Land Jet

I drive a 2002 996TT with ABS and PSM. My buddy who is an instructor, and has driven this track over 100 times, rode with me this past weekend after I was signed off by my assigned instructor. He has been the first instructor to tell me not to use the ABS. He also told me to progressively down shift while in the brake zone. He said this is an advanced technique of car control that is not taught to green students. His personal car is pre-ABS. On the main straight of this track, I reach speeds up to 155mph before entering the heaviest braking zone. Usually I would threshold brake while the car uses ABS to control the weight and stability. Is this the best way to brake this car or not? Please give me input into braking my late model car with the electronic driver aids. Thanks.

RedlineMan

Hey Larry;

I think your instructor's exception was that you may get into the bad habit of relying on electronic nannies to do your driving for you. Alas, this is the weakness - and great failing in my opinion - of the modern cars as learning tools, as they mask a tremendous number of ruinous events in a fog of electronic control, rewarding the driver with blissful ignorance in many cases. In other words, you are not learning how to REALLY drive.

Regarding the shifting, I suppose it is a matter of opinion, necesiity, and monetary capability. If you have a car that you cannot find gears in, then you might need to work your way down the order in sequence to avoid violating your valvetrain. For me, it is a matter of finances. I have no problem going from 4th/5th to 2nd/3rd, and brakes are cheaper than transmissions and clutches!

FTS

Larry,

Even though I am certainly not an instructor, but I would interpret Dave's comments as: you have LSDs in your car and if you can smoothly downshift going into T1, 5-4,3, and may be 2, the rear differential will keep your car under control and help tremendously. I have an open differential in my car, so rowing down the gears does nothing but use up my transmission, so I go from 5th gear to 3 rd with a single change and concentrate on my momentum going into T1, which to me is more important than focusing on getting the absolute most out of the braking zone.

As for ABS, I don't rely on it to help me with braking, but as a warning that either my tire pressures are too high/low, or that I need to slightly back off the pedal pressure.

Brian P

I try not to get into the ABS on my car. Not because I believe I can brake better without it, but because the 986/987 platforms have had issues with the ABS pumps. I prefer to use it as little as possible so that it's still there when I need it.

dbryant61

Larry,

It's simple. Sell that piece of crap and buy a wonderful old 911SC, or the like. Kidding. I agree completely with your instructor and John. ABS and PSM mask bad habits. If you engage them consistently in your car and drive someone's older car or take the Skippy school, you'll be seeing lots of tire smoke, replacing square tires, and probably spinning a time or two. If you are engaging ABS, you are not threshold braking, IMO. You are braking harder than the point of lock-up and you are slowing less that you would be if you braked to the point just before ABS engagement. I say this because ABS is intermittent braking on-off-on-off, often sliding in between. A consistent non-sliding braking would decelerate the car quicker.

As far as downshifting, it is a matter of preference. Going through the gears downshifting all the way and heel-toe-ing properly (I know several experienced drivers who do not heel-toe at all and some who do not do it correctly) is good form and good practice. It also ensures that you have available engine power to get your car out of the way of a spin or wreck. This applies mostly in racing, but could also happen in DE. Read "Going Faster" and the Carroll Smith books. You will see varying opinions.

2BWise

You're not going to beat a modern ABS system. It does not fully drop line pressure, so it is no on/off system and will control the car at peak decel. As far as learning to drive with it you need to consider that it gives you a very firm notification that you're at the limit of the tire. You should be able to then learn to brake just at the limit of entry into ABS control. Most people don't apply the brakes quick enough or hard enough. With ABS should be able to learn to feel the tire and when its reaching the limit. You should not be blindly applying as much pressure as you can because you will not learn anything that way, which is why I think a lot of instructor teach students to stay out of ABS. Otherwise, it is a very useful tool to get maximum deceleration.

himself

Is this right? When I threshhold brake I don't even hit ABS. I guess my threshhold is just below ABS engaging. To me, engaging ABS indicates something is not right with the car's balance, whether it is intentional or expected is a different matter.

As I see it, if you are engaging ABS all the time (every corner), I would venture to guess that your car is out of balance at least some of the time. That is, if your front brakes are locking up, you may have too much weight on the front from poor braking technique. You may be able to dive deeper into the corner, but that doesn't mean you will be faster, since the car has to rebalance itself before you can turn in.

To me, ABS or locking a wheel are the same. You should be braking just under that limit.

But what do I know. I'm a moving chicane most of the time

-td

2BWise

First of all, the more weight you transfer to the front the more braking force you can create. But, it takes time for the weight to transfer. Poor braking technique would be mashing the middle pedal before the car takes set. Once that pitching motion has taken place the more weight you get to the front tires means the more decel you can create.

Again, ABS will control near max decel, so why not use it. If you're not yet into ABS then you're not quite at the limit of the tire.

Driver8

For beginner to intermediate drivers knowing when the ABS kicks in is pretty easy, you can feel it in the pedal. To know when the PSM is working can be more difficult for them to detect. I just moved from an 87 911 to a Cayman S (throw stones now) and I do my best not to engage the ABS or PSM on the track. I feel it should be used as a safety net.

sbelles

IMO no, it's not. If you are hitting the ABS you are not threshhold braking. I'm amazed that any instructor would encourage you to use the ABS intentionally. The only time I hit it is if the grip is reduced by dirt or water or the tires are toasted. In those cases, yes the ABS can probably do a better job of modulating then I can but otherwise I hate feeling out of control. Same goes for the rev limiter. Bad things can happen when the car adds inputs that you are not expecting. I also always turn off TC because if I don't it cuts off power on corner exit. Without a LSD I need all I can get even if my tire is spinning a little.

NJcroc

Larry, intentionally using ABS is a very very bad thing to do all the time. ABS causes quite a bit of heat when engaged and in street cars can cause failure at the worst time. there are times when it is great to have abs and it sure does save flat spotting tires, BUT learn to stop the car with out it and you will become a much better driver.

another by product of braking correctly is a much longer life of your rotors, repeated abs heat will cut lifecycle in half

Trak Ratt

When ABS is engaged your tyres are beyound their limits and are being controlled by the "ABS." Stopping distances under ABS are generally longer than threshold breaking. Though less than would be if all the tyres were sliding. That's why most references recommend NOT releasing the brakes in panic stops (on the street or track) once the ABS is activated. By definiftion the brake has to release for the tyres to regain tracktion.

For me it comes down to; do I want to learn to drive the car fast, or just drive a fast car.

Downshifting when slowing from high speed may not be for everyone. But it certainly helps stabalize the car, helps keeps from over reving the engine because of miss timed shifts and keeps folk from holding the clutch in (which a lot of Green/Blue drovers do)

NJcroc

you should always go through the gears as you decelerate, there are times when releasing the clutch in each gear is helpful and sometimes when you must just row through them.

I am assuming you are refering to front of summit main, which should be 6th to 2or3 for you. plenty of time to go through the gears and get the car slowed down right

Brian P

One other thing.... In a DE, threshold braking is not really all that useful. Too many people are trying to threshold brake down to the last millisecond and end up overslowing the car way too much. Try about 80% braking instead and that will give you FAR better control of the corner entry speed and a much more balanced car entering into the corner.

Land Jet

Great info guys, thanks much. If I hear you correctly, I should stay just out of the ABS activation zone. What happens if ABS starts to come on? Do I just lift a bit and continue at the reduced level? I was under the impression that using ABS is threshold braking. Now I see that it is not.