NoEsFacil

I recently started racing a 2002 Z06 T1 Corvette in road racing environment. My previous racecar did not have ABS so I am kind of relearning braking procedures. So far we tried to do regular treshhold braking and try to activate the ABS as little as possible. Is this the correct thing to do? I understand that theoretically the ABS should stop the car faster but my question is if the system will hold the pounding of 30 minute and 1 hour sprint races. My speed at the end of the main straightway is close to 150 and the sound the ABS fully activated is very disconcerting, seems like the brakes are going to fall apart.

Any light or sugestions will be greatly appreciated.

davidfarmer

In my experience, the OEM ABS system is very advanced, and you can get away with MASHING the pedal to the floor. It can modulate each wheel individually, something you cannot do.

Bink

Dave - do you guys run ABS in Speed/World Challenge GT series?

NoEsFacil

Dave

Thanks for the input.
Will the OEM hold for the duration of a 30 minute or 1 hour sprint race. Will using the ABS fully make the brake system hotter and thus more prone to spongy feeling after a while?

Next race is April 2. Will try out and post results.

Mighty-Mouse

Like Dave said the ABS is very good and is track worthy.

As far as durability, well the system was not designed to be an aid for track driving.

All systems are tested far beyond normal street use where ABS will only be activated on occasion. But with the track in mind??

Fortunately, cars with traction control and stability control (Active Handling) have components a bit more sturdy and are designed using specifications that anticipate more frequent use. The reaction time is much faster and the pressure much higher in TC/AH than ABS. Which in turn requires better seals and more robust parts from the master cylinder on down.

I doubt you will get any catastrophic failure, but you will probably reduce the life of the main ABS pump and valve block. By how much is difficult to say, but in my experience it's usually not reduced enough that people are affected. Usually the car has been sold before the components need replacing. If you keep the car seven, eight years or longer you may have to replace the valve block or pump. They SHOULD last 10 years under "normal" circumstance.

You may also have issues with the wheel speed sensors and tone wheel. All that banging around and vibration can unseat them. They usually don't break out right just need to be re-installed and aligned. Not that big of a job or deal.

And the speed you brake from has no effect on the ABS system pressures, just on the duration of activation. Your using the ABS just as hard from 50MPH and you are from 150MPH, just for a bit longer.

Tips for keeping the system healthy:

*Frequent fluid changes with quality fluid. Brake fluid is like oil and coolant to an ABS valve block.

That's it!

ABS activation will heat up the brakes more than lock-up. But not more than normal.

What I mean by that is that if your able to threshold brake right up to the point of lock-up and modulate the brakes with your foot. You'll see the same temperatures as you would with the ABS doing that same thing. Of course no human (except a few in OT) can do as good as the ABS.

During lock-up the brakes aren't doing anything, so there's no friction and hence no heat.

So in theory the ABS does not create more heat, but in reality there is a bit more. Not enough to be significant and not enough to over come the benefits of a good ABS system on the track.

There will also be slightly more wear.

But again, this is not because the ABS has faults, it's really a sign of the ABS systems effectiveness at using the brakes optimally.


Personally I prefer ABS on the track. And only had one system (Bosch system on a BMW) fail prematurely, IMO. The only place I've seen ABS be a hindrance is on Rallye cars, ABS is not effective on loose sand, loose fine gravel or powder snow. Everywhere else it kicks ****.

NoEsFacil

Thanks.

This is a dedicated track car so from what you are saying the only real concern should be regular inspection of speed sensors and tone wheel. (what do you mean by Tone wheel?).
We do change the liquid for each race event using Castrol liquid. We have DougRippieair ducts installed and use Cobalt VR brake pads which brake great and generate, in our experience, less heat than the performance frictions we were using before. I say this because after the first 30 minutes of a 1 hour race last year using performance friction pads the brake pedal got very spongy and scarily low. When we bleeded the castrol liquid which is certified at 600+ degrees came out very dark. Last race we switched to the Cobalt pads and got shorter stopping distances and did not experience brake fade at all and the liquid came out like new when we bleeded.

Thanks again for your help.

Mighty-Mouse

Tone wheel is that thing that looks like a straight cut gear ring.

It's mounted on the hub directly under the wheel speed sensor. It's how the WSS measures the wheels rotational speed.


[img]

Not a Corvette, but you get the idea:
In this photo the tone wheel is called "electro-magnetic ring," how fancy

z060ntrack

Interesting about the pads, but I'm not sure why.They have to be generating less heat but yet you say they stop better (deeper)?

Like Dave mentioned above do not try to feather the pedal to stay out of the ABS, you will only be going slower. You should be into the ABS way late in the braking zone just before turn in

Timz06

How can pads heat up less? If you stop a car from a given speed you have to dissapate a certain amount of energy. Where does it go? Into the pads and rotors. Seems to me the amount of heat has to be the same?

