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Vorshlag 2018 Mustang GT + S550 Development Thread

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  • #31
    Re: Vorshlag 2018 Mustang GT + S550 Development Thread

    Originally posted by zirfj312 View Post
    I have been following your 2018 S550 build as I have the same base setup and am/will be modifying my daily driver/track HPDE setup. First, your posts have been a wealth of great info and inspiration and I am currently implementing the brake conversion setup (booster + master cyl + the 15" rotors + PP brembo's). I have a question which may seem 'noob-ish' but here goes...During track days I have been disabling the Traction Control + Advanced Trac (per the Manufacturers recommendation) but what about the ABS? I've heard talk of disabling it via the fuse, or just leave it alone. Could you give me a recommendation? For this or all the 'traction systems'.
    Yes, turn ALL of the traction control systems off. Factory TC is good for randoms driving in mixed conditions, but REALLY slows you down on track with even a small amount of skill. It uses rear brake applications to keep the "yaw" and wheelspin down, as well as throttle pushback. KILLS rear brake pads on these car.

    Sure, maybe if its raining and you don't feel comfortable pushing it in the wet, leave the "Advanced Trac" on, to some degree. But once you get to a certain level of driving skill, you will want to turn it off in the wet, too. It is too limiting, slows down lap times a lot, even in the wet. OEM traction control systems are SUPER conservative and limiting.

    But DO leave the ABS alone - this is a very GOOD system, and it can brake better than any human could dream of. These two pictures above are from a NASA event at COTA, where I was running my E46 BMW (with ABS and a big brake kit) on track with some Miatas, many of which have no ABS (these were some of the last "modern" cars to get ABS as standard). That BMW was fairly low on power in TTD class, and some of the TTE Miatas could almost hang with me... but not under braking. When they tried to brake as late as the ABS equipped BMW, boom! Their inside front tires would lock. This guy took his tire down to cords in one stop. That's what ABS prevents.

    Ford's ABS programming on this car is one of the best in the world. The computer can cycle each caliper independently 100s of times a second, to keep the tire right on the verge of lockup. Maximum braking. Of course you won't be "in the ABS" every time, but the confidence of this flawless system will make you faster, as you know you won't ever lock a tire.

    The picture above was in our 2018 GT, also at COTA. It became easy to "outbrake" and take huge chunks of track distance away from lighter cars in this 3925 pound pony car. Why? Because our had an immense big brake kit and aggressive pads + one of the best ABS systems in the world. The Ford ABS is so good, any car equipped with the 2005-newer Mustang system is penalized in some classes (NASA American Iron being one such case).

    The Ford ABS works great, rain or shine, better than any car GM has ever built. Do not needlessly cripple one THE strongest aspect of these S197 and S550 Mustangs!

    Last edited by Fair!; 03-01-2019, 10:47 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


    • #32
      Re: Vorshlag 2018 Mustang GT + S550 Development Thread

      Project Update for February 28th, 2018: I started writing this over 4 weeks ago, showing the work we have done since the last update. More and more parts kept showing up and it blew up into a mega-sized post, and I couldn't wrap it up. So I have shortened it to the prep we did right before the 2019 season opener NASA TT competition weekend, over the last weekend in January, which I will instead show next time. Plus ALL of the mountain of parts we have added since then.

      In this update we will show some horsepower that was added, by way of ARH 1-7/8" long tubes + JLT CAI kit + SCT X4 tuner. After a dyno tuning session and average power dyno calculations, this forced a last minute NASA classing change, which I will go into further below. Running TT2 was never in the game plan, and we will switch back to TT3 after this January event.

      Then we removed the Ohlins R&T coilovers after three successful track tests and some street miles to reinstall the MCS RR2 coilovers. These went on with a new revision of our spherical rear shock mounts, with which we tested 3 different shock lengths. We also installed a strut tower brace and made proper remote reservoir brackets this time.

      Two new sets of MOMO wheels with both street and race tires were procured, so we could test out their new flow formed wheel offerings in 18x11 and 19x11" sizes. I bought a new helmet, which was long overdue. Made production seat brackets for the S550 and installed the passenger Sparco seat and Schroth belts. Then we go into a brake pad wear analysis on the Powerbrake X6EL fronts compared to the wear on the base 14" 4 piston as well as the PP 15" 6 piston front brakes. We also put together two new S550 front brake cooling tricks, one of which did not work at all and another we will be testing soon.

      Let's get started!


      In the last year we have done a lot of events and upgraded from the the base GT 14" 4 piston "inverted hat" rotors and OEM pads -> to G-LOC pads on the 14" bits -> to the 15" PP 6 piston brakes with G-LOC pads and brake cooling -> to the Powerbrake 380x34 6 piston brakes with cooling + Powerbrake pads. We note that not only stopping power/longevity improve, so did the pad wear after each braking system improvement.


      The single biggest disappointment with our "base model" GT were the front brakes that came on these 480 hp cars. They aren't just "not great" on track, they are downright UNSAFE. I've even had HPDE1 students in base S550 GTs cook these pads/rotors on easy 70% effort laps at some tracks. We spent our first few track days doing "one lap stints", even with GOOD track pads on the car. If I pushed hard I could overheat the fronts AFTER ONE STOP, so it was a study in restraint to make them last a lap and still get a "decent" time.

      The inverted hat front rotor design - which allows no airflow through the back of the rotor and through the vanes - is the single dumbest idea I've seen in the automotive world in the last 15 years. And remember: I've worked on SUBARUS! (these car combine many of the worst ideas into one single platform)

      We tried to keep track of the brake pad wear rates since the beginning, but the 14" brakes were so horrendous that we had trouble. If you followed along in this development thread, you might remember that we saw very high wear rates on the stock 14" front brake pads (only 8 laps took new OEM pads to the backing plates!) and even the rears (3 track days). We put on some R8 G-LOC front track pads, then shortly after new R16s, and while the wear rates got a little better, the fronts were continuing to wear rapidly - and would still overheat the fronts within about 1-2 laps.

      The rears pads, even though those are inverted hat rotors, still have the same set of G-LOC R16 pads with plenty of meat left, a full year later. Rear brakes never wear as quickly as the fronts.


      After the upgrade to the larger 15" PP front rotors and 6-piston calipers, we could finally add some brake cooling - since the rotor wasn't made "backwards". This helped in two ways - the larger pad/rotor as well as basic forced cooling.

      We went with another new set of G-LOC R16 front pads for this caliper, and initially we had WORSE brakes, due to the large hydraulic ratio difference in the master cylinders between the base and PP cars. We fixed that and had working brakes, yay. These front pads were still wearing a bit faster than we liked - closer to what we saw on our S197 with the same pads on the 14" Brembos with cooling.

      After seeing the pad wear rates I had started planning for front pad replacements every 4-5 weekends, similar to the S197 saw on the ducted 14" Brembos. Still, these 15" PP brakes were a DRAMATIC improvement over the 4 piston S550 brakes, and probably what most casual to semi-serious track days S550 folks should run. If you do go this route, brake cooling is still a very wise investment - saving brake pad and rotor wear, as well as extending wheel bearing life significantly.


      We probably could have run these 15" PP brakes for a few years and just cycled through rotors and pads regularly. But I wanted MOAR! Powerbrake made the prototype set of Powerbrake 380x34mm 6 piston "X6EL" S550 big brake kit for our car and we put that on before NASA Nationals at COTA.

      With the upgrade to the Powerbrakes, we not only lost 21 pounds from the 15" 6-piston Brembo PP brakes, we gained even more rotor cooling, a more rigid caliper, thicker pads, and after a number of events since then, we are seeing even better pad & rotor wear.

      We try to take pictures of new brake system consumables like this, to help track wear after events. This is after two high speed NASA event weekends, at COTA than NOLA. We see our highest speeds all season at these two tracks (145 mph+).

      The two pics above are after 5 full weekends of testing and TT events in the car, shown above. The Powerbrake PB13 front pad thickness is still thicker than the backing plate, which means we still have some life left in these. One side is worn more than the other, which is explained by an issue we had at MSR-H with the brake ducts (see below), but still well within usable limits. Happy with that wear, might get 1-2 more weekends out of these pads, and the rotors look like they should last another 6-12 months as well.


      So the brake ducting we have on this car consists of 3 parts: the brake inlet ducts (2018-19 GT specific parts), the brake backing plates (which fit all S550 Mustangs with either the 15" PP brakes or the 380mm Powerbrake kit), and a length of 4" diameter brake duct hose on each side.

      Ideally these brake cooling parts parts should last forever, and our metal parts will do just that. But there is one part that becomes a consumable on the S550 when you run wide wheels and tires - the brake duct hoses.

      With 11" wide front wheels and the massive 315mm Hoosiers, the tires "get into" the brake duct hoses at full steering lock. You shouldn't ever turn the wheels to full lock on track, but you will do it surprisingly often in the paddock, or parking lots when driving around on the street. Over time it wears a hole into the hoses - about once a season we replace the hoses. This is a hassle, so we tried a new solution.

      Above is a test we did to try to alleviate the brake hose wear issue - a stainless steel oval 4" tube section, which was "squashed down" a bit, and bolted to the chassis. The hope was to make a thinner cross section piece of tubing that can allow for more steering lock yet not wear down if the tire touches it.

      Great idea, in theory, and I sketched out what I wanted fabricated while I was going to be gone on a week long vacation which I was taking 2 weeks before the 2019 season opener at MSR-H. They did a good job, but if I was there it might never have made it onto the car.

      Evan made it bolt to the chassis with two riv-nuts added to the inner fender section shown above right. The hope was that it could be "crushed" right where the tire would hit at full lock and yet still flow enough area. Well the 4" oval-ized tube starts to pancake and buckle pretty quickly when put into a press, and it ended up still being more than 2 inches wide at the tire intersection.

      The problem is, the 11" wide wheel and 305-315mm tire BARELY fits this car under the stock fenders, and even then it takes some camber to fit. At full lock the tire just starts to rub the inner liner. Well with a 2" thick tube in there, this massively limits steering lock.

      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


      • #33
        Re: Vorshlag 2018 Mustang GT + S550 Development Thread

        continued from above

        At MSR-H this became a real nuisance in the paddock and grid. I kept running over cones and doing 3 point turns and felt the tire rubbing the tubing HARD in paddock.

        Never on track, but the grid tire rubbing eventually ripped one of the stainless steel tubes off, which blocked the LF brake duct hose. This led to some brake temperature issues that made uneven pad wear, which I will describe in the event write-up next time. Long story short - this did NOT work, and we will be going back to hoses for the next event.


        When the S550 first arrived in 2014 we tore one apart and looked at things to improve. We got to explore Aaron's 2015 PP1 car, then this red PP1 I ordered but decided not to buy (the dealership was happy to sell it for more).

        We noticed the "scoop and flap" brake cooling that came on the PP GT cars, and while we felt the flaps were a bit on the small side, we had plans for a more traditional "forced" air inlet-hose-backing plate cooling.

        Of course the hoses can become a challenge with wide wheels and tires, and of course adding the inlet scoops can force you to cut on the front of your car. We also had some advice from a Ford engineer that a bigger flap than the PP cars came with would help. And strangely, the Shelby GT350 is missing the flaps altogether - but has the undertray duct.

        So we took the PP1 brake deflector scoop that mounts to the front control arm and made it significantly bigger. The prototype above is ready for testing, which we will do soon on our car - comparing it to no cooling (like the base GT) and then to our forced brake cooling package on the car now. We will share the results, and if it is as helpful as we think it will be, these will go for sale on our website shortly thereafter.


        After 3 events/weekends testing with the Ohlins R&T coilovers, it was time to go back to the MCS Remote Double adjustable coilovers, which we call the "RR2" (shown below). This setup is valved for a higher spring rate, and has separate Rebound and Compression adjustments. This will help us dial i the setup for running both 200 Treadwear street tires and the Hoosiers in the same weekend, which we have planned for 2019.

        We ran these dampers before at COTA during the 2018 NASA Nationals, but the lengths of the rear dampers changed from the 2014 design we helped come up with (which was not inverted then), and the rear was running out of shock travel, until I raised the ride height. There were two ways to fix this - make an extended height shock mount and/or shorten the rear dampers. In this case, we did both.


        The factory rear shock on the S550 uses a "divorced" spring, located inboard on the rear control arm. The shock mounts to an aluminum upper shock mount, which has a rubber bushing to allow for shock articulation during suspension travel. Rubber in a damper path is never wanted, as this delays the shock's reaction to suspension movement.

        The real problem comes when we convert to a "coilover" spring location on the rear. This moves ALL of the suspension loads (not just damper loads) to the rear shock mount. What can happen - and often does - is shown above. The steel washer that is crimped into the aluminum housing holds the bushing in place, but when you hit a big enough bump with coilover springs it can act like a fuse - and pops. The solution is an all metal spherical shock mount, made for these higher suspension loads.

