A new SLC hits the track/streets

I have been rather silent on this forum in the past but I wanted to announce the birth of our car. We recently finished Our SLC after 10 months (1500 hours) of pleasure. I had just retired and my son was between jobs so he moved home and we got busy.

It is orange, has Graziano transaxle, LS3 525, race tail and carbon fiber, well everything. I bought the car from a gentlemen who backed out a month before delivery so I only waited less than a month to get the car. Waited over a year to get all the parts to the car from SLC but that is another story.

Car is really built for track duty therefore all of the fancy carbon interior parts are up in the garage attic awaiting a rebuild someday. The interior therefore is spartan aluminum and yoga mat covered seats. WE are both over 6' 2"so the seats are pretty raked. We didn't do too many original novel things in the build. Probably the smartest thing was we opted to just clear coat the gelcoat which I thought would be an one coat deal but we had to put 3 separate coats to fill all the pin holes in the gelcoat. Turned out great and is really the way to go for the track.

We have put over 1000 miles on it since May 1, all track miles. The first 500 track miles were a bit rough. Suspension needed a lot of attention. Upped spring rates to 750F 850 rear, changed brake masters to 3/4 Front, 5/8 Rear. Changing the brake masters was really a good thing as it now stops well with what I consider to be reasonable pedal effort. Probably going to go with even stiffer springs depending on which track we go to. Took forever to get the bumpsteer quieted down. It still is not perfect in front because the the tie rod is hard up against the tie rod bracket that attaches to the upright and it really needs to go up a bit. Havent figured out how. Car has the extended foot box so will be tough to lower the rack. Any ideas out there? It took the better part of 2 days to align the car and then after experiencing some body rub issues on hard corners and changing out 3 wheel hubs we had to realign and re corner balance again. Good thing I am retired! FWIW, I cant imagine having anyone who was not pretty familiar with the car do justice in aligning it. It is a very tedious job that to do well takes some time. It is actually not that hard, just time consuming. As mentioned above in the first 1000 miles we have had to replace both of the right side hub assemblies and the left rear as well! Went back with Timken, we shall see how they last. In the end though the car really performs well.

Another thing that we made was a very simple low gear lockout (first, second, reverse) . It is a common door hinge from home depot that we bolted one side to the side of the gearshift frame and the other side of the hinge is spring loaded to flop down on the top of the gearshift frame when not in first or second. It will not permit moving the shift lever to the left far enough to go into the low gears. We put a sliding collar on the gearshift level that is attached by a stiff cable to the hinge so one can pull up on the "trapdoor" with the gearshift hand thus allowing entry to the lower gears. Ugly but pretty damn useful.

I really need to thank many of the folks on this forum who have come before me for their superb build logs without which I dont think we could have done this project. The knowledge in this forum is what gave me the courage to dive into this. I would also like to thank my son who had to put up with his dad for a year. It is a year I will always cherish.
 

Attachments

I went with a left side scoop. I made a plenum that pancakes to fit around the rear cage support bar and over the suspension. It is really ugly so have acquired a scoop for the back from Jack and am going to eventually change it to that setup.
 

HCF - John

Gearbox / Brake Systems
Welcome Paul!

Good talking to you the other day... I didn't put 2/2 together but you were out running with an old friend of mine, Robert (Radical), a few months back.

On improvements - I believe Fran uprated the springs to 650 / 850 in the more recent kits. Also know there were some changes to the brake system - think involving masters. Does anyone know if the 3/4 front and 5/8 rear masters are what's supplied with the kit now?
Best,
John
 

Howard Jones

Supporter
Paul, would you have the sizes of your caliper pistons? I have wildwood calipers (not the OEM set) and I have 5/8 masters in mine right now. Feels better out in the street in front of my house.

With the caliper piston sizes I can do the math and see what you have for system pressures. This would be a very important number for me going forward.

By the way I have 650f and 850r springs on mine. I think I will be going to move the 850s to the front and put 950s maybe even 1000s on the rear. My car seamed to squat a little too much resulting in what seamed like the front getting a light feel at speed (150) with 2 degrees on attract on the rear wing.
 
Hey Paul -

Congrats on the build, I have an affinity for the orange myself ;)

There's a lot of good information buried in your post, would you mind giving us a little more insight? What brakes were included in your kit - the wilwoods or brembo? The brembo kit includes a 3/4"F and 7/8"R master cylinder. Running a 5/8" rear would give you more (relative) braking pressure as compared to the latest offering, am I interpreting this correctly?

Approx what ride height are you running?

Hubs - this is the first I've heard of hub failures. What do you attribute this to? Isyour track particularly hard on hubs for whatever reason? I believe these are from production vehicles so should be ok for "normal" usage, perhaps track duty is too severe for the standard kit offering? Did you have to make any modifications for the timkins or were they a drop in replacement? Just the bearings or did you have to source an all new hub assembly?

