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2004 Cadillac CTS-V Race Car - Project Badillac

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  • 2004 Cadillac CTS-V Race Car - Project Badillac

    Project Introduction - May 6th, 2020: This road race car entered our shop during the global pandemic, when we (thought we) had an opening for another build. The owner is a friend of mine that I went to college with, Jason McCall, and he had been trying to get this car into Vorshlag for years. He bought it a couple of years ago, but it had some issues that kept him from driving it on track, and he needed a shop like Vorshlag to make it safe, reliable, and fast.

    I had gone to his home shop (above) to inspect and weigh this car back in 2019, encouraged him to get the car dyno'd to get a baseline power number, and helped point out a number of issues that would need attention before going on track.

    We have worked on his LS powered Z3 M Roadster (above left) as well as a number of other vehicles in the past. We also started his 1999 Pontiac Firebird endurance road race car build (above right), which they finished and have campaigned to a number of ChampCar and WRL podiums.


    I had inspected this car before it came into Vorshlag, over on Jason's 2-post lift, but we still wanted to get a better assessment before we dug into it.

    Pictures Gallery

    I know the guys he bought the car from, and they ran it in at least 2 endurance races, so it was technically log booked and running - it just needed a good bit of work before Jason felt like it was ready for WRL endurance events.

    The engine was pouring blue smoke out of the exhaust, since the moment he got the car. We assumed something was broken or worn internally. Jason followed my advice and had it dyno'd to get a baseline, where it made 275 whp with the 5.3L engine it came to him with (not the original engine, obviously). For the class he wanted to run (WRL GTO) it needs to make about 350 whp, and the smoke issues would have them black flagged quickly, so we needed to pull the motor for a rebuild, at the very least.

    This car started life as a Body in White, so it was never a street car and has no VIN. It was built in Canada by Powell Race Shop who ran this and an identical sister car in the Koni Challenge series back in the day. It has a custom 120 liter fuel cell, dual dry-break fuel nozzles (not legal for some series), and a proper fire system. This was NOT a Pratt-Miller CTS-V, which was a radical build that sectioned the body, and ran in another series with support from GM.

    The cage is nicely made, it has high end Ohlins remote reservoir dampers, and an external ARE dry sump pump and settling tank. There is a nice Ron Davis aluminum radiator, and coolers for power steering and oil. But the oil cooler is hidden behind the stock bumper beam - it gets nearly zero airflow, so that's something we can improve.

    There was round of work done to this car after it left Powell's shop. Lots of zip ties holding things together instead of proper hardware (we cut no less than 50 zip ties off to remove the front bumper cover), some fabrication work that needed to be re-done, and some plumbing work that needs a look. So we're going to address much of this as we add some items Jason wanted.

    Some aero bits were a bit messy, with bolts going through the carbon wing, with big hex bolt heads exposed on the lower surface. The front splitter struts were welded angle iron, and there was too much Home Depot hardware throughout. Not trying to throw shade - no telling who did some of this work.

    I had sold Jason these rear 18x12" Forgestars with 335 Rivals from my 1992 Corvette, when he had a 1986 Corvette. These bolted to the back of this CTS-V - which had been converted from 6-lug factory bolt pattern to 5-lug GM pattern. There was a little re-work needed out back to clear those tires, but he knew that already. Nice trans and diff coolers were already mounted in the trunk and we had some ideas on how to make those more effective.


    To verify the fuel capacity before the dyno test, Jason and his crew had filled the fuel cell completely. So we started with this full fuel weight test.

    To get a better base weight AND to get that 6+ month old E10 fuel out of the fuel cell (ethanol degrades the foam) we pumped out all 20+ gallons.

    There were traces of broken down fuel cell foam in the fuel, which our local E10 gasoline (10% Ethanol) can do. Ethanol is hell on fuel systems. Weighing the car immediately after pumping all of the gas out it was 3320 pounds, or 137 pounds lighter. Good baseline to start from.

    We put a gallon back in to drive the car around the parking lot for a quick drive.


    The first item on the punch list and the most important is to get the engine out. Evan started draining fluids and stripping the front end off in early April.

    We stripped the front end off to get a better look at the layout of the cold air intake and various coolers - There is a lot going on behind the nose that can be improved, for sure.

    I am not usually a fan of re-using the OEM crash beam on road race cars and this car had a pretty hacked up unit blocking all sorts of coolers. This would come off. As the radiator was removed something obvious jumped out at me...

    I asked the guys to grab a level and sure enough, the front subframe was very bent. That put the LF control arm into some wacky geometry, as it moved the front LCA mount up by almost 3/4" on that side. The crease is visible from underneath and I asked Jason to start looking for a replacement stock subframe.

    This is "the easy way" to remove the engine and trans from this car, due to a somewhat snug engine bay and a radiator support that is welded in place. After carefully marking then removing the wiring harness, headers, exhaust, driveshaft, intake, and dropping the cradle it took most of a day.

    Then the engine hoist was used to lift the engine+trans off the cradle, and the cradle was put back into the chassis. Then the transmission and bellhousing were removed from the back of the engine.

    This gave us the "long block" for the aluminum 5.3L engine it had been running for a few seasons. Of course we weighed it at 313 pounds, with ARE dry sump oil pan in place, front and rear covers, complete heads / valve covers, but no front accessories and no valley cover. We mounted this to an engine stand I built eons ago for LS engines and I delivered the long block to HorsePower Research down the road. I will show the engine build in another post.


    I had already helped Jason and his crew weigh the trunk, rear wing, and some other components at his home shop, before the car came to Vorshlag. Shortly after taking the initial weights Jason was curious as to "where the weight was", as were we. So we spent a half hour and weighed the gutted rear doors.

    These rear doors had already been gutted to an extent but still weighed 27.5 pounds. The driver's door had the crash beam removed, but none of the other 3 did, so I asked Evan to carefully remove the crash bar from this LR door to see what the weight was.

    He got the crash structure out cleanly but it netted less than 2 pounds. There was significant structure still left in the window frame and door frame, which had working hinges and a door handle. We spoke to Jason about pinning the doors on rather than having them hinged/latched, and he was on board. This should help cut the weight down significantly, and we will replace the old Plexiglass windows with fresh, scratch resistant Lexan. Will show that in a future update.


    As we often do on a number of race cars, Jason wanted a wider DOM tubing bumper beam on the front of this CTS-V. In conjunction with that we suggested re-mounting the existing radiator with a forward roll. A rolled radiator helps free up some underhood room and promotes better cooling with a vented hood. This car's engine bay is fairly cramped and the Cold Air Intake tubing + filter are compromised by that layout. All things on the list.

    This car already had a "vented" hood, but it was a little rough looking and the owner agreed that it was a good part to replace. There isn't a supply of carbon body panels for these 1st gen CTS cars, so we will make do with good OEM parts which we can then vent properly. To make room for the radiator roll we suggested cutting away part of the welded steel upper radiator mount structure shown above.

    The upper radiator support held 4 hood pins, of the old school type, and one of those was busted off. After carefully marking with tape, Evan cut the center portion of the radiator support out - which only weighed 1.8 pounds. We kept the lateral sections shown (above left) to mount the headlights, which have brackets that touch the horizontal and lateral portions of this support.

    The GM "race" ABS unit was removed, which did not work at all. The hacked up bumper beam and splitter mounts were also removed. I was a bit upset with that bumper beam when I labeled the image above, because one of the rusty jagged fabricated splitter arms had just taken a chunk of skin out of my arm. Another one had put a gash in Evan's scalp, working around them. We have both bled for this car...

    A new upper radiator support was made from aluminum (weighs less than a pound) and the bumper mounting flanges were trimmed to allow the radiator to roll forward. Threaded rivnuts went into the remaining portion of the stock radiator support to bolt the new aluminum unit to.

    With the bumper flanges trimmed we managed a 25 degree roll using the OEM lower mounts on the subframe. This required installing the stock bumper cover a number of times to verify fit. Then the upper part was taped in place.

    Evan and I discussed the design and he made a pattern out of paper that he transferred to aluminum. This was then cut and bent to size with a flange added in the middle and 3 holes to mount to the new upper radiator support. After the test fit the center flange (above right) was TIG welded in place.

    With a piece of dense foam to act as a spacer the new upper mounting bracket clamps over the top of the Ron Davis radiator. The foam prevents vibration issues from the upper bracket and aluminum radiator.

    Some additional threaded holes were added to secure the bumper cover / plastic shroud to the new radiator support, wrapping up that task.


    In conjunction with the rolled radiator work, Evan also built the tubular front bumper beam, which is much wider than the stock crash beam.

    We used 1.75" dia DOM steel tubing and he matched both the curvature and "beak" of the front bumper cover, then pushed it forward to the edge of the cover from behind.

    There was some delay as the tubing notcher kept eating mandrels, then we redesigned it, then it broke again, then I bought a whole new $500 tubing notcher from Rogue Fab - long story, but that slowed us down by at least a day.

    Evan dialed in the front-placement so that is is just behind the plastic bumper cover. Then he trimmed the the width to the edge of the cover, which is safer for W2W use.

    On the fab bench he got it all TIG welded then bolted it back into the car. Additional tasks for tow / tie down hooks can be added in the giant fog light openings (which will become brake ducts), and we will add splitter stand-offs before this is powder coated.


    Jason looked and found replacement subframes for both the front and rear, as well as a transmission crossmember. The rear subframe was to be equipped with metal subframe mount bushings and Delrin or Poly diff mount bushings. Jason removed all of the control arms and spindles that came with these subframes, which gives him a nice set of spares to have on hand during long endurance road race weekends.

    The ones he brought were in good shape but still needed the 6 bushings removed from the rear subframe before bead blasting and powder coating.

    Brad spent a good chunk of a day pressing, drilling, and burning out those bushings, then we loaded it up for the blaster.

    The front subframe had 3 creases/bent holes, which Evan cleaned up with some hammer and pry bar work. Typical damage from a wrecker driver putting chains on a subframe to drag a car onto a flatbed.

    Both of these crossmembers plus the trans crossmember were taken to be bead blasted, to both remove the surface rust and to highlight any areas that needed stitch welding. Both the front and rear subframes were fully welded, but the transmission crossmember had about half the seams welded.

    I picked up the trans crossmember yesterday and Brandon TIG welded the gaps in the seams fully, then I took it back to have all 3 pieces powder coated grey - to color match to the engine bay's POR15 coating.


    All of this work happened in 4 weeks, when we had people working at half schedule to "improve social distancing" in the shop. This post is long enough - more next time.

    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

  • #2
    Project Update: December 2, 2020: The 2020 year was pretty crazy for us here at Vorshlag. We had some people leave, hired and trained new people, and got side-tracked on the Vorshlag building construction and the addition of another CNC machine. Most of our "project build threads" have not been updated in months due to increased workload by all remaining staff - but we've been busy building cars!