        We used to make a spherical rear shock mount out of the OEM cast aluminum pieces, which we machined and added a CNC machined aluminum spherical cup to. But these were too expensive to make, pretty ugly, and didn't give us any additional shock travel - so we moved to this steel plate design with a CNC machined steel bearing cup welded into the structure.

        Jason and I have been stumped on how to make a dual height shock mount on our CNC machines, but ever since we purchased a CNC plasma table last year I have wanted to move to a welded design with a machined cup. Myles expounded on a sketch I gave him to create this mount and it has worked great.

        We have tested this new design on multiple cars, including our own, with two lengths of MCS rear dampers. The lower holes from the dual mounting positions adds 1.5" of additional "bump" travel, which helps accommodate OEM length shocks with lower-than-stock ride heights. Remote Reservoir style shocks can go even lower, and with the new shorter length we have, we get a LOT of bump travel. That's the setup we have on our car - the lower mounting holes and a shorter shock length (I like to run the car pretty damned low).

        We tested the bump and droop travel of these dampers on the lift with with the rear swaybar disconnected and the rear spring removed. Now we get extreme bump travel without running out of rear shock stroke.

        I tested these dampers + mounts at the very bumpy MSR-Houston and never had a single "shock travel" issue all weekend, so we can check that issue off the list. As you can see above, the rear "squats" pretty good on acceleration (even with 750#/in coilover springs), but its nowhere near the limit of shock travel now. Very happy with the new shock mount design, which is now available on our website for any "pin" style upper S550 rear shock.


        Our "base model" 2018 GT came with no strut tower brace. Not a huge deal, and I don't think most modern S197 or S550 Mustangs even need these items - not as badly as the floppy pony car chassis of the 1980s-90s.

        But I wanted to add one, mostly just for a place to mount the front strut reservoirs, like on the BMW above. That car didn't really need strut tower brace, either. Mostly these braces and doo-dads are another somewhat useless holdover from the 1980s...

        We looked at the Performance Pack and Shelby GT350 strut tower designs. There were OEM options (painted black) and a Ford Racing version (the silver one we bought). There's a big U-shaped stamped steel plate piece that attaches at the towers and back to a flange on the firewall, which triangulates the towers to the firewall. All of the mounting studs there there... and our car had "half" of this triangulating piece from the factory.

        Of course we weighed these bits. The strut tower brace was only 5.1 pounds, but the triangulating stamped plate piece was twice that at 10.6 pounds. Again, we took about 5 pounds off with the stock "half brace" at the back, so we gained about 10 pounds. In the grand scheme of things, not a big deal, and I don't expect any real "chassis stiffness" gain from this, either. Mostly wanted it for a shock reservoir mount.


        So we have installed this set of MCS RR2 double adjustables with remotes before, and ran them at NASA Nationals. Now we have had the rear shortened and of course the new rear shock mounts gain us another 1.5" in bump travel. Excited to get these installed.

        This time we had enough time to make some brackets to hold the reservoirs correctly, instead of just zip-tying them to the swaybar or underhood. We do want to place these in a place that is easy to access, allows for heat dissipation, and protect the hoses from any kind of chafing. The Teflon lined reservoir hoses are braided stainless steel and can saw through just about anything, but worse - if they get cut you lose both Nitrogen pressure and hydraulic fluid. This will turn a high end damper into a useless slug of metal.

        We mounted the MCS rear remotes in the spare tire well inside the trunk, which requires some 2-piece grommets from Seals-It to allow them to pass through the trunk sheet metal. No, we don't use "quick connects" on our remote shocks because those are damned pricey and you still have to discharge ALL of the Nitrogen pressure before connecting/disconnecting those. It is much easier in the end to just use a larger 2-piece grommet to seal the opening into the trunk. Those can be unbolted to allow the whole remote reservoir to pass through the opening.

        Pro Tip: One thing about the S550 rear is there is a lot going on back there. With an inverted shock and coilover spring mounting, the spring sits at the bottom of the shock. This puts it very close to the CV boot at the rear axle. Most mounting designs we have seen (AST, Ohlins, MCS) have either an offset lower fork mount (one side is longer than the other) or slotted holes in the lower mounting fork. Offset the bottom of the damper AWAY from the axle/CV boot and use the smallest diameter spring for that damper (2.25" ID is what we use on the MCS). This way the spring cannot rub the CV boot, which can expand at speed, tear, and then let all of the grease out. This will cause the CV internals to fail rapidly.

        The hose length on the MCS front struts wasn't quite long enough to allow those remotes to be attached to the strut tower brace like I had hoped. Evan still made some nice "saddles" to hold them, which are bolted in the front of the engine bay, away from heat sources and with adequate airflow over them. Also with excellent access to the compression knobs.


        I teased this upgrade last time, as I was tired of running TT3 class being down on power and/or heavy for the class. In 2018 we ran TT3 at ___ pounds, which was 240 pounds heavy or 21 whp down on power. With no great way to lose weight, we wanted to instead jump up by that ~21 whp amount in average power. There is no easier way to gain power on a modern V8 pony car than long tube headers and a cold air.


        Over the past 34 years of wrenching on pony cars I have installed dozens of sets of long tube headers, and backed with lots of dyno testing, I can see obvious trends. Having worked with ARH in the past we know that these fit and function the best of the available options for the Coyote 5.0L, and know that the 1-7/8" primaries work better even on otherwise stock engines than the optional 1-3/4" versions.

        I ordered the setup above, complete with catalytic convertors and an X-pipe merge. All 100% stainless steel, and American Made. No Chinalloy up in here!

        Again, this is the best bang-per-buck power mod on the planet for the Coyote. "BuT tHe StOcK hEaDeR iS tUnEd!" That's JUST a big load of nonsense. The factory tubular stock manifolds are constructed by the lowest bidder, made to "light off" the catalytic convertor quickly, designed to go onto the engine with the least amount of work, and have the drivetrain all pop into the chassis from underneath on an assembly line. That's it. LOOK at the visual tubing differences above. Then look at the dyno results below.

        The actual header install is the biggest challenge, involving partial removal of the front crossmember. This is done to gain access to remove the stock manifolds as well as slide in the new ones. Big fun! We bill this header install as an 8 hour job, but you hopefully only ever do this once. And once you see the gains...

        There was a little challenge merging the Magnaflow exhaust with the mid-pipe sections ARH included, with a cut and splice needed, but nothing we couldn't handle in our shop.

        The finished job looks mighty nice, and when I heard it fire up for the first time I knew we were in for a treat at the dyno.

        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


        • #34
          Re: Vorshlag 2018 Mustang GT + S550 Development Thread

          continued from above


          The stock air filter, filter box, and inlet tube are made to meet strict government "sound" rules (which apply to new factory vehicles), as well as keep any trace of dust out of the filter element box. This is done by restricting the size of the "inlet" into the filter box very small. There are often sound resonators and quarter wave tubes leading off of OEM air inlet tubes as well. The Mustang has a "sound tube" that pumps sound into the cabin, so it "sounds cool". We took that bit off long ago, but now it was time for a real "cold air" inlet tube, bigger filter, and integral MAF sensor housing.

          We waited six weeks for a particular brand of cold air to become available off backorder - a major brand that we can buy wholesale and hopefully resell. With only a few days before our first event I punted and got a brand that was available. Oh well.

          This JLT kit is unique for the 2018-19 GT, as it is based on their Shelby GT350 unit. The diameter of the tube / MAF housing is larger than the stock throttle body, so it has to converge slightly at the TB. But air is much more inclined to converge than diverge, and doesn't seem to hurt airflow as much at the latter factor.

          The picture above shows the two front MCS remote reservoir mounts and saddles we made

          This JLT unit did not have some of the features of the brand I wanted to buy, having to do with materials and a more sealed "box" for the filter element, but it was available and I had a deadline. This is still a popular unit, and the dyno results also speak volumes (we might have made 20 whp with the CAI alone).


          Our local tuner is True Street Motorsports, who we have worked with for many years. They stepped up again, moved some things around, and got our car slotted in and dyno tuned at the last minute. They are the ones that also dyno'd the car for us in stock form (well, it had a Magnaflow "race" exhaust), shown below with SAE correction.

          Previous dyno of our Stock 2018 GT with Magnaflow axle-back exhaust

          Above is the initial 435 peak / 417 whp average dyno number we have been using for the last year in TT3. Remember, with the stock tune the engine wouldn't pull past 145mph (speed limiter on the base GT, due to OEM tires) in 4th, but did make peak power at 6800 rpm, right before the speed cut. If you look below this is the same RPM the new tune made peak power, but could still pull to 7400 rpm. We have to test for NASA in the 1:1 transmission gear (4th gear on this year model) and that was the legal way to do that TT dyno test initially. Doesn't look like we left anything on the table with the 145mph speed cut before, good to know. All the gains in the dynos below are real, then.

          This time True Street reflashed the stock tune with this SCT "X4" handheld unit, an updated version of the SCT handheld that they used to tune our S197 Coyote Mustang. This re-flash allowed them to turn off the 145mph speed limiter as well as dial-in the fuel and spark tables to work with the additional airflow provided by the hard parts, the long tube headers and CAI.

          We also had them keep a smooth, linear throttle response curve, unlike the mail-order tunes that make it a logarithmic or regressive curve. Logarithmic throttle action is where a small amount of initial gas pedal movement makes for a LOT of throttle blade opening - making the car REALLY hard to drive, but it "feels faster". Just like those plug-in electronic throttle "tuner box" kits that uninformed dummies like to buy.

          True Street also supplied the JLT cold air, which got us out of a bind. While they are primarily a drag race tuner shop, we have worked with them over the years to have them tune 50+ road course cars, and they know what we are after: a linear throttle response (not digressive), a safe spark table (for long periods of WOT use), and an average power dyno readout + data plot with SAE corrections. I dropped the car off the day before the NASA event and picked it up that after noon, hoping for a +20-25 whp bump, but I didn't tell them to hold back.

          After the tuning it made an uncorrected pull of 485 whp peak whp... wait, what?! That's too much. What's the SAE corrected number???

          Peak with SAE correction (corrected down on this cool day) is still 474 whp peak, 426 wtq. Oh crap. I frantically started doing the average power dyno calculations the night I was loading the car up for a Friday morning NASA event departure.

          Yes, the car went from 435 peak/417 whp avg to 474 peak/460 whp avg. Notice how the peak gained 39 whp but the average went up 43 whp. This number was going to make staying in TT3 difficult. Time to weigh the car and do a quick corner balance (after the pic below). Last time we weighed it at 3825 lbs with driver, but that was less fuel (1/3rd of a tank) and no passenger seat at all, before 2018 NASA Nationals. With the ~62 pound roll bar in the car, though. Again, we were 240+ pounds heavy for TT3 then at 417 whp avg.

          Well "luckily" the car gained about 100 lbs from last time. I just came back from a week long Caribbean cruise, and we ate GOOD! Well, the second seat was installed (will show that next time) and added some mass, as did the higher fuel load and a few other updates - the strut brace, the long tube headers, oil cooler, brand new RE-71s (this weight) vs Hoosier (the 2018 weight), and some other doo-dads.

          So running the NASA ST/TT online car classification form, using a minimum weight of 3925 pounds (slightly less than it weighed that night, and close to what we claimed last year with full fuel load) and the 460 whp avg, with all of the bonuses (stock aero for TT3) only got us to 9.63:1 pounds per hp. Need to be at 10.0:1. Oops...

          With the "over 100 UTQG" bonus we would have been fine at 10.13:1 ratio, and we did plan on running our 200 TW on Saturdays and R7s on Sunday. But switching classes and sheets from Saturday to Sunday was asking a lot, and we were out of time to add ballast to make the Hoosier R7 setup TT3 legal. There was no time to de-tune the car, so there's no way to run TT3 on Hoosiers with this power level. We overshot TT3 by 25 whp -OR- I needed to add 204 more pounds and run the car at 4140 lbs minimum (wow!) Adding 50 pounds of fuel wasn't going to be nearly enough.

          It's 8:30 pm the night before I leave for this NASA event, the crew is long gone home, and I still need to load the car into the trailer. So I re-did my classing paperwork for TT2, a class which had grown to 10 cars for this event.

          TT2 ended up being brutally fast, and I will show "how well" this class jump turned out next time. Then how we will find a way to get back to TT3 (200 TW tires + a power de-tune after we add aero).

          HELMET UPGRADE FOR 2019

          I've had the same composite helmet since early 2010, which was a Pyrotect full face unit with a Snell SA2005 rating (the new 2010 rating hadn't come out yet when I bought it). I have used this lid in Autocross, Time Trial, HPDE, Track Testing, Karting, Drift Events, and Wheel to Wheel road races hundreds of times since I purchased it. Even around the office.

