make the install of these OEM style camber plates trouble-free. This can be done at home with hand tools and a floor jack, but an impact tool is needed to tighten the strut top nut. See this video for more explanation about that.

    continued below
    Last edited by Fair!; 03-13-2018, 02:10 PM.
    Terry Fair -
    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


    • #3
      Re: Vorshlag S550 Mustang Development

      continued from above

      One of our GT350 customer's had a right rear CV boot rip and let go, and it looked like a rash of them. They all show evidence of a tear in the boot possibly from the production line, so its likely not a design issue at all. Ford is fixing these all under warranty. We haven't seen this pop up again since late 2016.

      I haven't posted many pictures of the GT350 cars we have worked on, but took the time in today to share some things. There are a number of improvements to the GT350/R that are well thought out, with a number of innovative solutions to little problems - some of which stem from the 5.2L 180° firing order crank. One thing that caught us as strange was the plastic oil pan, only found on the Shelby GT350/R models until the 2018 Mustang GT 5.0L got it as well (as a weight saving measure).

      We talked to one of the lead engineers on the Shelby GT350 project and he said this and many other items were changed to deal with the added vibrations of this unusual crankshaft layout. There are primary and secondary harmonics that cause vibrations that make things want to rattle, loosen/unscrew (oil filters), and more. They were trying to tackle these "NVH" items up until the last minute before production started.

      There are mass damper weights mounted all over the GT350 chassis. It is amazing how much effort they put into damping the vibrations of this unusual engine, but people love the way it sounds, and it is made to rev up to a higher RPM, which helps it eek out more power (526 hp) than the 2015-17 5.0L (435 hp) or the 2018 GT engine (460 hp). The higher powered Shelbys also get a stronger 6 speed manual, the Tremec 3160 (read more here).

      Some Shelby owners had been asking us about the caliper mounting bolts, which are HUGE. They wondered if there was a way to add a stud in place of that instead, to keep from galling/stripping the thread in the caliper mounts on the spindle. I suspected that the closeness of the bolt head to the 19" stock wheel might prevent that, but it looks like somebody has figured out the trick.

      Ford has been employing what we call the "scoop and flap" method of front brake cooling. This starts with a front scoop that dumps high pressure air via a vent (see above) into the wheel well area. This is something Porsche figured out in the 1980s and we see it on high performance cars all the time. It is nothing like ducted brake cooling, which is common for race cars - where they take high pressure air from an inlet and plumb it through flexible hose to the back of the rotor. But the scoop-and-flap is at least... something.

      Normally there is a "flap" that is attached to a control arm that directs the air stream towards the hub and rotor. The regular Mustang GT has this but the GT350 does not. Yet the control arm has the mounting bosses for the flap. Did it get left off for a reason?

      The front 15.5" diameter, 2-piece, pin drive aluminum/iron front brake rotors from the Shelby are quite large, and they weigh in at 30 pounds. This is lighter than the front 15" rotors from the GT's Performance Pack, shown below at 33.3 pounds. The Performance Pack was a $2500 option from 2015-2017 on the base model GT and included those front brakes with 6 piston calipers, and they are pretty dang good. The Shelby had to be BIGGER so they went 15.5 and 2-piece.

      2015-18 GT Performance Pack front rotors are a little smaller and a little heavier, but a lot cheaper to replace

      While we worked on our first Shelby GT350 this week we took a number of other pictures with it in the air.

      Here are a couple of rear "underskirt" shots, showing some scoops leading to rear mounted coolers. We also measured axle width to the wheel mounting surfaces, just because.

      This red GT350R (weights shown above) was out at the track with us a few weeks ago, when I was getting a baseline lap in our stock 2013 FR-S. We were at Motorsport Ranch Cresson (MSR-C) running their 1.7 mile CCW course. Pics are here.

      The owner, Josh, hasn't done track events in a few years and just sold his Miata before getting into the GT350R. He drove in 3 thirty minute track sessions that day, hot and humid, and the cooling system did great. He ran a best of 1:25.22 but there was probably some time left in braking, as you might notice in the video above. Not trying to show a Stig lap here, just a regular guy making some fun laps in bone stock form on the stock tires. In the screenshot below and in the first lap of his in-car video you can see him passing me in the FR-S like I dropped an anchor (I was wide open throttle there!)

      Some reference times for the MSR-C 1.7 CCW course:
      • My quickest lap time in a street legal car here is a 1:17.25 from 2014 in our NASA TT3 classed 2011 Mustang GT on giant Hoosier A6 tires + aero.
      • TTC classed 1992 Corvette (gutted, prepped, but nearly stock in every way) was a 1:21.9 on 245 Hoosier R7s.
      • 1:27.6 the same day in our TTD classed BMW E46 330 (with cord showing on the 245 R7 tires).
      • Stock 2016 Focus RS to the best of a 1:27.40 on the stock 235mm Michelin PSS tires.
      • 2015 VW GTI to a best of 1:28.10 on 225mm MPSS tires (stock but with our camber plates and a tune).
      • Stock 2013 FR-S to a 1:31.90 on 320 treadwear 215mm tires.

      So far I'm fairly impressed with both the GT350 and R models, and once the price gouging ends these should make for fairly good track cars. I am heading back to Cresson this Friday to run the Focus RS on a 275mm Bridgestone RE71R on custom 18x9.5" wheels, with coilovers and a big oil cooler. Will also drive some laps in a 2017 C7 Corvette Grand Sport that we are aligning and weighing today. If Josh is there in his GT350 and finds more time I will post up the laps here.

      Last edited by modernbeat; 03-12-2018, 03:15 PM.
      Terry Fair -
      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


      • #4
        Re: Vorshlag S550 Mustang Development

        Project Update for March 6th, 2018: I should lead with this bit of news first: Vorshlag bought a brand new 2018 Mustang GT two weeks ago! We're finally coming back into the Mustang market in a big way with our new S550 shop test mule.

        We bought this car because the 2018 GT model has an exciting list of changes and upgrades that made it attractive to jump back into a new Mustang. The all-new 460 hp direct injected Coyote V8, new MT82-D4 6-speed manual transmission with a twin disc clutch, and of course the all new front bodywork, lighting, and other cosmetic updates. There are a ton of products we have wanted to develop for this 2015-up Mustang chassis, which we can finally do now.


        In 2010 we ordered a 2011 Mustang GT. We used this test mule for extensive S197 product development for 5 years. The changes in the 2011 model were significant for the 2005-2014 S197 chassis - all new bodywork (2010), new brake options (14" 4 piston Brembo package), new transmission (MT82), and an all new motor (Coyote 5.0L) in 2011 that gained 100 hp from the previous 4.6L V8. It was a perfect time to get an S197... and Vorshlag has been known for S197 parts ever since then.

        This 2011 GT won a lot of races, set 16 track records, and helped Vorshlag develop a lot of parts

        Sure, the S550 chassis debuted in model year 2015, and we have done a good bit of product development on these cars since the beginning, but it has been difficult to find and keep some local "testers" to work with for long term testing and prototyping.

        Our first S550 tester's 2015 GT (left) next to our shop S197 Mustang test mule (right)

        Our first S550 test car was Aaron's 2015 GT PP, shown above at left. This car was borrowed in the first months of the S550 introduction to develop the first coilovers from MCS and our first S550 camber plate - which went from concept to CNC machined parts in 48 hours. We also used Aaron's S550 to help us come up with 10", 11", and even 12" wide wheels, which we have had built for us by Forgestar for this chassis since 2014.

        We built 18x11" F14s for Aaron initially that he raced with in Optima series on a 315 Rival-S, and for the first year and a half of competition he used our prototype wheels, MCS shocks and camber plates. We have provided many many sets of wheels for S550 customers since. We also worked with G-LOC to come up their various S550 brake pad versions, which were also used on Aaron's 2015 GT. Aaron has since sold this car, so we lost our local S550 development tester.

        Our second S550 tester was Brian from Houston with his white 2015 GT PP above. We developed a brand new S550 camber plate revision that could work the OEM springs for both the GT and GT350 - it was a complicated engineering, but this version works VERY well for stock springs, and we have sold many hundreds of sets of these camber plates.

        Aaron's 2015 GT PP in bone stock form, testing at ECR Dec 6, 2014

        But beyond those first few handful of items for the S550 (MCS coilovers, Forgestar wheels, and two camber plate versions) we have been limited on what we could develop and sell for this chassis, due to a lack of local testers or an in-house test car for the last 2 years. People haven't been rushing to Vorshlag for other S550 parts we carry, because we aren't "known" for racing a S550. We are fixing that now.

        Look at that front end rise! Me putting in Baseline Test Laps in in Aaron's 2015 GT at ECR, Dec 6, 2014

        What did it was a ride along on track. I had only ever driven Aaron's 2015 GT in stock form at ECR back in 2014, but I rode in Brian's white car (now owned by his buddy, Matt) at a NASA event in October 2017 at MSR-Houston. After riding/coaching with Matt for a session I was pretty damned impressed with this S550 - it only had our camber plates, some 350R springs, a Torsion T2R, the 19x11" wheels we sourced, and some 305/30/18 Bridgestone RE71R tires. It was just flat out fast, put all the power down easily, gobbled up bumps and curbs like no Mustang I had ever driven, and woke me up to the reality of how good the S550 can be with a few tweaks.

        We are a little late to the S550 party, but this 460 hp direct injected 2018 Mustang GT is now part of our test fleet!

        I started looking closer at the 2018 GTs last Fall when new cosmetic changes were introduced, just before the drivetrain upgrades were announced. The new motor having more power, the stronger twin disc clutch, the stronger version of the Getrag 6-speed manual with all new gearing and synchros (MT82-D4), and some other changes. I waited until this Spring until I drove one... we quickly found one with help from our friend Corey White at Roush and his compadre Rich at Five Star Ford in Plano. We bought the bare bones 2018 Mustang GT two weeks ago (above) and they made me keep it a secret - which nearly killed me. This car will be our in-house development mule for new S550 parts as well as our primary autocross and time trial car for the next few years.

        First autocross was run on bone stock suspension, brakes, wheels and tires. It was hilarious!

        So if you enjoyed the build thread and S197 development we did on our 2011 Mustang GT, buckle up because this S550 is likely going to be faster than that car. We are going to try to keep it streetable for at least the first 2 years, so it doesn't get too scary for some of you guys!


        There are many reasons why we didn't buy an S550 when it first came out in 2014, and why we did now in 2018. I will go into that briefly below.

        "The one that got away" - the 2015 Mustang GT we almost bought

        We did look at purchasing a 2015 GT in the Fall of 2014, shown above. The dealer even brought it by our shop to test drive, measure, and check out - it was perfect. Performance Pack (15" 6 piston brakes + bigger wheels/tires), leather Recaro seats, touch screen Nav, Race Red. Problem was the $43K price tag was a bit more than I could swallow at the time. We had just renovated and moved into a new shop space (which costs $$$), just got back from two weeks of the whole shop going to SEMA/Optima shootout in Vegas (which cost $$), just bought CNC machines ($$$$$!), and I was tapped out. Bad timing, but our dealer was happy to sell this car to someone else for more money - it was the "hot new car" with the perfect options and color. It was sold within 24 hours.

        "The one that got away" - the 2015 Mustang GT we almost bought

        I have second guessed this decision ever since - this was a perfect test car, right when the S550 was new and hot. Sure, we could have gone into more debt and made that purchase happen, and we would have surely developed a stronger S550 following by now. But moving CNC manufacturing in-house was a big necessity back then, and tooling up was a giant time and money suck. We needed to concentrate on this aspect to keep growing our business.

        "The one that got away" - the 2015 Mustang GT we almost bought

        3.5 years later its a whole different situation at Vorshlag. Our CNC operation is running smoothly and our reputation for having a backlog on suspension parts is long gone - because we did concentrate on the CNC aspects instead of buying another car. We are now way ahead on our inventory production, and have been developing new parts every month since. The business is growing and yet... I still wanted an S550 to test some new product ideas. So we waited until the big round of 2018 changes and got one.


