Looking for advice and suggestions about how much I really need to do to set my new C8 up for a 2 mile road race track (Road Atlanta). I have 3800 miles on my C8 now. I'm doing the Ron Fellows course in las Vegas at the end of Nov. After I complete that school, I'd like to take my C8 out on the Road Atlanta Track in Brazelton, GA. I read the C8 Track Guide. It says there are three things to change for a track setup.
1. Add two liters of Transmission Fluid
2. Change the alignment to Track Specs offered in the Track Guide
3. Change the suspension settings on the shocks

So I called a local Atlanta automotive shop that does track setups. They gave me an estimate of "around $1,000" to make those three changes. But the mechanic also told me if I'm new to tracking (which I am), I should start slow and not make the alignment and suspension changes. He said they would be too aggressive for a newbie to tracking. I'll take his advice there.

As for the 2 liters of extra transmission fluid, I read an article somewhere that said the reason you need to add 2 more liters of transmission fluid is because when you get into a high-g turn on a banked track, it forces the transmission fluid to go to one corner or one side of the transmission - not good for the moving parts that are no longer being bathed in fluid. So, by adding extra transmission fluid, you maintain the necessary lubrication on all the moving parts. But that explanation only makes sense to me if you're taking the car on a banked oval racetrack. It doesn't really make sense on a road track with right and left turns that are relatively flat. You may be going faster and experiencing some higher G turns, but those will be momentary and the sloshing fluid will go back and forth in the transmission. Can the C8 be safely tracked on a road track without adding the 2 extra liters of transmission fluid, or is that just asking for trouble?

Second question about the extra transmission fluid. I think the track guide, or maybe I saw this in the Corvette Forum, says once you add the extra two liters of transmission fluid there is no need to take it back out. But when I talked to the local Chevy service advisor, he said I should drain out the extra fluid once I'm done on the track. Any advice on that?

Thanks,
KBS

 

I currently track a '21 C8 Z51 and have a '22 C8 Z51 as my street car. Both with different alignments Street vs Track. No problems.
1) Yes, definitely add the two extra liters of DCT fluid and leave it in. There is no reason to remove the extra fluid.
2) You can run a modified alignment of Front -2* Camber, -7-8* Caster with zero toe, Rear -1.4* caster, 0* caster, .06* toe in
This alignment is fine for the street (my street specs) and track if you start more tracking add more F&R camber (-.5*+ each)
IMHO the GM track spec a little too much camber, my track specs of 2.7* F & 2.2* R yield perfect tire pressures and temps.
3) I recommend a better DOT 4 brake fluid I have used Motul RBF600 for years in all my street and track cars with zero issues.
4) Start out in Sport, then if comfortable Track but with some nannies still helping you.
Good luck, have fun work on being smooth, fast will come later. Hope this helps.

 

2nd the above and you can add the 2 liters yourself in about 30 minutes.

 

Find a different Chevy advisor.

 

Good info here; The advice on camber is right on. Too much camber on the front will wear out the inside edge of the tires. Too much camber on the rear and the car will spin out on the straight. Anything over 1degree negative on the rear may work at the apex of the corner, but on the straightaway the contact patch is so small that you will lose traction. High temp brake fluid is absolutely necessary. Do not go to the track without it, unless you are just cruising around. My motto from years of competition "If you are not boiling fluid or cracking rotors, you are not pushing it hard enough". That's what it takes to win.

 

Just a comment and info to ponder, r.e. your statement about why add two extra quarts. Been following this issue since I got my early 2020 Z51. Don't Track but live in a rural area, have 25 mile trip to town and take all back roads where there are sections where there is often, no traffic, there are no homes, or people where I can achieve high lateral "g" turns, safely.

First there is no need for all gears to be bathed in fluid. In fact the specified fluid level for a gears is low as once they start spinning there are lots of oil particles all through the case in a big cloud of oil! See pic below for details. The issue is the DCT uses high pressure fluid to engage its two clutches, the hydraulic actuators that move shift forks, eLSD components, etc in this essentially two 4 speed standard transmissions. The oil pick-up for that high pressure pump is located at the bottom of the case just above the small removable pan.