          I have used this lid with a "horse collar" neck device as well as 4 different HANS devices, and have had to change out the anchors each time (we had to drill the holes the first time - the helmets rarely included anchors for HANS units back then). In the 2018 season the fabric inner liner was starting to come unglued (and would fall down in my eyes), and some of the hardware on the visor hinge was worn so badly that if I hit a bump the visor would SLAM down.

          Why do so many of my Mustang events look like drift events??

          Racng groups are starting to refuse SA2005 helmets this year, so I had to step up to a SA2015 rated helmet. After some neck strain at a few events, I wanted to move to lighter unit, maybe even carbon? The costs can get into the $3000 range for a Stilo carbon helmet, and I had no intentions of using one of the fake China-Carbon helmets.

          Again, since I try to use brands that I can actually resell, I looked at Sparco. We do move a decent amount of Sparco seats, so this brand helmet could "match" the seats in my car. This Sparco Sky RF-7W model retails for $950 and includes the latest FIA 8859-2015 and Snell SA2015 ratings. This composite design "has a carbon fiber outer shell reinforced with layers of carbon-Kevlar", like any Carbon helmet under $2000 usually does. The visor closure is pretty slick and can be opened easily with gloves on, and the venting works very well.

          The fit for me turned out to be perfect on their XL sized helmet. I like the chin strap, it came pre-drilled and with HANS anchors installed (which we switched out for the NecksGen anchors), and the visor is really nice. Using it on track I am only mad that I didn't get this sooner. And the "MADE IN ITALY" tag on this helmet makes me a lot more confident than "MADE IN CHINA" of my old helmet.

          It always frustrates me how little weight data there is out there on just about anything. How hard is it to snap a pic on a digital scale? So the weight of this helmet was a bit of a mystery until we snapped this pic above. Luckily it is indeed 0.52 pounds (or 14%) lighter than my old Pyrotect helmet. Not an insane weight drop, probably due to some of the upgrades required to meet the one decade newer SA2015 standard. But when you are pulling 1.5g in a corner or under braking, every little bit helps.


          It is no secret that we have been a dealer for Forgestar wheels ever since we first found this company and dragged them into the motorsports field back in 2012. Some ownership changes have been brewing for a while, with Weld Wheels buying Forgestar, then MOMO bought Weld and their subsidiaries. Which eventually led to MOMO developing, then introducing several Flow Formed wheel designs in late 2018, which we ordered for testing on our car for the 2019 season.

          I showed some of these in my PRI 2018 posts, including this video above.

          The first two sets we ordered include the "Heritage 6", shown at left, and the RF-20, shown at right. The Heritage 6 is based on their popular 6 spoke Formula 1 wheel from the past. It comes in 17" and 18" diameters from 8" to to 11" wide. The RF series has 3 styles, and we chose the 20 spoke RF-20 for our first set. This wheel comes in 18" and 19" diameters from 8.5" to 12" wide.

          These two models both come in 3 depths or "concave profiles", which are somewhat visible in the images above. The width and offset range of the initial "blank" determines which depth of spoke or outer lip is provided. We picked the sizes that fit our car, ordered the bolt circle and offset we needed, and MOMO finish machined and powder coated these in the color we wanted.

          We ordered the Heritage 6 wheels in 18x11" for use with 315/30/18 Hoosier race tires, and the RF-20 in 19x11" for use with 305/30/19 street tires. We switched to Hoosier R7 compound for this set, to track wear/life and lap times. We will use these on the same days back-to-back to get good data against a new set of RE-71R street tires, for 200 treadwear events.

          With the sets mounted and balanced, we installed the RF-20 set, and loaded up the car for the first track event of 2019. And while you might be asking about weights, know that I will show all of that and much more - next time (this post is running long!)

          WHAT'S NEXT?

          This post got really long and I had to pick a place to stop and post.

          Next time we will cover the 2019 season opener NASA TT event (TT2), talk about the RE-71R vs Hoosier R7 lap time comparisons, and then all of the parts and work that followed. This included a gearing/speed analysis, the Auburn Pro diff + 4.09 gears + aluminum diff housing build up and install, and an S550 pinion flange "running change" issue we learned. We will show the new Anderson Composites GT5 carbon fiber hood install (with weights), PP2 splitter install, show some wheel/tire weights, a new rear muffler upgrade (bigger, quieter mufflers), Mishimoto radiator install (and weights), then cover an SCCA autocross and another NASA TT weekend we should have completed before the next post drops (weather permitting). We might have the carbon rear trunk install and GT350R wing on by then, too.

          Thanks for reading!
          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


          • #35
            Re: Vorshlag 2018 Mustang GT + S550 Development Thread

            Thanks for the feedback Terry. Got a TE at Daytona in April and cant wait to test it all out.


            • #36
              Re: Vorshlag 2018 Mustang GT + S550 Development Thread

              Project Update for April 15th, 2019: The last update was cut short due to the volume of info we had to share and the limits of most peoples' attention span. This time we will cover the event right after the first round of 2019 mods (power!), which was the 2019 season opener NASA TT event (where we ran the car in TT2) in January. While running at MSR Houston that weekend we got more RE-71R vs Hoosier R7 lap times to compare, then another round of work followed that event that we will cover.

              This post MSR-H work included a LOT of things: a gearing/speed analysis, the Auburn Pro diff + 4.09 gears + aluminum diff housing build up and install, which included both a last minute rear axle install and an S550 pinion flange / driveshaft "running change" issue we found. We will also show the new Anderson Composites GT5 carbon fiber hood install (with weights), PP2 splitter install (and the many items we had to order!), show some wheel/tire weights, a new rear muffler upgrade, Mishimoto radiator install (and weights), and stop there.

              We have since changed classes again (above) and attended another NASA TT weekend (March, TT3) plus an Autocross (CAM-C), but we will cover those events next time. The power level and weight are both getting to the point where it is nearly impossible to stay legal for TT3, so look for a move back to TT2 for the rest of the season for this car. The TT2 and TT3 classes are serious enough in Texas region that it looks like we might not be competitive (we'd do better in TTU or TT1) in a street car we refuse to cut on - so be it. The NASA classing is secondary to the parts development and raw lap times we are wringing out of the car.


              We are sponsoring a new series of 200 Treadwear sub-classes in TT for NASA Texas in 2019, and made these Trophies for those entrants.

              We made these on our CNC plasma table, then cleaned up the surfaces, and bent them to shape. With some graphic design done we ordered decals and applied them. Came out pretty slick. Of course we were down to the wire making 40 trophies, until the night I loaded up for the event. But deadlines lead to progress!

              2019 NASA SEASON OPENER AT MSR-HOUSTON CW, JAN 26-27, 2019

              That event highlighted not only that you shouldn't up-class when you are 500 pounds too heavy, but also how badly the gearing and worn out OEM Traction-Lok differential were. Since then we have finally made the upgrade to the built aluminum "Super 8.8" housing, new gears, and a prototype Auburn Pro differential. Wish we had the time to get it finished before this January event, and that plus being wildly overweight/under powered for TT2 definitely put us on the back foot for the weekend. Of course TT2 became the largest and most competitive class at this event - I sure can pick 'em!

              Event Photo and Video Gallery:

              Amy and I left early Friday morning to make the 6 hour tow down to the southern tip of the greater Houston area from our shop at the extreme northern end of Dallas metroplex. We got there at 1 pm and in hindsight, we should have done the relatively inexpensive test day at the track, to try out all of the new changes to the car over the Winter and work on dialing in the new setup (going from Ohlins R&T back to MCS RR2 remote dampers and stiffer springs).

              DAY 1 - SATURDAY

              Saturday morning we got there with a brand new set of 200TW Bridgestone RE-71R street tires mounted onto the new RF-20 MOMO 19x11" wheels. The plan was to run Saturday on 200TW tires (for test purposes and to support the new sub-class) and switch to R7s on Sunday. I ran the Saturday "TT warm up" session and was 4th quickest of all of the ~30 TT cars, on street tires, so I felt good about that. 1:43.0 lap. This of course gave me a false sense of security, as the other drivers got a LOT faster in later sessions.

              Making a good time in TT practice put me pretty far up the grid, which gave me clear track for the first few laps. In the second TT session I went out and ran a 1:42.05, but predictive showed high 1:40s. I went out again in TT session 3, but with rising track temps, I could not find any more time. Took my HPDE1 student (GT350 owner) out for a few laps in HPDE4, to give him a sense of the lap times his car is capable of - and he really enjoyed it.

              Throughout the day I fell from 4th fastest all the way to 8th on the grid going into the final TT session, as others found more time in their cars. I guess I found our car's best laps early, while the steadily increasing ambient and track temps tapered my times off later in the day? Never felt like I really nailed the laps on street tires, for a number of reasons. I don't run at MSR-H more than one event per year, and sometimes we switch configuration from CW to CCW from year to year, so I always feel like I am still learning this track. I never do all that well here.

              Watching the in-car video above of my 1:42.0 laps, sure there are some issues and of course driving mistakes. The rear rebound was set too soft, and it takes a bit of work to access the knobs for that on the inverted rear (we should have a revised MCS setup soon that will make it easier to reach the Rebound knob). I turned the Rebound up a LOT and it settled down in later sessions on this bumpy track, but I couldn't find more time. The extra power we added was very nice but the noise level was LOUD AF. I vowed not to run another event with a car this loud that is also this slow.

              The extra power and torque from the long tubes/CAI/tune made the "wrong gearing" issues even worse. Having to use 2nd gear in the Diamonds Edge and Sugar and Spice corners and stuck in 3rd gear in the Carousel made the rear end want to step out ALL THE TIME. I tried laps using a higher gear in these corners - it was easier to drive, but considerably slower. Kind of disgusted how far off the TT2 pace I ended up, but again - it was 500 pounds heavy + narrow street tires + no aero, in what was a TT3 legal car (with the bonus for 100+ TW tires). I would have handily won TT3 that day, even on street tires, but some key TT3 regulars were missing.

              Engine oil temps were fine, and trans temps as well. Diff temps were moving up fast, sitting on the 250°F limit of the gauge after 4 laps. I kept the lap count shorter to minimize the diff temp issues, but we had planned on the new aluminum diff housing going in before the next event. Other than diff temps the car was flawless - brakes, handling, etc.

              Decent NASA party that night, and the street tire trophies we handed our were welcomed (7 cars declared 200 TW before the day began). Lots of people still finding out about the 200TW sub-class competition and more folks promised they would look closer at these tires for use later in the year - including some HPDE4 regulars who have TT licenses but didn't want to commit to Hoosiers.

              I ended up 6th out of 10 in TT2, 11th fastest overall of all cars, and the quickest car of all TT competitors on 200TW tires for the day. When 8 of the 10 cars in TT2 were full aero/Hoosier cars, I should be happy to get mid-pack in what was a TT3 car. I could not blame traffic or poor grid positioning - just didn't have the pace for a serious TT2 effort.

              Costas won TT2 in the red G-Speed C5 Corvette (above left), running a 1:36.9 and resetting the TT2 lap record here. Sticker Hoosier A7s help, as does the HPR built motor was turned up over 100 hp more than when he ran it in TT3 last year and won the TT3 class National Championship. This same car also ran in ST2 with another driver, running double duty for the weekend. Pretty cool. Kevin in a Lotus was 2nd (above right), Dennis in a black E46 M3 was 3rd (below left), Casey's white C7 (below left) was 4th, and Chet's black C5 was 5th.

              It was good to see Yuri back in his TT2 classed EVO, which we haven't seen in a while. He and I diced it up a bit and I barely stayed ahead of his times. Again, most of this class were prepped race cars with Hoosiers and Aero, except for our car (6th) and another (8th) on street tires.

              Meanwhile my friend Brian Matteucci won TT3 outright in his 2017 Camaro 1LE... with V6 power, on 340 TW Continental street tires! He was there mostly to do some testing on the new Vorshlag 6th gen Camaro camber plate, which we built and shipped him the prototype of the week before. Worked great and that is in production by the time you read this. Previously he tested our first OEM perch S550 camber plate, too. He was the only outright TT class winner on 200TW tires for the weekend.

              I realized Saturday night that the left front (?) brake duct hose had come off. Last time I showed these wacky experimental 4" stainless oval tubing brake tubes we made for the front, which absolutely did not work. This led to accelerated pad wear on the LF caliper, which I showed in the last update.

              DAY 2 - SUNDAY

              We mounted up the 18x11" MOMO Classic 6 wheels and new 315/30/18 Hoosier R7s first thing Sunday morning, with a bit of a time crunch involved, and I also "fixed" the brake hose that had fallen off. Vowed to remove these tubular sections as soon as we got back, of course.