        We have both short term and long term development, testing, and racing goals for this new shop 2018 GT. Unlike the S197 chassis, the S550 Mustang is a "world car", meaning it will be exported to 140+ countries for both Left Hand and Right Hand drive. The Ecoboost made it popular in countries were fuel is $10+/gallon, which helps over there. This exported model is paying off in Europe (out selling 911s in Germany!) and for the 2016 model year the Ford Mustang was the Best Selling Sports Car Globally.

        New coilover S550 inverted rear remote double adjustable monotube design from MCS was tested on our car

        This world car status has pushed German, Dutch, and Swedish shock makers to take the S550 more seriously, so we want to test some of the new coilover options from Ohlins, Bilstein, Whiteline, and MCS - this car let's us do that. Last week with the car only days old we already tested a new inverted MCS RR2 version (inverted) on our 2018. Sure is handy having one of these around!

        Since here in America fuel is cheaper than bottled water, we got the big 5.0L V8! #Murca Our goals there are to get as close to 500 whp as possible without ever pulling a valve cover. We've seen road race and autocross Coyote 5.0 guys try to get there and spend a fortune in upgrades and repairs, but this Direct Injected Coyote has the right foundation to build on.

        New heads, cams, block, bearings, oil pan, fuel injection and compression ratio (12:1) puts power up to 460 hp @ 7000 rpm and 420 lb-ft @ 4,600 RPM (up 25 hp and 20 ft-lbs from 2017 GT) and runs from 0-60 mph in under 4.0 seconds. This article has a stock 2018 GT running a 11.8 quarter mile with the new 10 speed automatic!

        What may come as a shock is that we did not buy the $4000 Performance Pack 1 or the new $6500 Performance Pack 2, on purpose. Why? Well most of the parts in those PPs would be replaced in the long term, with our plan.

        Powerbrake X-Line X6EL 380x34mm front brake kit for a Ferrari F430 Challenge - similar to what we have on order

        Instead we will test the first production 380x34mm 6-piston Powerbrake kit for the S550 on our car. The image above is a similar setup made for a Ferarri F430 Challenge car, so the hats will be different - but otherwise this is what we should have on the car by April 2018. We want to make several other products for this chassis that we haven't seen the aftermarket make yet - this car will let us do that.

        The two SCCA autocross classes we will test this car in are CAM-C and STP

        To test these new S550 products there is no other better place than in competition. We are eyeing a number of racing classes and organizations to play with this car in. Jon is going to autocross it in CAM-C, Amy and I will autocross in SCCA's STP class, at least initially. It is always a challenge to build around SCCA autox classes so we will keep it fairly casual so that restrictions for one class don't limit products we can make that we know people will want. There's also the Optima series to look at, which has classing closer to CAM than STP. We will talk more about those class choices and potential restrictions in future posts.

        New wheels (19x11" Forgestar F14) and tires (305/30R19 Bridgestone RE-71R) are already here...

        For road course testing we want to run with both NASA and SCCA Time Trial classes, and of course Optima series as well. At first we want to keep 200 treadwear tires in mind, since this "200" limit is becoming so common across many series. We will start by using the 305/30/19 Bridgestone RE71R shown above (first set is here) on a 19x11" wheel (Forgestars just arrived today). We have already completed the first autocross and track tests in this car, which we will cover in our next post. We have a busy schedule planned, so we will have periodic updates in this thread to show testing and racing results.

        continued below
        Last edited by Fair!; 03-13-2018, 03:50 PM.
        Terry Fair -
        2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
        EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


        • #5
          Re: Vorshlag 2018 Mustang GT + S550 Development Thread

          continued from above


          Let's get into some tech here. Weight means almost everything in autocross and still a whole helluva lot on a road course. Tire-to-Weight and Power-to-Weight are damn near everything in Motorsports competitions (we expound on this in great detail in this SCCA Time Trials rules discussions, here). I am going to say it right now - comparing published "curb weights" is worthless. The car makers weigh their cars differently, with different options and fuel loads. Some with passengers, some without. Car magazines mostly just re-post those numbers. WE WEIGH CARS, with accurate, digital scales, always the same way. We weigh parts, wheels, and fuel loads, too!

          My 2013 Mustang GT was 3518 pounds stock, and 3493 lbs with 2" wider 18x10" wheels and 295s

          As I have posted before, the S550 is a bit of a fatty. Sure, its lighter than the 2010-15 Camaro by 100-200 pounds, and it's on par with the 6th gen Camaro, but *heavier than similarly equipped outgoing S197 models (*by +127 lbs, with similar options, comparing our base 2013 GT and our base 2018 GT). The S197s were not exactly lightweight cars themselves.

          Left: A 2017 GT350 at 3703 lbs with low fuel. Right: The first GT350R we weighed was 3649 lbs with 3/8th tank

          Much of the S550's weight gain over the outgoing "Stick Axle" S197 chassis was the beautifully designed Independent Rear Suspension that this car got. Unlike the bastardized parts-bin T-bird IRS on the 99-04 SN99 Mustangs, this S550 stuff is IRS DONE RIGHT. This is a game changer, boys. It puts power down like no other Mustang that Ford has ever built. Like... Ever.

          This is what makes the S550 worth the weight!

          These damn S550s also ride so well I forget its a pony car on the street. It is indescribable - if you have never driven an S550, do yourself a favor and go test drive a new one. Be prepared to never want to drive a stick axle pony car again. Yes, it's THAT much better.

          Market Comparison Tangent: It might seem insane to compare a 2013-2018 Scion FR-S/Subaru BRZ/Toyota GT to the 2015-18 Mustang GT, but it is a valid comparison on price, and some folks do cross-shop these cars (esp the Ecoboost Mustangs, which aren't that much lighter than the GTs, just a bit slower/cheaper). Look at the weight on our bone stock 2013 FR-S above - that is a solid ONE THOUSAND and ELEVEN pounds lighter compared to our stripper 2018 GT. Granted it has 200 hp vs 460 hp, but not much less tire (215mm vs 235mm in base trim). The road course baseline lap times compare remarkably close, too! /tangent

          We have weighed dozens of S550s and they range from 3600-3800 lbs

          Back to the S550 Mustangs - we have seen weights on 2015-up Mustang V8s as low as 3590 lbs (this base 2015 GT below left) to as high as 3800 pounds (the Shelby GT350 below right), depending on options and fuel load. We always remove anything from the trunk - like spare tires, jack, carpet mat, and easily removed emergency tire inflation kits - to get a fair, consistent "race weight" for a car. Because you'd remove this crap at an autocross or track event. We also try to weigh cars with as little fuel as possible, to equalize our numbers. It doesn't always work out that way, so we include a picture showing the fuel level gauge on our weight pics for consistency.

          We had hoped our base model 2018 GT would sneak into the high 3500s stock, but there has been some bloat in this model as the years have passed. The base GT now has two power seats up front, the 2018 now has a dual mass flywheel and twin disc clutch which adds some weight, as does the new Direct Injected motor (high pressure pumps and doo-dads)

          We found the lightest GT possible with our base model 6-speed 2018 Mustang GT, above. We saw a weight of 3645 lbs with low fuel (25 miles to empty) and the optional trunk-mounted spare tire and jack removed.

          The optional mini spare tire is actually really nice but we will likely sell this soon - its a $405 option and $650 from the dealership purchased separately. If someone wants that peace of mind it might be worth the 35.1 pounds it adds. Also, the stock wheels and tires are always heavy, as we saw in the identically equipped 2013 GT at the top. We will still lose weight with 3" wider aftermarket wheels and tires. And more with Sparco race seats. And more with the larger Powerbrake BBK, more with the ARH long tubes, more with the Magnaflow exhaust. Weighing this car at each step is a key part of the game plan. #WeighEverything

          The base model GT comes with these itty-bitty wheels and tires - 18x8" 5-spokes with 235/50/18 all season 400 treadwear tires. These things are AWFUL, and almost dangerous on a car with this power level, but we found this car with the least number of options for a reason: COST and an UPGRADE PATH that made the optional OEM upgraded parts pointless.


          One of the theories we want to test is how does a Base Mustang GT compare to the Performance Pack 1 and new Performance Pack 2 cars, both on track and with respect to cost. We also want to compare to the GT350/350R models. And let's compare to the 6th Gen Camaro SS 1LE. And not just in stock vs stock form - on our 2018 GT build we will show costs of parts after each level of modifications, and see how close in lap times we can get to the obviously faster Mustang models on cost.

          The 2018 Performance Pack 1 option package includes the 15" dia ront 6 piston Brembo brakes, 19x9/9.5" wheels a 255mm Michelin tire - it was once a $2500 option but is now $4000. Later in March of 2018 we will start to see the new Performance Package 2 option debuting with:

          Performance Pack Level 2 includes all of the features of Performance Pack Level 1 – unique chassis and antilock brake tuning, unique stability control and electric power-assisted steering, Brembo™ six-piston front brake calipers with larger rotors, a k-brace, larger radiator, silver-painted strut tower brace and a TORSEN® rear differential with 3.73 axle ratio.

          It’s highlighted by a lower stance, a redesigned front splitter and rear spoiler, and 305/30/R19 Michelin Pilot Sport Cup 2 tires wrapped around split-fitment aluminum wheels – 19x10.5-inch front and 19x11-inch rear.

          The tires, 1.5 inches wider than those found with Performance Pack Level 1, provide a firmer grip, and work with a retuned chassis to put the car more than a half-inch closer to the ground. The package is available exclusively with a manual transmission.

          Custom tuned MagneRide® dampers and quicker steering calibration provide better response. Other improvements over Performance Pack Level 1 equipment include a 67 percent stiffer rear stabilizer bar, a 12 percent stiffer front stabilizer bar, 20 percent stiffer front springs and rear springs that are 13 percent stiffer, all of which contribute to a more stable ride around corners with less body roll.
          The PP2 option is $6500 on the Mustang GT, and requires a number of other pricey options to be able to order it. It has almost everything track related from the Shelby GT350 without the problematic 5.2L engine. The 2018 Mustang Shelby GT350 (below) is also one we will compare our build to. It has all of the PP2 bits and 527 hp, plus that Shelby name.

          You can see more 2018 Mustang pricing here. We didn't buy a PP1, PP2 or GT350/350R car on purpose - because they come with a lot of parts that we would toss out at the first opportunity. Sure, these versions are faster right out of the box, but they come at a big price bump. We optioned up a 2018 GT with Premium, Recaros, PP2 and it was $52K. The Shelby GT350 starts at $57, the 350R at $65K, and they can quickly go into the $75K range with options, before considerable dealer mark-ups.

          This is the actual window sticker from our 2018 GT

          We decided to "keep it simple" on this 2018 GT and found a car with almost no options. We found 3 cars locally that were V8 GTs, 6-speeds, and almost nothing else added. This Race Red car was what we bought. Sticker was $36,695 but it wasn't hard to get them to knock $4200 off ($2000 rebate and the rest was just normal "under-invoice" pricing). The final $32,500 price (before TT&L) saved us nearly $20K off the 2018 GT PP2 I had optioned up, and $25K-35+ off the Shelby GT350s. What can we do with $20-35K in upgrades? We shall see...


          We talk to a lot of new Shelby GT350 owners every week that call us because they want to track their cars and need some front camber adjustment. We ask them what their previous car was, and many of them had never bought a Mustang before. In a lot of cases their former car was a 911 GT3. Ford is doing something right to steal that clientele. So we thought - "Can we do a more focused GT3-like Mustang?"

          2018 Porsche 911 GT3 RS is a glorious car - if you have $187K to spend

          The Shelby owners we talk to say they like the GT350 because it is so much cheaper than a $144K 2018 911 GT3 ($187K for the GT3 RS). They can afford to take their $57-75K Shelby to the track a lot more often, and these Fords have no "Porsche Tax" on repairs or upgrade parts. There are still plenty of buzz-word technical items on the GT350R that impress their Porsche friends (MagneRide, carbon wheels, rear wing, 180° crank V8 sounds exotic) and the lap times are strong, too.

