ABS/TC? Benefit or nanny?

[ammonman]

Hi all,

Porsche owner but Boxster newb here with a quick question. I'm looking for a base car to AX/DE for a year or two while turning it into a Spec car. Is it worth finding a car with the ABS/TC option as a base for a spec build? I get the impression the system is more a"nanny" for inexperienced/lazy drivers rather than something performance oriented.

Thanks

Mike

[stephen wilson]

I know you'll have to turn off the PSM for autocross or racing, it cuts the throttle too early. But the ABS may be a bit more aggressive on a PSM car "turned off", than a non-PSM car ?

[jsceash]

Originally Posted by ammonman

Hi all,

Porsche owner but Boxster newb here with a quick question. I'm looking for a base car to AX/DE for a year or two while turning it into a Spec car. Is it worth finding a car with the ABS/TC option as a base for a spec build? I get the impression the system is more a"nanny" for inexperienced/lazy drivers rather than something performance oriented.

Thanks

Mike

If you want to call it a nanny well look at it this way the second the ABS starts to cut in, you're braking too much and you can still lift a little, no harm no fowl. You didn't slide the tires and end off track, you didn't cost yourself $300-400 flat spot your front tires. Popping off the brakes too fast didn't put the car sideways. My opinion is it is a great tool that cost little or nothing. I look at it as an insurance policy until you have experience

As you gain experience and can feel those point with out PSM stop using it.

[ammonman]

Thanks for the input guys. I think the ABS is very worthwhile for an inexperienced track driver like me. I'm more trying to gauge the value of the ABS-based traction control system. If the car is equipped with the brake-based traction control system does it have to be switched off when on the track to comply with the spec rules? If not, is the system beneficial or detrimental to performance? Does using it on-track tend to promote bad habits in new drivers?

Thanks

Mike

[jsceash]

Spec BSR would have some cars in both categories but it says you can not modify the ECM or other electronic systems immobilizer ETC. Only a stock ECM is permitted.

[trygve]

For the Spec car years -- '97 to '99 -- I think there is only one optional thing on the car in this regard: "Traction Control". ABS is standard and you can't tamper with it for Spec although I suppose you could pull the fuse. I am glad to have it.

The TC option has two features:
- "ASR" (Anti Slip Regulator) - There is a dashboard switch to turn it off, and you really must turn it off for the track. (Unless it's wet!) ASR cuts the throttle when it detects rear wheel spin. You will get some small amount of "rear wheel spin" coming out of some corners -- that's desirable -- and it can be enough for ASR to complain about but you do not want ASR kicking in when that happens. ASR feels like the car is bogging down in that kind of full power sweeping corner exit.
- "ABD" (Active Brake Differential) - This cannot be turned off. However, it only operates at speeds under 55MPH so it's not relevant in fast corners, only the tightest/slowest ones. ABD detects left/right excess speed differential in the rear wheels and applies the brake to the inside wheel so that the outside wheel gets more power applied. This would seem to be activated when the inside rear wheel starts to lift off the ground and lose traction (maybe if you hop a curb too hard?). I have never really noticed any effect from this, although at Turn 11 at Sonoma if I hit the inside paint too much it's bumpy and I get something like "wheel hop", and I wonder if it's ABD rather than bad pavement. I think some people have talked about it causing rear brake pad wear (but I think that discussion was not about the Boxster).

I think TC is a fine option to have (ASR seems like a good thing for rain racing, and ABD is pretty much a non-event).

[ammonman]

Thanks again for the info. That is exactly what I was looking for.

Mike

[BYprodriver]

PSM prevents oversteering which is the funnest part of autoX to me & that's why I wanted my car without it. You can turn it off by the switch on the dash but, touching the brake pedal reactivates PCM. IMO TC is only usefull for winter driving. In Spec racing you don't want anything cutting back your rpm's.

[stephen wilson]

On my '06 , nothing re-activates when you hit the brakes. PCM ?

[MaxD]

Actually TC just plain sucks. In winter driving you can get stuck because you can't apply proper throttle when you need to. In A/X or track days it's definitely a no fun option.

[thstone]

ABS is standard on all Boxster's. Definitely a good thing, even on a track or race car.

Since the OP said that he's thinking about a "spec build" then we're talking TC and not PCM or PSM or any of the other 20 or so Porsche three letter driving aids.

My recommendation is to skip the TC option since it doesn't really help on the track. But if the car you like has it, then you can learn to live with it. How do I know? I have this option on my 1997 Spec Boxster racecar.

The early version (97-99) of Porsche's TC is relatively stupid (ok, sorry... its "unsophisticated"). Its a teeny bit useful when you are starting out as a Beginner on the track but once you have basic track driving skills it will only slow you down and once you're skilled enough to consider racing it will slow you down a lot.

The TC must be manually turned off each time that the car is started but it does remain off once you have done so (as long as the car remains on). Under Spec Boxster rules, you cannot remove the TC from the car.

Thus, I have to remember to turn off the TC every time that I go out onto the track (each session). If I forget, as soon as I drive into a corner the car will handle like a slug and the TC light will blink like a twinkling star reminding me to hit the Off switch.

[Brad Roberts]

First time you get beat by a TC car in the rain.. you'll wish you had it. Now I know SoCal doesn't get a lot of rain, but.. try some NorCal tracks

[san rensho]

I can see that ABS could be a problem in one common situation, a high speed spin. Lets say you start spinning at 120 mph. Eventually, the car will stop spinning but can still be moving at high speed. So lets say you stop spinning at 70mph, now because of the ABS, you get traction, even if the brake is to the floor.

So, lets say you regain traction when you are pointed sideways on the track and you are still moving at 70mph, you going to go flying off the track. With no ABS, the tires would be sliding, since you have your foot all the way down on the brake, and you essentially skid to a stop in a straight line or an easy arc instead of darting off the course.

[Brad Roberts]

No ABS in reverse.... (from experience)