              With the fresh Hoosiers mounted I went out in session 1, but heard a funky noise that sounded like a wheel bearing issue in the rear. I came in after a warm up lap and jacked up the car, checked everything, re-torqued the wheels and went back out in the 2nd session. I thought it was a bad wheel bearing, but it was fine once I drove on it again. Probably just missed a lug nut when torquing the wheels on, in a rush. Still seems crazy that these M14 studs need 140 ft-lbs of torque on the lug nuts, but with 95 ft-lbs it makes a lot of racket. Gotta follow the engineers' numbers!

              During that 2nd session there was some oil dry down from a previous racer's engine that had ventilated, but I still ran a 1:40.9 on the Hoosiers. Did that on my first lap, where I had gapped Casey's white TT2 classed C7. I caught him early into the 2nd lap, when he had an ICE mode issue with his GM ABS system. He pulled offline and let me by but my lap slowed down a full second. I tried a 3rd hot lap but predictive showed even slower times. By then the front of the field started catching the back markers, and it got impossible to get a clear lap.

              This time was a little over a second quicker than my best on 200TW tires, even getting held up a tiny bit during that lap.

              That ended up being my best time, as my next session was hotter and my times were slower. Missing that first Sunday morning session was probably why the gap from streets to R7s was once again only a seond, as that first Sunday session is usually quickest for me in any Time Trial weekend. Oh well, I was so far out of the hunt for TT2 it didn't matter much.

              Weather was beautiful all weekend, Sunny and in the 50s-60s. It rained Saturday night - the track was dry and a bit green Sunday morning, but people still put in good lap times. Gearing worked a bit better on the shorter 18" Hoosier tires (25.5") vs the taller 19" RE-71R tires (26.2"), so this cemented our plans to go to 4.09 gears before the next event.

              The stock clutch-style limited slip was completely wasted many months before, of course, and that is costing us time. We would have been using 3rd-4th-5th gear here with the 4.09s instead of 2nd-3rd-4th like we had to with the 3.55 rear and the new MT82-D4 trans gearing.

              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


              • #37
                Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                continued from above

                Looking at the results I didn't improve in placement (still 6th out of 10) but moved up to 9th overall out of 35 TT competitors, by going to the Hoosiers. That's how far out of the hunt this car is for TT2, and why we are going to great lengths to get back into TT3. On the relatively skinny R7s, we were 500 pounds overweight or 60 whp down from the limits of TT2, and still had no aero. Most of the players in TT2 are winged warriors on stickier Hoosier A7s in wider sizes.

                I stuck around to do more instructor duties, as my HPDE1 student moved to HPDE2 (solo). I did a number of check rides on Sunday afternoon, a 2 to 3, a 3 to 4, and a 4 to TT. The most fun ride of the day was in the "Alpha" LS swapped 2013 FR-S we built for another customer 3 years ago, now owned by Tyler Starr - who was moving up from HPDE4 to TT. That session was a blast and he more than earned his way into TT! Two months later we were competing head-to-head in TT3 at MSR-Cresson.

                It was nice seeing a car we "built for track use" being run in Time Trial, and working flawlessly. The radiator and oil cooling we added worked, the gauges we had added were helpful, gearing was spot on, and the custom shifter just falls right into your hand - inches away from the steering wheel. He was having a ball and even hooning a bit, after I encouraged him to "let the car eat". He added aero before he joined us in TT3 at the March event, too! I can't wait to get our shop V8 FR-S completed.

                Amy didn't drive this weekend, but she did at the next event in March. We had a few snafus with loading some of our gear, since we just had the trailer refitted and had stripped out all of our stuff. Will get those items added back before the March event. Had a lot of fun - got some sun, some good laps, and saw lots of friends, competitors and customers. Glad we missed the rain, which was looming the week before but only came down Saturday night and did not impact any racing.

                200 TREADWEAR RE71-R VS HOOSIER R7 - TEST #2

                So this is our first back-to-back test of a BRAND NEW set of RE-71R 200 treadwear tires vs BRAND NEW Hoosier R7s (the last test was worn A7s vs worn RE-71Rs). Was this a perfect test? Not quite, no. This track is the one I perform the worst at on the entire NASA Texas schedule, and my times on both days were hampered by my driving, increasing track temps and other factors. Neither the street tire or Hoosier tests here managed a lap as good as the predictive lap timer showed was possible.
                • Tire Test #2
                • Best lap on new RE-71R - 1:42.050 (MSR-H 2.38 CW, 1/26/19)
                • Best lap on new Hoosier R7 - 1:40.911 (MSR-H 2.38 CW, 1/27/19)

                But still, it is another data point. On this 2.38 mile track with the same driver, conditions, and surface, the R7s were 1.139 seconds faster than the RE-71Rs. This is less difference than we thought there would be.

                Looking at the AiM data min/max numbers, the minimum speed was slightly higher but the top speed was almost identical on the R7s (likely due to some gearing differences). Lateral grip wasn't radically different, 1.32g vs 1.28g on the street tires. But braking is where the Hoosiers seem to jump ahead, 1.16g vs 1.06g on the Bridgestones, and I could feel that ~10% difference. The RE-71R registered a higher "forward" grip level, .49g vs .56g, due to the fact that I was using 2nd gear in one slow corner on the taller RE-71R that just didn't work at all on the R7s (massive wheelspin). This only affected one small segment of that one corner. A change to the 4.09 final gear ratio would make 3rd gear work better in that corner on both tires, I suspect.

                We have another test of this at the March NASA event, where I ran the same two tires on the same day, and better matched what the predictive timing showed as possible on both tires. I will continue to do this back-to-back testing at all NASA events all season.


                Speaking of final gearing, we finally wrapped this up in February! We started this project back in November, analyzing ratios, and then gathering parts. Let's cover the what, why and how of this gearing, differential, and housing change.

                I have run the various Texas /Oklahoma / Louisiana road course tracks in over a dozen of my own cars and customer cars (100+) for the past 3 decades. None logged more laps than my red 2011 GT (shown above) with the old MT82 6-speed manual. In this car we would use 3rd, 4th and 5th gears on almost all road course tracks, with a 3.31 rear end ratio. This was a good gearing spread that worked at both low speed tracks (125 mph top speed) and higher speed tracks (160+) with the same 3 transmission gears. We never touched 2nd gear on a road course with this setup, yet autocrossing worked great like using 2nd, with a 75 mph top speed.

                Our current 2018 Mustang GT has a similar 6 speed and a 3.55 rear gear (shown above), but it always feels like I'm in the wrong gear on any road course, everywhere. Why is that?

                The 2018+ Mustang GT has a revised six speed manual, which has all new transmission ratios, called the MT82-D4. We have talked about this before in this thread, and listed out all of the ratios. The 2011-17 Mustang's MT82 manual had a 1:1 5th gear (plus one overdrive), whereas the MT82-D4 uses a 1:1 in 4th gear (and has 2 overdrives). So all of the gears "feel wrong" on track to me, compared to the old MT82 transmission. 2nd gear is too low for slow speed corners (like the T11 at ECR above - I have to upshift to 3rd gear mid-corner) but 3rd is too tall for many slow corners. 4th gear goes on forever - I can't even use "all of this gear" at big tracks like COTA or NOLA. Have never touched 5th or 6th gear on any track with the new trans -those 2 gears are completely worthless to me with 3.55 rear gearing.
                • 2011-17 rear ratio options for MT82 equipped cars: 3.15, 3.55, 3.73
                • 2018-19 rear ratio options for MT82-D4 equipped cars: 3.55, 3.73

                The real issue comes from the fact that Ford offered the exact same final gear ratio options in the 2018-19 cars as the previous MT82 cars... so every gear feels "off" for the 2018+ GTs. The Shelby GT350 uses a different and better built 6-speed manual called the Tremec 3160, so it was not affected by the MT82-D4 change.

                GEARING ANALYSIS

                The spreadsheet below has the new MT82-D4 ratios in for 1st through 5th gears, and you can see that with the existing 3.55 rear gearing we have and the two tires we use most, 4th gear goes to 165 mph and 5th gear goes to 203 mph! That's just not practical, making 5th gear totally worthless, so in essence we are giving up usable acceleration in 3rd and 4th gears. Plus 2nd gear is still almost unusable on track - too much torque at the rear tire.

                Jason made this spreadsheet years ago (we will gladly share it with you) with lots of variables he can change. "Low and high RPM" gives us the spread we want to see speeds for in each gear. We use two different tires so we have two tire heights. We input 4 different rear rear gear ratios (there are currently only 4 choices for the Super 8.8 at this time). After looking at the transmission / rear gear / tire heights and doing many calculations, we picked a new rear end ratio and ran it by swapping in a new ring-and-pinion.

                After analyzing the speeds our car is seeing on most tracks, from the slowest corners to the highest speed straights, the Ford Racing 4.09:1 rear gear set (which never came in any OEM Super 8.8 application) looks like it will work the best for our road course needs. That is the lowest ratio offered for the 34 spline Super 8.8 axle, in any case. This won't be perfect for autocrossing, as the 4.09 limits 2nd gear to 66 mph (18" Hoosier) or 68 mm (19" RE-71R). If you have one of these '18-up MT82-D4 cars and autocross is your game, look at the 3.73 ratio 2nd gear speed numbers above.

                WHAT IS A SUPER 8.8?

                The 2015-up S550 Mustang came with an all new independent rear suspension that utilized a new "Super 8.8" differential housing, in place of the solid axle 8.8" that has been in use in one form or another since 1985. This new Super 8.8 housing comes in two flavors: a cast aluminum version and a cast iron housing (both shown below). The Shelby GT350 and all 6-speed manual GT's use the iron housing, the rest (automatic equipped GT, all V6 and Ecoboost) use the aluminum housing, which is a tick lighter (more on that later).

                Both Super 8.8 housings bolt into the tubular steel rear suspension S550 subframe (see below) at the same 4 points. These are built to accept differential housings with 34 spline stubs for the halfshafts (axles), up from 31 splines in the 03-04 Cobra IRS 8.8" housing (the 1999-04 Cobra IRS diff housing looks nothing likes this, and has zero cross-over parts), and is stronger than the 28 spline axles used in the earlier stick axle Mustangs (1985-2006). More splines = stronger.

                The Super 8.8 uses all new guts (34 spline diff housing + gears + bearings) but luckily Ford Racing makes compatible gear ratios, just in a lot fewer options than the 1985-2014 solid axle 8.8. The Super 8.8 ratios include 3.31, 3.55 and 3.73 from the factory but there is also a 4.09 ratio available (new ratios might exist by now - we did this analysis late last year).

                We had weighed one of the bare aluminum Super 8.8" housings a couple of years ago when I purchased it for another development project, so when we thought about putting this heavy S550 on a diet (for TT2), this made the most sense. Weights above are ones we took of the bare aluminum housing and cover - we show the complete aluminum super 8.8 housing plus the complete iron unit below. Before the peanut gallery chimes in, I know what you are thinking. "BuT tHe AlUmInUm HoUsInG bReAkS!" No, not really.

                Of course drag racers can break anything on a good hook, at a prepped drag strip, with axle hop. Yet we have spoken to a 900 whp drag racer who vouched for the strength of his aluminum Super 8.8 housing, and the pro road race teams also use these also and don't break them. If we break it, then I will post that data point. We try new things and sometimes they don't work out - but we share that data.

                We already have some direct evidence from our S550 OEM camber plate tester's car, above (Brian M), who used one of these aluminum Super 8.8 housings with a Torsen T-2R that he built up in his 2015 Mustang GT 6-speed manual over 3 years ago, and its still holding strong. This car now spends time every week on track at MSR-Houston with the new owner Matt (now on MCS TT1s), running on sticky 315mm tires, turning fast laps. Again - all 2015-17 5.0L automatic GT's got the aluminum housing, so its not exactly unproven.


                The 2015-up Performance Pack GT and 2016-up GT350 models got a Torsen style differential, which is helical geared unit that "does not wear" and does not rely on clutches to have a limited slip action. Of course the cheap base model GT like our's came with the old "clutch style" differential unit Ford calls the Traction Lok. These are universally loathed and it was showing signs of wear AFTER OUR FIRST TRACK WEEKEND. Our car essentially has had an open differential since March of 2018.

                Stock (left) and upgraded carbon (right) clutch packs we destroyed regularly in our S197

                We regularly destroyed these clutch packs (even the upgraded Ford Racing carbon packs) in our S197 before moving to a Torsen T2-R... they would last one or two days before the differential needed to be rebuilt again (see above). The T2-R was a non-wearing, performance upgrade in that car.

                New Auburn Pro differential for 2015-up Ford Super 8.8 Housing

                This build thread gets around, and Auburn found out we were going to be testing a new diff. We talked, and shortly after Auburn sent us a new prototype Auburn Pro diff for the Super 8.8" housing. We will put in some test laps to help get their prototype Super 8.8 unit proven and ready for production.