          Most every gear head knows the track-focused 911 GT3 RS model, which comes from the factory with racing style seats, a roll bar, adjustable coilover suspension, wider/stickier tires, better brakes, more power, better aero, and less weight than the regular 911 - basically it has everything that can make this car faster on track, and nothing else. We think Ford tried to do that on the GT350R, but it missed the mark a little bit. There is no camber adjustment up front (so they KILL front tires), doesn't lose any substantial weight, the Recaros are not exactly race worthy seats, no roll bar, and they are still too softly sprung.

          Our 2011 GT had a 4-point roll bar, Schroth harnesses, race seats, and fire bottle

          So our plan for our shop 2018 Mustang GT will be to make it into as much of a GT3 RS clone as we can, for 1/4 the cost. Is this comparison a bit pretentious? Possibly, but we're going to give it a go. Look for an interior on our 2018 similar to the level (above) we had on our 2011 GT, before that car "went off the deep end" and became more of a race car. We will add racing seats, 4 point roll bar, and proper 6 point harnesses for track use. Adjustable coilovers and Motorsport level brakes. Of course our signature "max-width wheels" and the widest 200 treadwear tires. Some aero tricks that we will rob from the Shelby GT350R (wing) and PP2 (front splitter) initially. It will stay street legal this whole time, too.

          Whiteline's Max-G coilover kit will be one of the first shock options we test

          Should be a fun few years playing with this car and we hope you enjoy the write-ups. We already autocrossed and tracked this car in stock form to get some baseline numbers and have something to compare to. This post has gone too long so I will write that up next week - and have some better track numbers at Test # 2 (with the first round of upgrade parts) to show also.

          Thanks for reading!
          Last edited by modernbeat; 03-12-2018, 05:29 PM.
          Terry Fair -
          2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
          EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


          • #6
            Re: Vorshlag S550 Mustang Development

            Originally posted by docwyte
            What halo seat is that? I like that its got windows in it for sight lines....
            That wes the Cobra Evolution, GT width....

            Great seat, just hard to mount in some cars due to the huge halo section. But it does give some lateral visibility that other halo seats lack.
            Terry Fair -
            2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
            EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


            • #7
              Re: Vorshlag 2018 Mustang GT + S550 Development Thread

              Hmm, would it fit in an E36 M3?


              • #8
                Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                Project Update for April 3rd, 2018: Things are really busy around here and I started writing this two weeks ago, and every day that goes by more stuff is going into this 2018 Mustang.

                Track Test #2 at a NASA race weekend - the lap times were a welcomed surprise!

                I am going to cover what I can quickly and save the rest for next time. This time we will cover the first track test in stock form, the first autocross in stock form, a big round of upgrades, and then the 2nd track test with these suspension and a wheel/tire updates.

                On my way to the baseline track test # 1 I found a coin-op car wash and had brought my car wash supplies with me to hand wash the car properly. I don't know why but the First Wash I do is always sort of a bonding moment for me with a new car. (re-reading this - I sound a bit mental)


                Up and out of the house before dawn, I left to go to Motorsport Ranch Cresson (MSRC), our chosen road course test track for the past 4 years. I teased the picture below on Facebook - and this was before we had announced that we even bought a new car. Some sharp eyed people figured out what we bought within minutes. I suck at keeping secrets.

                The track layout we use at MSRC is their 1.7 mile CCW course, shown in the daily map below. This facility also runs a 1.3 mile course, which can be combined with the 1.7 to form a 3.1 mile course, and even the 1.7 mile course "backwards" (CW), which I am not fond of. We stick with the 1.7 CCW because it is the primary configuration that NASA uses, and it has the most room for "oops"... there are 100-200 yards of runoff from any corner, so I can use my hack skillz and push 10/10ths and if I screw up and have an "off", nothing bad happens.

                We went on a Friday morning where I met up with some friends for a member day. It had been raining hard for two weeks straight. It stopped raining the day before but the ground was saturated, so there was an unusual amount of drainage across the track in a few spots, as shown above. This meant we had to deal with some water on the track, but only in a few spots initially and it dried up (only damn in front of "Rattle Snake") by the time we went on track at 10:30 am.

                I went out that morning with two of my homies: Jerry Cecco in his C6 Z06 and Aaron Sockwell in his C5 Z06. Both of these guys have been testers for Vorshlag in the past; Jerry in his Boss302 that tested our TrackPro suspension and his C6Z which has tested a variety of our C6 specific parts, like our brake cooling and our 18x12F/18x13R wheel setup. He was on 335F/345R Hoosier R7 tires. Aaron's C5Z is relatively new to him but already has rear flares, 18x11F/18x12R wheels, 315/335 BFR Rival-S tires, and some CAM legal aero.

                MSR-C Track Test, March 2nd, 2018 - Gallery

                My hope was to go on track at the same time as these two and compare the stock lap times of the 2018 GT to them - who have both run this track many times as well. I waited until they both got to the track and we went out at the same time. This would be my 3rd track test at MSRC 1.7 CCW for 2018 so I was still "fresh" on this track layout, but the first time to drive this Mustang on track.

                The car was a week old, had 340 miles on the odometer, and still had the paper tags out back! Temps were 55°F and I had the tire pressures at 31-32 psi with some warmth in the tires from driving 85+ miles out here in the car. As you can see from the picture above right (which I took in a later session that the Corvette boys ran) the water on track was right in the braking zone for the first turn after the start/finish. So let's see the lap...

                Click here for in-car video of Track Test # 1

                If you click the image above you will see the youtube video of my best lap, which was anything but pretty. The stock tires are GARBAGE and it amazes me that Ford has upgraded the engine in this car SO MUCH yet still supplies the same base tires they put on a 2005 3V 4.6L Mustang. Laughably bad, borderline dangerous. Of course I ran with the traction control completely off and was not pushing the revs hard - because if the engine torqued up too much in a corner, it would just start spinning the rear tires.

                The worst possible tire Ford could put on their 460 hp Mustang - 235mm 400 treadwear all seasons!

                Though "Horseshoe" and "Boot Hill" the car wants to be in 3rd gear - the 6 speed gearing of the MT82-D4 is COMPLETELY different than the old MT82 - and it was all too easy to get the rear to step out under power. I was lucky if I could use half throttle through that series of 3 left turns. In normal cornering (turn in) the handling led to heavy understeer, and as you can see from the AiM Solo DL data logging (finally got a tach and throttle trace!) the lateral grip was between .90 (sustained) to 1.02g (peaks). In my best lap (hot lap 3) I was using all of the track surface, and maybe a little dirt, before the tires got so hot they fell off.

                The brakes were atrocious. If I tried to stop with more than .85g it would overheat the pads in two stops (2 corners). After a total of 8 hot laps I lost brakes completely, even babying the pads with 8/10ths stops. Pedal got HARD and would no longer stop (we did have Motul RBF600 fluid in the car - I won't use stock brake fluid on track!) My best lap time of 1:31.412 stacks up pretty poorly to many other cars (see listing of lap times in the Track Test # 2 section), but most of this was due to the base model's sub-standard tires and undersized brakes. We expected the brakes to kinda suck when we bought the car, and had plans to add better pads to these and maybe brake cooling (which we later found to be impossible), before ditching the 14" 4 piston fronts for something more appropriate. The Performance Pack 15" 6 piston brakes are much better factory offerings than these.

                After 8 hot laps brakes were DONE so I parked it. The Corvette boys went out again at 12:00 (member days here run 30 minute sessions that alternate between sports cars, open wheel, and motorcycles) but gave up after a handful of laps due to the water into Rattlesnake. This BADLY affected both Corvettes' ABS systems, but the 2018 GT took the wet braking in stride and still pulled the same .85g stopping through this water. It was so sketchy in the C5Z (Ice Mode) that Aaron parked it after trying just a few laps in both sessions. Ford ABS still rules supreme.

                After grabbing some lunch with Aaron and Jerry at the BBQ joint next to the track, I headed back to work on this Friday, armed with the knowledge that this 460 hp Mustang GT was only 1/2 second quicker in stock form than our 200 hp FR-S at the same track, on equally crap tires and brake pads (1:31.90). The extra power didn't help when the Mustang has to carry an extra 1000 pounds around on only 20mm wider tires... the tire-to-weight ratio winner in this battle goes to the 2634 pound FR-S.

                FIRST AUTOCROSS - SCCA @ TMS, MARCH 4, 2018

                "Even after 31 years, the SCCA finds new and interesting ways to piss me off"

                So the gluttony for punishment in stock form continues, plus I subjected myself to the typical shenanigans of the SCCA to boot! I was mistakenly looking forward to this autocross - the first I had done in years in a car I owned and had planned on prepping around an SCCA autocross class (STP). Yea, that was a short lived plan.

                Amy and I drove out to Texas Motor Speedway to run this, the first autocross (of 9) for the year with Texas Region SCCA. Jon Beatty (our order manager here at Vorshlag) was to meet us there and run the car in CAM-C, while I was going to run in STP and Amy in the paxed Womens class. We have a lot of friends in this region and all 3 of us were looking forward to seeing our autocross buddies and running in this car - even knowing it would suck on the stock suspension, tires and brakes.

                We got the car teched and headed over to the registration trailer to sign the waivers and see our worker assignments, then walk the course. That's where "the bus went right into the ditch"...

                So this region is a stickler for checking your SCCA membership card and driver's license. Some insurance thing they say. My license had expired a few weeks earlier, but I didn't think about it - because I had updated my address and got a fresh one just a few months earlier. They saw the two week expiration and said I was not allowed to drive.

                So I got to WATCH as Amy and Jon autocrossed our brand new car for the first and last time in stock form, on the day we debuted to the public that we owned it. I was less than thrilled with the people involved and thus began my spiral of disdain for all things SCCA, once again.

                I did get to ride shotgun with both Amy and Jon on some of their runs, to experience the awful stock suspension and tires.

                CAM-C is a pretty hotly contested class in the Texas Region SCCA and they had 12 drivers that day. There were 7 seriously prepared cars on Bridgestone RE-71R or Rival-S tires that day, and a few more coming to the class in the coming weeks. So Jon had a pretty tough job to get any regional championship points with such a painfully stock setup.

                The grip levels were junk but he was still able to work on corner placement (getting close to the cones), figuring out the gearing of the new motor/trans setup, and overall learning to manage understeer.

                The tire pressures were the only thing we could work with so we adjusted them down slightly (29 psi rear) to try to mitigate the severe lack of grip. You can see the deformation and camber loss in the front suspension in the images posted here. The stock suspension is SO soft that it allows the 3650 pounds of Mustang to flop around like a dying fish.

                Both Amy and Jon liked how predictable the 2018 GT was to drive, even on the tiny 235mm tires. Unlike the stick axle S197, the S550 is very easy to drive with no prior experience - no gotchas. It went where you pointed it, just not very quickly. The rear tires struggled to put the power down but Jon felt like it didn't have the grunt of 460 hp engine. That could be a torque management thing for new motors - we barely rolled 500 miles on the odometer on the drive to the site that morning.

                Both Amy and Jon put in some hard driving, yet the car was holding them back. Jon managed a 51.108 sec 4th run while it was just starting to mist rain, and sat as high as 6th out of 12 at one point, but fell to 9th in CAM-C class at the end. Amy managed a slightly quicker 50.646 sec run on her 5th and final run (in another run group), within 2 tenths of the 2 drivers ahead of her, but the STP "PAX" is almost identical to CAM-C (bad), so she took 4th out of 5 in this PAX factored Women's class (a regional only class).

                YouTube Video:

                We took video from most of their runs and I have video posted Jon's best one above. On one of his runs and two of Amy's runs the AdvancTrac warning light came on, bonging away with warning chimes. Of course they run with the system completely turned off, but something about the sliding around triggered it to come on again. Nothing bad happened it just freaked them both out. The brakes felt awful but we later found out that the 8 laps on track had killed the stock pads - they were down to only a sliver of material left.

                Lastly we will talk about overall PAX placement - our only indication from event-to-event on how well the car is improving since the courses are different each time. Out of 160 cars Amy took 88th and Jon took 96th, so we have a ways to go yet with this car. It did about as badly as we expected for stock suspension, tires, and brakes.