JCD

If the wheels are locked up the heat gets generated between the ground and the patch of tire that's getting rubbed off, as opposed to the brake pad and the rotor.

turtlevette

damn,

i guess i should buy a modern car and let the computer drive for me so i can look like a boy wonder too.

in my club they say ABS is dangerous and can put you into a wall.

DREGSZ

Go Deep
Brake Hard...
No Lockups Woo HOO.

Man I wish my ABS worked

The guys in that MA club that say ABS is bad, are gay.=P

turtlevette

Its more likely to get you wrecked or killed. If the car is skidding sideways at speed the safest thing to do is to lock up and go off course in a predictable mannor. The ABS will not allow the wheels to lock and will send you darting off in a random direction at speed and bad things are more likely to happen. Bad things man.

I don't see how allowing a computer to correct bad driving behavior is a good thing. Most of the newbies who are accustomed to driving their C5 with computer copilot wouldn't live very long in my C3.

RogueVette

How is being able to control the direction of the car (ABS) worse then locking the brakes and being at the mercy of the direction the combination of terrain/momentum wants to take you? Most times there is a wall of some sort in front that you want to ba able (read as have steering) to avoid. That said I was faster in a C4 with the ABS off but in a C5 you need it. I wish the C4 ABS reacted the way the C5 does.

I'll take ABS anyday of the week.

But hey what the hell do I know

AU N EGL

I have a funny feeling that Evan has a few slips and slides under his belt, or tires to properly control a car

How many years of racing Evan?

John Shiels

The track events I do I worry about someone slamm'in in the back of my car if I activate the ABS. If they have a diffrent car that doesn't stop as good or a Corvette with lesser brakes and tires there could be big trouble. If I had used ABS a bunch I know I would have collected a few already. If you overtake some at a higher speed and pass just before the corner then swing wide in front of them hit the brakes it is risky. I do think they work great unless you hit wet grass then the tires will never stop you.

NoEsFacil

I agree it is weird but everything else was the same including the track, rotors,brake lines, tires, etc. It was kind of surprising since the performance frictions come highly recommended. The fact remains that the liquid suffered and the brake faded. I will find out the compound we were using but I think it was 01.

Bill Dearborn

Actually the ABS allows the wheels to lock up when you are in a spin and hit the brake. In 1994 I went off the track at the Inner Loop at Watkins Glen with my 86 and found out how such a feature works as I spun 3.5 half times across the grass. When my wheels left the pavement the car was going about 75 so I had quite a ride.

As mentioned above ABS is not quite so good in dirt or snow where you actually want to lock up the wheels to build up a wall in front of them to help slow you down. The ABS allows the wheel to overrun the wall and you never get enough build up to help slow the car.
Bill

TrackDayLT4

I agree to a certain extent, but remember that ABS is REACTIVE while a driver can be PROACTIVE.

I have been doing Track Days for years in my 96 with ABS and most of the time mashing the brakes works fine. If the track surface is consistant in the braking zone it works great.

If the pavement is variable in the braking zone all bets are off. An example would be at Buttonwillow raceway in California. When I run the track CCW with the full back straight, I am going about 130mph when I hit the brakes at the end of the back straight and slow to about 60 for the next corner. The ABS cycles at about 10 cycles/second. 130mph is 190 feet/second or 19 feet between cycles. It can take a few cycles (60 feet or more) for the system to decide what to do next, remeber it is reactive.

In that braking zone you cross an area with a patch that has low traction, another section of track joins and has a lot or rubber, also there is a sharp crest followed by a dip. Since I can anticipate the changes, I initially mash the brakes, ease up for the patch, brake hard again for the join area and up the crest, off completely at the crest and push like I am going to break the pedal off in the dip.

If I braked at the same point by mashing the pedal and let the ABS do the work it happens more like this. Initial braking is hard. When the car hits the patch the ABS lets off the brakes but by the time it senses the higher traction join area and increases braking again, I am past the high traction area and it lets off the brakes again. It reengages again about the time I am going up the rise, but at the crest it completely lets go of the brakes and does not reengage until the end of the dip and I am heading off the track because I am about 20 mph too fast.

In that case I can beat the ABS by a significant margin.

At the end of the front straight, the track is very consistant so I just mash the brakes and the ABS light is flashing all the way to my turn in point.

Cheers,

Lawrence

turtlevette

WOW,

i didn't realize that so many people used the ABS and active handling as a crutch in racing.

Not only am i up against vastly superior cars but computers as well.

I guess when the C7 comes out the owner will just enter a program hit start and watch the whole thing from the bleachers.