Our cars are very similarly spec'd, race tail, carbon, orange, LS3/525, and Graz. More pics would be awesome!

Thanks,
Cam
 
Howard- I have the brembo calipers that come on the 2010-14 Camaro SS (among others). I found a great website that lists many of the important dimensions for doing brake swaps for late model GM.
(GM Brake Upgrade Option Measurements - Thirdgen F-body Brake Upgrade )

The Brembo front calipers are the same as on the CTS-V.
04-07 Cadillac CTS-V Brembo Front Piston size-40/44mm; Number of pistons-4; Area 8.61 sq. in. 5554 sq. mm; Thickness 32mm;
Gm Part # (L) 89047727, 172-2287 (R) 89047726, 172-2288

The 10-13 Camaro SS Brembo Same as 04-07 CTS-V calipers; uses 14mm mounting bolt instead of 12mm on CTS-V and painted differently (L) 92244287, 92233189 (R) 92244288, 92233188.

The rears are same as 04-07 Cadillac CTS-V
Brembo 28mm and 32mm 4 piston 2840 sq. mm 28mm thick rotor (L) 89047742, 172-2309
(R) 89047743, 172-230810-13
Camaro SS & ZL1 rears Brembo Same as 04-07 CTS-V calipers, just painted differently (L) 92233177, 172-2503 SS
(R) 92233176, 172-2502 SS
(L) 20944519, 172-2539 ZL1
(R) 20944518, 172-2538 ZL1, 172-2309 (R) 89047743, 172-2308.

With a 3/4" front and 5/8"rear master cylinder setup with what I would call moderate braking force on the pedal the system generates about 1200-1400 psi at the calpers. Full emergency pedal pressure (push as hard as I can) about 2000psi which will easily lock up the wheels with pirelli slicks. I have it set up with more bias in front as i was getting a bit of rear lockup under certain situations like trail breaking. I found some 4" 800# springs for the front and I going to move to 950# in back. I plan to go to COTA in August for a DE with Chin. The track is very smooth so I think the increased spring rates will be a plus.
Hope this helps.
 
John, Per our conversation about the hub sizes and potential rotor swaps as I mentioned on the phone the c4 hub diameter is 2.78" and the 2010-14 hubs (and therefore rotors) are 2.65" so the rotors that we use for the Brembo setup dont work with our hubs.
This perplexed me mightily. A phone call to RCR revealed that they mill out the mounting hole on the Brembo Rotors to fit! I had to figure all this out because I damaged a rotor so I got a cheap blank from local parts store for $60 and VERY CAREFULLY milled out the center to 2.78. John, If you get two piece rotors I imagine you will have to do the same. You could try and find rotors that have 2.78" hub holes to begin with as a ton of GM cars have this setup but finding the right rotor offset and diameter to fit these calipers may be a challenge. The iron blanks weigh 25lbs and I imagine you could drop 5lbs going to aan aluminum hat. That's 20lbs total. If you do go the 2 piece route let me know what you find.
Here is the website I referenced GM Brake Upgrade Option Measurements - Thirdgen F-body Brake Upgrade
 
Hey Paul -

Congrats on the build, I have an affinity for the orange myself ;)

There's a lot of good information buried in your post, would you mind giving us a little more insight? What brakes were included in your kit - the wilwoods or brembo? The brembo kit includes a 3/4"F and 7/8"R master cylinder. Running a 5/8" rear would give you more (relative) braking pressure as compared to the latest offering, am I interpreting this correctly?

Approx what ride height are you running?

Hubs - this is the first I've heard of hub failures. What do you attribute this to? Isyour track particularly hard on hubs for whatever reason? I believe these are from production vehicles so should be ok for "normal" usage, perhaps track duty is too severe for the standard kit offering? Did you have to make any modifications for the timkins or were they a drop in replacement? Just the bearings or did you have to source an all new hub assembly?

Our cars are very similarly spec'd, race tail, carbon, orange, LS3/525, and Graz. More pics would be awesome!

Thanks,
Cam
Cam, WRT the hubs I have been told that the c4 hubs are not particularly robust hubs. The right side hubs (front and back) failed after about 500 track miles. Most of those mile were at Texas World Speedway which is a somewhat rough track. Also, Full disclosure, I did spin over a low curb early which may have contributed to the failure. However my experience with several other production cars (BMW 3, Porsche 911, C7 Vette) that were turned into track cars using the OEM hub assemblies and running over many curbs I have only had 1 bearing failure in probably 10k track miles. I went back with Timken hubs so we shall see how they hold up.

I was riding at 3 7/8" in front and 4 1/2" in back but I had to raise the front maybe 3/16 to try and stop my tires from rubbing on the roof of the fenders. I actually raised the body a bit recently so i may go ahead and lower the front end again.
 
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