                We have worked with Motion Control Suspension for half a dozen years and often they will make something for a new car based on measurements and/or drawings we send them. This time they wanted to test an inverted shock design for the rear of an S550 - so they shipped it to us for a test fit just a few days after we bought our 2018 GT. Nothing of note has changed on the rear shock/suspension from 2015-up on the S550 chassis.

                We always try to start with a side-by-side shot against the stock damper. The MCS version looks properly shortened, assuming it was 50mm shorter or so. Which is ideal. The goal here is to shorten the shock enough to allow for a good balance between droop and bump travel - at a lower than stock ride height. The shock length is critical to getting this right... and why so many people have terrible experiences with lowering springs on stock length shocks and struts (all of the lowering gobbles up bump travel... one good bump and BAM, its bottomed out).

                Above left is the stock S550 rear shock mount / shock / divorced spring. Above right shows a spherical upper with the MCS inverted remote double installed on my 2018 GT.

                continued below
                Terry Fair -
                2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                • #9
                  Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                  continued from above

                  You can see the lower spring perch clearance and rebound adjuster knob at the bottom of the strut shaft, above left. Then we checked the shock for full bump travel measurement (above right).

                  These pictures show the shock at ride height (above left) and full droop (above right). This is the ride height we shoot for on S550s = 14.5" center of wheel to fender lip (1" lower than stock). From these measurements we can calculate total wheel travel (5.25", which is a lot) and pick the ideal ride heights based on bump vs rebound travel. Maybe not super interesting, but this is some of the work we get to do when working with shock manufacturers.

                  STAGE 1 MODS TO OUR 2018 MUSTANG GT

                  There were several suspension items we upgraded in our first round of mods to our 2018 Mustang GT. We're going to keep a running tally of the parts costs and in the case of parts that are removed or replaced, we will adjust the "Mod Budget" as well as lap times at our test track Motorsport Ranch Cresson.

                  This was a substantial change that happened over 24 hours at our shop, but its a typical round of upgrades that people tend to do all at once. Coilovers, camber plates, swaybars, wheels and tires. We'll break it down into 3 sections below to show what we did and why.

                  Whiteline Max-G Coilovers + Vorshlag Camber Plates

                  This is the first of several monotube adjustable coilover dampers we will likely test on our shop 2018 GT. The S550 chassis benefits due to its "world car" status and higher global sales volume in that many higher end shock makers cover this chassis vs the S197 before it. There are good coilover kits we sell made by Ohlins, Bilstein, MCS, and now Whiteline.

                  This "Max-G" kit is made by a high end Dutch shock maker and is private labeled for Whiteline with spring rates and damping set to their specs. We had such good luck with the "Max-G" Whiteline coilovers on our shop 2013 FR-S (#Agent86) that we decided to test a set for our S550. Whiteline was thrilled to have some good test data so they sent these and the swaybars to us as soon as they heard we ordered this car. The shock kit arrived as shown above, with front springs on the front that were coilover at the bottom but made to fit the OEM style upper perch and strut top mount on top.

                  We haven't seen many people try this S550 Max-G kit yet, so we got this set in and took a closer look. This kit is made to be a "suspension in a box" and is supposed to work with the OEM front strut top mounts and OEM rear shock mounts. Jason rated the included springs (click on the chart, above left) on our digital spring tester. While the rear's looked to be in the right ball park (avg rate of 535 #/in) the fronts were pretty soft (205 #/in). So instead of "burning an event" with a test of the included soft front spring, we just jumped in and did what we've done on many other "kits" that come with springs - we substituted our own spring and camber plate up front with something more aggressive, and used our spherical rear shock mount as well.

                  The Hyperco 60mm coilover spring we chose for the front was 400 #/in. When you run the numbers for the motion ratios out back (with a coilvoer spring instead of the stock "divorced" spring location) this gave us nearly an even split with about a 400 #/in front and rear wheel rate. Having sold and tested MCS dampers with many different spring rates on the S550 chassis, we felt this customized 400F/535R spring set would offer a very streetable ride yet should still substantially cut down on the "floppiness" of the stock suspension on track.

                  We used a front spring length long enough to keep the spring package "above the tire" while making sure they weren't too short that they had excessive slack at full droop. Out back we used the Whiteline spring and added our prototype "Version 1" S550 spherical rear upper shock mounts - which are admittedly a bit ugly, due to a plating choice I made that didn't work well.

                  How were these made? We took the cast aluminum OEM upper shock mounts (above left) and drilled out the crimped in upper washer, which acts like a "fuse" - this pops out when someone bottoms the suspension hard enough in a crash. But it also pops when people convert the S550 rear shocks to coilover springs, and we don't want that. Moving from a divorced spring to coilover spring moves the suspension loads through the shock, and the stock top mount cannot withstand that for very long. We CNC machined a spherical bearing holder section and welded it into the modified stock casting (above right). It works, it just doesn't look very good, so we're not going to sell "Version 1" and instead will make a fully CNC machined "Version 2" with an additional feature we think is warranted. I will show that and explain further in a future post.

                  Both the rear shock and the front strut are inverted, which puts the single adjuster knob on the bottom. This is actually easier to access this way on the rear, and up front you just turn the wheels to lock and you can get to them fairly easy. An inverted front strut housing is very strong and has little deflection under lateral loads. We installed the modular camber "slug" inserts with zero offset on the upper spindle mount, to gain maximum wheel room. As we will show below, there is still plenty of camber adjustment on the plates so you don't need to "kick the struts" to get camber in the mounting holes. That gobbles up much needed inboard wheel room, and changes the SAI geometry, so we avoid that trick at all costs.

                  Installation up front is fairly straight forward. The Whiteline strut is about 2" shorter than the stock piece and getting the front spring and strut out is relatively easy on that end. Above you can see the installed Max-G coilover and swaybar.

                  OEM rear spring removal is not that easy - it takes a few tricks. Removing the rear shock while supporting the lower arm, then lowering the control arm doesn't release tension on the spring enough to remove it. You have to unbolt and lower the rear subframe from the chassis to unload the long, massive rear spring that Ford uses in the divorced location.

                  Even with the rear spring and shock removed, the rear control arm does not pivot freely. At all. Two guys can hang on this control arm, because it has so much bushing bind in it. It is amazing that this works in stock form, but it somehow does...

                  You can see the inboard bushings (left side of pic above) and how out of axis they are. These are fighting each other badly during suspension travel. One of these lower control arm bushings is a sealed spherical from Ford, the other is a big nasty rubber bushing, with chunks removed to allow it to rotate in bind. Of course we will look at fixing this down the road.

                  Weight loss was a benefit with the aftermarket coilovers - as it usually is. Even with the beefier inverted 44.5mm shafts the pair of Whiteline front struts they were still 5.0 pounds lighter than the stock front struts, with springs and top hats installed.

                  The weight loss out back was even more substantial at 9.2 pounds on the pair of rear shocks/springs/top mounts. This is mostly due to the massive OEM "divorced" spring being replaced with a 60mm coilover spring. If you look closely at the "T-bar" lower mount, it is asymmetrical, to kick the lower part of the shock away from the rear axles. If you install this backwards it will be pretty apparent, as the spring will be close to the axle, but Whiteline thought of this little trick to gain more room.

                  The rear shock is inverted so that the spring can sit "inside the barrel" of the wheel and not restrict the inboard wheel room for wider wheels and tires. With our 19x11" wheel it wasn't even close - we could move inboard another 1/2 to 3/4" and never get near the shock top. Moving the spring out to the shock can sometimes have negative side effects, but on the IRS suspension here with the ample wheel room its a non-issue. The effective wheel rate is higher due to the change in motion ratio - the lever effect of moving the spring out closer to the tire compared to the stock inboard "divorced" spring. 60mm springs are not only lighter but come in a lot more rates and lengths for adjusting around different conditions, tracks, and tire setups.

                  Whiteline Swaybars and End Links

                  The factory front swaybars on this 2018 GT were 32.5mm and the rear was 22 mm (0.855"), and of course non-adjustable. Since the rates the Max-G coilovers came with still looked a tad soft for what we had in mind for our next track test we went ahead and ordered up a set of adjustable swaybars from Whiteline.

                  The Whiteline bits are 35mm front and 25mm rear, with 3 adjustment holes on each side. The BFK006 kit comes with the front and rear bars, body mount bushings, locking rings, and Whiteline shortened/adjustable endlinks for both ends.

                  Installing these was relatively straight forward and when doing coilovers doesn't add a lot of work. We always test fit any aftermarket bar with the supplied bushings and sleeves, then shim them to fit so that they rotate with "pinkie finger effort". Once they are shimmed and fitted, the body mount bushings and sleeves are removed and drilled/tapped for grease zerks. This allows us to squirt in fresh grease every 6-12 months for a low stiction, noise-free rotation.

                  The factory S550 swaybar bushings are not just stuck to the bars - they are BONDED to the bars! This adds massive bind in roll - for the life of my I cannot see why Ford did this. Watch the video below to see what we are talking about. Bizarre. Of course we want the swaybars to pivot freely in the body mounts, without much deflection under load (rubber) or bind when they rotate (roll). This way the swaybar adds a known amount of "anti-roll" and the adjustability gives you some quick track-side adjustment to control under- or over-steer.

                  This video shows the S550 swaybar bind and how we fix that

                  The end links are adjustable in length and have sealed ball bearing ends - not open metal sphericals, that get full of dirt and start banging around in weeks. This is a great for both track-only and dual purpose setups - we love their end links so much we use them in all sorts of customized suspension kits we make, on both race and street cars.

                  Weight change was about a wash, with the hollow, larger aftermarket Whiteline bits within a tenth of a pound of the hollow but smaller stock bits. We set them all to full stiff to start with, knowing that the spring rate on these coilovers was not super stiff.

                  The swaybars were shimmed, drilled for zerks, mounted, and greased. The end links were adjusted and the car was set for ride heights and it was time for wheels and tires...

                  Forgestar 19x11" F14s + 305/30R19 Bridgestone RE-71R Tires

                  We have sold a lot of 18x11 and 19x11" wheels for the S550 chassis, and luckily we had some 19x11's on order months earlier. The lead times are really out there lately and having a few sets in line helped us get a set quickly for our shop car. We got them raw and had them painted locally to save time. We picked 19" diameter because of the multitude of tires available in 305/30R19.

                  The tire we decided to use for these was a Bridgestone RE-71R. There are virtually no 315mm tires in 19", but this "305mm" model runs a tick big.

                  continued below
                  Last edited by Fair!; 04-03-2018, 01:55 PM.
                  Terry Fair -
                  2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                  EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                  • #10
                    Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                    continued from above

                    We compared the 305/30R19 RE-71R to the 315/30R18 Rival-S above. The 18" Rival is a good bit shorter, but for the S550 the extra tire height from the 19" tire model actually helps gearing.

                    We took weights of the 19x11" wheels and at 26.7 pounds. The flow formed 19" Forgestars are not super light, but this is a normal weight for a 19x11" wheel priced under $500/corner. The 305mm RE-71R tires are heavier still at 32.1 pounds, but that's typical as well.

                    Three of these RE-71Rs are stacked up evenly with all four of the OEM tires, above. We are adding another whole tire's width of extra rubber, yall!

                    Once installed we checked the tire/wheel package for rub everywhere - not a problem. The wheels clear inboard and out, but it is of course a tight fit. They even clear at full lock, as shown above.

                    This video shows our 19x11" wheel tire clearance on an S550 chassis

                    There isn't anything magic about fitting 11" wide wheels under these cars, but you can get into rubbing (inboard) or "poking" past the fenders if you get the offsets wrong.

                    We had a 2018 GT "PP2" stop in this week and took the pics above. Ford got the offsets a little on the "poke" side with the 19x10.5" front and 19x11" rear. I'm sure they had their reasoning - maybe to clear tire chains in the Great White North - but that's not how we do it.

