schuepbach

I recently purchased a c5 z06 and have started doing DE's/open lapping sessions with it to get some seat time while my track car is being built. The last couple event's i've noticed the ABS system is very sensitive and can easily be triggered under medium to hard braking situations.

I usually run the track w/ all the nannies off and was trying to see if there was an easy way to just bypass the abs for the track. Could yanking a wheel sensor or pulling a fuse be the quick fix? If so will there be any adverse effects(like a cut in power) aside from ah/tc/abs being disabled? I don't want to pull the whole abs unit and do a line reroute because this car is my DD and I like to have abs on the street.

geerookie

Just pull the ABS fuse. No need to disconnect a wheel sensor or do anything else.

Jason

I suspect you'll find them very hard to modulate. I've tried to run without abs and flat spotted 4 tires for my trouble.

FlamingZ06

With the ABS disabled, you will also have a degradation of proportioning, since the C5 uses the ABS for DRP (Dynamic Rear Proportioning).

If you have another problem appear, or under the right conditions, you could experience rear brake lockup (not fun).

schuepbach

Flat spotting might be a concern but I'm not braking that hard. Also I had no idea about the DRP. I'll pull the fuse for a couple laps and see how it feels.

Out of curiosity does anyone know which fuse it is?

0C5stein

Are you running tires that are close to the same diameter on the front as the rear or are you retaining the stock stager.

If the tires are too close the the same overall diameter, the ABS system will think that the fronts are about to lock up long before they actually are. With stock front rear stager, the computer knows that the front tires are supposed to rotate faster than the rears at any given speed.

schuepbach

I didn't think about that at all, the car has z06 chrome repo's on them from the previous owner that are 18's in the front. I know the tires up front are 265's but forgot the aspect ratio, I'll check it when I get out of work today.

SouthernSon

Problem occurs because very seldom is weight equally distributed on all four while negotiating a road course. If you threshold brake, the lightest weighted tire is gonna lock up. Been there, done that.

If the ABS is bothering you, you might consider getting stickier tires or back off on the brake pad compound.

schuepbach

I'm running carbotech xp8 pads all the way around with goodyear F1 GSD3 in the fronts and BFG KDW2's in the rear. If the aspect ratio is off on the front tires, I guess it would be time to step up to some NT-05's.

SIK02SS

Non ABS vs ABS driving is very different. Non-ABS driving you have to be very in-tune with your car and it's limits. I've ran my C5 on track for races, hpde, etc with no fuses and have not flat spotted anything nor had any trouble modulating.

With that said, if you are a beginner leave the ABS in and just start with turning off the nannies. Learn to become a smooth driver

SouthernSon

I don't know about what you consider smooth, but Jason has been know to set TT records at very respectable tracks. I'm just sayin'.....

SIK02SS

Nothing against Jason and I don't have any track records. The smooth comment was to the OP, not Jason.

I started my racing in a vintage formula ford; no abs..so when i pulled the fuses on my C5 I loved it because it was more natural for me and I could elicit a better response from the car. But I've also locked up rears with ABS and trail braking, so..

schuepbach

I'm fairly confident with non-abs cars on a track. I'm not a professional driver by any means, but I have some decent school/de/track day experience under my belt.

schuepbach

I checked the fronts and they're 265/35r18 and the rears are 295/35r18 which i believe maintains the stock stagger. I'll give it a couple shots next track day w/o the abs to see if I like it or not. I think the track surface may also be playing a factor because the abs didn't bug me nearly as much at road atlanta.

0C5stein

265/25.4= 10.4" cross section width
10.4 x 0.35 = 3.64 side wall height
3.64 x 2 = 7.3" tall plus rim diameter of 18 = 25.3" OD

rears are 26.1" outside diameter

This should be about right for C5 so disregard my prior post, but issue may be useful to others with similar problem

Timz06

I've talked to a lot of people that are fast in C5's and I can't think of anyone who disables the ABS. If you want to do it properly, you should install a proportioning valve for the rear.

It's also normal to run a different rear / front pad. X10/XP8 for example would mitigate some of the tendency for the rear to lockup.

Tim

schuepbach

It may just be the track surface then, it seems to happen alot at Circuit Grand Bayou, a road course north of New Orleans.

Hopefully I can get the car out to Barber's in the next couple months(I hear the track is immaculate) and see how it reacts to a better surface.

SIK02SS

what kind of tires are you running?

wallyman424

Just to reiterate, doing this on a c5 is downright dangerous. The ABS being off isnt the problem either, its the damn electronic brake force distribution. When my EBCM went, I was stuck on track w/o abs and even worse, the brake balance was WAY off.

Like others have said, ABS is fast. The C5's system is top of the line, and really there are very few issues with it. If you must delete it, youre going to need a proportioning valve for sure.

Jason

I used those black marks down the back of Nashville Superspeedway as a brake marker for the rest of that season.