                BUILDING THE SUPER 8.8

                After we gathered the new Auburn Pro diff, the aluminum housing, cover, new 4.09 gear set, new bearings, pinion flange, plus all the seals and shims it was time to build a new Super 8.8 assembly from scratch.

                First, we needed to modify the new cover for our aftermarket diff temp sensor. The original rear housing cover on our 2018 GT had a BLIND threaded hole that looked like a perfect diff temp sensor location (between the fill and drain plugs), but since it was blind the hole had no direct access to the diff fluid. We had purchased an extra rear cover, since we need a complete Super 8.8 for another project we are working on. The new cover was slightly different - it only had a "cast" blind hole, no threads, but still looked perfect for a differential temp sensor location.

                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


                • #38
                  Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                  continued from above

                  We drilled and tapped that cast hole for 1/8" NPT threads, and fit the external diff sensor - and it can touch fluid. On the previous setup we had made an adapter to mount this sensor in the threaded hole for the lower drain plug in the housing (see this image).

                  After reading some of the small amount of tech we could find about installing a new differential and gears into a Super 8.8, we found we would need a "spreader tool". This tool can be used to help install the pre-loaded diff bearings and shims, so we built this. We built something similar for the SN99 aluminum IRS 8.8" housing we used in a customers V8 BMW.

                  Now we were ready, right? We looked for instructions and torque specs for assembling a Super 8.8 from scratch. There wasn't much out there, so I called up one of my old employees - who used to free lance doing gear swaps for us for many years. He came by the shop in late February to put this Super 8.8 together.

                  Torque values are somewhat hard to find for the aluminum Super 8.8, but here's what we unearthed from this document and some other sources:
                  • Main Bearing Caps = 71 lb-ft on aluminum super 8.8" housing
                  • Pinion Bearing Preload: 16-29 lb-in (how much drag it should have)
                  • Pinion Nut = Has no set torque value?!
                    + Ford says to "measure the removal torque and replicate on re-installation"
                    + We used 3 Ugga-Duggas with the 3/4" impact gun
                    + 1985-2014 Mustang 8.8" stick axle requires 140 lb-ft, for reference
                  • Ring Gear Bolts = 100 lb-ft "Use new bolts with pre-applied thread locker"
                  • Rear Cover Bolts = 34 lb-ft
                  • Ring Gear Backlash: 0.008-0.012 in

                  Donnie was familiar with setting and checking the gear wear pattern, back lash, bearing installs, and torque settings. The wear pattern on the ring gear marking paint looked good, then Donnie buttoned up his work. The rear cover went on with a thin line of RTV sealant and new Ford hardware bolted the cover to the housing.

                  We filled it with Motul Gear 300 along with the friction modifier supplied by Auburn. After driving it and listening for noise on decel, backlash, etc - its dead silent, perfect.


                  One of the small goals was to possibly reduce some mass. We had heard rumors that the aluminum housing is "30 pounds lighter" than the iron unit. We had weights on the bare aluminum housing, but not the iron. During the install for the new aluminum unit we weighed them both, and the difference in weight was less than we had been told.

                  As you can see the weight difference was closer to 15 pounds - but we have a bit of apples to oranges comparison here. The Auburn Pro diff is built differently and could account for some of the weight difference. Still, its 15 pounds less mass that we need to haul around, and if we move to TT2 for good we will need every pound we can find. If we see any adverse wear or cracks in this lighter aluminum housing, we will share that here.


                  We had an extra step we hadn't anticipated here. When the new pinion flange was mated up to the driveshaft... it didn't fit. The ID of the flange was different and the 6 driveshaft bolts wouldn't line up.

                  Apparently there has been some change to the Super 8.8 driveshaft rear CV joint and pinion flange. We figured this out after the unit was in the car and ready to button up, of course.

                  The "black" unit on the left was the one that came on our base 2018 GT. The "silver" pinion flange on the right was the one we bought, when we looked up a similar model S550 housing. The inner diameter differs by (4.316" black to 4.443" silver), and the 6 driveshaft attachment bolt holes are on different bolt circle as well. We pulled the flange off of the base GT axle assembly and swapped it in place for the new aluminum unit.


                  Installation is relatively straight forward, but not exactly easy. We had the rear exhaust out of the way for a muffler change, and it helped to have this extra access. Next you disconnect the axle at the diff, then go to the rear uprights. Undo the upper mounting bolts at the upright and let them dangle on the lower mounting points, which allows lateral room for you to "pop" the rear axles out of the diff housing.

                  Then secure the diff housing with a trans jack and partially drop the subframe - loosen the front two mounts and remove the bolts from the other two, then drop the rear down. This lets the rear cover of the housing clear the back of the car and come out. Installation is the reverse of this. We did this twice, as we found the diff flange issue buttoning up to the driveshaft the first time. Fun.


                  We have had 5 different rear shock setups on this car in the last year, including the inverted Whiteline/AST coilover units (once) and the inverted MCS coilover rears (twice). One time we must have had the shock and spring slide a hair too close to the right rear CV boot on the outer part of the halfshaft, and it nicked it... a little grease was starting to come out, so I pushed to repair this boot before it lost all of the grease and failed.

                  No worries - we just ordered a new CV boot kit from Ford. Had to get it over-nighted from Detroit, but how hard could it be to replace? Evan was a Toyota tech and has replaced 100s of CV boots in the past...

                  To get the new boot over the internals you have to cut the old boot off, take the joint off the shaft, and slide it in place, reassemble the joint, and push the boot into place. Its a 1-2 hour deal, normally. But this new boot was made of some VERY INFLEXIBLE rubber...

                  I was busy doing something and checked in on Evan and Brad,who were fighting this new CV boot. They had made a pair of "spreader" tools, tried the heat gun, but nothing worked. This CV boot would not go on.

                  Evan called a technician he knew who worked at a Ford dealer, and he said "Oh we don't ever try to replace those boots! Impossible to get on. Just toss in a new axle!" We checked, and sure enough, the new rear axle is only about 3x the price of the dang boot kit. And it just goes right in....

                  PRO TIP: DO NOT EVER TRY TO REPLACE A REAR CV BOOT ON AN S550! JUST BUY A NEW HALF SHAFT. The additional labor of replacing a CV boot is more than enough to offset the difference in cost on the parts.

                  MONITORING DIFF TEMPS

                  Now that we have engine oil temps under control (never see more than 220F now, used to touch 300+ when it went "into the red") we can make more than 3 laps in a session. The Mishimoto oil cooler was a life saver there.

                  The differential fluid temps shown below are from the the January 2019 NASA event are still a bit frightening. The diff temp gauge only goes from 100 to 250°F, but often "sits on the peg" after 4 or 5 laps, so we don't know really how hot it is getting. We will see if this aluminum housing can shed heat better than the iron housing, but I suspect we will see a diff fluid cooler in the future on this car.

                  CARBON FIBRE!

                  With the rear axle built with the new gearing, housing and Auburn Pro diff, plus the drive flange and right rear axle replacement, we could move on to some other upgrades. We ordered this shiny carbon fiber hood from Anderson Composites in January and it arrived (along with a GT350R replica rear wing we will install later) after we got back from the MSR-H NASA event.

                  These double-sided hoods are real carbon-fiber replicas of 2020 Mustang Shelby GT500, with fully functional hood vents. These will work with factory hinges and latches. This was shipped via freight truck and was very well wrapped in foam inside of a big shipping box. The hood was bolted into the box via the threaded mounting bosses. This is a double-sided carbon fiber hood, no fiberglass, with a glossy gel coat to give it some UV protection. We plan on painting this but not for a few months.

                  We weighed the stock aluminum hood at 41.2 pounds on our 2018 GT and this carbon hood weighs only 27.3 pounds. That gives us a 14 pound weight savings without any of the compromises of a Motorsports level dry carbon hood (which has to use hood pins and must be clear coated, painted, or wrapped). The glossy gel coat looks good, is super smooth, and should withstand the elements - but a clear coat or layer of paint never hurts.

                  This carbon hood has a fully-finished underside layer with enough structure in place to mount the factory hood hinges, latch, and prop rod - but Anderson recommends not using any aftermarket lift struts. This hood features a large 19 x 26-inch louvered vent totaling 3.43 square feet for heat extraction and reduced front end lift. We have both the 2015-17 and 2018-19 versions of this "GT5" hood listed on our website.

                  The video above is a quick walk-around showing the fit and finish of this hood, and how it was installed. We spent 30 minutes bolting this on and tweaking body gaps - no joke. So much easier than the 8-12 hours of bodywork most aftermarket composite hoods for these cars need to be installed.

                  PP1 LOWER LIP + PP2 SPLITTER

                  As I have said many times before, our base model GT is missing many of the performance tweaks that come on the Performance Pack 1 or PP2 optioned Mustangs. Radiator, Torsen, 15" brakes, and on and on. Well we found another thing that was missing - the slightly larger PP1 lower lip.

                  As we investigated what it would take to install the PP2 "extended splitter" we found that we needed to order the PP1 lower lip, among other parts. We had seen many forum posts as to what the 2018-19 GT PP2 splitter required and found all sorts of parts numbers, many of which were wrong or incomplete.

                  So we ordered the lower lip and installed that onto the front bumper cover - which is luckily the same as the PP1 and PP2. Next up we noticed the undertray was all wrong...

                  We noticed that the base GT undertray would not line up with the PP2 "splitter", so we ordered the PP2 undertray next plus a bunch of new hardware.

                  This PP2 "splitter" piece is supposed to go on with plastic rivets, but we used nuts and bolts instead, to make it easier to remove later (which we might do if we have a "TT2" splitter).

                  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


                  • #39
                    Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                    continued from above

                    Next the PP undertray was installed, but then we noticed more parts that were different. This "rear" section of undertray no longer lined up from the base car, so this steel brace and a completely different shape rear panel was ordered. The various hardware we ordered earlier all finally arrived and all of the PP1 and PP2 parts from 6 different orders (including some mistakenly ordered parts we sent back) were finally secured properly. Whew!

                    This work shown took place over several weeks, of course. This is what the undertray and PP2 splitter looks like in all its glory. We might offer all of this as a kit for other base model 2018-19 GTs - it took a lotof research and trial and error to get these parts that worked together.

                    Brad noticed that the molded in "tunnels" in the flat PP undertray piece did not line up with the base GT fender liners. That is because the base GT had the goofy INVERTED HAT FRONT ROTORS, which cannot flow any air through them to cool for track use. He trimmed the plastic fender liners to fit with the tunnels, which can now route air to the front brakes. This is a key upgrade because we want to test a new brake cooling technique that doesn't use any hoses. More on that side-by-side track test and data in a later post.

                    Last but not least, you can see the newly replaced 4" brake duct hoses that went in after the failed experiment with 4" oval stainless sections, which were removed. Sure, the hoses get a bit squeezed a small amount at full steering lock with 11" wide front wheels, but it just "is what it is" for now. The stainless tubes restricted steering so badly that one ripped off the car.

                    I'm happy with how this turned out, just wish it would have been easier to piece this PP2 splitter/undertray package together. This will be our front aero for classes that restrict splitter sizes or only allow "OEM option packages", like SCCA CAM-C or Optima GT class - both of which are on our schedule for later this year.

                    Of course this is still a bunch of plastic, and won't offer a lot of real front downforce. I'm hoping the GT500 style vented hood will help this PP2 stuff make more than the "24 pounds of downforce" Ford claims. The lower plane of the PP2 splitter is still way too high off the ground - we barely need any ramp to get the car in the trailer.

                    Look for a longer, more substantial, reinforced "real" front splitter later this season for TT2 use. This car might not ever make the power-to-weight limit for TT2, but we're damn sure going to make some proper aero to try to close the gap!


                    Speaking of things that come on the Performance Pack GTs... the PP 15" brakes are a huge improvement over the inverted hat 14" brakes that come on the base GT or Ecoboost Performance Pack cars, especially the base Ecoboost and V6 brakes. We have talked about this here before, and until now we only offered the 380x34mm Powerbrake big brake kit. That just isn't in everyone's budget, so we did some research, checked a number of new sources, and put together our own version of the PP brakes for sale. This Ford based kit we assembled is heavier than the Powerbrake BBK, but the price is significantly less.

                    When Ford built the S550 they tried a new technique for the rotor design on the front and rear, in all sizes: the ridiculous "inverted hat" rotor design, shown above left. Initially both the 14" and 15" rotors had this "no way to cool" design, but an engineering team at Ford led by our friend Marco proved the inverted hat design can not work on track. He has reams of test data to back this up. We talk about a lot of that in this forum post.

                    The track worthy solution he pushed through, at least for the 15" Performance Pack brakes, was to go back to a conventional rotor design as well as some tunnels in the undertray and cooling deflectors. This all happened right before the S550 was released, and some of the inverted hat 15" parts are still floating around out there. We accidentally got a set of brake backing plates from these backwards 15" rotors when we were putting together our 15" 6-piston Brembo upgrade kits - which we showed Marco and he got a good laugh at seeing.