                    I was pretty dang happy when I saw this angle, above. That's how you fit 19x11" wheels square on an S550, folks. There is no giant spacer or long wheel studs needed. No, they cannot rotate front to back but neither can the stock PP1, PP2 or GT350 wheels. If you have a decent suspension setup you shouldn't need to rotate. I will show tire wear after our first track event in the next post, to show what I mean.

                    Initial Ride Heights + Custom Track Alignment

                    The car's alignment was first tested for max negative camber up front, which was -4.0 degrees at this initial ride height. This is pretty extreme and would only be appropriate for Hoosier A7s on a very aggressive track-only setup.

                    Instead we setup the car with -3.4° camber up front and -2.0° out back, which is about the extent we would run for dual purpose street/track use. We used a 1/4" of total toe in on the rear axle and zero toe up front (front toe out kills tires on the street). We left the caster setting in the "forward" (stock) position on our camber/caster plates and ended up with +7.2° caster up front, which is about perfect (we shoot for 6-7 degrees on most cars).

                    Ride heights are a little on the low side, and after a few scrapes on the street, we have since raised the car a full inch from these numbers. This happened after our first NASA event, so I will show the new ride heights next time. We ran at these lower ride heights at the second track test, below.

                    First Front Brake Pad Upgrade + Major Flaw in 14" S550 Brakes

                    We need to talk about S197 and S550 brakes for a minute, because we found a fatal flaw in the 14" S550 brakes on our car. Not many people knew about this but several folks had seen the same thing, and just never knew why until we showed a few pictures. Bear with us a minute here, its worth it.

                    All of my previous experience on track in S550 Mustang GTs - both coaching and driving - has been in the Performance Pack optioned cars. These 15" diameter / 6 piston Brembo brakes are MASSIVE and fairly unflappable. I was amazed that I could not cook these brakes when I drove Aaron's 2015 GT at a brake intensive track (ECR) back in December 2014 - on stock pads and fluid!

                    2015-18 Performance Pack 15" dia front rotors are heavy but effective

                    These 15" front rotors from the Performance Pack S550 Mustang GTs have regular rotor venting with access for cooling air from the rear. These bigger rotors are much better at absorbing and shedding heat to begin with, but with some forced brake cooling can be made pretty amazing for track use. In 2015 the Performance Package (PP1, which mostly consists of this brake upgrade) was $2500, but in 2018 it went up to $4000 for the same thing - so we skipped it. These are the same 15" 6 piston brakes used on the new for 2018 PP2 ($6500) package as well.

                    These are the front (left) and rear (right) brakes that come on the 2015-up S550 base model GT and Ecoboost Mustangs

                    Well that's not what comes on the Ecoboost or the "basic b!tch" base model GT we got, of course. For 2015-18 base model GTs, Ford picked some pretty looking 14" rotors and 4 piston calipers, but they are not labeled "Brembo". Somebody at Ford must have had a hand in designing these, and they done messed up. They look to be bigger calipers than the S197 cars. This one uses a completely different pad shape, different rotor, etc. The S550 rear rotors are very sizable so there's a small improvement out back.

                    The 2015-18 S550 Mustang front 14" rotor (above left) got heavier than the S197 14" front rotors (above right) by about 3 pounds. And usually more rotor weight means more heat capacity, since a brake systems' ability to absorb and shed heat is loosely related to rotor mass. But there is one key downgrade Ford made in the S550 14" rotors. Do you see it yet? It wasn't obvious to me until after I bought the car - and this revelation has shocked people that have seen the issue when pointed out, even people that work at Ford.

                    I've seen the interwebs all abuzz with talk about using the 14" 4-piston S550 brakes on earlier model cars. We would recommend against this. While they do look pretty, they are worthless for track drivers. I have first hand experience with the 14" brake system's failures on track, which I will explain using the picture below.

                    What the what!?! If you look at the back of the S550 14" front rotors above notice that the cooling vanes are on the outside! This means we cannot ever add brake cooling to these rotors. They are ass-backwards! The access to the inner portion of the rotor's cooling vanes are only accessible from the outside, and you can't exactly run ducting to the rotors from the wheel side.

                    With no physical way to force feed air through the back of the rotor face and through the vented rotor section, we cannot cool these down. Ever. They will eventually get so hot that they stop stopping. Which is exactly what we are seeing in use. We ran these brakes with the factory pads with the tiny 235mm base GT tires and they lasted 8 laps on a "brake easy" track, in our first track test # 1. EIGHT LAPS. After the 7th laps in that first test session they were no longer capable of stopping the car at even my mild .85 g stops. I almost went off track, so I came in. The (Motul RBF600) fluid never boiled, I never lost pedal, they just wouldn't stop anymore.

                    The S197 "upgraded" Brembo 4 piston fronts also had 14" rotors (above left). The 11.5" rear rotors (above right) used a floating single piston caliper brakes, and these rotors were easy to kill on track (but we can and do upgrade them cost effectively to 14" dia GT500 rotors). The fronts were still just as undersized for the weight and power of the S197 chassis GT as the S550 14" versions, but we could make the S197 rotors work with forced brake cooling from the rear. Vorshlag sells 3" and 4" diameter backing plates and inlet / hose kits to force cooling air from the hub side out through the cooling vanes of the rotor, to shed heat. We tested these for 4 years on our car and they can make the 14" Brembos work for most folks up to even the pointy end of the grid.

                    We looked at the pads soon after this first track event (forgot to shoot pics!) and noticed that the material was 85% gone... just a sliver of pad left, with 300 street miles, an autocross, and those fateful 8 laps at MSRC. Those handful of laps KILLED the pads completely. So we ordered new front pads for the NASA weekend (above) and installed them before Track Test # 2. Since we had a Powerbrake 380x34mm / 6 piston big brake kit already on order for our car, and figured a simple pad upgrade would be enough for this "one track weekend" and the following autocross, we just got G-LOC's R8 compound front pads. This is their 2nd step up from their 7 track pad compounds. Mild enough for autocross and some limited daily driver use. Would they be enough...??

                    2018 MUSTANG - TRACK TEST # 2

                    After installing the Whiteline coilovers & bars + new wheels & tires I signed up for the next available event at MSRC on the 1.7 CCW course, which happened to be a NASA Texas competition event.

                    Ignorging the street tire aspect, the car slotted nicely into TT3 class (based on power and weight) using some internet dyno charts from 2018 GTs I found and calculations for avg power (we still had not dyno'd this car yet). We declared a minimum weight of 3800 pounds (with driver and fuel) and a declared avg power of 399 whp (in reality we ran at 3950 pounds with driver and a full tank). We were well within the max limits of the class using these "bonus" modifiers for TT3:

                    Power to Weight for TT3 = 10:1
                    Comp weight 3750-3899 lbs = +0.5
                    OEM Aero = +0.4
                    Adjusted Power-to-weight max = 9.1:1

                    3800 lbs / 9.1 = 417 whp avg max

                    (real weight of 3950 lbs / 9.1 = theoretical 434 whp avg for TT3, for reference)

                    Not to mention we were on 200 treadwear street tires! We had no prayer of winning the class, but we turned in our sheets and ran with TT3 anyway. I wanted to see how far off we would be from the rest of the class - which had 6 competitors (4 of which were on Hoosiers), everyone else was in gutted race cars, and 4 of those had full aero. We brought a letter opener to a gun fight - but this really was about testing for us.

                    We also wanted to generate some lap time data for NASA about the modern 200 treadwear street tires, in the hopes of possibly starting a 200 treadwear TT class - at least in this region. We think there are a lot of untapped Time Trial racers who run in other series that limit tires to 200 TW (Optima, Goodguys, some GTA classes, some of the new SCCA TT classes) that could open up new potential NASA TT customers. These guys don't want to run head-to-head against NASA TT cars on monster Hoosiers with massive aero. These tires last a lot longer than Hoosier A7s, we know for a fact, so the cost-per-lap goes way down. Grip level is lower, too.

                    SATURDAY MARCH 10TH - RACE DAY 1

                    Due to some last minute work needed to get the suspension installed (this was only one week after doing our baseline lap times in stock form) we were not able to get out to the track on Friday. This would have been helpful to get a good paddock spot and to tech the car for the first time. Every TT car needs a logbook and special tech inspection, which is good for the year.

                    We got to the track early (7:15) and quickly found a paddock spot and unloaded our BMW (there to just show it was for sale). Amy drove the Mustang out to the track (1.5 hour drive) with no issues. She quickly got into the tech line and waited. I ran to my TT meeting and came back, and the line had grown but hadn't moved. At this rate it might take hours to get the car teched. So we jumped outta line, went to G-Speed's shop on site and got the logbook.

                    Sadly NASA has removed the right to give out annual Tech stickers to even their certified logbook shops, so we had to get back in line anyway. We finally got the Annual Tech sticker but by this time I had missed the TT Warm Up session - which is used to only get lap times for gridding purposes.

                    continued below
                    Last edited by Fair!; 05-14-2018, 02:16 PM.
                    Terry Fair -
                    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                    • #11
                      Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                      continued from above

                      With no lap time I had to slip into the first open spot on grid for the non-timed cars who missed the warm up, which was 34th! We had 51 TT entries this weekend, so it was a bit crowded on the 1.7 mile course. We also had over 270 total entrants that weekend - a NASA Texas record as well as a record for any event at MSR Cresson. This meant people were parked everywhere, and the all groups had to grid on part of the 1.3 mile course.

                      51 cars in TT is insane - we have never had that many sign up before. Luckily we never had all 51 TT cars on track at once, but it sure felt like it! In that first session I ran the Big Red Pig passed at least a dozen cars, maybe more. It was a total mess but it was another lesson learned - get your car teched before race day! Vorshlag is a certified NASA "HPDE" tech shop but not a "Logbook" shop. Not yet - we are scheduled to take the SFI exam soon.

                      Somehow my old TT3 lap record in our 2011 GT, "Big Red", from 2014 was still holding strong (1:17.310) all day, and a previous customer KenO was chasing it once again in his fully prepped E46 M3 (shown above). He was on a sticker set of A7s with the most power and aero he had ever run on the car. I suspected he would win the class and take the TT3 record away from us...

                      in-car video of our 2014 TT3 track record lap - which was still holding

                      On this first day the TT3 record still eluded him, but Ken was faster than he'd ever been before. His is a dedicated TT3 build with no compromises, and I was lucky to be within 5 seconds of him on street tires. Amy was also co-driving the car all day in HPDE4 an I took some laps with her using the helmet radios from the right seat, and she dropped a bunch of time.

                      The handling was spot on all day, and the only adjustments I needed to make were to tire pressures. I was looking at scrub at the sidewall and adjusted hot pressures to 34psi front, 33 psi rear. #500psi There aren't any major bumps at this track but damn, this suspension was downright plush. The roll and dive weren't bad and it was super easy to drive. I did managed to fuel starve the engine in a long left hand sweeper at 1/2 tank of gas, which triggered a CEL on the dash. We kept the fuel tank full for each session after that. The CEL stayed lit all day and into the next - but it ran great (it went off in her drive home Sunday night).

                      I fought all day with traffic, slowly working my way up the grid to 8th fastest TT car at one point. Since we grid based on your fastest lap times, the later sessions helped removed slower traffic from in front of me the next time sessions. Strangely I ran almost the exact same lap times in session 3 and 4 -within .001 sec of each other - but was still only 3rd fastest out of 5 in TT3 class. To have already found EIGHT seconds on my first day of testing - in heavy traffic - was outstanding, but I knew there was more in the car.

                      The brakes were not good. At all. I had to baby the braking to keep from overheating the rotors and upgraded front pads. Once again I never lost the pedal, so the fluid was fine, it would just lose stopping power if I pushed the brakes as hard as I used to push the S197, so I had to brake earlier and less aggressively or it wouldn't last 2 hard stops in a row. There was ample time between my TT sessions and Amy's HPDE4 sessions to cool the rotors down, so it was not compounded from double driving the car. Weather was beautiful all day, sunny in the afternoon, so we packed up and headed to the hotel to clean up and rest after the last HPDE4 session. We foolishly left our sun shade partially extended on the trailer...