    We fully expected to have this Cadillac completed by now - as well as several others - but that's kind of how 2020 went for a lot of shops and racers. In October we were fully staffed up again and, after a three month hiatus, we got back to work on all customers' car builds in our shop. We will start showing these types of updates more regularly now.


    I kind of skipped this last time, but the modified OEM bumper beam was really hacked up when it came in. Looked like it had been cut with a chain saw.

    Replacing this narrow yet heavy crash beam with a full width tubular beam that is pushed out toward the bumper cover opened up space and makes for a safer, more crash worthy front structure.

    This shape was made to match the front bumper cover shape and pushed as far forward as possible. This means a light tap likely won't deform the bumper cover, just transfer into the beam that touches the plastic cover on the back side.

    Curved and bent 1.75" DOM tubing version we built is almost 8 pounds lighter. This new bumper is much wider than the OEM unit - the above right picture shows the extra width visible inside the "fog light" area. The splitter struts can tie into these extended sections of the tube here.


    When he bought this car, Jason was under the impression the 5.3L engine had been recently rebuilt. There was obviously an external suction stage ARE dry sump pump and ARE oil pan, but it smoked SO BADLY at idle that he never drove it on track. I convinced Jason to get this thing dyno'd, where it made GOBS of smoke and an underwhelming 275 whp.

    The amount of smoke it made did not jive with the rebuild claim, and tearing it down at HPR proved that this was just a worn out, old, stock 5.3L aluminum engine.

    In the first week of April we had the engine out and striped down to the long block. The guys at HorsePower Research started the tear down immediately and I happened to be there right after it came apart. They took pictures as it came apart (like they do for most customers).

    HPR technicians carefully took apart the long block, looking for clues as to the excessive oil smoke blow by. Instead of just ripping apart critical fasteners with impact tools they loosen each bolt by hand - trying to feel for loose or under-torqued head bolts, rod bolts, or main bolts. The old engine was assembled with all OEM fasteners, which meant this was likely just a totally stock (read: junk yard sourced) engine. The camshaft had lift and duration numbers that matched an OEM LS6 Corvette engine, but otherwise this was just an old. tired, worn out 5.3L truck longblock. At least the aluminum block was still good, and the head castings ( XXX series) were worth using for cores.

    I shot this 2:34 minute video above on April 15th, right after the engine was torn down. It was a strange time at HPR - with the Covid-19 shut down in many states they were out of a number of critical parts, so most of their race engine builds were stalled completely.

    This is why this stock 5.3L was tackled so quickly, and why 3 different HPR technicians were on hand. In the video Erik Koenig (beard) is laughing a bit, because we told him this was supposed to be a refreshed engine. It was obviously not. The original cross hatching on the bores was wiped out - this engine had hundreds of thousands of miles on it. The piston rings were also worn completely out. The cylinders needed to be bored to come back to round, so HPR took the block to 3.903", and a 4.000" stroke Callies Compstar crankshaft was fitted.

    The GM 862 casting aluminum 5.3L cathedral port truck heads were good cores that ended up being CNC ported by Bischoff Racing Engines to HPR's specs. The heads were then fitted with larger 2.02" valves, with new conical springs (7230), retainers, and locks supplied by Comp Cams.

    These changes to bore and stroke increased displacement of the original 5.3L out to 6.3L (382.858 cubic inches). HPR sourced lighter (600 gram) 6.125" Scat I-beam 4340 rods and Wiseco forged pistons for this setup.

    One of the many things that sets HPR apart from the rest is their meticulous assembly - every bearing clearance is checked and perfected, each spring is tested and shimmed, every bolt torqued to perfection. They even set the valves on every long block. One less thing we need to worry about.

    After some minor delays with a few parts (pretty small considering the pandemic shut-downs crippled this industry) they wrapped up the 383" cathedral port stroker engine in September 2020, and I picked it up a couple of weeks later to bring it back to Vorshlag September 28th.


    Due to staffing changes, the technician that pulled the old flywheel and clutch off back in the Spring was not the same one to put it back together. And even during the final assembly we had yet another staffing change. 2020 was crazy, y'all!

    As soon as I looked at the old flywheel and clutch surfaces (Oct 2020) I sent these pics to Jason, and recommended replacing the steel surface on the Spec aluminum flywheel + order a new clutch and pressure plate. They all looked pretty cooked, and doing a clutch job now was essentially free labor (it was all out of the car and apart). He agreed.

    Instead of trying to push any clutch brand (because I hate selling clutches!) I let him decide, and we had identified the old setup as a Spec Stage 3 clutch and pressure plate. We ordered that exact same kit + the replacement surface plate for the Spec aluminum flywheel, which was surprisingly affordable. Brad bolted that steel ring onto the flywheel and a pilot bearing was installed into the crank then the flywheel went on. He also built a flywheel holding tool (above right) and torqued that on with Loctite.

    The clutch and pressure plate parts were installed next, then the RAM heavy duty hydraulic throw out bearing was inspected. It looked good, but now we wanted to measure and confirm the TOB shim stack.

    There are several online videos and charts showing how to check for TOB free play and shimming. the RAM kit comes with shims, and we just wanted to make sure the previous install was right with the same (but new) clutch, flywheel (resurfaced), and transmission (stock Caddy T56).

    We checked and the shims on there worked well for the new parts, at .120" clearance. Measuring down to .001" is a bit optimistic, considering how you have to check this (with a straight edge - it isn't .XXX accurate). Basically you don't want the TOB surface pressing on the fingers of the clutch when released, but you also don't want them more than .200" away - which can cause for TOB over-travel. On a hydraulic TOB this will work for a short while, then the TOB eats itself and you lose clutch function. THAT IS NO FUN. It is worth checking this as it goes together for any hydraulic TOB, and we used two different charts to make sure our math was spot on for this endurance car.

    With that measurement double checked the transmission was stabbed into the clutch and bolted to the bellhousing. Now it can go back into the Caddy, but we have some other work to tackle first - that would be a lot easier to finish with the engine out of the way.


    As I mentioned in the intro, when it was purchased the GM Anti-lock Brake System (ABS) on this car didn't work at all, and even when this car was built it had a switch added to the dash to kill power to this unit - as they were pretty terrible on track, even when new.

    The brake hard lines in this car had also been hacked all to hell and back, and we begged Jason to let us replace all of this mess with a BMW Mk60 ABS from a BMW E46 M3 - as it uses the same wheel speed sensor signal type as many GM cars.

    This is a simple but effective unit that we have used on other cars in the past. It consists of a self-contained ABS hydraulic unit, 4 wheel speed sensors, 2 pressure sensors, and a yaw sensor. Getting all of this wired up took a custom wiring harness from Douglas Wardell of Racing Harness Technologies.

    After sending Douglas the wiring run lengths, he built the ABS harness to spec and we received all of this from him in August of 2020 - the Mk60 ABS unit, two pressure sensors, the Yaw sensor, and the custom built wiring harness.

    I had Evan mount the ABS pump back by the booster - a good place we made room for by relocating the coolant reservoir. Well after it was fully mounted I realized how terrible this location was to access, wire to and plumb to. So I got to eat all of that work and convince the client we needed to relocate this.

    I had Doug (who worked for us for 2 weeks) make a bracket to mount this ABS unit in the LF corner of the engine bay. This allowed for easier access to connect the harness and many hydraulic lines we needed to build. The Mk60 unit is mounted to this bracket which bolts to the chassis in 4 locations through rubber isolator mounts.


    In the last post we showed how the old front subframe was badly bent, so Jason sourced another unit + another transmission crossmember. We had both units bead blasted, then we stitched welded them and had them both powder coated - back in May 2020.

    The blasting / welding / powder coating took a few trips back and forth to our powder coat shop, and happened pretty quickly, so I missed my chance to get any pics of this work.

    Among the many problems we have uncovered on this Caddy this bent subframe was probably the most problematic - fixing this should clear up some suspension geometry problems the car likely had, as the lower control arm bushing mounts were tweaked on one side. Brad replaced the front subframe during some of the brake line work, as we needed to mount line separators and brackets to the subframe. It was time.

    Front subframe swaps are never fun, but at least the had the drivetrain out of the way. The trick is to not get stuck to where a car cannot "roll" for days at a time. With our shop space and limited number of lifts, we cannot affords to get a car stuck on a lift for long.

    Brad got this swapped out quickly and efficiently. The powder coat color matches the POR-15 gray of the engine bay well, which is what Jason wanted. It is also stitch welded and NOT BENT so that is a big improvement over before.

    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


    • #3
      continued from above


      Once the ABS pump was mounted we were stuck waiting on a lot of fittings and stainless 3/16" line - some fittings took weeks to arrive (welcome to 2020). The brake hard lines were in rough shape on this car with lots of needless splices and beat up lines. There are all sorts of janky repairs and changes that make the soft lines custom at each corner, with a mix of flare types. And now we had to splice in this BMW ABS pump, which uses Metric flares...

      This ABS was installed at the front left corner of the engine bay (top left) but on other cars we mounted this in the trunk (above right). The top right pic shows the two pressure sensors we need to add plus a small fuse block for the additional circuits we needed on a similar install. We left room on the Caddy's ABS bracket to mount the additional fuse block.

      The fittings, adapters, tube nuts and hard lines were ordered by a different former tech that has also since left. This meant that Brad had to figure out what the initial plan was, and I stepped in to help. These metric adapters were installed to convert the hard lines and tube nuts to a more common -3 AN style. Brad did some research to mark what the circuits are on the BMW ABS pump - the two inputs from the master cylinder and the 4 outgoing circuits to each corner.

      The annealed stainless steel tubing was straightened and bent to fit the new routing, using TIG welding rod as a guide for each path. Tube nuts for each end were installed before the ends were flared - using this Eastwood flaring tool. Some were single flare, others double flare, depending on the end needed.

      Brad ran the four lines to each wheel, removing unnecessary splices whenever possible.

      With a number of splices needed I went ahead and invested in a variety of SAE junctions and tube nut ends, which is how the new stainless lines were tied into the rear circuits.

      The new lines are routed and secured with these Vibrant double brake line holders, bolted to threaded nutserts in the chassis and subframe.

      There are two lines we need to make that go from the MC to the ABS, shown above left. The pressure sensors for the new system need to tie into these lines, and instead of making a big mess of adapters with a "T" in each line, we're using some slick adapters made just for this exact Mk60 setup from E30 Motorsports. These are coming from Germany and when they arrive I will show what they look like, in a future post to this thread. We borrowed one from another Mk60 install in the shop (above right) but that was already removed and reinstalled on the donor car.


      This was another area of "dubious modifications" that we told Jason that HAD TO BE CHANGED. The front control arm bushings were modified to use a Delrin & aluminum bushing, but they were not setup to be greased. And after a short time those types of bushings start to lock up. Every time this car was raised or lowered on the lift it made this LOUD and ominous CREEEEEAAAKKKK noise, until the suspension settled. These bushings are damn near locked up - it will negatively effect handling.