                    After ordering a variety of parts to see what worked together best, we put together our version of the 6-piston 15" Brembo kit for the 2015-up non-Performance Pack cars to get the maximum benefits of that testing and development. If you have the inverted hat brakes on your S550 Mustang and plan to do more than parade lap pace on track, you will want to look at this upgrade. After camber adjustment, this should be the next track upgrade on your list. Our kit even includes the required master cylinder (one for manual, one for automatic), unlike the Ford Racing M-2300-V kit that is priced higher. And we use all new, Ford-sourced parts.

                    Of course you can still get these brakes hot on track, so good track pads, track rated brake fluid, and even brake cooling is still a good idea. If you can see the rotors glowing, they are getting hot enough to cause trouble! Nobody likes "losing the brakes" on their car on track, most of all me. We have brake cooling solutions for the S550 15" PP brakes and the 21 pound lighter 380x34mm Powerbrake option for this chassis, of course.


                    The Magnaflow "race" exhaust has been on this car since the beginning and was the only mod when we got our "baseline dyno" pulls last year. It fit great, sounded great, and had provisions for the optional exhaust bypass valves (which our car did not have).

                    Once we installed the long tube headers the sound got to be a little bit much. This thing sounded like a full blown race car at the January MSR-H event, just minus the full blown race car lap times.

                    I took some measurements of the existing exhaust and back of the car and found the biggest Magnaflow mufflers in the same 3" tubing diameter.

                    After many years of testing this theory we know how much muffler case volume works in knocking down decibels of sound, but the right style not only keeps the same power level it usually ADDS power. This Magnaflow 12249 part has a straight through design you can stick your arm through, but more batting inside. We mocked them up and they fit, as long as I was OK with losing the two exhaust tips and the space needed for the bypass valves (which this car doesn't have).

                    I was worried that the larger muffler would add a few pounds... nope!The smaller case "race" muffler was heavier when you added in the twin tips and the straight pipe adapter for the bypass valve. The new setup was 9 pounds lighter.

                    The installation was a bit custom, with some cutting and welding. I snapped this shot while the muffler was being welded in - the arc light inside shows the straight through muffler design.

                    These were welded in and some brackets were added to line up with the factory mounts on the chassis. We went without any tips and just have the muffler cases stuffed up into the back of the car. The first time they fired up the car.... WOW! So much quieter! I've driven the car with this setup at another track event and an autocross, and at both events had people come by and ask "What have you DONE to this car?! It sounds amazing!" And it really does. Very happy with this, and we will see soon if it made a small improvement in power.


                    One of the best improvements on the S550 chassis over the previous generation S197 Mustang, is the double-ball joint front suspension. This was lifted straight from the BMW playbook, but it works. There are some big rubber bushings in this suspension, especially the forward hydraulic bushing in the front location (see below right).

                    Just like on the S197, this one hydro bushing is there to reduce NVH transferred into the cabin, but it allows for a lot of deflection under braking and cornering. We worry about replacing this one with polyurethane, as it might bind during travel. This bushing needs to move freely in 2 axis...

                    Our friends at SPL Parts have two products to replace the front lower control arms. Their S550 Front Tension Rod kit includes the replacement arm that gets rid of the massive hydro bushing, replacing it with a spherical. This arm is also adjustable in length and has geometry correction at the spindle side (with a spherical and adjustable height pin).

                    This went in with ease and gives some caster adjustment and other geometry corrections. Removing that massive hydro bushing is key here - and replacing it with high end spherical bushing in that location.

                    The other SPL Parts kit is the S550 Lower Control Arm kit, which is the lateral piece of the 2 arms. This arm gives additional camber adjustment while also replacing rubber bushings with sphericals - and giving adjustable geometry.

                    With both arms in place we have removed a lot of rubber and hydraulic bushings, added lots of adjustment, fixed some geometry that gets altered when lowered, and... lost some weight?

                    Looks like these are 6 pounds lighter per side, so we lost another 12 pounds with these parts. Not a huge amount, but the small weight drops from this round of changes is adding up.

                    The rear suspension link and swaybar end links above are new, and SPL sent these to us to test. They have been by our shop and at the track measuring some things on our S550, plus we loaned them a rear subframe and complete set of S550 rear control arms. Look for some additional prototype SPL parts on our car for more testing later this season. I will give my first hand impressions of these after an autocross and TT weekend in the next update.

                    WHAT'S NEXT?

                    This update ran long but we covered our first 2019 competition event and a huge array of new parts added. Next time we will cover two more events where we get to test all of these upgrades (on track and autocross). I will show the new weight of the car - which was lighter than I had calculated, and that made moving to TT3 impossible with the Hoosiers.

                    We also added a few more things to this Mustang, such as the Mishimoto radiator. We have pictures of our production S550 and S197 seat brackets, some new prototype clevis style rear shock mounts (requested by one of our shock manufacturers), and some other bits and pieces.

                    Thanks for reading,
                    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


                    • #40
                      Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                      Terry, any chance you’d share the offset for the Momo RF-20 19”x11” wheels and if the fronts require spacers with your spring setup?


                      • #41
                        Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                        Originally posted by zirfj312 View Post
                        Terry, any chance you’d share the offset for the Momo RF-20 19”x11” wheels and if the fronts require spacers with your spring setup?
                        We get this question a lot, and I guess it cannot hurt to ask, but we don't share our custom wheel offsets. We can sell you the wheels to fit your car, and we have a set of RF-20 in 19x11" in stock for the S550.

                        These offsets have been gained from many years of testing, measuring, and ordering wheels for our cars. It is no accident that our wide wheels fit these cars the best - we put in the homework.

                        This work helps us perfect the offsets so that our wheel customers get wheels that fit without the use of spacers, without "poke", without interference with suspension components... we even have some tricks that we share to maximize wheel and tire room.

                        Again - this is a business, and part of our "value add" to get customers to buy wheels from Vorshlag is doing the research and perfecting our wheel sizes, unlike some of our competitors who just copy other peoples' wheel offsets.

                        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


                        • #42
                          Re: Vorshlag 2018 Mustang GT + S550 Development Thread

                          I totally understand and appreciate your response and honesty, you’ll have a customer in me as soon as I get my suspension sorted and it’s in the budget. Appreciate this thread as ‘inspiration’ for what I plan to do with this car. Thanks again.


                          • #43
                            Project Update for July 25th, 2019: I originally started writing this update in April for a release in mid May - then about a day before I was going to post this update there was a change on our host server which knocked out the forum. This turned into a 2 month outage, major server upgrade and migration, then a new version of vBulletin software, and other fixes. I am going to cut this release in half and get out what I can quickly. This round will cover 2 more competition events and the associated changes we did between them.

                            These events two include Texas Region SCCA autocrosses at two different sites, where Amy and I both drove the 2018 GT and both did pretty well. Running the Mustang in CAM-C on 200TW street tires is probably where this car is best suited, and it also prepares us for the autocross portion of the Optima event at NCM in early June.

                            There was a NASA event in May at COTA which I was going to cover, but I ran out of space. Instead I will show installation steps on a few items we added plus a weight analysis of weights of this 2018 GT - which has gone up and down.

                            We added a quick release handheld fire extinguisher, Aerocatch latches to the carbon hood, tested a hood "buffeting" fix, added a new S550 Mishimoto radiator, and tested and learned a bit about AiM SmartyCam data integrated video. Let's get started.

                            CHASSIS WEIGHT CHANGES OVER TIME

                            Let's look at one of my favorite data points for any car - the weight. Dropping weight is universally seen as one of the best places to gain performance in the Motorsports venues we like to do. We usually compete in some sort of power-to-weight restricted class, and the lightest weight isn't always what we need to shoot for. Getting to some weight also has compromises we are not willing to make - at least on this 2018 Mustang, which we plan to keep only 2 years. For the first year (2018 model) we ran this car in NASA TT3 class, which has a 10 pounds per average whp limit. We were skirting near that limit early on, with some heavy OEM bits on the car and bone stock power levels.

                            2-23-2018, factory stock, very low fuel, spare tire removed, low fuel, 3645 lbs

                            This is where we started, and of all of the weights shown it has the lowest fuel level. I try to weigh cars with ZERO fuel, as it is easy to calculate that "up" to compare. But as we found out right after installing real tires and suspension, these cars will FUEL STARVE BADLY on a road course in left hand turns, so we almost never let this Mustang get below 1/2 tank of fuel. On Hoosiers I top off the fuel before every session on track - it starves that badly. But here, on the super janky 235mm M+S tires the base GT came with, grip was not high enough to worry about fuel starve. I ran it low on fuel at the first track test. Stock 18x8" wheels were skinny but HEAVY, and the 14" 4-piston brakes weren't exactly light.

                            9-13-2018, 3/8 tank, with 4-point roll bar (58 lbs), no passenger seat, 3607 lbs

                            This is 6 months after buying the car and by then we had done a good bit of updates to this Mustang. I don't seem to have a weight of this car on the 15" 6 piston PP brakes, as they were on the car for only about 6 weeks before we got the lighter Powerbrake motorsport brakes on the car (as shown above). I'm going to point out that this is only weight taken with ONE seat, and its the Sparco composite unit at that. Keep that in mind when comparing with all other weights here, which all have two seats installed. Here we have the roll bar added, which is 58 lbs, but the rear seat bits removed (62 pounds) makes that about a wash. Magnaflow mid-pipe back exhaust replaced the OEM bits. The Powerbrake 380mm 6 piston bits replaced the HEAVY 15" PP brakes (21 pound drop).

                            1-24-19, over half a tank of fuel, 3711 lbs empty and 3936 with driver + gear

                            This was the heaviest the car has weighed to date (as well as me!), but we had added a lot of big parts to the car at this point. The oil cooler, gauges, strut tower brace, and the 2nd seat (40+ pounds with side brackets, base bracket, and harness). I didn't expect the car to sneak below this weight any time soon, so all of my TT3 plans for 2019 had this weight as the basis...

                            3-19-19, 1/2 tank fuel, 3626 lbs

                            Well, I was wrong - the car got a bit lighter before the March NASA event. Crap, I was not expecting the car to be lighter than before, but we had added a carbon hood, new "bigger" mufflers (which dropped weight), the aluminum diff housing was lighter, and the SPL Parts control arms, the long tube headers, updated mufflers, as well as a few other bits that all dropped weight. Losing 10 pounds here, 14 pounds there, and pretty soon it was 85 pounds lighter. That, plus the nice bump in power added after the long tube headers/CAI/tune pretty much wrecked our chances of staying in TT3 class. Changing classes mid-season is never a good idea, but we had to.

                            This car has moved from TT3 (left) to TT2 (right) and it is staying there, where it is 300 lbs too heavy

                            After this new weight and power level we moved to TT2 - where the car is 300 pounds overweight. Sucks, but the car just ended up stuck in a zone clearly "between two classes". For reasons that will become apparent in a later post, I'm not willing to A) cut the car up to try to find 300 freagin pounds, B) not going to add a LOT of ballast to run TT3, or C) drop a LOT of that power to get back as well.

                            This car was always planned to be a two year development mule for us - we plan to "de-content" the final version to an easily sell-able setup and recoup as much as possible "next year". This car has helped us test and develop a LOT of S550 Mustang parts, but ultimately its still a full weight street car that has more value than a cut-up race car. I talk more about this next time.

                            MISHIMOTO RADIATOR UPGRADE

                            At this point, the heat issues we had seen on track for the first year of use were already fixed - it was all in the base GT "oil pre-heater" and the funky electronic grill louvers (that don't come on the PP cars). With the Mishimoto oil cooler we could extend our stints from 2-3 laps at a time to "run the whole session". But we still haven't run this car with the aftermarket oil cooler in a REAL Texas summer yet, so we went ahead and invested in a larger Mishimoto aluminum radiator. We had excellent results with the S197 Mishimoto radiator in our 2011 GT and I figured, why not? Cheap insurance.

                            Wow, that picture says a lot. We always like taking this "side-by-side" shot of the OEM radiator vs the larger Mishi unit. Now the base model GT has a smaller radiator core compared to the Performance Pack GT unit or the Shelby GT350, of course, but the up-sized Mishi unit absolutely dwarfs the base OEM radiator. You can read more about the specs on this S550 Mishimoto radiator here. We recommend and sell this unit for all tracked S550 Mustangs.

                            Brad started by draining the factory fill of anti-freeze and water. Now we always try to get that slick stuff out of a radiator whenever its a car that doesn't see harsh winters or sub-freezing temps, which fits this car (it isn't daily driven like some dual-purpose cars). We went back with distilled water plus Motul MoCool additive. If we have a coolant leak on track this mixture won't be an oil slick like anti-freeze would.