                      SUNDAY - RACE DAY 2

                      As perfect as the weather was Saturday it was 100% more awful on Sunday. We woke up to hear the wind howling and rushed from the hotel to the event site. Sure enough we were greeted to a trashed sun shade. Lots of E-Z-up tents were down and destroyed, everywhere. Wind was blowing hard all day, which made it COLD.

                      We managed to retract and secure our now ruined sun shade and then got the Mustang ready with plenty of time to make the "golden session" of the weekend - the coolest of the day, TT session 1 Sunday. Was worried the wind might slow us down but it didn't. I started in the 10th grid spot (really 7th, we had some no-shows) and quickly passed the car ahead of me when he spun off track in the first lap, shown below.

                      Our best lap Sunday in the 2018 GT - 10 seconds quicker than a week earlier

                      That was good because I was held up badly on the first hot lap. Lap 2 was pretty good and my times fell a little, then lap 3 was perfect. Tires were up to temp, brakes were still working. Lateral grip on the RE-71R tires was 1.2g sustained with 1.34g spikes (see below). Braking was limited to about .90g stops, otherwise it would overheat the rotors/pads (it could spike to 1.0g stops but only about once every lap, for one good stop). I also had to compromise the last corner on my best lap because I had a 1:10 sec lap TTU car driving up my tailpipe into the last turn - scary fast! I got outta his way and braked a hair early, but that 1:21.733 lap was still 1.5 seconds better than Saturday, so I "banked the lap" and came in. Rear tires were already getting hot.

                      When I used 2nd gear in "Rattlesnake" it could easily spin the tires on corner exit. Even 3rd gear exits on "Little Bend" and "Boot Hill" had to be made at part throttle or risk sliding the rears. The Base GT has an old style clutch Limited Slip Diff, unlike the Torson style diff that comes in the PP1/PP2/GT350 models, so we plan on upgrading to a Torson-style LSD later this season.

                      I didn't run in any other sessions that day. I felt like it would be wasting consumables to try to catch P2 in TT3 class, and I might only find a tenth or two. Instead I worked with Amy (see above) coaching her for a couple of sessions, and she found more confidence and lap time. We packed up by lunch time and headed home for some hard labor at the house - we're building a shop behind our house and we needed to shovel 6 yards of crushed concrete to start making a road back there. It was back breaking work, so we bought a tractor the next week - we have many more tasks like this to tackle.

                      Some of the temp data I am getting via OBD-II isn't super accurate, but the dash does have a readout for some things. Cylinder head temps were at 220°F after my last session, oil temps were creeping up into the "yellow". This car does have a factory oil cooler (at the oil filter, aka: the oil heater) but we may do something more substantial this summer.

                      Sunday's final results were about the same: the #BigRedPig took 3rd out of 5 in TT3 class - and everyone got quicker. KenO finally beat my old TT3 record with a 1:17.1 lap, and the second place driver dropped into the 1:20.3 range, which I was never going to catch that day. Final thoughts - the stock seats suck, big time. I had to go to the chiropractor Monday to pop things back in place, ha! The crushed concrete shoveling that night didn't help, either. Great event overall, lots of good data learned. To end up 10th fastest out of 51 TT entries, in a car we drove there on street tires, was pretty remarkable.

                      MOD BUDGET VS LAP TIMES

                      We want to show where we are on lap times vs overall budget for this car, to compare against other NEW Mustang options. I am not trying to compare against an older car, or another new car model, but instead between the various OEM 2018 Mustang purchase options. I will show the MSRP or street price for models at our time of purchase + our mod costs to date. Sure, deals change and rebates come and go - these new purchase price numbers are relevant for Feb 2018.

                      2018 Mustang GT PP1 w/ Premium + Recaros = $48,270
                      2018 Mustang GT PP2 w/ Premium Plus + Recaros = $51,280
                      2018 Shelby Mustang GT350 = $58,140
                      2018 Shelby Mustang GT350R = $65,640

                      Our "basic b!tch" 2018 Mustang GT base model 6-speed = $32,500 (what we paid)
                      + Whiteline MAX-G+ Coilover Kit for S550 Ford Mustang GT - TrackPro = $3,154
                      + Whiteline Front & Rear Adj Swaybar Kit, S550 Mustang = $585
                      + G-LOC Brake Pads, Front, Base GT 4-piston, R8 = $234
                      + Forgestar 19x11" F14 wheels = $1720
                      + Bridgestone RE-71R 305/30R18 tires = $1368
                      $39,531 in the budget, dropped ten seconds a lap from stock, and we cannot find a quicker lap time from any stock S550 at this track.

                      Now we have spent less than that, since we make some of this stuff and we're a dealer for the rest. And we kept labor out of the tally because not everyone pays for wrenching. I'm not going to count fluids - those upgrades are a must, and would be done on all of these Mustang options for track use. That's like tracking fuel costs - its a consumable. The tire and brakes are consumables, but I'll factor those into the budget since these really are upgrades. When/if we change out one of the "mods" listed above we will show the subtraction of their costs and the addition of the new upgrade in place.

                      Remember I showed Josh's stock Shelby GT350R lap time on PSC2 tires earlier in this thread at a 1:25.22 lap (different driver, so its hard to compare). Sadly I do not have any first hand experience in a stock S550 at this track, yet. If I can finagle my way into a few laps in any of the above cars I will update the "lap time list" below (any volunteers??) For now here is our list of data logged videos showing lap times in cars I have driven personally at MSR-Cresson on this same 1.7 mile CCW configuration:
                      • 1:31.90 in our stock 2013 Scion FR-S
                      • 1:31.412 in our stock 2018 GT
                      • 1:29.630 in our 2013 Scion FR-S with camber and front brake upgrade
                      • 1:28.564 in our 2013 Scion FR-S with Whiteline Max-G coilovers & bars
                      • 1:27.40 in Todd's stock 2016 Focus RS
                      • 1:26.212 in Todd's Focus RS on coilovers and camber (which then ran a 1:23.658 on 275 Bridgestones later that day)
                      • 1:25.10 in a Spec Iron Mustang on Toyo tires (with passenger)
                      • 1:25.075 in our TTD prepped E46 330 (195 whp)
                      • 1:22.63 in Jerry's stock 2012 C6 Z06
                      • 1:22.56 in Joe's modded 2013 1LE Camaro on Hankook RS-3 tires
                      • 1:21.90 in our TTC prepped 1992 Corvette (288 whp)
                      • 1:21.89 in Joe's stock 2017 Corvette C7 Grand Sport
                      • 1:21.733 in our 2018 GT on Whiteline Max-G coilovers & bars + 305mm RE-71Rs
                      • 1:17.310 in our old TT3 Prepped 2011 Mustang GT on 335/345 Hoosier A7 (447 whp)

                      As you can see the 2018 GT has both one of the slowest and one of the quickest lap times listed here. It improved a dramatic amount in only one week, and we have more plans to upgrade brakes and power very soon. Gonna be fun to see how far we can push this one!

                      WHAT'S NEXT?

                      Next time we will show our second autocross - with the new suspension and tires. Or will the SCCA or other outside forces conspire against us and thwart out second autocross test????

                      We just ran an SCCA Club Trials event event at ECR last weekend (above), which was a very brake intensive track. Before this event we upgraded to the craziest G-LOG compound pads, both front and rear, to deal with this track. Will it work? Can the Mustang hang with the swarm of Corvettes and 50 time trial racers that attended? Tune in next time to find out!

                      Thanks for reading,
                      Last edited by Fair!; 04-04-2018, 10:52 AM.
                      Terry Fair -
                      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                      • #12
                        Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                        Mini-Update April 11, 2018: Just answering some questions on this forum from TMO. Good questions, and we have some teasers of the next round of mods buried in here.

                        Originally posted by TrEvoRS, post: 197404, member: 4118
                        A lot of great information! Just curious, have you not addressed the bushing / roll-center related concerns yet, or are you just not mentioning those and focusing on the bigger stuff you are developing?
                        There are definitely "bushing issues" we have run across, and I mentioned the worst offenders so far as being the rear lower control arms. We have some ideas on what to do there and we will continue to investigate other bushing issues as we tear into this car. But so far, there's no "catastrophic" issues so far - its pretty dang fast for what we've done.

                        As "bad" as the rear bind we found is, this car still puts power down better and soaks up bumps on track more composed than our S197 ever did... so... ??

                        Originally posted by stuntman, post: 197409, member: 88
                        It's interesting to hear your praise of GT3 & (especially) GT3RS as a good dual purpose car when they ride quite harsh on the street compared to GT350s. Really the GT350 only needs camber plates and it's pretty much good to go for extensive track use without overheating.
                        True, but a lot of GT350 owners we talk to used to own a GT3 or GT3RS. They make these comparisons to us, and yes - all the GT350s seem to need are camber plates and a more aggressive alignment to haul ass on track.

                        Originally posted by Krispy, post: 197566, member: 3305
                        Any ideas to fix the fuel starvation issue aside from running atleast a half tank of fuel?
                        Originally posted by bpracer, post: 197588, member: 2988
                        I've run my GT350 down to "5 miles until empty" without an issue so not sure if this can be car specific or not.
                        Honestly, I don't think everyone is going to see this issue. Look, we're putting spikes of 1.45g and sustained 1.28g lateral loads through this car, and with that kind of loading it will slosh the fuel out of the "dead" side of the saddle tank in LOOOONG left hand turns at our main test track (MSR-C). Neither the S197 or S550 like doing that, in any form (GT/Boss/GT350). And while most OEM saddle tanks have some sort of vacuum jet pump to keep the fuel pump pick-up side loaded with fuel, they don't really work all that well with an OEM saddle tank in any car I've ever tested here. Not any Ford, BMW, Corvette, nothing.

                        The solution most folks will point to is "get a fuel cell" but that's not always the answer. We've seen slosh in those, too. What it takes is either an internal surge tank/accumulator (which is what we order for fuel cells) or an external tank.

                        The fuel cell above was made for a BMW we're building for a customer, and it is shaped to match one half of the OEM saddle fuel tank, so it can mount in the same position. We built the enclosure and had the fuel cell built to fit that. It uses an internal accumulator section that has dual pumps that feed from and return to this trapped area. Horrendously expensive solution for a dual purpose track/street car!

                        We fixed this once and for all in Jamie Beck's 2013 Mustang race car (ST3 now ST2) by modifying the stock tank to work with an external surge tank/pump. This Radium surge tank sits in the trunk and is fed by the stock in-tank pump, and then the surge tank has an internal pump that feeds the engine. The surge has an overflow return goes back to the stock tank if this is over-filled. This way we can keep this ~1 gallon tank full down to the last drop in the main tank.

                        After a half dozen races it seems to be working perfectly, and he no longer has to keep a "half tank of ballast" fuel in the car. So we will do the same to our S550 when we have the time.

                        On our S550 we still need to add larger brakes, longer wheel studs, some brake cooling, tow hooks, racing seats, roll bar, harnesses, and much more before we tackle a surge tank. Until then we'll just keep the tank full for every session.

                        Originally posted by bpracer, post: 197588, member: 2988
                        The non-torsen diff is probably already toast. The PP offers a larger radiator over the base car, so between the lack of transmission/rear end coolers, the smaller radiator and the minimal engine oil cooler, I don't think the car will be happy in the Texas summers.
                        True, the clutch-style diff is "losing its battle with longevity" and the stock radiator looks TINY in his GT.

                        We never keep the plastic end tank OEM radiators in any S197 Mustang, so we will begin the search for a proper aluminum radiator for this S550 in the coming weeks...

                        Originally posted by stuntman, post: 197603, member: 88
                        The base diff is crap, but it will still generate heat and probably cause a limp mode. It would be an interesting bet on which causes it first: water, trans, or diff temps. Anyone want to make a wager?
                        Everyone betting on failure - no faith in Ford's engineering here?

                        Originally posted by stuntman, post: 197409, member: 88
                        It will be interesting to see how well the trans and diff holds up once you get some brakes under your 2018 and can actually put down some hard laps, especially in summer. That's one area where the GT350s and Camaros have a big advantage over the GT, and while weighing very similar to a GT with all those heavy coolers.