      Both the upper and lower control arms are afflicted and the car owner Jason researched some options. He found an aluminum/polyurethane option for this chassis that was built around a greaseable thru-bolt.

      The big thru-bolt has been gun drilled for a grease zerk in the end. Grease can be injected here via a grease gun and it comes out along the shaft inside the aluminum insert, which has passages to allow the grease to get to the outer poly shell. Pretty clever and these will not seize up like the Delrin versions, if grease is applied periodically.


      Strangely, this car still had an OEM glass rear window when it rolled in, as well as some really janky back door plastic windows. The door windows were held in with WOOD SCREWS and had a lot of wear and tear.

      As most of you know it is common to replace some glass with Lexan, as it weighs half as much and won't shatter like tempered glass (used in side and rear car glass). Double pane safety glass in windshields is MUCH harder than plastic and won't shatter, so this is often kept as the front facing windshield. This allows for wipers to be used, which is critical in an endurance car. They are also cheaply and easily replaced - on most cars.

      Our suggestion to the owner was to replace the rear glass with scratch resistant Lexan, built from a curved sheet that is pre-cut, has a pre-painted border, and to order. We had our glass pros at Titan Auto Glass come out and remove the rear glass (shattering this would make a huge mess) and we removed the scabby old plastic windows from the rear doors as they were being trimmed down for weight.

      Above is our final install of the pre-cut rear Lexan. I'm not going to name the manufacturer because they will not get our business again, due to an excess of mistakes on an order that was supposed to be for 5 cars. But this one piece was made right.

      After three long months (?!) the Lexan order arrived and we test fit the back glass piece right away. It fit well and had the 2" painted border on the inside that we paid extra for. Brad laid out some blue tape and marked evenly spaced bolt holes in the tape. Yes, many Lexan windows are glued in place, but we like to put them in with a 1/8" foam weatherstrip and small M4 stainless bolts, counter sunk with load spreading Tinnerman washers. This makes removal easy and clean and we have done this on numerous race cars.

      Brad cleaned up the channel on the car, which was painted various colors. He taped up the good paint and inside the window the sprayed the surfaces with a couple of coats of semi-flat black paint.

      He transferred the hole spacing to the center of the inner channel, drilled them, and began installing M4-0.8 threaded nutserts. Of course whoever last used the nutsert install tool broke the M4 mandrel, so I had to order that and wait a couple of weeks - but eventually it showed up and Brad finished the nutsert install.

      We like to use these countersunk, stainless steel M4 bolts and matching stainless Tinnerman washers. Using a SHARP countersink bit, Brad countersunk the holes he made in the Lexan to fit the Tinnerman size we chose. This makes for a flush mounted, all stainless steel attachment that can be re-used countless times.

      A layer of 1/8" thick x 1" wide weatherstrip tape was applied to the channel in the window, with the adhesive side down. The holes were pushed thru this from below and the window was placed on and bolted down. The bolts are torqued down evenly and carefully, to avoid a wavy edge.

      The 1-piece side windows were made from a template that Jason made and we mailed to the manufacturer. This was supposed to have the 2" border pre-painted but they missed that step, so we will do it at the end. We mocked this up and it fit well, requiring minimal trimming.

      Unlike the stock glass, I wanted this Lexan to sit as flush as possible to the outside sheet metal. We found a way to slide this behind the outer door trim. Brad added nutserts and M4 bolts/Tinnerman hardware into a channel on the inside of the door. We had cut out a LOT of structure in the rear doors easier in the build but we left this inner channel, to give the door some structure and to hopefully use it for this window mounting - which worked perfectly.

      The leading edge of each rear door window overlaps the frame of the door, and Brad cut part of the "T" shaped door trim to fit over the edge of the Lexan. This made it so we needed no hardware on the leading edge. The trim piece bolts in from behind and secures that edge of the glass.

      More of the 1/8" x 1" weatherstripping was used as well as some custom chunks of Delrin, made from some stock we CNC machine. These "L" shaped blocks secure the glass to the frame, as shown below. About five of these bolt-thru spacers are used to secure the top and trailing edge of the Lexan.

      The Delrin spacers are visible from inside the glass, but they disappeared once Brad painted the border on the Lexan.

      I was very happy with the final, flush install of the Lexan (as was the customer), especially when compared to the scratched up plastic that came out. We managed to lop several pounds from each door and still had a more secure glass install than before. Just takes some planning, patience and time.

      WHAT'S NEXT?

      There are lots of parts arriving soon to wrap up the engine bay. The ABS fittings from Germany, the Holley EFI system, and a few more details then we can install the new engine and the T56 once again.

      There will be another post soon when these last EFI items are installed.

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


      • #4
        Project Update: September 5th, 2022: The CTS-V owned by Jason McCall is still here at Vorshlag, but it has been driving for some time. Some "scope creep" happened, and continued supply chain / manpower / tuner delays drug things out a bit. It is nearly done now, as you can see below.

        There is simply too much work to show in one update, but I will try to cover as much possible without having a huge 5 part entry (this 3-parter is over 50K characters). I have a lot of build threads to catch up on, but this writing / editing / compiling of pictures takes a lot of hours (still took me 2 days of writing this time). This entry covers work performed from Dec 2020 through April 2021, plus a little bit of related work in June-July '21. Last time we left off in early December of 2020, so let's dig in.


        Like almost everything else on this car when Jason bought it, the bushings were totally fried and needed to be replaced. Some lower front arm bushings were changed in the last update but Jason and his buddy Paul (I have been friends with both of these guys for 30+ years) were more than capable of doing the remaining front upper control arm bushing swap, so I let them come into the shop on a weekend and knock out this work in the middle of December of '20.

        They did the front upper bushings in a few hours and then swapped in some new rear control arms - which allows for more inboard rear wheel room.

        The car came into the shop with these 18x12" rear wheels installed (which I sold Jason from my 1992 Corvette) and the rear wheels were rubbing - but he knew that and had these Creative Steel arms on order.

        The Creative Steel arms finally arrived - they are curved inboard and allow the wider 18x12" wheels to actually fit, and the worn bushings were replaced with sphericals in this swap, too. There were still lots of other worn bushings to replace in the rear suspension, but we will cover that later.


        I have already shown a variety of safety issues that were on this car. We fixed as many as the owner felt were the most dangerous - including these many unsealed holes in the firewall. There was some attempt to make proper block off plates, but the previous owners failed to take these to the finish line.

        Having soft hoses and wiring bundles passing through gaping holes in a firewall is scary. The firewall is there to prevent FIRE from passing into the cabin, where the driver is. After slapping some aluminum tape around holes that were too big - - tape is later easily torn or falls off - big gaps remain that you can see light through. That just isn't good enough, and these jagged metal edges like to chafe wires and hoses in race cars.

        What Brad built here isn't hard to replicate - these weren't CNC made, but rather hand cut with a vertical band saw. We always start with cardboard templates, trace them onto .063" or .080" thick aluminum, then cut them out to fit the opening in the firewall. That is attached with rivets and an opening for a grommet is included. The unit on the driver's side needed to pass a wide wiring connector though it so Brad added a rectangular opening for that side (see below)

        We usually make the openings in the block-off plates to fit a Seals-It 2-piece grommets, which can be removed if a large harness plug needs to pass through. These are thick rubber grommets that will seal up gaps in a firewall "air tight", which slows down a flash fire and also prevents wires from being cut by the firewall or block-off plate. Each one costs about $2 in aluminum sheet and about $30 for the grommet - to prevent wiring damage as well as an engine fire from burning the driver. Mostly just takes time, but not any special skills or tools. You can do it!

        HPR 383" LS6 INSTALLED

        Last time we showed the HPR built 383" LS6 being attached to the original T56 manual trans with a new clutch and the subsequent slave cylinder measurements. That step is critical to having a properly functioning clutch. It was finally time to get the drivetrain installed.

        On December 29th, in the short week between Christmas and NYE, Zach and Brad installed the engine and trans into the Cadillac's engine bay.

        This was a big step but it passed quickly and without any drama. We still have a lot of plumbing and wiring to tackle, but this was a nice step to check off the list!


        Now that the engine was in place a few more important bits arrived for the Mk60 ABS swap, namely these pressure sensor adapters from Atec in Germany.

        Last time we had shown the installation of the Mk60 ABS unit (on a custom bracket with isolators) then Brad made four new brake hard lines going from the ABS to the four corners.

        We needed two more lines - from the master cylinder to the ABS brick - and all of the wiring done, plus mounting of the yaw sensor. And later on, we had some hub changes to make, but I will cover that next time (to get the "active" yellow wire hubs on the car that the Mk60 needs to function). But in the above steps, Brad built the two lines to the master cylinder.

        Mounting the yaw sensor from an E46 M3 is the next bit - Brad made a bracket to mount this with the "Ears up" and the "sensor plug forward", as shown in the marked images. This needs to be mounted near the "Center of rotation" for the car, which is usually on the transmission tunnel as we did on this car. Got questions about Mk60 ABS installs? We are combining the knowledge we have gained on this and several other Mk60 swaps and putting it in another forum thread soon.

        Wiring of the Mk60 needed a switched power circuit, but the factory wiring on this 16 year old Caddy was a hot mess. I wish we would have dug into this fuse box sooner, as a complete re-wire of the car was likely warranted. Plastic coated copper wire gets brittle with heat + age and this chassis had seen a lot of both.

        The wiring under the dash has been hacked and hacked and hacked... Brad had to dig into wiring schematics to figure out what was stock and what wasn't. We needed a brake pedal switch for the Mk60 AND a functional brake light switch for this car. The Mk60 needs a normally grounded switch that "breaks" ground when the pedal is touched. The Caddy (like most cars) needs a switch that is normally "open" then "engaged" when the pedal is touched (backwards from the Mk60). We made all of that work with the same switch - with a relay that is engaged when the circuit is open (you can see the relay above the switch, below right).

        To mount this Painless Wiring brake pedal switch we needed a bracket, which Brad made from a section of bent steel plate. The two holes mounted to the steering column mount above and the Painless switch was mounted at the small "bent foot" on the end, then adjusted so that the plunger just touches the brake pedal arm when it is all the way up. As soon as the driver touches the pedal, this switch is "released" and the Mk60 gets that signal + the signal to the relay activates the brake lights on the car. As always, any wiring Brad touched he "de-jankified", marked, and bundled inside proper loom and secured.

        I will cover details of the remaining Mk60 ABS swap work in another post in this thread as well as a separate Mk60 ABS swap thread. Just use "Control F" to search for terms like "Mk60", which I use repeatedly to help find those things when people (or I) are looking.


        Like everything else on this used race car, does it make sense to keep the old water pump of unknown age? It seemed like everything we touched was "rode hard and put away wet", so a new ~$200 ACDelco Professional (252-921) water pump was a no-brainer.