There has been speculation r.e. high lateral "g" force having DCT fluid move away from under of the DCT Fluid pump, including by myself initially. BUT GM has not said that is the reason! Only a semi official statement was reported at a seminar in Carlisle PA. A GM Rep said the reason is "IF TRACKING AND GOING DOWNHILL AND TURNING THE DCT FLUID MAY MOVE TOWARD THE TOP OF THE CASE." Assume he means away from the fluid pick-up.

Since we have no hills in NE SC I am never in that situation! So even the 1.3 lateral "g" recorded the other day on my PDR (in one of my favorite safe turns,) does not fit his description! To reinforce, in a recent video the Corvette Marketing Manager, Harlan Charles said with the C8 Z06 they changed the oil pan configuration and IT IS NOT NECESSARY TO ADD THE EXTRA 2 QUARTS with the tires that come with the car. That includes the Cup 2 tires and the high lateral "g" they can achieve! He said IF you use racing slicks you might want to add.

BTW Tadge Juechter ,the Corvette Chief Engineer, in an early comment said there no need to remove the extra fluid after Tracking. He said it does cause some extra drag that has a small effect on mpg. Note he never said why they required the addition.

Here are some pics I have used over the past two years that reinforce why I did not and will not add the extra fluid unless it's clear why it's needed. GM says add for Tracking so it should be added. BTW I don't Track, I make many high "g" turns but not sustained or where there are back to back turns as in a Track etc.

GM's method of adding is not cheap as you have to remove the Trunk liner and intake air housing etc to access the high oil fill plug. One tech quote 2 to 3 hours. IMO it's an obvious afterthought and last-minute decision as they could have put the fill plug further back and a simple cover in the truck bottom would be all that was needed to access. Also they did NOT provide a way to check the fluid level with the extra 2 quarts or refill the small amount of fluid when changing the DCT filter.

A reported knowledgeable YouTuber said GM found someone doing sustained foolish donuts (like a NASCAR winner!) That would cause a sustained high lateral "g" force. But I take that comment as strictly roomer. It is possible they discovered an issue making sustained lateral "gs" when measuring on a skid pad? Or perhaps it was not until they were testing at Laguna Seca that has a unique turn called the Corkscrew where you crest a hill then go down a very twisty road while turning?

Lots of pic with comments. Just Sayn!


Per the comment by the GM Rep at Carlisle PA seminar, IF Tracking and going down the Corkscrew at Laguna Seca with it's turn at the bottom or jumping your C8 - add fluid will help!


Good info on what lubrication in a gear transmission looks like! Banks found when developing a dif case cover to provide more fluid for cooling the design was very important to prevent foaming that reduces lubricating properties.
Below top pic shows the fluid level needed for gears. You don't want those spinning gears immersed in lub! In addition to adding drag, it can cause foaming, which is not good for lubrication.



This pic is from the other day on a "safe place" driving home from town. No cars, no homes, no people. Only farm fields. I'm not concerned about the 1.3 "g" I hit in that turn causing lack of fluid or pressure!

.

 

Check with Ron Fellow instructor. They should have a very good idea what will work best for you. I added the 2 liters to the trans because I track my C8. It dropped the DCT temps about 25 degrees. Highly recommended. No noticeable difference in mpg.

 

Here's my problem with NOT adding the extra 2 qts of DCTF,

GM says you MUSTadd them if you are tracking the car. GM also says you MUST change the brake fluid to high temp fluid if you are tracking the car.

If you don't do these things (AND KEEP A BONAFIDE RECORD OF IT), and then you experience a DCT failure, you might give them an excuse not to honor a warranty repair/replacement of your DCT.
You might give them an excuse that the damage to your brake system was due to boiling the brakes, and there will be a record of that too.
Keep in mind, GM knows precisely where your car drives. It has a GPS receiver and sends telemetry back to GM via OnStar, etc regardless if you have a "plan" or not. They will know of your car spent time at a track facility.

Maybe I am paranoid, but I prefer to have these done at the chevy dealer so there is a record in their system that it was done. Same for required service interval items, I will do those at the dealer so there is a record of meeting all service requirements. Why? Because many people have been screwed out of warranty repairs that should have been honored, or "extended service contracts", etc, over stupid little things like you have a failure in your transaxle but they deny your claim because you failed to REPLACE THE CABIN AIR FILTER during recommended intervals. Stupid crap that lawyers think up.

FYI, the cost to replace the brake fluid is $149 total at my dealer.

Good luck at SpringMountain. You will never be able to drive your C8 on the street again without feeling insane urges to push it harder. Save it for the track though...

 

Absolutely agree. If tracking add because GM says to. They just have not formerly said why BUT don’t have to. Their warranty their rules.

Although my racing days are over IF tracking I would change brake fluid. Even Z51 brakes are marginal and I drive aggressively. Not a good feeling to have brake fluid boil and pedal go to the floor.

 

After pushing the C8 at SpringMountain on the track, I can see how higher temp brake fluid is necessary! It was the first time I had taken a C8 from wide open throttle and >120mph and then going to full on brakes, pedal to the FLOOR in order to slow enough to get into the balance for a turn.

 

Add the 2 quarts to the trans. GM recommends it, so it would be crazy to not add it. It will help to keep the trans oil temp down, and help to dilute all of the contamination from the clutch wear.

 

We track our 2021 Z51. You need the extra two quarts of trans fluid. Leave it in. Do not take it out. That is per the GM track prep guide. You need the rear brake cooling ducts on when on the track. Also, at a minimum, your brake fluid needs to be less than a year old. We switch to DOT 4 racing brake fluid. Higher boiling point. Conventional wisdom is to flush the brake fluid before each event. If your brake fluid is not dry, it will boil at a lower temp and that is a real bad thing. Search for the track prep guide and read it. Alignment and lowering are optional, but pay attention to the part on brakes and the target warm tire pressure.

 

Maybe I missed it, but after your initial track introduction, I think upgraded track pads will compliment your improved brake fluid. It’s usually basic principle to upgrade your brake fluid and brake pads together. Not so much for the beginner, but good habit to get into.

Starting tire temps are also important. 30psi is a good starting point. The performance manual probably my has specific tire pressure recommendations. Very important as your temps will shoot up and potentially lead to higher than recommended pressures = less traction.

 

The C8 track prep guide gives target warm tire pressures and suggested starting cold pressures, but of course that depends on ambient conditions and how hard you are driving.

 

As someone who just started tracking this year, my advice... Don't go straight from 0 - 100, take your time and figure out how deep down the rabbit hole you want to go!

Go stock for a 1st or 2nd track event:

1. Add 2L of trans fluid and leave it in there. DCT fluid + Z51 = warranty covers tracking. Your Chevy Service Advisor is an idiot, but you are on the Corvette Forum, so you will know more about C8 maintenance than most SAs!
2. Attach brake cooling ducts. It's literally a handful of screws you can zip on in minutes.
3. Burnish your brake pads. If you can't safely follow the exact procedure, most important to get moderate-firm brake applications followed by periods of no braking for cool down.
4. Drop your tire pressures at the track, try 27-28 psi as a starting point and target 32-33 hot. You can always let more air out btw sessions. Air out is much easier than air in.
5. Have Fun!!

You DO NOT need a track alignment, or high temp brake fluid, or new wheels and tires, or new rotors and pads for just a couple HPDE type track days. Get out there and have fun! If you enjoy it, then spend more $. Also estimate your street vs track use. You wouldn't want a ***** to the wall track setup for a car that is driven 98% on the street... squeaky brakes, uneven tire wear, etc.

I started out stock + 2L. Then I added forged wheels and 200tw tires. Then I got a track oriented alignment: -3 F / -1.8 R and 0 toe all around. I ran stock brake fluid all year (autoX and track) without issue, and I'll switch to SRF in spring. I might also lower the car a bit and re-align, but I've been happy with this setup so far. Approx 10% of my mileage is on track or dodging cones. YMMV

 

Most sports cars reduce rear toe in bump to give the car a feel in ordinary driving. So a track setup should have toe-in at the rear.

Or fix the situation with stiffer springs for less suspension movement into bump. However, less spring pre-load will not help. Zeroing out the spring pre-load is a show-car setup that would be a risk of bottoming on a race track.

Stiffer springs for less suspension movement into bump will also keep the suspension bushings from wiping-out which can plow the front-end at the cornering limit. However, stiffer springs make a faster responding car so consider what the driver can handle.

For tire tuning, do a google search for Goodrich g-Force Control Manual. And there's two of them
.

 

Always need to be careful with the brake fluid. People have boiled it. At my first DE I was going into turns at 140 and braking hard. Flushing the fluid to ensure it is dry is relatively cheap. And the rear cooling ducts are a must.