                        These are all valid concerns and we are monitoring all of the temps we can. The 14" brakes that come on this car are what have held us back so far, and at our last event I couldn't make more than 1 hot lap at a time. So the fluid temps were less of an issue.

                        The Getrag still worries me, and I was seeing some higher oil temps (into the "yellow") on longer stints at MSR-Cresson both times we have run there so far. So before our 3rd track weekend we swapped to 8 liters of 5W50 Motul synthetic in the engine and the trans got Motul DCTF. We noticed cooler oil temps at a warmer event at ECR, so that might buy us a little margin - but a proper oil cooler, radiator, trans cooler and diff cooler are in the works.

                        Today we are upgrading to the 15" 6 piston brakes + brake cooling so we will see what is the next limitation. Tonight we load up to tow 9 hours to run this weekend at NOLA with the Optima series. I will show much more detail on these improvements in my next post. A Torsen style Wavetrac diff is also going in as soon as we figure out what gear ratio we want to use. Normally I'd use a 3.31 with a Getrag but ALL of the trans gear ratios changed in 2018 so we're still chasing the right ratio for this 26.2" tall tire.

                        We will account for the costs of ALL of these upgrades and keep tally in our base GT budget and compare to the GT350 and PP1/PP2 cars as we go. We still haven't run against a GT PP1, PPP2, or GT350 that has similar or faster lap times, tho.

                        More soon,
                        Terry Fair -
                        2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                        EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                        • #13
                          Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                          Project Update for May 1st, 2018: We have been testing our 2018 Mustang on track and finding all sorts of issues, bad advice, and eventually the right fixes. Read along and learn what we have found in our first hand testing, along with a number of videos I shot discussing what we have found. Lots to cover, so I will "try to be brief", ha!

                          In this round we will start with coverage of Track Test #3, where we ran the car with a new set of R16 pads on the 14" brakes (2nd round of brake mods) at Eagles Canyon Raceway (above). Poor braking endurance for both drivers, me and Amy. We also cover an autocross we tried to go to, and show the reasons why the car didn't make it.

                          I had hoped to cover a a few other events we have attended since my last post: Track Night in America at NOLA, Optima 2 day event at NOLA (above), another track test at MSR-C, but the post ran long so I will save that for next time. Let's get started...

                          BASELINE S550 TEST AT ECR WITH FACTORY PP BRAKES, DEC 6TH, 2014

                          A little bit of a time jump backwards 4 years, to show some baseline track testing I did in a stock 2015 GT PP car at Eagles Canyon Raceway in 2014. I used to consider this my home track for many years, and have a lot of laps here. It is known to be a BRAKE KILLER track with a bunch of long straight always followed by tight turns, where you have to shed a LOT of speed: esp Turns T3, T6, T7, T9, and T11.

                          The track map of the 2.5 mile ECR layout, which has a lot of elevation change for a Texas track

                          Every December ECR held a Charity event where they collect money, toys and canned food for "Toys for Tots" - and they only charged $50 for a full day of HPDE fun. We went every year and 2014 was no different. The super low entry cost meant this event always PACKED with drivers, as you could imagine.

                          I drove a bunch of cars that day and recently Aaron had to remind me about this track event - which was my first drive in an S550. It had slipped my mind completely. ECR is a 2.5 mile course which is known to be BRUTAL on brakes but it has no high speed corners, and it got pretty bumpy for a while there, so I haven't driven here much since 2015.

                          I mostly remember that day being very hectic. It was the 2nd time I drove Jerry Cecco's 2012 Boss302 (above left), to perform the "after" track test with the prototype TrackPro coilovers we had built for this car. It was also last time I drove our 2011 GT on track (above right). I had a bunch of customer cars out there, people I rode along and coached with, etc.

                          Aaron Sockwell had just picked up his brand new 2015 5.0 6 speed Performance Package GT, above. It was an unusual "base" interior with the only option being the PP1, which came with the Torsen diff and 15" 6 piston Brembo brakes for $2500. Heck of a deal back then (its $4000 for 2018 model) and it was the first S550 I ever drove on track.

                          I drove two sessions in the car. The first time I was by myself (first pic in this segment) but without a lap timer or camera. It was just a few laps but it felt amazing, so I begged Aaron for a few more laps on track...

                          Event Gallery, pics and video:

                          In-car video from ECR test in bone stock 2015 GT PP car - Dec 6, 2014

                          In the brief second session shown in the video above I am driving and Mark Council was in the right seat for some commentary. This time I had a video camera and a smartphone with Harry's Lap Timer on board. The video above shows 4 laps in this stock 2015 Mustang GT where I drove some ~90% laps. Fastest lap was a 2:06.01 in this bone stock car with the OEM pads, fluid, etc. Ignore the G-load trace after the first lap - the GPS data and timing seemed accurate, though. These factory 15" brakes were pretty amazing to me at this brake killer track back then, and it's what pushed me to buy these for our car (you will see this later in this post) for interim use.

                          While we are time traveling looking at ECR lap times, for comparison back in Oct 2012 I drove a 2:07.31 lap in a 2013 GT (stock but with 18x10" wheels and 295/35/18 NT-05 tires) but killed the brakes and had a huge "off" at Turn 7 doing that. That car had abysmal 13.2" base 2 piston brakes that were new pads when that session started, on the metal backing plates after 15 minutes.

                          We took this same 2013 GT back to this track on the same wheels/tires but with the 14" 4 piston Brembo fronts, brake cooling, and some mild coilovers and ran 2:03 laps. Which is the same lap time we ran at ECR in our red 2011 GT on these same 295mm 200 treadwear tires (before Hoosiers & Aero). Keep this 2:03 lap time in mind for the ECR event section.

                          BRAKE MODS, ROUND #2 (14" ROTORS)

                          We ran the 2nd track test with the 2018 GT at MSR-C (NASA weekend) on stock rear pads and new G-LOC R8 fronts. In hindsight the R8 pads weren't the best choice for how we were using the car - heavy car, lots of power, decent grip level, driver is a hack (me).

                          The OEM front pads were destroyed in the first MSR-C track test, 8 laps on the stock tires, nothing left. We went with the replacement R8 fronts but left the old OEM rears on for NASA event at MSR-C. As you can see above, the rears were down to 1/4 pad life after this 2nd track test (2 days, 2 drivers), so we bought R16 rears for use at the next weekend. As I mentioned before, using the bass-ackwards 14" inverted hat rotors, the rotors overheat very quickly. The rear rotors are built the same way.

                          We had a set of Powerbrake 380mm front brakes on order, but we had to buy some time. To hopefully get a little more brake system endurance, and with about half the life of the front R8 pads destroyed during just the NASA weekend, we bought a new set of R16 compound G-LOC fronts as well.

                          Not too many folks had made loud noises about how bad the 14" S550 base GT brakes were, so at the time I just hoped it was just a pad compound issue (the R8 is their entry level track pad). Here's how the pads are ranked:

                          G-LOC Pad Compound Chart
                          GS-1 ~.45 ambient up to 800°F (426°C) - Street pads
                          R6 ~.51 ambient up to 1000°F + (to 537°C+) - Autocross pads
                          R8 ~.55 74°F-1250°F+ (23°C to 676°C+) - Entry level track pads
                          R10 ~.59 118°F - 1475°F (47°C - 801°C) - Track pads
                          R12 ~.62-.63 173°F to 1860°F (78°C to 1015°C) - Track pads
                          R14 ~.60 210°F to 1400°F (98°C to 760°C) - Endurance pad for light cars
                          R16 ~.65 255°F to 2000°F (123°C to 1093°C) - Aggressive track pad
                          R18 ~.70-.71 610°F to 2100°F+ (321°C to 1149°C+) - Aggressive track pad

                          We have sold G-LOC pads to HPDE folks with these 14" S550 base brakes many times, I just hadn't ever driven on or ridden in any S550s except for 15" PP brakes before buying this car. With no way to cool these backwards 14" Front rotors we just hoped that the next test at ECR with "better pads" would show some promise. Pushed some Motul RBF600 fluid through and system (it wasn't boiling or discolored) and then we looked at the bumpy conditions at ECR....

                          I wasn't happy with the ride heights we picked initially. The rear shocks would run out of travel on heaves and big bumps on the street, and with how bumpy ECR is, I had the guys raise the ride heights at all 4 corners.

                          The numbers above represent a 7/8" increase up front and and about a 3/4" ride in the rear. This 14-1/2" setting represents our ideal "dual purpose" (street/track) S550 ride height, with coilovers. To take tire height out of the equation we measure from center of wheel to fender lip. We got that squared away, double checked alignment settings, and loaded up for ECR.

                          TRACK TEST #3 - SCCA CLUB TRIALS @ ECR, MARCH 31, 2018

                          I was excited to get back to Eagles Canyon Raceway after about a 3 year hiatus. The new owners have done some much needed track improvements, and it shows. Amy and I both signed up to drive our 2018 GT at this SCCA Time Trial event. Amy ran in yellow group, I ran in red group, both of which had Time Trial competitors. Lots of fun, and somehow we ended up 6th fastest time out of 50 TT cars and won our class.

                          It is "less than ideal" to double-enter any car for any track event, but two people driving the same car on a one day Time Trial - with marginal brakes at a brake killing track - was a terrible idea, but we did it anyway. And we ran back-to-back in several sessions, which did not work. At all.

                          Event picture and video gallery:

                          I won't go into a bunch of boring detail here - this isn't even our "chosen test track" - but we did learn a lot at this ECR event. We learned that the 14" S550 brakes are pretty much hopeless for us. Even with fresh R16 pads front and rear, good fluid, and careful modulation, I could not brake hard for more than ONE LAP before the brakes were done. Again, it wasn't boiling fluid, it would just overheat the front rotors and the car would no longer stop.

                          This was only our 3rd track event in the car, and 2nd on the new suspension, so we were still experimenting with shock settings, camber, tire pressures. I have been raising the "hot pressures" on these 305mm RE-71R tires from 28-30 psi (based on recommendations) to 34-36 psi. This was after seeing too much deformation and shoulder scrubbing with lower pressures. #500psi

                          I ran a quick-ish 2:02.754 lap in the 2nd lap of the very first TT session of the day, avoiding a spinning Corvette in front of me on that lap. I struggled with the brakes after that lap, even in a dead cold car we took right out of the trailer. After 3 laps I came in. Then the car cooled down a bit, then Amy went out and had a lot of fun, as for once she got the car "cold" and then gave it to me hot in the red session right after she ran - brakes and tires would be overheated. This went on for 5 sessions, and eventually I just stopped going out. In one session I had a complete loss of brakes in the 2nd stopping zone on lap 1, went off, and blew off the session. I ran a nearly identical 2:02.699 lap in a later session, also in traffic.

                          continued below
                          Last edited by Fair!; 05-01-2018, 04:13 PM.
                          Terry Fair -
                          2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                          EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                          • #14
                            Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                            continued from above

                            In total the car ran 9 sessions that day, and it was a bit hectic with a LOT of traffic putting in wildly differing lap times in even the yellow and red groups. At least they were gridding us by lap times, so I was usually P1 or P2 in our group. Amy and I agreed that I would skip a session, give Amy the car two sessions in a row, and then I'd go out after she skipped her last session.

                            This way the brakes might be cool enough for me to make ONE hot lap. I knew the two previous 2:02.7 best laps were slower than the car had in it, but the track surface was getting warmer so I doubted I would find much time. But with a cooled off car, a slow out lap (you can see I'm just talking to the camera and keeping the C6 ahead in sight in my video below), and a focus on getting my FIRST hot lap in clean... I managed this.

                            In-car video of my final session, first hot lap was a 2:00.619

                            That was a pretty decent lap, if I say so myself. I've driven a LOT of cars out here in the past 10 years but never have I run a 2:00 flat lap in anything with street tires. It took every amount of restraint I had to not "over brake" any one turn on that one hot lap - and the brakes were getting worse in every major braking zone - but it was just enough.