        The CTS-V and C6 Corvettes share the same front-to-back pulley offset, but the later LS7 has a water neck that is offset towards the driver's side. The Ron David radiator was to be kept and the neck lined up with the early LS7 style placement of the upper outlet, so we went with that one. Sometimes we will use the later LS7 pump (252-966) which moves the outlet to the left several inches - just depends on the radiator neck location.

        Later on we swapped the OEM style spring loaded belt tensioner with this ICT Billet version - which is a manual tensioner for the main 6 rib serpentine belt.

        Why change that? Two reasons. First, we have seen the spring loaded OEM style kick the belts off at high RPM (7000+), as they can get an oscillation at high engine speeds. We used to always use a Katech version of this manual tensioner, but the ICT Billet version works great and costs less than half as much - and its made in the USA.

        The second reason was the ICT 551617X-1 manual tensioner gained us some room with the Chinese / Amazon 102mm DBW throttle body we used for a while on this car. The manual tensioner along with a shorter belt gained us some much needed room there. Then we changed the throttle body anyway, as this $99 imported TB had some tuning issues that a $700 Nick Williams 103mm unit fixed.


        The exhaust headers that came off this car were old but stainless, somewhere under all of that oxidation, header wrap, and funk. Instead of replacement Jason decided to get them blasted, ceramic coated and polished - which we do on most of our race builds. There are often long discussions online about this type of coating vs NO coating (for stainless headers) vs header wrap.

        While debate is "great", in the real world we have seen IR gun measurements that are lower with this type of coating, and it doesn't act as a SPONGE FOR OIL like header wrap does. Wanna guess what burns like a torch when there is an underhood fire? Oil soaked header wrap material. We still apply header wrap to SELECT areas when warranted, but not on this underhood application.

        These newly ceramic coated headers went back in with multi-layer steel (MLS) exhaust gaskets and new ARP 12 point stainless bolts. We will dig into the rest of the exhaust upgrades in a later post.


        On all LS engines there is a factory "steam vent" plumbing system that normally takes coolant from the highest point in the engine at two points, then directs that to the coolant reservoir. This is to allow steam or air bubbles to purge out of the top of the engine, to prevent an air bubble from building up inside the engine. Most factory "car" LS installs block the rear steam ports on the heads and just draw from the front two - but our engine builder recommended a 4 port system.

        Back in July '20 (above) we got to the "let's install the intake" stage on my 2015 Mustang (on a nearly identical HR 385" LS6) using the same FAST LSXR 102 intake. And on that car we learned that most 4 port steam vent kits do NOT fit this intake. Evan looked and found ONE system that is made just for THAT intake - from a company called Nitrous Outlet.

        We have successfully fitted that to my Mustang so we bought the same system for Jason's CTS-V here, shown below. Again, if you are building with a cathedral port you will likely WANT to use this same intake, and if you are doing road course events you will likely WANT a 4 port system. So use the Nitrous Outlet kit and save yourself a lot of headaches.

        Unlike the ICT Billet valley cover on my Mustang's engine, on Jason's LS6 we re-used the stock valley cover and two knock sensors that are built into that, and this went together with the 4 port steam vent kit.


        As we mentioned above, we know from experience and from talking to the experts at HorsePower Research that for a cathedral intake port headed LS V8 engine, the FAST LSXR 102 is the best plastic intake out there. Yes, it is better than the MSD Atomic (but the MSD is better for the LS7 shaped intake port). This FAST intake tends to be worth 20-50 whp on a built engine over the stock LS6 intake (which is also restricted to a 78mm throttle body)

        We bought one of these intake manifold kits, and after the correct 4-port steam vent went on, it was time to fit up red FAST fuel rails that were used on the gutless 5.3L engine from before. This was an older set of FAST rails that were made to fit an LS6 intake manifold and the TALL injectors, but the mounting brackets did not line up with the cathedral port FAST 102 LSXR or the shorter injectors from Fuel Injector Clinic.

        FAST makes a LOT of fuel rail kits for LS engines, each with unique brackets with spacing based on the intake you use. We mocked up a set of black rails from my LS550 (FAST rails for this LSXR intake) and they worked, so instead of wasting HOURS trying to machine custom brackets, a new set of rails was the cheaper and SAFER way forward.

        With the correct FAST rails + the injector spacers made it all fit. The 102mm "import" (China) throttle body was also mounted up at this point (more on that fiasco later - in short DO NOT use these cheap DBW throttle bodies!) On to the next challenge.

        This Caddy had a customized "strut tower" brace which fit above the little LS6 intake and under the hood. We mocked that up with the new FAST intake to see if it would fit - nope. The FAST 102 has a VERY LARGE plenum and is a good bit taller, so the STB would have to be altered.

        This is how things snowball - just trying to use a better intake manifold (FAST > LS6) turned into several additional tasks. Not what we or the customer wants, but its done in the quest for horsepower! Instead of making a new STB, Brad modified the steel unit by drilling the heads off dozens of rivets and removing the aluminum reinforcement that added to its height (underneath).

        That still didn't clear the FAST so 1/4" thick spacers were machined up. These went under the 4 mounting points at the upper control arm mounts (this is not a McStrut car) and then the steel STB finally cleared the taller FAST intake, and just cleared underneath the hood.

        continued below
        Last edited by Fair!; 09-07-2022, 10:50 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


        • #5
          continued from above

          Next up was the fuel filter - which was tiny unit that was hard to access (behind the now much taller intake). Nobody knew how old that filter was so we convinced Jason to allow us to change to a better design.

          This Radium Engineering fuel filter + heat sink mounting bracket were purchased (we had just used a similar one on another project) and Brad built an aluminum mounting bracket, which itself was mounted on the firewall in a more accessible location than the little tiny version it had before.


          The goal on this project was always to minimize changes, but we had to point out anything we felt was worn or dangerous to the owner. There were a few safety things we insisted on, but things like the fuel system left mostly alone. This car had a really good 120 liter fuel cell and "quick fill" bulkhead in the trunk for a pressurized / vented fuel rig for some Pro series in the past.

          The fuel pressure regulator is in the trunk, which is unusual, but we let that one go. It feeds regulated (likely 54 psi) fuel through a single -6 AN (3/8") braided line all the way up to the fuel filter in the engine bay, then along to the fuel rail.

          Normally we would spec a "return style" fuel system for a 500 hp engine like this, with a -8 AN line from the fuel cell feeding a regulator in the engine bay, then a -6 AN return line back to the fuel cell. That was a bunch of unnecessary plumbing Jason didn't want to get into, so we left the fuel lines alone - right up to the fuel filter we added in the step above.

          With the Radium filter and heat sink mounted in a more accessible location we ran a -8 (1/2") Fragola braided fuel line from the filter to the fuel rail. We had to make that short line anyway, so we up-sized it in case dyno tuning showed a fuel line restriction / lean condition later on.

          The entire quick disconnect double fill / vent fuel bulkhead and dual 2.5" hoses in the trunk really should have been changed out - but I lost that battle. Jason and his endurance team felt they could make this work, so we left it alone - mostly. Since they won't have the old Pro series provided fill/vent connect system, and will be filling with 6 gallon cans, I did insist upon adding a "bib" to catch any fuel spills. There are a couple of electric pumps and circuit breakers right under this bulkhead, so a fuel spill from an overfill could make for a situation nobody wanted.

          This is March of '21 at this point and Brad made the pattern and cut out the aluminum spill catcher, bent that up, and I think it was Zach who TIG welded that up on the fab bench.


          This was then bolted to the fuel fill bulkhead and a drain line from the lowest corner goes underneath the car. In an endurance race fuel fill they can fill the cell and any overfill splash should be contained in this bib, then drain under the car - to a waiting catch pan that is slid under the car during pit stops.

          another thing that was sending up red flags early on was the clear hoses used for the 2.5" fill and vent lines, which included two slight bends at the fill bulkhead and two 90 deg bends at the fuel cell (see the images at the start of this section). These clear fuel lines are always suspect and tend to harden and turn hard after years of exposure to fuels. We found these fuel rated 2.5" ID bends from Mocal and imported them from the UK - took 8 weeks to get here during the pandemic.

          These replaced these nasty "not bends" that were really just straight pieces of hose that had been heated up and "bent" to fit in that 90 deg section. The spliced together worm gear clamps were also replaced with the right sized units.

          Getting those 90 deg Mocal bends in was extra fun - ultra tight confines. The clear hose at the back is actually fuel rated straight with a slight bend in it - so the fuel flow can be looked at visually and hopefully if the cell is over-filled you can see that before it burps into the bib. This isn't 100% perfect but it is a lot better than it was before and the green crusty hose "bends" from before are at least gone.


          The power steering and engine oil coolers obviously needed to be changed (see that section below - yikes!) and it is well known that hydraulic power steering leaks are a leading cause for underhood fires. This flammable fluid is run at very high pressures (1500psi+) and a small leak - especially on the pressure side - can lead to an engine fire.

          At this point in the build we had found so many issues that needed updates or repairs that Jason decided - damn the budget, let's make this car SAFE. So the power steering pump (again, unknown age and wear) we replaced with a Turn One HP2 series pump. This was mounted up with the old fluid reservoir and cap on the CTS-V brackets.

          After seeing another build we were working on with a remote reservoir, Jason pushed for one for his CTS-V also. This holds 3x as much fluid as the plastic unit and we had a way to get rid of all of the "slip fit / clamped" low pressure lines with the remote reservoir. We test fit a few and found a tall, cylindrical unit from Canton that fit well.

          Unlike the pump on the other project we had no option from Tune One for a threaded AN fitting at the pump - just this "slip fit" hose bend. It is a press fit into the pump but a simple hose barb end, which needs a low pressure hose and clamp. Granted, this is the suction side and not seeing pressure, but he wanted "AN hoses on everything" in the power steering system, so Zach TIG welded a AN weld bung to the end of this fitting.

          The reservoir was mounted to the shock tower behind the ABS hydraulic unit. This custom suction side fitting was mocked up and "clocked" carefully" to clear the billet power steering pump pulley and aim at the area we wanted, marked, then pressed back into the pump housing (with some green Loctite). Now the plumbing could then begin with braided hoses.

          It took some ingenuity but Brad managed to route and build a -10 AN Fragola suction hose from the bottom of the fluid reservoir to the pump. This FAT hose routes underneath the ABS bracket so well - it looks like we planned for this 6 months earlier.

          A -6 hose was built to the return side of the cooler (the lowest pressure "pressurized" portion of the power steering system). The hose from the pump to the steering rack is a 3000 psi Fragola / Parker industrial high pressure hose we built for the high pressure size. I will show more in the cooler section, below.


          When we started this build the goal was to be able to do 24 hour endurance races but with a 6.3L engine with 2x the power that the anemic 5.3L had before. To pull that off we would need to increase cooling for the engine oil and power steering fluid.

          What came on this car was a bit suspect. The tiny Setrab cooler for the engine oil (above) was damaged at both fittings and curiously mounted behind the large OEM bumper beam. Maybe 15% of the surface area was in the (completely un-ducted) front grill air stream. We wondered how this worked at all? The heat exchanger was also hard mounted with steel brackets - no isolators - and we've seen long term damage (cracks) happen to coolers when hard mounted.