                            After the coolant was drained, the cold air tube and coolant reservoir were moved out of the way. Then the plastic upper radiator cover is removed, then the upper mounts can be unbolted from the black fiber-reinforced-composite radiator support. The radiator hoses are disconnected and the electric fan assembly removed from the top.

                            The new unit fits in place of the smaller stock unit. The upper metal cover from the Mishimoto oil cooler kit was adjusted slightly so that the seal mates up to the front of the new, thicker Mishimoto radiator.

                            The radiator fans are installed, the radiator hoses connected, and the upper radiator mounts go back in place over the mounting pins on the larger radiator. It all fits like stock, even with the big increase in size. The cold air and reservoir are reinstalled, as is the upper vent line. Then the upper radiator plastics go on (below).

                            At this point it was time to fill up the cooling system with distilled H2O and MoCool, then we went through a start and warm-up phase, to let the thermostat open up, then keep topping off the coolant with the cap removed. Many shops like ours will have a pressurized radiator fill rig like this, which makes this a much less time consuming procedure.

                            At this point we were done with any updates before the next event - an SCCA autocross. We slapped on some "CAM-C" class letters, loaded up the car into our trailer with the 200TW tires installed, and got ready to head out to the SCCA autocross.

                            SCCA AUTOCROSS, LONE STAR PARK, MARCH 24, 2019

                            This event was only the second time I have autocrossed this car in the 2 years we have owned it. Amy and I used to do 10-15 autocross events a year for nearly 2 decades, but now I'm lucky if I do two events a year - my last autocross event was April 2018 at the Optima event at NOLA.

                            I have run at this Lone Star Park (horse race track) parking lot many times over the past dozen years, and honestly, its one of my least favorite event sites around Dallas/Ft Worth. There is some elevation change - which is good - but the surface is aging and coming apart, there are many massive bumps, and plenty of light poles. All of this makes it very difficult to design a course in advance (there is a committee that has to see a course map and approve it) without some part of the course going over the bumpiest sections.

                            And no matter how you lay it out the unsealed asphalt top surface "comes apart" after just a few runs, which makes a very narrow clean line but piles of gravel just off line. There's also a tendency in this region to design courses that massively benefit very narrow cars (Miatas) where some sections are straights for some cars but offsets for the wider cars like the S550.

                            Event photo and video gallery:

                            Even when driven VERY well, a wider car is not going to do well in raw time or PAX factored times here. Due to the course being adjusted during the morning runs to miss the really deteriorated sections, the 180° turn-arounds in corner station 3 and the other in corner station 5 were pinched even worse than the map shows - to the point of being painfully tight. Its just the nature of this site - its hard to make a "new" layout here without that sort of impact.

                            Luckily we already knew this site was bumpy and we raised the ride height before this event. Glad we have GOOD shocks, but we would have benefited from a softer spring setup here. There were 3" and taller humps we had to take at speed, and the softer sprung CAM cars probably had a slight advantage there. We unloaded the car from the trailer, then walked this "Jekyll and Hyde" course - the first half was nice, flowing, easy to see, and fast. The second half was an evil monster made to inflict pain and suffering. Super tight, visually obscure, and with the 180s that damn near took full steering lock to navigate in our car.

                            We ran the 4th and final heat, which meant the very edge of the driving line in every corner was all gravel. If you step off the "common denominator" driving line you're going to hit those marbles and go wide. Which I managed to do on every single run, yay. Always felt like I nailed the first half of the course, but the "exercise in restraint" for the second half just never came together for me. The one run I made that actually felt pretty good, the timers didn't trip (got a rerun).

                            The new 4.09:1 gearing worked out perfectly for this tight course, and the new Auburn Pro Limited Slip was letting the rear tires really dig out of corners. For the first half of the heat I was in 1st and Amy was in 2nd, but I never felt secure - one of the local hot shoes (the regional exec, Matt Lucas) was hitting cones but running faster raw times. He moved ahead of me into 1st for a bit, then I bounced back into 1st briefly, but eventually Matt found a lot of time in a later run and took the win.

                            It has been a year since Amy had done an autocross, and the seat isn't really setup well for her shorter stature. We borrowed some seat cushions and got her sitting higher in the seat, which helped. She was fast right out of the box - a multi-time SCCA National Champion like her never loses this skill set completely. She hung in 2nd for a bit but struggled in the tight bits and fell back to 5th in the 16 car CAM-C class.

                            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


                            • #44
                              continued from above

                              The video above is my 4th of 5 runs, which at the time was good enough for 2nd place. I felt good about the first half of the course, really attacked those sections. I was struggling to get the braking points down in the very tight 2nd half, slipped into the gravel in two spots, wrecking the run. I never hit a cone all day, but never nailed the whole course, either. Frustrating.

                              Amy's 3rd run was her best. She ran almost the exact same time on her 4th run and found a half second on her 5th, but caught a cone. She was pretty happy for her first autocross back in well over a year, especially considering she could barely see over the dash.

                              As you can see, the CAM-C class was made up completely of late model Camaros and Mustangs. There were five 6th gen F-body 1LEs entered, and some of them were pretty hotted up. I guess we should be happy with 2nd and 5th, considering the lack of autocross events we have done in this car. Other than the ride height change and one shock adjustment, this is exactly how we run the car for track events.

                              Left: 3-4-2018 (stock suspension & 235mm M+S tires). Right: 3-24-2019 (coilovers + bars + 305mm tires). Car has come a long way in a year!

                              Its interesting to see the "attitude" difference of this car from the bone stock (above left) and current setup (right). That 3-4-18 event looked pretty painful. These S550s are VERY soft in stock form, and the base GT tires are laughable. We've added a good chunk of power, grip, roll stiffness, spring rate and damping since then.

                              We had fun, even considering the course frustrations and lack of a win. Rain held off so the weather was partly cloudy, windy, with a high of 79°F. Beat sitting at home on the couch! 165 cars that day, but a lot of reruns, DNFs, and stoppages - made for a long day. We need to hone our autocross skills a bit before we go to another Optima weekend, so I'm glad we did this one. We will work on the seat tilt angle so Amy can see better, stick to the local event site that is less janky (TMS Bus Lot), and do some more local autocrosses later this year.

                              AIM SMARTY CAM TESTING

                              I am always taking in-car video when we run on track or autocross - this is both to chronicle what is going on in the car for these write-ups, but also for me to use to LEARN TO IMPROVE. Seeing the video, the data overlay, and even watching my hands and where I'm looking helps me improve. And while many of you love GoPro camera, I have had some pretty poor results with these. Also, the "phone apps" for lap timing are generally not very accurate - whereas we have had the 10Hz GPS driven lap data from our AiM within a couple of hundredths of a second of the AMB timing loop, which is what every racing group uses for competition lap timing.

                              The videos from the autocross event above were not particularly good, especially the audio. We really have to run an external microphone with a "dead cat" noise sock on it to get clean audio on a windy day (see below). I was lazy that day and didn't bring the powered external mic, and it shows. Every time a gust of wind blows sideways into the cabin from the open windows, the on-board stereo mic on the Sony just explodes with noise, which I tried to edit out for these videos.

                              Always use an external mic with in-car video, it is 100% better sound quality. I like mounting them down by the center console inside the cabin - that way the wind buffeting is minimal, you can still hear the engine noises, and also I can somewhat narrate the runs in real time. It seems nuts, but I am used to having "conversations with the camera" as I'm driving, which helps me remember what was going on, rattle off temp data, etc. Many folks mount their mic behind the rear of the car, out of the direct wind and with the mic pointed at the exhaust - that works, too. I just bought another non-powered external mic (Rode Micro, shown above left) and test that also (The Boya powered mic eats a 9V batteries - one more thing to remember to charge/replace).

                              The Sony HD video camera we have been using the last 3 years (shown above in the bottom right corner) normally takes excellent video and audio, but the wide Field of View lens (which distorts the edges of the field) means it only captures good in-car video if you stick it right next to the windshield. Stick it behind the driver and only about 25% of the video image is of the forward view outside of the car. Wide angle lenses kind of suck for in-car video when you place it behind the driver.

                              Mounting it close to the windshield is tricky, but we built a special RAM mount on the FR-S where it can sit "right side up", above left. This is normally where we have Amy's cell phone holder, for street use in that car, and we swap in this vidcam for track events. We just added that type of mount to the Mustang and the video is complete garbage - too far from the glass? Don't know.

                              I will show some of this video from Optima @ NCM next time taken with this new "right-side up" dash mount, but it was not very good. When using this vidcam with a suction cup mount and running the camera "upside down" means I have to flip the video and re-render before I can bring it into Race Render, to merge it with data. Then it goes back for a 3rd round of edits and another render in my video editing software once the data is overlaid. Real time killer... I usually spend 90 minutes to make a 3-5 minute in-car video. It didn't help that I had a dead CPU fan for almost a year, which crippled rendering times (just fixed that - and my PC is 5x faster rendering)

                              I've also wanted to get back to a "roll bar mount" camera location using a "narrow" Field of View lens. My previous Sony vidcam (2012-2016) worked pretty well, and even had a nice wired remote (with indicators for on/off, recording, etc), with a narrow FOV and a real adjustable lens. The quality from that 7+ year old 1080P vidcam started to look pretty dated, and the lack of a external mic was a real killer. Now that the 2018 Mustang has a roll bar (like we ran in our 2011 GT) it is time to install the I/O Port vidcam mount behind the driver, get a modern vidcam with a narrow FOV lens, and finally be able to see what the idiot driver is doing as well as a good view out the front.

                              If you have been following my build threads for the past 8+ years you will have seen that I don't drive on track without my AiM Solo. I have two of these units, the $399 SOLO (my loaner/spare) and the $799 SOLO DL (which can read data via OBDII or CAN). There are newer units called the SOLO 2 & SOLO2 DL, but they don't have a lot of new features (and they shipped with a few bugs). Again, merging the captured data to the video is a bit of a pain in the ass, and its something that gobbles up time after every event. I've also never data logged any autocross runs (until recently), but I knew it was possible with the AiM SOLO and a custom course setup for the day (walking the course to "set" the GPS points for a separate start and finish).

                              The obvious answer to all of these issues - if you ask anyone online - is the AiM SMartyCam HD. This $1000 camera can "talk" to the AiM SOLO (as well as AiM's other data logging digital dashes) and merges data and video real time. It also auto-starts and auto-stops, well according to the literature. We have sold and installed a number of these for customers, so I figured it was finally time to test this on the Mustang.

                              Crucially, I have never personally setup/used/tested one of these SmartyCams with an AiM or digital dash. This is how these two devices are supposed to be connected together and to the car. I have the OBDII/CAN wiring cable, and the SmartyCam came with the 5 pin to 7 pin AiM cable needed to connect to the SOLO DL. So now I need to learn to use these two devices for future videos - how hard can it be?

                              I thought I knew the array of AiM software that was needed, but I was wrong. There is Race Studio 2 and Race Studio 3, SmartyManager, Race Studio Analysis, GPS Manager, plus some software I have used just for AiM firmware updates. Over the years AiM has killed off some of this software, but they never really remove it from their website, and still have YouTube videos up that show how to use them. One of these was SmartyManager - something that crashes immediately when you use it on Windows 10 with an SD card connected (that is configured with the SmartyCam). After a few hours with I got it to work, but it was pretty limited, and the auto start/stop had major issues when tested at an event.

                              Don't use the SmartyManager software - it is obsolete junk!

                              After using the out-of-the-box SmartyCam config setup at an event (an autocross you will read about below), I worked on the setup of a "custom data overlay" for the merged data. You do this by using the SD card associated with the SmartyCam. After fumbling around looking at a bunch of dated videos from AiM, I finally figured it out (trial and error). Connect the formatted SD card (not the SmartyCam itself) to your computer, then run their Race Studio 3 software.

                              Once you are in the right software package (RS3), and it recognizes you have a SmartyCam formatted SD card connected, then you can create the data overlay, move the data readouts around, add a logo, etc. The auto start/stop bits are setup in menus on the SmartyCam, which I am still learning how to use. Of course I setup all sorts of things and almost none of it shows up when I use the unit.

                              Crucial tip here - these AiM video cameras usually come with a 4GB SD card. Throw that card away, as it will fill up in less than 60 minutes of use (ask me how I know). The SmartyCam ver 2.1 supports up to a 128GB SD card, so buy a Class10 or better (how fast it can write) name brand card. $25-30 will get you a good one. That 128GB card should hold 32 hours of video + data, so you won't fill it up in 3 track sessions like I did. The camera won't tell you its full, of course, it just won't record anything.