                            Eight of the top 10 cars were Z06, Grand Sports, or other Corvettes with lots of mods. KenO's E46 M3 TT3 race car with aero on Hoosier A7s took FTD and our piggy Mustang with no brakes managed 6th overall and "won our class". Don't ask about classing here, its something based on autocross classes and PAX factors that will make your head spin. We were 4 seconds ahead of the next Mustang, another S550 on RE71Rs. I was happy with that, considering how marginal the brakes were. I look forward to coming back here with better brakes to see if we can dip under a 2:00 lap on street tires.

                            FIRST S197/S550 TECH TIP BRAKE VIDEO

                            This first video explains our experiences with the S197 4 piston Brembos and then our frustrating experiences with the 14" S550 base GT brakes.

                            The video above is the first in a series of videos about these brakes we made and we feel it is worth watching.

                            SCCA AUTOCROSS EVENT # 2, LONE STAR PARK, MARCH 25, 2018

                            So while I missed the March 4th autocross with our local SCCA region due to a drivers license debacle, I was excited to finally autocross the car - and this time on real suspension, wheels and tires. Jon had made us some magnetic door cards for STP/W and CAM-C classes. We had another race car in our trailer but this is a street car, right? So we decided to drive the car to the event, across town. These are street tires after all!

                            Well there was a lot of construction going on in our area and we think the car got a flat leaving our neighborhood. Amy was driving and said "Hey, its really pulling pretty hard to the right." Hmm... turn around and go back to the house to air up/check the tire, or drive down the road to the gas station to check it there? We needed fuel, so I said to heck with it, let's go another 2 miles down the road. Mistake.

                            She's on the highway, within a half mile of the gas station, and the tire lets go. Pop! This car just does NOT want me to autocross it! And while we had the factory optioned spare tire and lug wrench in the trunk - we didn't have the jack or the right 19mm socket for the lugs we had on the Forgestars...

                            Jon was just ahead of us on his way to the event (he would be co-driving) and when we called, he ran back to his house, grabbed a floor jack and the right socket, and we put on the spare. He brought a plug kit in case it was just a flat, but when we removed the tire and saw the inner sidewall gone, we knew it was way beyond saving this day.

                            LESSONS LEARNED

                            Every time I make a mistake in my life I try to learn from it. I haven't had a tire blow out in a sports car in... well, ever. And getting caught with the wrong lug wrench and no jack was a dumb mistake, so I bought a cheap 1/2" torque wrench, thin wall lug nut long socket kit (17, 19, and 21mm), and a short 1/2" extension. Probably spent $50 but I won't be stuck again. I actually doubled up on all of this so my 1/2 ton truck would have the same setup on board.

                            I also bought the Ford Racing TMPS kit shown above, along with the programmer. Having on-board tire pressure readouts is super handy and would have prevented this blowout completely - the instant the pressure dropped below 30 psi we would have seen an alarm. The next time I have these tires off these wheels we will install these sensors, program them to the car, and never be without tire pressure data any longer. #500psi #streettires

                            Sadly the Right Front tire (which took the most wear at the MSR-C event) that popped had 6/32" of tread left, as measured above left. They only come with 7/32", so it was wearing nicely! Instead of buying just ONE replacement Bridgestone tire I bought TWO - so we would always have a spare with us in the trailer, for any unforeseen mishaps in the future away from home or the shop. And by damn this would be the LAST time we did NOT tow this car to an event. Three people missed out on autocrossing this day due to our lack of a proper spare RE-71R tire, TPMS sensors, etc. This sure isn't going to happen again over a $330 tire or the ease of loading/unloading a car in our trailer.

                            BRAKE MODS, ROUND #3 (PP 15" ROTORS & 6 PISTON CALIPERS)

                            When I saw an opening at the normally sold out Optima series event at NOLA coming up in a week, without much thought I signed up. I knew this track well, plus we found a Track Night in America test the Thursday afternoon before the Saturday-Sunday Optima series event. Time for an Intermediate Brake Upgrade and subsequent test...

                            Since we might use them only for one event I got the cheapest Centric rotors and rebuilt calipers

                            I knew this track would need better brakes than our 14" stuff, and our prototype S550 380x34mm Powerbrake kit wasn't going to make it in time. With little to no research I ordered some Centric 15" rotors and rebuilt Brembo 6-piston calipers off of the 2015-18 Performance Pack Mustang GT. There was some small hardware to round up, new front pads to order (G-LOC R16 once again) for the new calipers, but the brake hoses would fit. There would be zero time to do a local track test before going to the Optima event so this was a total roll of the dice! But again, I had used the stock brakes at ECR in 2014 with good luck... they should work fine.

                            It was a pretty tight schedule and everything we needed only showed up with hours to spare before we loaded up for the 9 hour tow to NOLA. The "Tech Tip" video in the section above shows many of these caliper/rotor weights, as I shot that as soon as the calipers and rotors arrived. The above gaggle parts were also ordered and arrived, including: ARP long wheel studs for the rear, Ford Racing hubs with ARP long wheel studs for the front, and Ford Racing trailer tie-down hooks.

                            First Ryan put the hubs, rotors, and calipers on then fabbed up prototype 4" cool brake backing plates for these 15" OEM brakes.

                            These prototype brake backing plates (we will have these in production later this summer for the S550 15" PP brakes) serve two purposes. First, they cool the front hubs - which get hot and become a wear item over time (just like we saw on the S197). Second, they pump air inside the "hat" of the rotor, seal the air into this area, which then forces it into the vented portion of the rotor - which acts as a centrifugal pump and pushes this cooling air through the center of the rotor casting, to cool both the inner and outer rotor faces.

                            We have seen a few people propose that you can "make brake cooling for the 14" inverted hat rotor", but we feel that is pretty much pointless. While this might help cool the hubs, it would do little to cool the rotor itself, especially the outside face - since there is no way to pump air through the vented portion of the 14" rotor. This is a lot of work for very little benefit. Now if there is a non-inverted hat 14" rotor on the market that fits the 14" 4 piston calipers, yes, that might be worth trying. But we've moved beyond the 14" bits on our car.

                            HOW THE MOVE TO 19" WHEELS MAKE 15" BRAKES POSSIBLE

                            We stuck with the 14" brakes on our 2011 Mustang for 5 years mostly because of one thing - we ran 18" wheels that didn't clear the 15" brakes. At the time we were using Forgestar F14 wheels in 18x10, 18x11 and 18x12" widths. And back from 2012-2015 the Forgestar F14 wheel in 18" could barely clear a 14.5" rotor/caliper setup.

                            Forgestar knew that the 15" / 6 piston Brembo kit was coming down the pipe from Ford (S197 GT500) so when they introduced a newer wheel design - the CF5 5-spoke above, they changed the barrel to clear this 15" / 6 piston profile. The shape of the inner barrel on the older F14 is very different than the newer design CF5, which I am holding below.

                            Starting in late 2016 Forgestar began phasing out the old tapered barrel design of the F14 to the "stepped" barrel (above) of the CF5. So if you have 18" wheels of the F14 style from this company bought in the last 2 years they likely look like the black wheel above and can clear the 15" brakes. Barely.

                            Of course many S197 and S550 drivers have moved up to 19x11" wheels due to the abundance of 305/30R19 street tire options available. But when it comes time to slap some Hoosiers on this car well... we will likely go with 18x11" wheels, so we will have to watch out for that rotor/caliper to inner wheel barrel clearance.

                            continued below
                            Terry Fair -
                            2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                            EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                            • #15
                              Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                              continued from above

                              OTHER UPGRADES AND MODS

                              Next we changed the fluid in the manual trans at 1000 miles, but strained the trans fluid to check for the rumored "trash/metal" that would be in the fluid. We strained it, looked perfect, but still replaced it with Motul DCTF.

                              Engine oil was also upgraded to Motul 5W50 Ester based synthetic. This lubricant is one we have used on several race cars in the past couple of years and they tend to drop oil temps by up to 30°F. If any engine needs it, it's this one.

                              During the oil change we also upgraded the tiny OEM oil filter to this larger Mobil1 filter that has at least twice the volume. It uses a synthetic filter element and is a Mobil1 Oil Filter part number M1-212, cost is around $17. It clears all of the "stuff" around the filter by a mile. The plastic oil pan still makes me giggle, but I'm sure there was a cost/weight savings there.

                              We had not seen any proper brake cooling inlet kits for the 2018 GT's new nose, so I asked Ryan to remove the bumper cover so we could have a better look. After looking under the skin we noticed that the area Jason and I wanted to draw air from was fairly unblocked, so I asked Ryan to make a quick 4" oval inlet to bolt into this lower grill section.

                              In the same general space we found a good spot to bolt a front tow hook to, behind the 4 bolts that hold the bumper beam in place on the right front corner. This tow hook was cut from 1/4" steel plate, welded up, painted, and bolted in place. A small slot was cut for the tow hook as well as a 4" oval hole for the inlet duct. We plan to make these in production later this summer and offer them with modified lower grill inserts (which just snap in place into the pumper cover). Some of the other options out there require you to drill into the bumper beam (its hard AF!) or worse, remove it altogether. This is a simple bolt-on part that doesn't sacrifice crash structure or require you to cut into the upper grill or painted parts of the car.

                              The rear bumper is not any different than the 2015-17 models, so we looked at what was offered for a rear tow hook. Oddly enough they tend to mount where the lower/center mounted reverse light goes - and we don't want to remove that. The others require a hole cut in the rear bumper cover and/or the removal of the license plate. Not really what we wanted.

                              We looked at the rear section, the bumper beam, and the many ways other shops have made rear tow hooks. And like in the front, we found that bolting behind the bumper beam was the least intrusive, strongest way we could find. Routing the hook above the exhaust tips made it so nothing had to be cut whatsoever. Maybe someone else has done this but we hadn't seen it yet. Another part we will make for all 2015-18 S550s later this summer.

                              We have a little tool that allows for on-car removal of splined, press-in wheel studs... but Ford did us no favors here, and there's not enough access to install the longer ARP studs. So the rear hubs have to be removed.

                              With a few fixtures and a 30 ton press the new ARP studs went right into the rear hubs pretty quickly.

                              The OEM front hubs felt fine (above left) but I wanted the longer studs for this car, and ARP was sold out (we could only find 10 quickly). So we bought the Ford Racing front hubs with the same 3" long ARP studs installed, and the old hubs will become spares in the trailer.

                              The images above compare the base Brembo 4 piston calipers to the PP's optional 6 piston calipers - which are similar in size and mass. The pads are different between the two but also similar in total size.

                              In our rush to install these parts, on a 2 day timeline before this Optima event, we neglected one piece of advice from a racer, Chris Wynne. He told us we might get a poor pedal feel with this 15" PP brake setup using the stock 4 piston master cylinder and booster. While many other folks that saw me posting about these upgrades said that this was an easy upgrade, and that "The Ford Racing kit doesn't come with the PP master or booster, so it isn't needed". The latter folks were wrong, wrong, wrong. But we wouldn't know that until we drove 9 hours to New Orleans and put it on a race track.

                              I took a quick drive around the block after they bled the new brakes, it "felt ok to me", and we tossed it into the trailer. I foolishly thought we might have a shot at this Optima GT class if we can get past the D&E judging (more on that in our Optima coverage), but that was wishful thinking. Having functional brakes matter more than you'd think.

                              WHAT'S NEXT?

                              This post is running long so I will share the results from our two TNiA / Optima track events at NOLA and the Optima Speed Stop/D&E/Autocross events next time. Yes I finally got to autocross this damned car. Surprisingly I won one of the Optima competition segments, just not the one I was expecting. It all came down to not having any brakes.

                              One piece of good news from this round of mods - the Ford Racing "tie down hook kit" for the S550 chassis was a real nice addition and makes hooking the straps up inside the trailer a whole lot easier. We modified the front tie down hook mounting locations to make it even easier - I will get pics of that on the lift and show it next time. We will also show the fix for the 15 PP brakes we needed - the PP's master cylinder and booster. Then the track test at MSR-C after that was installed to prove it. There's a lot more going on also, but I will cover this next time.

                              Thanks for reading,
                              Last edited by Fair!; 05-01-2018, 02:27 PM.
                              Terry Fair -
                              2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                              EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev