twinsnail

Looking for some "tips'
anyone autocrossing their 996 turbo tiptronic?
I have run mine in auto; thinking about manual for next time..
any thoughts about which is fastest? I found the auto searching for gears
Also, PSM on or off?

Scootin159

I've never autocrossed a 996, nor have I even ever driven a 996, but my suggestions would be:

Manual mode - you'll typically only need one upshift from 1->2 at an autocross, and then will run the whole course in 2nd gear. This should be easy to manage, and will prevent the transmission from trying to go to 1st in slow corners or 3rd mid-corner. Otherwise you could end up with a slight delay as the transmission has to shift back into 2nd when you hit the gas.

I'd run without PSM as most autocross courses are very 'safe' in terms of possible body damage if you loose control. Thus you won't need the PSM to help protect your investment in the case where you really screw up. Also the PSM is likely to dislike the aggressive types of car rotation required at autocross.

knfeparty

If there is a shift lock or shift override button, hit that too so it will stay engaged in whatever gear you have selected.

I would also suggest PSM off...you will learn much more quickly (:
Just be careful. You CAN mess up a car at an autocross.

twinsnail

thx Scott,
the tt's 1st is defaulted to 2nd, 1st is for pulling tree stumps in the Black Forest
I am thinking 2nd/3rd We turned the PSM off in performance school and the car rotated nicely. Will let u know after the next autocross

twinsnail

thx,
I agree that the PSM introduces too many variables, and makes the car hard to feel One of my buddies commented that @ over 100mph in a parking lot course everything (obstacle) is a possibility.....

sjfehr

PSM gives you electronic limited slip dif, and computerized 1-wheel braking to allow harder cornering than you might otherwise get. You can't ever really turn it off as it engages when you press the brake, even when turned off, so you still can't properly trail brake. It will, however, still let you get rotated about 7 degrees off your direction of travel, so you can still oversteer a bit into most corners without PSM kicking on. I found I'm much faster with PSM on than PSM off, simply because I can not only drive to the limit, but intentionally push it faster, knowing that PSM will catch me and straighten out the turn better than I can (1-wheel braking), and let me take corners way faster than I really aught to be able to.

Also, don't use auto. Set the tip to M, launch in 1, upshift to 2, and leave it there. You'll find it a LOT easier to control your speed when you can do so with a consistent gear. You can run in 2nd gear at highway speeds; the computer will NOT let you redline it, so don't worry about that, it will upshift automatically if it's needed. Be aware that tip has one big advantage in autocross: you can downshift to 1st in corners with just a flick of the thumb and both hands on the wheel, and without an abrupt change in weight transfer. Of course, you probably already have way more horsepower than you can really use for most autocross courses.

I'm a mere 986S, but the biggest piece of advice I'd like to give to Porsche drivers in general (especially Turbo drivers... though I don't know if this applies to you or not) is to simply DRIVE FASTER! Don't worry about breaking your car, cones buff out, it's OK to hit them, really! (Just try not to get one stuck under you, those panels are expensive.) You're losing 0.2 seconds for every foot away from key cones, so it pays to drive as close as possible where you need to. And your street fires should be singing on every turn. Squealing is bad, but squeaking is good- squeaking means you're driving right on the edge of traction, which is exactly where you want to be.

Joe Weinstein

PSM costs about a second or so a lap. Turn it off unless you're running
with standing water.
Joe

http://www.sfrscca.org/solo2/Results...onship/t2.html
http://www.sfrscca.org/solo2/Results...nship/asp.html
http://video.yahoo.com/video/play?vid=112495

LJpete

I'll echo Joe on this one. On my MY99 I can buy myself quite a bit of time as traction control kicks in a bit to early and won't allow a lot of rotation. With it on I loose a bit over a second. Thankfully, my year the traction control is completely defeatable and does not reactivate once disengaged.

When driving a friends 02, I experience just over 2 seconds SLOWER from when with PSM is on vs off. Even so, PSM (at least on the C2) will engage when you reach a pre programmed slip angle and hit the brakes. It then fixes you so I wouldn't be to concerned about it if you are a novice as it does still intervene.

As you grow in experience, you will start to dislike it as it's still way too intrusive as the car fights trail braking in mid corner corrections and you really have to fight the car to allow utilize trailing throttle over steer (something, I suspect the AWD turbo won't allow you to have a lot of). I can't comment a lot on a turbo as I have never driven one. I have driven a C4 with PSM and didn't like it much with the E gas and it understeered a lot and you're only option was to back off when you hit the limit of front end grip.

00r101

If you have never autocrossed before than start as simple as possible - leave it in auto and leave PSM on. You will have plenty of trouble just staying on course to worry about shifting.

Of course this setup is not the way to make your car go as quickly on an autocross course as possible - for that you will want to go to manual shifting and PSM off.

But in autocross the limiting factor is almost always the driver. Most new drivers improve several seconds each run as they learn the course. Experienced autocrossers usually only make small improvements from run to run as they alreadty know what they are going to do just from walking the course. When you get to the point where your last run is only about 1-2 seconds faster than your first then you know that you can graduate to shifting on your own and trying it without PSM.

PedalFaster

Not exactly. ABD mimics a limited slip differential by braking a spinning wheel, but it's a ways from an electronic limited slip differential, and it stays on even if PSM is disabled.

Also, on your Boxster, pressing the PSM button really does disable PSM. Panic braking will allegedly cause PSM to reengage, but I say "allegedly" because in two seasons of autocross I never had PSM reengage on its own.

It's your increased confidence that's making you go faster, not PSM. PSM overreacts to any slip angle by killing the power. For that reason, an experienced driver will be faster with PSM off than with it on, at least on a 986.

MechanicalEng

I autoXed my 996TT @ summit point 2 weeks ago and I found that in a low grip track Suck as S.P.) I was faster with PSM ON!! my car is a 6sp and I found that the huge amount of torque was just too difficult to put down on the road.. I am also using crappy tires (Continentals).. I Autoxed a C2 for 3 years and was always faster with PSM OFF..

sjfehr

I think rather it's my overconfidence making me overdrive the car. PSM corrects for that, so I don't lose much time. PSM off.... doesn't. If I enter the corners at the same speeds with PSM off, my *** end is just all over the place and it costs a lot of time.

For the most part, PSM has been completely unintrusive for me when it engages. Occasionally, there will be a course section where it engages and delays throttle response coming out of the turn, but that's certainly not every corner PSM engages on. Maybe it's just my present skill level/driving style, but I'm definitely faster with PSM on than off.

I'm on street tires, if that makes a difference. This is only my 2nd year racing, but I've been doing respectable in street tire class in both local clubs, 1st or 2nd place every race (out of 15-20 drivers). I know I have room to improve, though; I finished 5 seconds down from the AS leader in the SCCA divisionals last weekend, and that's not all tire. If I can gain a second by turning PSM off and learning to handle the oversteer, I will. I'll try it Sunday and see how it goes, this particular venue is a good one for this. I just don't see that I'm losing that much time wth PSM on.

twinsnail

what are you driving? This is a specific question about the 996 tt tip

twinsnail

thx, the tip is interesting in a number of ways
the soft ware is very sophisticated and I find myself trying to out-think the computer when in auto mode; this is further complicated by turbo lag
the shifts are fast and positive in manual but the car will search for a gear (always "up") in an attempt to prevent over-revs You really have to have driven one of these to understand this trait. It would be very cool to have some software which could defeat/simplify this algo

sjfehr

My Boxster is a tip; I drive in manual mode when racing autocross. May be N/A for you because of the differences with turbo lag, etc. I leave it in auto for the street just because it is so smart; with the right throttle input, it'll downshift from 5th to 2nd at highway speeds for passing, and then jump right back to 5th. I can't do that in M! For autocross, there's little reason not to use M, though, as you'll always be going sequentially through the gears to take maximum advantage of your power curve.

Last weekend's course ended up being really tight and I was just plain overdriving it and smashing cones left and right so I found excuse- yet again- to leave PSM on. One of these days I'll finally practice driving with it off and see how much of a difference it really makes for me. If nothing else, there's an Evo school in the fall.