                              Using the on-board SmartyCam mic is a mistake - its hot garbage. I had to buy a special $80 cable from AiM to use a remote mic ($30), which is the same 5 to 7 pin cable as before but with an external 3.5mm mic pig-tailed off of it. This lets me use a dedicated external mic placed where I want it. The on-board mic on the SmartyCam is total TRASH - as you will see in my videos from COTA below. Of course when I went to test that it didn't work - no audio whatsoever. And if the configuration of the SmartyCam isn't just perfect, and you have the Solo DL data logger connected to the camera, the DL won't log ANY data.

                              Can you sense some frustration here? Yes, I have lost video and data from a number of events testing out the $1000 AiM SmartyCam. The video I managed to get had garbled or no audio, and usually no data, or started at the wrong time, or ended early. At best - when it all works like it should - you will see 720P video. That's 10 years or more out of date, yet this is their latest, greatest, $1000 camera. Somehow many people do manage to make this work - I probably need someone who has gone through these painful lessons to come fix all of the weird config issues I am having.

                              For the past 2 years I have only had the generic "OBDII data" from our 2018 Mustang. This is limited in scope, slow to transmit (data lags about a second, sometimes more), drops comms often (OBDII data seems to go away and come back several times per lap). AiM has to create a CAN protocol for each ECU, and while the S197 units had a CAN proocol, the S550 did not until very recently. During some online frustration rants in the previous weeks, someone informed me that there is a new CAN protocol for the 2015 Mustang, finally. This adds 8 more data channels (4 TPMS + 4 wheel speed sensors), and hopefully using CAN now all 15 channels are faster and more reliable than OBDII. I will configure that and try this at a future event.

                              I will keep working with these AiM software & hardware gizmos at future events and hopefully I will be able to get better videos with data overlays that are easier to edit, without all of the extra time spent merging data/video, or the other limitations. The idea of an auto starting / stopping camera that logs data and overlays it in real time is appealing, just have to work through a lot of hardware and software teething pains. Out of the box it is a bit of a mess, and at best we will have lower rez (720P) video, which does not thrill me. And before anyone says, "Maybe its you, homeslice!", you might be right.

                              SCCA AUTO-X, TMS BUS LOT, APRIL 28, 2019

                              We loaded up for another autocross, but this time at Texas Motor Speedway's "Bus Lot", which is a smooth, flat, sealed asphalt lot in excellent condition in front of the Texas Motor Speedway tri-oval NASCAR track. We got there at around 7 am, stopped at Buc-cee's to get breakfast and fuel, planning on running the Mustang a low on fuel as a test (1/4 tank). We drove through some rain on the way to this event, and we thought that was all of it.

                              Video and Picture Gallery:

                              Got the car unloaded, then teched, then it rained for about half an hour straight. Yuck. This sealed asphalt site is very slick in the wet, but I've autocrossed ~20 times here in the wet and always do well in this stuff. Normally, though, it rains briefly then dries out before some heats run - and luckily it dried out right as we went to grid for fir first heat.

                              Amy and I drove the Mustang together in the 15 cars in CAM-C, which ran in the first heat of four. This meant we ran first, worked third, and could leave during the fourth heat if we wanted. During the 2nd heat we went to lunch across the highway, and lately there are a lot of great places to eat that cropped up.

                              And you might have gathered from the course map, the course was very busy with some extremely tight turn-arounds once again. Luckily in the past 18 years I've run every manner of course layout here, so this course looked somewhat familiar. The speed we could hit on some straights was more than 68mph, as I was riding the rev limiter in 2nd gear on my first run. I started up-shifting (short shifting) to 3rd gear in one section, and it was worth the time to up- then down-shift.

                              The 4.09 rear gearing with the 2018-up MT82-D4 trans gear combine to be less than perfect for autocross, but damn if it ripped out of the tight corners well. It does works very well on a road course, so I'm not going to complain. As you will see in a future post the 4.09s work REALLY well for shorter course (like Optima autox + speed stop).

                              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


                              • #45
                                continued from above

                                The ambient temps were low when we started, in the mid 60°F range, but the sun was out so by the end of the first heat it was 82°F. The track surface temps climbed rapidly, and I felt like the grip on the RE-71Rs fell off on my last couple of runs. With 2 driver's running almost back to back over a total of 10 runs, we should have probably sprayed the tires to cool them on those last couple of runs. Too hot to touch. Still not sure we made the right call to "let em get hot". Hell, I just don't have enough autocross seat time in the last 3 years to know exactly what these Bridgestones "like" on a heavy car like this. Most folks let em just boil.

                                We started the tires at 28 psi cold then bled them down to 30 psi hot - which felt fine, but might not be the ideal settings. We really need to do a proper autocross test day to learn what these RE-71Rs work best at on this car for low speed events.

                                As you can sort of see in the video linked above, 2nd gear was almost ideal everywhere here. I used the out-of-the-box SmartyCam setup with the AiM SOLO DL connected, using a custom start-stop track location I set for this course. The problem was the auto-start delay on the SmartyCam must have been 20+ seconds long, so the first HALF of the run didn't record (on all 10 runs). The data overlays were also super crude, with the default overlay settings, and the audio was the on-board mid, which is junk. I was still learning a lot at this point.

                                Our alignment settings of -3.5° Front /-2.2° Rear camber and 1/8" toe out Front and 1/4" toe-in Rear felt GREAT. The stiff road course spring and shock settings worked fine as well - didn't touch a knob, just kept tire pressure stable at 30 psi. The handling overall was REALLY good - the turn in was super fast, car liked to rotate, and I had ZERO complaints. I hope we can replicate this "feel" in any autocross car we ever build again, wow! Acceleration, braking, slaloms were just spot on. Absolute driving perfection.

                                I have always liked running at the TMS Bus low, with its clean, smooth surface. Even after running here so many times before, it has been a while, so it was nice seeing some of the "rust" come off my autocross skills. From pictures I can see that I was putting the car an inch or so off the base of most cones, still with 2 of my 5 runs getting cone penalties for a bit too aggressive placement. My 3rd run was my quickest, and I won the class only by a tenth - with virtually the same folks that ran CAM-C at the previous event. The tires really felt greasy by run 4 and 5, and I really should have sprayed the tires. I don't know how much I could have found in the car, as it really felt hooked up on the first 3 runs.

                                Amy was less than a 1/2 second off my times, which made her super happy

                                Amy pulled off a quick 5th run and moved into 5th place overall once again, but this time only a half second back from 1st. She felt REALLY good to be that close to me after only running this car twice in this setup, ever, and she was still fighting seating & visibility issues. Her PAX factored times would have won the local Women's class by over a second, if she had run it, but she was having fun co-driving in the open class.

                                This yellow 2001 "SN95" Mustang GT had a pair of hot shoe drivers who came down from the Oklahoma Region and took 2nd (and 11th) place by only a tenth. This car looked and sounded like properly built CAM-C car, likely weighing close to the class minimum limit of 3300 pounds without driver (our car is about 350+ pounds over that weight). Matt Lucas took 3rd and his co-driver Tim took 9th - in the orange 2012 Boss302 that beat us last time. Would feel better if we were a bit farther ahead than only a tenth, but this class is brutal locally, so I was happy with the 1st and 5th we pulled off. Again, a half second covered the top 5 finish positions.

                                After our run heat we drove the Mustang to lunch and filled up the gas tank for the next track event. The fuel level was down to 1/4 tank after our combined 10 runs, but it never fuel starved. The fuel sloshing in this saddle tank in a parking lot is nothing like a long sustained left-hander on a road course, especially with Hoosiers. That's where we need to be at least 3/4 full to prevent fuel starvation.

                                Weather was great after the rain left and dried up and the event ran very smoothly, with very few reruns or DNFs among the 157 entrants making runs. One of the best run autocross events I can ever remember. Normally we stick around after the last heat for awards with the rest of the competitors, but it was a long week with some wacky weather - since the sun was out, we had yard work to tackle back on our property.

                                ADDING AEROCATCH LATCHES

                                The carbon hood from Anderson Composites has worked well with the OEM latch for a bit now, just always makes me nervous having a composite hood held in place with a stock latch. We usually add two positive locking, visible latches on all composite hoods we install and after some "cowl flutter" I noted at one track day, we decided to add a pair of Aerocatch brand hood latches to our 2018 GT.

                                This is where the factory 302S race cars place them - out on the edges, but about a foot back from the leading edge. I think they were trying to keep the pins on the leading edge of the sheet metal upper frame horn sections. When we looked at the carbon reinforced composite radiator support we found what we felt was a better location, farther forward and easier to mount the pins at.

                                Evan installed some pointed marking pins inside some reinforced holes we wanted to use for the hood latch pins, which were then transferred to the underside of the carbon fiber hood.

                                Once this pin location was marked the underside opening could be cut in the hood. This isn't super critical, not like the upper surface hole, and was cut out with a pneumatic body saw.

                                Then the pin adjusted to point at the top layer of the carbon hood, the oval shape could then be laid out and cut. We like to cut the top opening with 2 hole saws then connect them to form the shape, but some like to free-hand cut this with a jig saw or body saw. We always smooth the edges and then drill the holes for the top flange to mount (we never use the flush, bottom mount version).

                                With the upper openings cut and the latches fitted, the lower pins were installed. These almost never point "straight up" - the pins need to be clocked correctly, usually bent to line up perpendicularly with the hood surface (which is not flat). Using this factory hole at the radiator bracket hole allowed us to install the pins without drilling the radiator support, which makes this easier to "un-do" when we go to sell this car (to be announced soon).

                                We kept the stock hood "double latch" in place, just to be triple sure the hood never comes open at speed. This makes it a 3 step process to open the hood - you open the Aerocatch latches, then pop the hood latch, then release the secondary safety latch.

                                The Aerocatch latch opening in the lower carbon skin is right where the hood prop rod mounts on the driver's side, so Evan drilled and slotted a mating hole a couple of inches to the left. We don't use gas strut lift kits on composite hoods, as I have had one of those fail when the hood was open into the wind - cost me a windshield and hood.

                                HOOD BUFFETING FIX

                                As I mentioned, some of my in-car videos show some serious hood flutter at the cowl on this carbon hood. I showed to former Ford / S550 Mustang engineer Marco Garcia when he stopped by the shop - he suggested that we still have some pressure build-up under the hood, yes, even with the massive "GT500" sized vent opening.

                                We might not be helping things with so many changes - the PP1 and PP2 undertray bits, removing the electric grill louvers, and adding the vented GT5 hood. There is a lot of weird aero pathways going on under this car. Marco's suggestion - remove the rear cowl plastics at the back of the engine bay (see above left). These help seal the opening at the back of the hood to the windshield and cowl.

                                So we did. And at the next event - viola! - the hood flutter was gone. Looks a little funky with the hood up, but I'm not worried about car shows. Well... maybe I should have been (Optima event foreshadowing!)

                                QUICK RELEASE FIRE BOTTLE ADDED

                                As I have mentioned before HPDE and Time Trial generally have fairly low safety and fire suppression thresholds to enter. 3-point belt + a helmet, and some groups have some minimal clothing and shoe requirements. You don't even need a hand-held fire bottle in most series. Wheel to Wheel road racing, however, almost always requires a dedicated fire system with nozzles - pointed at driver, engine and other potential fire sources.

                                Even with a full fire system on a W2W car, we often add a hand-held bottle in an easy-to-reach location, like the S197 Mustang race car above. This way if you have a tiny fire in the pits, or a simple grass fire when pulled off track, you don't "blow" the dedicated system putting out something that a 2.5 pound fire bottle could have easily extinguished. We also put these little fire bottles in HPDE and TT cars, and it was long past time to add a fire bottle to our 2018 GT...

                                I ordered the same Drake quick-release bracket and a Halon replacement (Halotron) 2.5 pound fire bottle we have used dozens of times. Brad then fabricated a bracket to fit in the stock lower seat holes for the passenger side. Yes, we are making this with an eye to producing more for an easy bolt-in setup for a number of cars.

                                This mounts cleanly with the OEM seat or even our new S550 production seat mount bracket, which also uses the front seat mounting holes. I can reach over, pull the red pin and the fire bottle swings out quickly and cleanly. Its also out of the way of the passenger's feet. A minimum fire standard for a car tracked as often as we do, I'd say.

                                WHAT'S NEXT?

                                That's a lot to read in one sitting, so I am pushing the May NASA @ COTA event coverage until next time. We have done FIVE track events since this update now and more coming in August. Now that our forum is back up and working I can catch up on these posts. Plenty of events,upgrades, and news in the pipeline to cover next time.

                                We still have a busy competition and test calendar as we try to cram in as much testing and development in 2019, before we announce what we are doing in 2020 with this car. Do we keep racing it in a class at 300 pounds overweight, with tires that are too narrow for the weight (but we don't want to cut the fenders) in TT2 for 2020? Or is it time to build a dedicated S550 race car (or another chassis altogether - or a C8?) for next year? Tune in next time to see!

                                Until next time!
                                Last edited by Fair!; 07-25-2019, 10:40 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