          The power steering cooler was also extremely suspect - it was a generic, $20 finned loop cooler you might see at an auto parts store, mounted haphazardly with some zip ties. The plumbing wasn't terrible on either unit, but they were just massively under-sized, poorly mounted, and placed in strange places with no regard for airflow. We planned on rolling the radiator and replacing the butchered bumper beam early on, so new fluid coolers were always on the short list.

          We have utilized Derale coolers on a number of track builds lately, including my own Mustang. We chose their highest efficiency 10000 series 40 row stacked plate cooler for the engine, with -10 AN ends. We chose the similar 19 row unit for the power steering cooler, with -6 ends. Then picked up a set of the Derale mounting brackets of two sizes.

          As we have on similar Derale mounting projects we CNC plasma cut some vertical pieces to complete the assembly as shown above right. This makes for a very secure set of brackets and heat exchangers with the hose ends coming through holes cut into the aluminum brackets. Very slick and with just the vertical bits it looks really nice.

          And if you thought the CNC cut verticals was slick - check this out. Zach went to town on this set of brackets, which were designed in CAD, CNC cut, then TIG welded to form the vibration isolator mounts...

          These were welded to the existing Ron Davis aluminum radiator, which was tricky but done with a watchful eye on heat with the TIG. These attach the radiator through the high temp isolators to the engine + power steering heat exchanger assembly.

          We added a few pounds to the already heavy radiator but the heat exchangers are isolated and won't beat up the radiator. There is an air gap between the coolers and radiators but not enough to require any ducting - the air will go through these before the radiator without any other tricks. The factory pin mounts on the top of the radiator got new isolator bushings as well, which we incorporated into the rolled radiator mount.

          All of this tucked into the larger space we made between the grill and tube bumper - there's not a 1/4" of room to spare, and this is the biggest set of heat exchangers that will fit under the grill without changes to the front subframe. Really happy with how this all came out, but if Jason allows us we will add some ducting from the front grill opening to this stack of coolers - to seal up the air flow path for the top, bottom, and sides. It may work well enough in testing that this isn't needed, and he might also tackle that work on his own.


          This Caddy came to us with an unusual and somewhat dated oil filtration system. This System 1 filter with an internal replaceable element was pospular 15+ years ago but that isn't something vintage we wanted to hang onto - and Jason agreed.

          Jason had seen the Improved Racing remote oil filters we have used on numerous builds (including my LS550 Mustang, below) and decided to go that route. Now I fought to be able to use this thermostatic bypass style - which will bypass the coolers until a preset temp is reached on the oil (I usually picked 185F), but Jason said that since this was an endurance race car, there would be almost no time when the engine was run hard at low oil temps. And for that case, he was right - just hope he remembers that if he does any Time Trial or short sprint races.

          So we picked up this less costly Improved Racing remote filter mount, without the bypass, and we had a limited number of locations where that could be fitted.

          It needed to be accessible to change the large spin-on Wix filter during oil changes, and the spot on the driver's side frame rail behind the radiator was a natural path - on the same side as the System 1 filter was located (but it was bolted to the back of the stock bumper).

          Of course Brad made one of his aluminum brackets that is always "art meets function", and with a few large rivnuts added to the frame mounted that to the rail, then the remote filter assembly bolts to that. The hose end fittings were mocked up to get the routing to the cooler, up front.

          Finally, Brad built the braided Fragola -10 AN hoses to go to and from the massive Derale oil cooler and back.

          These Vibrant aluminum "line spacers" were added later to keep the -10 oil and -6 power steering hoses grouped together and routed away from any sharp edges. They don't hang down as much as it looks - they fit well above the splitter and cannot touch anything sharp.


          The cooling system needed to work with the new radiator roll. The stock remote coolant reservoir - which is normally mounted in the back left corner of the engine bay, next to the master cylinder. That is a less than ideal spot, as it makes for a number of cross engine bay plumbing paths.

          We discussed adding a heater, which Jason absolutely did not want. But the stock reservoir was old and still replaced and relocated. After trying a few we had on hand we picked this Joe's Racing unit.

          The radiator hoses weren't bad but they were very old and the wrong length so they needed to be changed (the top of the radiator is nearly 9" further forward than before).

          Brad started with some templates then made an aluminum bracket to hold the unit, which was bolted to a number of existing holes near the fuse box.

          A little testing by hand after that bracket was bolted in showed a need for another brace. Brad took a piece of aluminum and added one lateral brace to the bracket, and that made for a great mounting platform for the Joe's Racing aluminum reservoir.

          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


          • #6
            continued from above

            This unique aluminum manifold below was spec'd and ordered, which has three threaded openings for 1/2" NPT fittings. Two are for the two common sizes of heater hoses used on this LS7 water pump: 5/8" and 3/4" hose barb. These stainless steel fittings shown below go into those two holes, then the third opening is for the tie-in to the reservoir - the black Fragola fitting in the end of the aluminum block.

            This makes for a good way to get water to go through the normal "heater hose circuit" without the heater core, and still feeds into the reservoir from the bottom (via the black hose outlet on the manifold). Some folks might just loop the heater lines but we wanted a proper tie-in with the remote reservoir.

            Then we rounded up some silicone hoses in those sizes + smaller stuff for the steam vents, plus a straight black anodized thermostat housing.

            Various HPS silicone hose bends and even "adapter bends" (different dia on each end) were ordered along with some aluminum tubing, which we use to splice the bends together to make the radiator hoses. Brad cut the pieces of tubing and added rolled ends with our tubing bead roller.

            This along with some T-bolt clamps (for turbo hoses) makes for very secure, leak free radiator hoses that can have bends, various lengths, and can even adapt from two radiator nipple sizes along the run.

            The pictures above show how we start with the bends at each outlet and then route and connect them with the aluminum tubes. Its not hard to do, just a bit tedious and you have to order parts from a number of sources.

            Above left is the best shot I can find of the finished radiator hoses. Above right shows there is a 180 deg looped silicone hose that goes from the bottom lower port on the remote reservoir to the front of the manifold block, for the heater circuit tie-in. The steam vent from the 4 port kit shown earlier is tied into the top of the coolant reservoir at a "T", which also ties into the top of the radiator - again, to release any air or steam pockets.


            The cold air intake tube and filter, or "CAI", that came on this Caddy (below left) was built for the smaller 78mm DBW (drive by wire) LS6 throttle body this came with from the factory. The filter was small-ish and just sitting out there in the hot engine bay, without any containment from hot air from the heat exchangers in front.

            Since we were moving to a 102mm DBW throttle body we had to upsize ALL of the CAI tubing, and that starts to make things tricky. I am also a big proponent of putting the LARGEST air filter on that you can fit as well as keeping it away from hot air - to get the "cold" back in cold air.

            After the main components were added to the engine bay and the radiator was rolled we realized we actually had MORE room for the larger tubing needed with the 102mm TB - in front of the engine - but the large air filter and cold air "box" I wanted to add was going to be tough to package under the hood. The headlight units are quite large and the vertical spot I wanted to stuff the 4.5" tubing down into was tricky.

            The 78mm ID of the LS6 throttle translates roughly to a 3.5" ID hose, which is a pretty common size (silicone bends and hoses come in most sizes every 1/2"). The 103mm TB we were upsizing to translates to a 4.25" ID hose, which is NOT a common size. We want to get from 4.25" to 4.5" hose and tubing, because going smaller COSTS POWER but going large only helps. The 90 deg bend in 4.5" size is common and low cost, but we needed something to convert from 4.25" at the TB...and I was struggling with the same challenge on my 2015 Mustang.

            I finally bit the bullet and bought a pair of these problem-solving HPS silicone 90 deg bends that convert from 4.25" to the more common 4.5" size, then it was time to trim the radiator support to clear the large 90 deg aluminum bend in 4.5". That points down to where I wanted to stuff a giant air filter.

            To clear this 4.5" dia aluminum tubing bend we also had to modify the headlight. This was done with the blessing of the car owner - he had planned on making something custom with LED bulbs for endurance use, beyond the OEM incandescent bulb. That was done first on a "junk" headlight housing.

            The Vibrant aluminum tube need to be extended a hair so Zach TIG welded on another few inches, to allow it to be one piece. A mounting bracket / tab was also welded on.

            The customer really liked the DEI Gold foil covered intake tube on my LS550, so Brad wrapped this 4.5" intake tube with the same radiant / reflective barrier covering. It can be a nightmare to lay down perfectly smooth - don't worry, you can have some wrinkles!

            Above you can see the mostly finished intake tube, and how it routes. This might seem like a long pathway but it was necessary to get the big air filter down where we wanted - behind one of the massive fog light openings in the front nose. You can see the opening in the picture, below left.

            To keep the filter from getting just "any air" down there, we wanted to make an airbox that was sealed to the front nose's foglight opening. Brad built this in cardboard first, then transferred to .063" thick aluminum sheet...

            This was cut, bent, and riveted together to make a semi-rigid airbox that seals pretty well to the front nose opening. We came back later (July 2021) and added the bung for the IAT - intake air temp sensor. Oops! A little oversight - would have been easier to weld that on before the DEI gold wrap!

            This shows the finished cold air intake system - from throttle body to filter - and the airbox the filter resides in. Again, not easy fitting this massive 4.5" diameter tubing inside the engine bay, but with the rolled radiator it fit. I will show more pictures of the filter from down low at the fog light opening, but trust me - it is getting some good, cold air and even a slight "ram air" effect how it is built.

            WHAT'S NEXT?

            Wow, that 3 parter got pretty detailed and barely got us through 5 months of work - from Dec 2020 through April 2021! I better stop here and attack more of the 2021 work in another sitting.

            Next time I will show a lot of things - from the fire system updates, to digital dashes we tested, and the many "fun" challenges we had with the Holley Terminator EFI. A word of advice - ask around and do a lot of research before you pick a brand of EFI, and have a good tuner nearby for tech help. We will show the V firing up with the new engine next time and possibly some aero work, too.

            Thanks for reading!
            Last edited by Fair!; 12-31-2022, 06:13 PM.
            Terry Fair -
            2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
            EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


            • #7
              Project Update for Dec 31, 2022: I started writing this update Dec 31, 2022 - to try to catch up the build through the end of 2021! This Caddy has been completed and left Vorshlag several months back, but I am woefully behind on updating build threads (each one of these takes hours to write, add pics, and edit).

              This CTS-V was one of the more popular cars we have ever built, and I want to show the steps it took to un-do some less-than-perfect work that had been done to it. We are happy with the final result but there were some bitter lessons and tough challenges along the way - not the least of which was the Holley EFI.

