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2004 Cadillac CTS-V Endurnace Race Car at Vorshlag

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  • 2004 Cadillac CTS-V Endurnace Race Car at Vorshlag

    Project Introduction - May 6th, 2020: This road race car entered our shop during the global pandemic, when 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.

    INITIAL INSPECTION

    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.

    GET INITIAL WEIGHTS

    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.

    INITIAL TEAR DOWN & REMOVE DRIVETRAIN



    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.

    REAR DOOR WEIGHT TEST

    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.

    ROLLED RADIATOR WORK

    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.

    TUBULAR BUMPER BEAM

    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.

    PREPARE SUBFRAMES FOR POWDER COATING

    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.

    WHAT'S NEXT?

    All of this work happened in 4 weeks, during a period where we had people working about half their normal schedule to improve social distancing in the shop. This post is long enough - more next time.

    Thanks for reading!
    Last edited by Fair!; 05-07-2020, 04:28 PM.
    Terry Fair - www.vorshlag.com
    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
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