ABS and autocross

[PhillyCobra]

Got to do some autocross this week in my Cobra, and noticed that ABS tended to trigger when I was trail braking and starting to turn in (even if I didn't trigger it on initial straight braking). Car seemed to do fine and was very stable, but not nearly as tossable as Viper that I drove that had ABS turned off. Anyone have an opinion as to whether or not you can rotate the car quicker and maybe get better times if you remove ABS module fuse?

 

[Shangsta]

anyone one know?? I know that alot of bimmers remove the fuse for track events and autocross and they say it performs way better. Im guessing that it would probably help with getting better times

 

[newcastle]

subscribing

 

[PhillyCobra]

Yo, maoun should chime in here!!

 

[maoun]

lol....me? what do i know about this new-fangled technology....lol...

well, yes, ABS disabled is definitely a fun little thing to do for better times....now, there's a lot to think about

first off, keep in mind, you can get better times by not spinning tires uselessly...but rather spinning them on the floor.....now granted that's not necessarily more fun

it HAS been proven that you can invariably stop quicker without ABS if you're a trained driver that hits the brakes to the perfect edge point. now, for daily use, and non-pro drivers, leave it on.

on track, most people don't bother with it....as it doesn't really get in the way too much....unless you're a race car, it's usually not worth the effort.

NHTSA on ABS:

"Do cars with ABS stop more quickly than cars without?

ABS is designed to help the driver maintain control of the vehicle during emergency braking situations, not make the car stop more quickly. ABS may shorten stopping distances on wet or slippery roads and many systems will shorten stopping distances on dry roads. On very soft surfaces, such as loose gravel or unpacked snow, an ABS system may actually lengthen stopping distances. In wet or slippery conditions, you should still make sure you drive carefully, always keep a safe distance behind the vehicle in front of you, and maintain a speed consistent with the road conditions."





now, my personal notes. do i think your times will get better by removing ABS? hell no. if anything, they'll get worse. but hey, there's only one way to find out, eh?

and yes, it's safe to just remove the relay or disable via the PCM.

 

[maoun]

keep in mind two last things, most ABS units are shut-off at low speeds..... < 10mph.

removing ABS can very easily mess up your brake bias...and we don't have little proportioning valves on ours :-(

 

[maoun]

i don't need no stinkin ABS!

hehehe, sorry, i was bored.

 

[Serpentor]

did you leave your rear qtr windows up for aerodynamics?
(It bugs the heck out of me when people do that witht he top down)

 

[PhillyCobra]

Maoun,

Knew you would help on this.

My observation was not that ABS kicked in with maximum braking in a straight line before the turn, but kicked in as I trail braked and turned in, trying to rotate car before I got on the gas. The ABS settled the car, but it didn't rotate like the Viper with ABS disabled.

I guess I'll just have to try both ways.

When you say to disable by removing the relay, do you mean the fuses? There's 2 listed, F1.8 and F1.1 in the Battery Junciton Box in the wiring diagram and 1 in the Central Junction Box, F2.29. Do you know which of these should be pulled to just deactivate the ABS (and TC)?

By the way, I insist that all my family and friends buy cars with ABS for street use. I'm a total believer.

 

[maoun]

i leave the rear quarters up because it has sponsor decals and because we worked hard to make the roll cage match the contour of the rear windows perfectly....so it looks great from the side...hehehe, sorry!

philly, several things...first, trail braking is fun, but not necessarily the fastest if you've got a good suspension in your cobra....try the alternatives...see what works out best....i do, however, see your point....really depends on the turn...most people overuse t-b.

as for disabling it, several ways....there's an override that works if you disconnect ANY ABS cable goin to the wheels...though, most people don't like that...i like it because it allows the system to stay happy and cut itself...rather than just cutting its power and confusing the system.

by fuses, i would kill it with:
Battery junction box (BJB) Fuse:
ABS 1 (50A)
ABS 2 (20A)

--03 mustang ABS system--
Principles of Operation

The anti-lock brake control module receives wheel speed readings from each anti-lock brake sensor and processes this information to determine if an ABS event is necessary. The anti-lock brake sensor electrically senses each tooth of the anti-lock brake sensor indicators as it passes through the anti-lock brake sensor's magnetic field.

The anti-lock brake control module continuously monitors and compares the rotational speed of each wheel, and when it detects an impending wheel lock, modulates hydraulic brake pressure to the appropriate brake caliper. This is accomplished by the anti-lock brake control module triggering the hydraulic control unit (HCU) to open and close the appropriate solenoid valves. Once the affected wheel returns to normal speed, the anti-lock brake control module returns the solenoid valves to their normal position, and normal (base) braking resumes.

The anti-lock brake control module is self-monitoring. When the ignition switch is turned to the RUN position, the anti-lock brake control module will do a preliminary electrical check, and at approximately 12 km/h (8 mph) the pump motor is turned on for approximately one half-second. Any malfunction of the ABS will cause the ABS to shut off and the yellow ABS warning indicator to illuminate, however, normal power assisted braking remains.

The ABS control module has the ability to store multiple DTCs in memory.



btw--some good ABS primer's: http://www.mustangworks.com/articles/misc/AutoFAQ.html

 

[ShelbyGuy]

if your ABS comes on while trail braking, then you're doing something wrong. Go back to straight line braking before the turn until you learn to take your foot off the brake pedal properly. Ask yourself why your foot is still on the brake at the apex. That's killing your corner exit speed.

Maoun, I can't believe they let you run with windows up :uh oh:

 

[maoun]

shelbyguy, who said they let me hehehe

they're only the rears......at least not the front windows, eh?

m.

 

[Boostin01]

Sorry, little off subject but where do you guys get rear ss brake lines??

 

[maoun]

custom...

MM doesn't make em as part of their kit....so i used theirs for the front (at first, until i put on nicer calipers/rotors and they came with em) and customs for the rear

 

[Boostin01]

Thanks
What upgraded calipers/rotors did you go?

 

[maoun]

I'm sponsored by The Brake Man.....i got their bad-ass 4-piston F4 caliper, dual-piece rotor....ss lines.....i love em....

i can get people deals on em...if interested....but keep in mind they aren't your light low-quality brake kits..they're heavy duty and pretty serious.

m.

 

[ShelbyGuy]

Both Goodridge and Russell sell kits with four hoses for IRS cobras. I was unable to buy just the rears.

I got mine from http://www.raceshopper.com/

Originally posted by 03Boost
Sorry, little off subject but where do you guys get rear ss brake lines??

 

[maoun]

good info shelbyguy....didn't know that.

thanks man
m.

 

[Jimmysidecarr]

I have not autocrossed in 12 years !!!
And never in a car like this!!
I didn't get any abs action until later in the day... after my fear of looping had diminished, and I started getting aggressive...
At that point I welcomed the settling effect it had....
At apex if I was not rotated enough at that point........... I gassed it.... very fun but easy to over do...
I finally did get my best times with very aggresive braking and just a touch of throttle over steer...
It was very tough to rein in the "YaHOO factor " though!!!

Jimmy:thumbsup:

 

[PhillyCobra]

ShelbyGuy,

Trail braking is only on turn in, letting up on the pedal as you start the turn. It's over way before apex. I think it is pretty well accepted as a technique to keep some weight up front on a basically understeering car to help turn in. It's easy (or too easy)to induce oversteer after the turn is started, using the throttle.

I think my ABS problem is because the system is so damn sensitive. I trigger ABS under moderate braking on this car when I hit a small bump or depression with one front wheel and it has to climb up or down, resulting in a slightly different wheel speed from side to side. I have never driven an ABS car with the system so sensitive.