              We pick up from last time with work we were doing on this car in May of 2021 and cover work done through the end of December 2021 - when we fired up the Caddy for the first time. In May '21 we had the engine bay pretty well cleaned up, the new HPR built 383" LS6 installed, the cooling system massively upgraded, oil cooler / remote filter / plumbing complete, the Mk60 installed and new brake lines plumbed, and the airbox built. Some little issues we uncovered kept stacking up and that made the timeline, scope and budget creep out there. Nobody likes it when this happens, but you sure hate to uncover a problem and ignore it. Luckily the owner Jason is meticulous and safety conscious and agreed to everything and more.


              The old wiring on this car looked worse the further we dug into it. To start off it was an 18 year old car, and "old car problems" start to creep up in any stock wiring (especially underhood) when they get this old. And this car's wiring had been hacked on by many hands over 18 years..

              In hindsight we should have re-wired this entire car. It was a tough call but after discussing it with Jason we agreed to only alter what was absolutely necessary, and the Holley EFI came with a brand new engine harness - which would replace a lot of really hacked up wiring underhood. At this point we needed to mount the Holley Terimnator X-Max ECU, and it was decided that the right side of the cabin wold be ideal.

              Brad used aluminum sheet, laid out the ECU mount, added curved edges to make it stiffer, added rivnuts for the ECU to bolt to, then installed the Holley computer. This plate mount was then attached to the firewall just behind the dash bar, as seen below.

              It took some time for Brad to lay out the various relays, fuses, wiring runs, main battery junctions, add all of these devices and run the wiring. The end result is very tidy, clean runs, and everything is labeled.

              The old engine wiring harness needed to be removed - and that required a bit of disassembly. The old fuse box was "discombobulated" from the chassis harness, removed, and the engine harness and some other nasty bits came out.

              With that big mess of bad wiring removed (above left) the Holley EFI harness went in quickly and cleanly. The harness seemed well made, but come to find out the Terminator X harness is notoriously sketchy. We had TWO of these identical Terminator X LS engine harnesses that were mis-pinned, which bit us in the butt on a different Holley EFI project in the shop. Somehow Jason's Caddy's Holey harness was not afflicted.

              Brad labeled every trunk in this harness for easier maintenance down the road, and grouped the different trunks better than the way Holley did.

              As the wiring work progressed more issues cropped up, like hoses that were burned from touching header primaries, bad relays, crappy battery cables to the starter, and more.

              Instead of trying to salvage some 18 year old OEM circuit for the fan and starter relays we sourced this 2 relay + 3 fuse unit from Waytek wire. Brad built a little panel in the back corner of the engine bay and added that unit, then got to work on the starter.

              The starter tested good but the wiring connector had been snapped off and just duct-taped in place, so Brad replaced that wiring connector. As the starter was installed but Brad kept finding more hoses and wires underneath that needed re-routing, heat sleeve, P-clamps, and more. Find, fix, and move on.

              As Brad installed the new wiring for all four wheel speed sensors along the chassis, more hoses were secured, and the wheel speed sensors were connected to the wheel bearings. We thought that was the last of the ABS work - but that proved to not be the case. We had been given some bad information about these hubs being compatible with the Mk60, but it turned out we needed to update these old 5-lug Corvette "passive" signal hubs to the 2009-13 "active" yellow wire hubs, which we did in early 2022. I will cover that in another post.


              The old LS6 engine from these cars had a somewhat antiquated Drive By Wire (DBW) throttle body that was very small. We wanted to use a more modern 102mm DBW throttle body with the Holley EFI, and likewise we needed to upgrade the DBW throttle pedal as well. We picked one of the Holley approved AC Delco units from the LS3 Camaro.

              The wiring pin-out and connector are different, but we had ordered the Holley harness for this LS3/LS7 pedal, and luckily that unit bolted into the same bracket as the old LS6 pedal unit - 3 bolts through the side.

              Normally when we are swapping DBW pedals we have to make a bracket - like we did on my S550 Mustang LS swap, above. We make that bracket for the S550 to use this same LS3/LS7 pedal assembly, which is cost effective and works on all of the modern LS3/LS7 swap compatible harnesses.

              If you ever have to swap the pedal to something that doesn't bolt to the factory firewall bracket remember to check your spacing - for both "heel-toe" pedal (above left) and "left foot brake" spacing (above right). Again, not needed on the CTS-V because the LS6 and LS3/LS7 pedal mounting holes are the same. Whew!

              MK60 BRAKE SWITCH & BRACKET

              One of the last things to complete the Mk60 ABS swap was to add a pedal switch. This tells the ABS system that you are pressing on the brake pedal, even if just slightly. The type of signal it needed was different from how the CTS-V's original brake pedal switch was wired (potentiometer vs limit switch), so we decided to make a bracket and mount a limit switch to the pedal arm.

              This was fairly easy - Brad took a piece of 2x2" angle iron and cut out a portion (see above left) to mount to the steering column / pedal mount (see above right). This placed a portion of the bracket in-line with the axis of travel for the brake pedal. A reversing relay was also mounted to this bracket, to flip the brake signal as the Mk60 wanted. Took some research to figure out the signal type but the switch, relay and bracket were "tens of dollars" of material and parts.


              With the hacked up factory engine harness removed, we looked at what was left of the OEM start switch circuitry - including the factory key!? - to see if that could be incorporated into the Holley. As you can see below-left, that wiring under the dash was a HOT mess - not worth chasing these wiring issues, time to bypass that.

              A push-to-start button assembly was custom ordered online by car owner Jason, with "Release The Bald Eagles" printed on it. Hilarious and functional.

              Brad then built a small curved aluminum panel to mount this button, which was then mounted to the dash. We tested the placement before mounting it, to make sure the tallest driver on his WRL team could reach this start button while belted in, and yes - it works. Some wiring into the Holley harness and into the starter relay that was shown underhood (above), and we could bump the starter! Getting closer to First Fire...


              Even though there was a digital dash on the way, we wanted to have one of the old analog mechanical gauges that was already mounted in this car to work - it would be a critical back-up gauge if the dash wasn't working for some reason. Nothing else trumps oil pressure!

              The old oil pressure sender (above left) for the mechanical gauge (which itself mounted in the center stack) had a bundle of adapters along a short hose that connected to the back of the block where the "stock" oil pressure sender went, behind the valley cover. This sender was zip-tied to a fuel rail. The new sensor for the Holley EFI was now connected there, so we relocated the sensor to a port on the Improved Racing remote oil filter adapter. That needed a different fitting - luckily, one of the extra stainless braided hoses from the 4-port steam vent kits was the perfect length and had the exact end needed - so we utilized this.

              Brad made a cradle bracket out of some Delrin we had in the CNC shop. This was a hunk of Delrin that he hole sawed, cut in half, then drilled mounting holes, then made a "zip tie channel" underneath.

              This was then bolted to the inner fender structure under the Mk60 ABS bracket. This then allowed the somewhat bulbous pressure sensor to be remote mounted and attached to the new bracket, away from engine heat and out of the way. We found out later (working with old parts without documentation is fun!) that this sensor needs to ground through the body, and with our Delrin mount it wouldn't work. So a single ground wire was added to the outer casing then grounded to the chassis. Then it worked.


              One of my "cost saving measures" for my own LS550 swap that we incorporated into this CTS-V build was using a ~$100 Chinese 102 DBW throttle body. I figured - hey, there are thousands of folks using these, how bad could they be? My tuner was telling me to use a Nick Williams 102, but those are $700 and sometimes out of stock.

              Well as soon as the serpentine belt was installed it was evident that we had a problem. No matter how we sliced it, the China 102 TB's wiring harness was going to hit the belt.

              We looked at shorter belts but it was part of the big OEM spring loaded tensioner itself - it was always hitting this connector. Time for plan B!

              Having tried "manually adjusted" tensioners in the past (Katech) I looked at an ICT billet version - ordered one up ($75, made in the USA) and it worked brilliantly.

              They make this manual tensioner in 3 front-to-back belt offsets - "4th gen F-body", Corvette / CTS-V, and "LS truck". The belt alignment was perfect and the smaller billet bracket swivel end cleared the TB's wiring connector by over an inch. And also, no spring loaded tensioner to kick a belt off at high engine revs (this HPR engine can be safely spun up to 7500 rpm). This whole task was less than 45 minutes - easy fix!

              DIGITAL DASH - ATTEMPT #1

              Back in June 2021 we were looking at digital dash options, thinking (FOOLISHLY!) that the Holley EFI systems could send CAN data to any digital dash. Oh how wrong we were. In reality the Holley EFI systems are built TO PREVENT the use of anything BUT a Holley branded dash. What a silly decision by Holley - SHAME ON THEM for going out of their way to encrypt their CAN data. No other major EFI manufacturer does this - nobody.

              So we made these 1:1 scale cut-outs for dash options to use on this Caddy and another project we were using a Holley Terminator X-Max on. I much prefer to use AiM Sports digital dashes with all race car builds, as they have an industry leading predictive lap timer with good race track support, and "pretty good" support for OEM and aftermarket EFI.

              Above are the two best "fitting" dash options, the AiM MXG and the Holley Pro 6.86" dash. There were two options for their newest "Pro" dashes, which both have touch screen support - this little 6.86" and a massive 12.3" dash. The prices have gone up considerably on the Holley dashes since 2021, but those were the prices then. After some research we found out that only the Holley dash would work, and Jason wasn't too keen on the small or big Pro dash options...

              Then we found out about a larger 7" dash from PowerTune Digital in Australia - and the owner there said they had Holley Terminator EFI support! We reached out and they saw the build and sent us a FREE dash. Wow, great! So when it arrived Brad made a bracket to attach their back plate bracket to the column.

              We had 6.52 hours of time logged mounting, wiring, then testing with this dash. Never could get it to work. Reached out to them in Australia (support via email only) to find out that no, we needed to log a bunch of CAN data, send it to PowerTune, then "in a few months" they could probably make it work. Ugh. So that was a - total DEAD END and I had to eat all of the hours wasted (more than the cost of the dash) for this non-functional install.


              The old 3-point strut tower brace (origins unknown) was already modified to clear the massive FAST 102 LSXR intake manifold, and still needed spacers at the tower mounting points.

              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


              • #8
                continued from above

                The old nozzles were mounted to the rear part of the 3-point bracket, but the new Radium fuel filter blocked that mount. The engine bay was getting tight and it wasn't going to fit back there. Plus every time the STB came off the fire system lines were bent and/or had to be disconnected - and that brace comes off a lot during maintenance.

                The car owner signed off on converting this to a "2 point engine bay brace". This car isn't really a strut suspension, its an SLA, so there aren't big suspension loads going through the "towers" or this "strut tower brace" anyway. The rear mounting studs at the firewall would come in handy for something else.

                Brad modified the 3-point brace once again, now turning it into a 2-point, then painted and finish mounted that. Clean, functional, and it opened up some room at the back of the engine bay we needed for the two fire nozzles.

                With that space opened up at the firewall it was time to lay out the two fire nozzles and a mounting bracket. Cardboard Assisted Design once again.