We run the GM track alignment with camber backed off a bit to -2.6 front and -2.1 rear. Good on the track, very drivable on the street, and no uneven tire wear. We have done side to side rotation.

 

Hi KBS, what did you end up doing? I am in the same situation now looking for advice on pre and post track setup for my 2023 C8 Z51 for Road Atlanta. Also I've seen someplace where it mentions to install and uninstall the additional air channels for pre and post track setups.

Thanks, Gene

 

^^^^
Spent a lot of time investigating the added "Overfill."

1st clue as why came from a GM rep at a seminar in Carlile PA event where it was said it's IF Tracking going downhill and turning (assume high "g".) He was quoted as saying it was fluid going to the top of the case but assume it was just moving from the fluid pick-up at the bottom of the DCT case. Nothing said about backing.

It was said from day 1 the extra fluid causes somewhat more drag and a modest reduction in mpg. BUT it was not necessary to remove.

A Tech who investigated ~50 DCT issues, some with the added fluid some without said only needed if Tracking and do not add if not. He also mentioned the >100 CELS and sensors that protect the DCT. That included 3 which monitor pressure and if low it will generate a CEL (and I assume put the car in a limp home or limp back to the pits mod. It appears to be an issue found at the last minute when Tracking C8s. In addition to added drag may be other issues why Tremec didn't just add another check level/fill plug slightly higher than the existing one. Tremec finally designed the case and oil pick-up so even when Tracking as Harlen Charles (Vette Marketing Manager) said, even with a Z06 z07 with Cup2 tires not need to add the Overfill.

My guess is one Track turn where, as indicated the issue might occur, is the Corkscrew at Laguna Seca. Watched my friend Tom drive his Maserati Birdcage down that turn many times in Vintage Races (my pics of Tom.). Fits where it was said the fluid might leave the oil pick-up.

 

100% you should install the full Z51 brake ducting system. TBH, I just leave mine on all the time now front and back. In 2 years I have only had one small pebble get stuck and it did no damage to the rotor, just screamed like hell until I could get to a place to run the car in reverse to dislodge it.

I run a -1.75 vs -3.00 track camber. Helps a little on the track, but also doesn't wear the tires down too much for daily driving.

If you switched your brake pads to low dust street pads, you will need to put the track pads back on the car.
Also the brake fluid that comes from the factory in the Z51 is NOT rated for high temp track use, it MUST be changed. I tried Motul 660 RBF initially and had trouble with it. Trouble meaning COMPLETE brake system failure on the track going ~100MPH into a turn that was fortunately high banked. Not sure if it was the fact the fluid was in my car for nearly a year at that point and the Motul 660 is very sensitive to moisture fouling causing the boiling point to lower or if it was because the service center screwed me and just did a basic brake bleed vs a fluid swap as I had asked and paid for. Honestly, I think the shop screwed me. So I did the brake fluid swap to Castrol SRF myself using a pressure bleeder and was sure to run fresh fluid through each line and also used the caliper/piston squeeze pattern (up/down/inside/outside/criss-cross/etc) to move the old fluid out of the caliper passages.

You should get tow hooks installed just in case. The little tow hook covers have tabs at the TOP that are brittle and WILL break off if you pull the cover from the top. You should pull the cover from the bottom edge, use a suction cup, etc. There is a little cut out on the bottom to insert a plastic spudger tool or thin flathead. I use a spudger though. The cover has a retention piece that I just squeeze and remove the cover fully (toss it in the glove box). I don't want that cover flapping around in the wind and scratching things up or breaking off and getting lost on the track. I always install these hooks at home and don't waste any time at the track fooling with them.

I also carry a V strap as the two hooks are only for direct straight pulling.

I also added the 2L of fluid to the DCT because a 2021 version of the M1L DCT and the GM service manual states it is necessary for track use.

You should bring a torque wrench with you and check your lugs before you go out, and especially after the first hot laps when you come off the track.

Be sure to do at least 1 cool down lap, I usually do two cool down laps, so watch your time because you don't want to get forced off the track and park your car with super hot brakes, also do NOT use your EPB when parking with hot rotors.

I did the RBF, DCT +2L, and the track camber adjustment at the dealer to have a paper trail in the event of a warranty issue. As noted, I did the 2nd RBF myself. I just want something in the Chevy/GM system that shows I followed their service manual requirements prior to any issue occuring on the track.