                With the cardboard design perfected Brad then turned this into aluminum using some .080" thick 3003 sheet. And while he could have kept it pretty basic, he went overboard. And damn it looks good.

                Who would think to find beauty in a fire nozzle bracket? But its there. A couple of dimple dies add strength and lightness. The nozzles were re-mounted with some new aluminum hardline, bent to tie together into the line from the cabin at a "T", as seen above right.

                The finished engine bay nozzles are plumbed into the existing system with the new hardline, and they point at the two fuel rails - which is where the highest chance of an engine bay fire can happen. These spots also cover the parts beneath this upper engine section, too.

                The Caddy's engine bay is really starting to shape up here - wiring is now clean, protected and properly routed. All of the plumbing underhood is new or inspected and routed better than before. The Mk60 ABS is mounted and plumbed properly. The radiator hoses, fuel filter, fire nozzle, engine bay brace and relay panel are all new and complete.

                Another couple of brackets were built for the fire nozzles in the cabin, as the old brackets were poorly placed and janky. This was a small step but a crucial part of the safety plan for this car.

                FIRST FIRE TEST WORK

                In late July 2021 we thought we were ready to fire up the engine for the first time (aka: First Fire). We have a huge checklist we go through on a new build / new engine, with Brad powering through that. Final wiring systems were completed, including brake lights and headlights - in a somewhat premature anticipation of a test drive.

                All manner of fluids were filled into various systems - 93 octane fuel went into the 100 liter fuel cell, distilled water and Water Wetter into the cooling system, and some Mobil1 synthetic oil went into the engine.

                This car already had a supplemental dry sump system from ARE , which adds 2 suction stages to the stock LS6 pump's pressure stage. We had to double check all of the fittings and lines to prevent leaks before dropping 3 gallons of oil in, with both old plumbing and new. All of the old stuff was literally "old school" stainless braided lines with red and blue fittings. Anything we added was black 3000 series Fragola aluminum fittings and black nylon (outer jacket) braided lines from Fragola.

                Once all the fluids were in and leak free it was time to load a "start up tune" from our tuner friend Jon Simpson. He asks us for all manner of data - fuel injectors, throttle body style, sensors utilized, crank trigger wheel tooth count, and more. He takes all of this data + engine build data from Erik Koenig at HPR and comes up with a somewhat simplified start-up tune. We futzed around with the PowerTune Digital dash for a week and wrote that off, so now we are into August.

                We then had to wait a couple of weeks for a Holley CAN splitter cable to arrive, to be able to connect both the laptop and the optional 3.5" Holley touch screen at the same time. Ultimately the goal would be to connect whatever digital dash we ended up with and the 3.5" at the same time, or the dash + laptop. If you are adventurous enough to use a Holley Terminator EFI, you REALLY SHOULD order the can splitter wire (see above left pic) and the 3.5" touch screen (above right) to have this emergency backup.

                Then we had a delay getting the engine to fire - some of this was from our inexperience with Holley products, but not all. This was our first of 3 Holley EFI installs we would subsequently tackle in 2021, and the learning curve was there - and many hours of logged time were written off as we picked up the intricacies of the Holley software and hardware. Lots of firmware mismatches, some struggles with the software, but we got truly stuck at one point. The Drive By Wire throttle body just simply would not get past the "TPS Autoset" procedure.

                We were hitting a wall and could not get the engine to do more than just crank - testing fuel, compression, plugs, spark, and the tune. The TPS issue was driving us nuts, but our main tuner guru Jon happened to be in town Sunday night (above right) getting something from HPR. He stopped by our shop, tested a few things, and tweaked the tune, but we still had some issue. He was positive it was no longer any tuning / firmware mismatch.

                The next day Zach and Brad fought and fought the EFI, then finally purged the tune, zero'd the voltage on the ECU (using a jumper), and reinstalled everything - firmware and tune - then the TPS Autoset finally worked. Just another "Holley being Holley" issue, who knows? On Tuesday the 24th of August, it fired up for the first time. That First Fire was glorious, but the Caddy was VERY loud so we didn't run it for long. Now we at least had a running engine, good oil pressure, an EFI system that mostly worked, even if only reading data to the laptop of tiny 3.5" screen. I was happy and the car owner Jason was as well!


                During the period between adding fluids and First Fire, the Ohlins dampers were removed and sent off for a rebuild. These were some fancy "5 way adjustables" from Ohlins Motorsports, and a bit old. We found some leaks and several reservoir hoses had been rubbed by tires, so the car owner decided on a rebuild.

                Another reason for the rebuild were the fact that these dampers all had very short hoses leading to the remote reservoirs, which put the reservoirs and some adjustment knobs in very hard-to-access places. The front reservoirs in particular (see below left) where mounted where the tire could rub into them at full lock, and we had new wider wheels coming that would only make this worse.

                We had already mapped out a new routing for each reservoir and gave those notes to Chris at Inertia Labs when I delivered them July 19th. By September 20th these were rebuilt and ready (he had some parts sourcing delays) and our crew was ready to install them.

                The new reservoir hose lengths up front allowed the canisters to be mounted under the hood, with the hoses secured away from any moving parts - including the 18x11" front wheels and 315mm tires that would be going on soon.

                Out back the old routing for the reservoirs to pass into the trunk was compromised due to the super short hoses these dampers used to have. The pass-through hole was getting rubbed by the rear tire, including the hoses - and we were moving to an 18x12" wheel and 335mm tire, only making this worse. So we proposed a new pass-thru and the car owner signed off on that.

                The old holes were patched with aluminum panels and the new 2-1/4" diameter hole allowed the reservoir to pass through. That opening was sealed with a 2-piece Seals-It 3" grommet, with a 3/8" ID inner hole. This keeps water and grit from getting into the trunk better than a strip of tape like the hole pass-thrus had.

                If you read ANY of our build threads we take remote reservoir mounting very seriously. I've seen the results of doing this wrong (pinching pistons inside of the canisters!) and not being able to access the adjustment knobs only ensures that you NEVER adjust your dampers. Doug built these custom reservoir mounts for all four corners - I showed the rear reservoir mounts in the trunk above.

                Under the hood these half-round brackets were bolted to the 2-point engine bay brace, which puts the reservoirs in good airflow to keep them cool AND lets you access the adjusters easily. These are all clamped to the brackets AT THE ENDS of the canisters, where they are made to be attached, using hose clamps covered in heat shrink tubing. This prevents the stainless steel hose clamps from scratching the anodized finish on the canisters.

                Last but not least were the front swaybar endlinks - the were too long and allowing the swaybar to touch the bottom of the dampers. We measured for and ordered some new Whiteline KLC-090 shorter and adjustable endlinks. These arrived in early November and wrapped up the last of the suspension changes.


                One more delay that was keeping us from driving the Caddy after First Fire was a missing stock driveshaft. The factory 2-piece steel unit was gone, missing, nowhere to be found. We tore the shop apart, and 18 months later now still haven't found it. This has never happened in 18 years of running Vorshlag - where some critical part that went missing. So I said I would replace it with another OEM 2-piece unit -or- apply a partial payment to a new aluminum 1-piece driveshaft from The Driveshaft Shop.

                Jason chose the latter option, and a DSS 1-piece driveshaft was ordered (see above), with a big discount from me (for losing his stock unit) plus it was much lighter than the OEM 2-piece steel driveshaft.

                The factory rubber driveshaft isolator at the back of the T56 6-speed transmission gets replaced in the DSS kit with a series of adapters and a CV shaft. The adapter is bolted to the 3-bolt yoke on the trans then the 6-bolt front flange of the new 1-piece driveshaft bolts to that, as shown above.

                Similarly the rear flange at the differential gets another adapter piece machined from steel, then the 6-bolt rear driveshaft flange gets bolted to that, at the rear CV on the driveshaft.

                The 3" diameter DSS driveshaft fits tight in the tunnel - the OEM 2-piece steel driveshaft was smaller in diameter and had the center bearing mount that this 1-piece does not. Which gave us an idea to mount a safety strap for the driveshaft there.

                We have done this on high powered V8 swapped BMWs in a similar way - using the beefy mount for the factory driveshaft center bearing as a spot for a "driveshaft restraining strap", sort of half of a safety loop. The upper structure for the center bearing mount completes the loop. Doug made this from a thick piece of aluminum sheet (.100" thick), bent it to shape and bolted it in place.

                With the driveshaft in place it was time to install the exhaust, so we could run the engine for more testing without being open header (LOUD) but sadly, the extremely tiny "mufflers" on the car left much to be desired and made the Caddy still brutally loud when running.


                The driveshaft and Holley wiring delays had pushed things back. We are now into the first week of November 2021 - and everyone was anxious to get this car driving on the road. Time to bleed the all new brake lines.

                Now on a car with extensive brake line and fitting changes we have learned to use lower cost DOT3 fluid for the first test drive. Why? Leaks always appear during the first bleed of clutch or brakes, and using $22 per 500mL bottles of RBF600 or $32 bottles of RBF660 is foolish. So we used a gallon of DOT3 that costs $10, until any potential leaks are repaired.

                The brakes bled fine, and we will swap the fluid out later for proper DOT4 racing brake fluid. But the hydraulic clutch system was nothing but problems.


                This led to its own task - fixing a problematic clutch master cylinder that kept failing. We quickly realized that during manual bleeding of the clutch, the pedal stopped having any resistance. Doug pulled our the aftermarket Tilton master cylinder and tried to bench bleed it. Somehow the seal on this old Tilton master had blown during our bleeding procedure?!

                We ordered another new Tilton, of the same size and style, and that was installed. But once again during manual bleeding (compressing the pedal and bleeding via the remote clutch bleed hose) that one ALSO failed.

                This meant one thing - there was too much allowed over travel of the clutch pedal and it would keep failing the masters until we added a clutch pedal stop. There was also some serious side loading of the pedal pushrod within the clutch master cylinder, exceeding the allowed amount by Tilton. The entire mounting of the aftermarket clutch master needed to be re-configured.

                Once we noted this side-offset issue with the pushrod, Doug got to work and added some length to the clutch pivot arm, which would re-align the pushrod from the OEM clutch pedal directly to the bore of the clutch master.

                After the newly lengthened clutch pedal arm pivot was added, and the second replacement Tilton master installed, then a critical step - an adjustable clutch pedal stop was added.

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


                • #9
                  continued from above

                  The pedal stop consists of a threaded nut added to the firewall, then a bolt (with a jam nut) that the head of pushes against the back of the clutch pedal arm. This now prevents the clutch master cylinder from over-traveling and puking the seal out. Now we could finally bleed the clutch.

                  Many more hurdles to overcome that were unexpected, but we finally had working hydraulic brakes & clutch, dampers that were rebuilt and properly mounted, the new engine ran, all of the new plumbing and wiring was working better than ever. Now we needed to focus on the digital dash dilemma.

                  DIGITAL DASH - ATTEMPT #2 - HOLLEY 6.86 PRO DASH

                  After extensive searches we kept coming up with the same limitation: the Holley Terminator EFI system would ONLY work with Holley digital dash units. Until someone spends the hours to decrypt the Holley CAN protocol we are stuck with their brand of dashes, which are not exactly "good" products. But we're stuck so it was time to choose.

                  Our earlier template testing showed that the 12.3" dash was simply too big to mount without extensive modifications to the factory dash, but the smaller 6.86" touch screen color Pro dash would fit. It is a very short display (top to bottom), and in hindsight maybe the 553-106 dash would have offered better screen "real estate" but no matter - the customer chose the 6.86 touch screen version.

                  We had one of these Holley 553-112 dash units for another project on hand, so Brad took that and made a template for mounting it into the Caddy, to the same mounting points we had for the PowerTune dash that didn't work. The cardboard then became aluminum.

                  This is the bracket above left, made from .080" thick aluminum sheet. Of course it has a brushed finished, rounded insider corners, and looks great. The 553-112 dash was bolted to that and that was bolted to the column. All told this task was 2.45 hours, and it fits great inside the opening of the steering wheel.

                  Due to "supply chain problems" we wouldn't see the actual 6.86" digital dash for a few months, but in April of 2022 (above) we had the unit, the correct cable, and it was programmed for use before the car went off for tuning.

                  MOCK UP SPLITTER & FLARES

                  When this CTS-V came to our shop in April of 2020 it already had rear flares made for this chassis. They are no longer available and missing a small cosmetic piece that goes on the rear doors, and those clear the 18x12" wheels and 335/30R18 tires Jason wanted to run out back. But the front was on some old 18x10.5" wheels and 315/30R18 tires - which didn't come close to fitting the stock fenders.

                  Some previous owner had "hammer flared" these front fenders to clear the 315mm tires - and they looked like they had been chewed up by a rabid dog. The owner Jason had always planned on fixing this by adding proper flares - and now we found a short cut!

                  At the same time we were working on this Cadillac we were also working on four other major customer race car builds + two of our own race cars (which is too much for only having 2 full time tech to do this work + all of the product development work they get roped into).

                  One of these other customer builds is Joe's Smurf Blue 2010 Mustang GT - to which we have added a Gen2 Coyote 5.0L engine, massive aero, as well as 18x13" front and 18x14" rear wheels with 335/345mm Hoosiers. To make these giant wheels fit this Mustang we utilized a set of TruFiber fiberglass flares that were available for this S197 Mustang chassis, and while it was still in the mock-up stage, we borrowed those and tried them on the CTS-V.

                  As you could see in the picture of the shop above, one day I taped them to the body for testing. Installing the front fender flares involved a bit of fab work, some aero theory, and some body work to the CTS-V. But by damn, they fit the front Caddy fenders VERY WELL. We would need to make a lower extension to tie into the future splitter, but as you can see above we had to make that for Joe's Mustang also. That bit was within our wheelhouse - making fiberglass flares from scratch was not. So the S197 front flare was a huge score, and I ordered another pair for the V.

                  Next up we had been tasked by Jason to move forward with the aero (while we awaited the Holley dash and some other parts), so Brad, Doug, engineer Jason McDaniel and I mocked up what the lower splitter plane would look like, after setting ride heights on the Ohlins coilovers previously. We wanted the rear of the splitter to extend back to the Front Axle Centerline (which makes it legal in many classes), which would require an air dam of a little over 1" tall at the front lip (see above right) for a level splitter.

                  We mocked up a piece of plywood and I took a picture from a high vantage point (ladder) then marked out the suggested splitter shape for the owner Jason to approve. This was after our Jason had looked at many potential classes beyond WRL "GTO" class this was originally built around, in case the owner wanted to do some Time Trial or sprint races in NASA ST1/ST2 or the like. The 6" forward extension would work well and the blended shape around to the sides with a 2" extension would fit well with the S197 flares we had in mind. Jason signed off on all of this and we began moving forward almost immediately - on December 14th, 2021.

                  FAB SPLITTER & REAR BRACKETS

                  The day after Jason approved the design mock-up (above), Brad got to work on the splitter. We all agreed that a 1/2" thick plywood splitter would be ideal for the endurance racing he had in mind - making replacements cheap to produce. Brad knocked the basic shape out from a plumb bob dropped on a pen from the front fender shape, traced on the plywood, then moved forward 6" and outward by the 2" I drew in the picture above.

                  Some time is always spent tracing out clearance for the front tires, and this time we had to add a little more for the 18x11" wheels we had coming to replace these old magnesium 18x10.5" wheels. Steering is turned lock to lock at full droop - the worst case scenario - to make this shape. These wheel cut-outs are also dictated to some extent by the control arms at full droop, steering tie rods and other moving parts.

                  A good jig saw makes quick work of this splitter shaping, and this was completed on day 1 of the splitter work. And while this looks like the bulk of the work for making an all new splitter (and is most of what you need for a replacement), there are other time consuming steps needed - mostly to do with mounting to the subframe at the rear, then splitter struts, and an air dam.

                  This was the first car we utilized these Professional Awesome branded rear quick release brackets - and I don't ever want to use anything else! These are pretty amazing, being based on a CAR DOOR LATCH and a pin on the end of the triangular black bracket above. You pull a cable to release these, and down they go. Makes for a QUICK removal of the splitter (reinstallation is a bit more work, but so be it). Brad mocked up the splitter plane with our level once again and had the PA parts above that.

                  This is where the time starts to accumulate - the majority of the 11.2 hours logged in making and mounting this splitter went right here - to the brackets Brad built. These went from cardboard to aluminum, and these aluminum brackets will stay attached to the factory front subframe (which we seam welded and powder coated earlier).

                  Sometimes you get lucky and the provided flat plate mounting brackets can attach to the frame rail or something else, but in this case we needed to make these aluminum mounts - which Brad designed and cut out, then Doug TIG welded the rounded cups to. These were then bolted to large M8 rivnuts added to the subframe. This puts the black PA bracket level with the top of the splitter plane - it then bolts to the plywood splitter.

                  Once the first bracket was completed and tested for release and hold strength, the second bracket (above left) had to be built - luckily it is symmetrical and could use the same template. The above right pic shows the door latch portion that stays with the subframe - and the black triangular PA bracket is not installed, as it stays with the splitter. The PA brackets were then bolted to the plywood with 8 bolts (that we later changed our for counter sunk bolts, so they would be flush with the bottom plane of the splitter - and not get ground off!)

                  With some basic fab skills and a piece of plywood, plus the Professional Awesome bracket assembly, you could emulate this quick release splitter install in a weekend for almost any car. There isn't much money in all of this, and at the time the PA kit was $150 + $47 for the 4x8' sheet of 1/2" plywood + some hardware. Again, 11.2 hours of time is what was spent, maybe 4 hours on the design and shaping of the plywood portion, then the rest on the brackets for the quick release PA bits.

                  MOUNT SPLITTER STRUTS

                  The above task was to make the splitter's basic shape and mount it at the rear - but of course there was more work to do. The front needed support, and we decided on 4 splitter struts also from Professional Awesome.

                  How those mounted to the chassis remained to be determined. We had hoped to use the 4 holes already in the bumper cover, but like some of the recent work that had been done to this car by a previous owner, the existing strut mount holes were wildly out of level. It isn't even surprising anymore how bad some of the previous work is. I'm not trying to imply that the work we do is perfect and everyone else's work is crap, but man - this stuff is bad. We all just shake our heads and move on...

                  We were able to tie into a one of the two existing center holes in the bumper cover, with threaded steel round bar machined on the lathe to make these mounts for the Professional Awesome splitter struts. They came with "fork" mounts that can bolt to our threaded bungs, which themselves will be welded to the tubular bumper beam we built previously - all as part of the plan for splitter mounting.

                  For the outer two strut mounts I wanted to try something we had recently done to the S197 - where we added two massive front tow hooks to the tubular bumper beam, and double that up as a splitter strut mount. These tow hooks are also a GREAT place to both strap a car down inside a trailer as well as winch them into/out of the trailer - and of course for emergency flat tows / extractions on track. I cut out a pair on our CNC plasma table for the Caddy from the same 3/16" steel plate we have used on other cars.

                  Doug laid out the tow hooks, angle cut them so they were parallel with the centerline of the car, and tack welded those to the Caddy's bumper beam - which we left exposed in the massive rectangular fog light openings for this purpose, months earlier. Above right you can see the carbon strut rod assembly from Professional awesome being mocked up.

                  We purchased these splitter strut rod parts at the same time we purchased the rear splitter quick release latch kit. The splitter struts are made from a graphite rod (like a fishing rod - flexible in bump, rigid in tension), compression fittings, and the forked ends - with quick release pins for easy removal. The rods are cut to length, then assembled and tightened in place. After that the quick release pins are used to remove or install them.

                  And yes, we have tested them on other cars, and that can take hundreds of pounds of static load in tension - and are flexible in compression, if you bump something with the splitter and push them "up".

                  With the two center threaded bungs attached to the bumper beam and passing through the plastic front cover, the two outer holes were drilled into the tow hooks, and all four upper mounts were now complete. Now we can measure for all 4 splitter strut lengths and cut those for assembly.

                  At this point we had everything mocked up and Doug could move onto fully TIG welding the tow hook mounts and two center mount bunts to the curved, full width, tubular bumper beam for the Caddy. Threaded studs were made to attach the four upper mounting forks (above right) to these four mounts. Those can stay in place - the slide through the round center holes in the bumper beam - so the threaded bits were installed with a dab of red Loctite.

                  The threaded bungs were made on the lathe, but the lower forks (fancy CNC aluminum) upper (basic steel) forks were sourced from Professional Awesome. We don't sell their parts but highly recommend them - this is a game changer when it comes to splitter struts.

                  The lower four mounting holes were marked, drilled, and counter sunk bolts installed - flush from underneath. Finally, two braided stainless cables were attached to the rear mounting latches (above right) and they route up under the front air dam - once in the paddock you can pull these cables and the rear of the splitter drops.

                  That is the basic splitter strut layout, upper mounting, assembly, and lower mount install all shown above - in a task that we charged 8.73 hours for (we spent 2 more hours than that). It involved some careful measurements, drilling, machining, welding, CNC plasma cut work, and a lot of fiddly bits. But this should work for years to come and makes for a quick splitter removal - pull the four splitter strut quick release pins and pull the 2 cables and the splitter is down in less than 45 seconds.

                  WHAT NEXT?

                  That took us through the end of December of 2021, but there were a few more steps on the front aero I will show them next time, including: the proper installation of the flares, building the air dam, creating front fender flare extensions / wheel spats, and adding tunnels in the lower splitter section - which feed brake cooling ducts at each front wheel.

                  We also tackled some front brake upgrades, swapped to active sensor hubs (and tested the ABS), installed a bunch of new rear suspension parts and subframe bushings, added proper mufflers, and took a real test drive on the street. Tune in next time to see more of the creation of this Caddy that zigs!

                  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