sjfehr

That sounds like less of an observation about great braking, than about poor acceleration

Modern tire tech is amazing, though.

Auto-X-er

Ive been lurking researching info for a potential Porsche for my dad, which this is helpful to read, but I noticed the wheels comment. I found this site a while back that has a bunch of OEM wheels from unknown sources and they do have 18X12s, but didn't see any 18X9s for the front. http://www.wheelsandcaps.com/w_selec..._MAKE=&_MODEL=

Don't know if anyone from this group has tried them. I tried to get 4 rear wheels from an NSX for my miata from there, but they turned out not to have enough stock in the ones that were listed cheapest. I found it originally from the S2000s, because they were buying extras rears to put up front. The consensus was that they looked exactly as stock but were about a lb heavier than they usually were.

They also have replicas very cheap for some of the more common styles.

MagnusB

Ok here we go, did my first autox with the new 997.1 S with PASM and PSE yesterday.
I had the car in sports mode and "turned off" PSM. There was a lot of gravel which was fun from a testing perspective :-)
PASM is clearly not good enough for autox (and track), the car felt like a boat compared to my 996 with JIC coilovers and GT3 swaybars. The lag on throttle and the non-linear torque is also not helping.
At the end I pulled the plug on PSE to enable it on all the time since the car was choking at the start, I think it made an improvement.

The suspension part can be fixed, at the price of everyday comfort so I'm not worried about that but what about the irritating lag on throttle and the on/off torque when applying throttle?

Overall the car is clearly better handling and faster than my 996 with the added torque, but it could be so much better.

Oversteer/understeer comments I don't get, you can fix that a number of ways. The easiest ones are tire pressure, different width of tire and sway bars with stiffness settings.
And check your alignment, mine is way off.

utkinpol

not make torque more linear replace cats to 200cell ones - fabspeed or awe and put on softronic flash. it will pull better.

kouzman

This past weekend i autocrossed my 997.7 3.6 for the very first time.

On Saturday i attended the Autocross school with the PCA Metro guys... Lots of experience, lots of tips and i got to see what my car can do in a controlled environment.... Actually the experience was even greater since it was raining from time to time so the surface was wet at times... The old school guys were very impressed with my brakes and the ability of the car to hold its line when you though it would understeer or oversteer...

On Sunday my very first competitive event in autocross... It was a dry event and i got to see where i stand in terms of times with the more experienced guys... I started running in the 59.6 sec and by the end of the day i went down to 53.4 sec... 8 passes in total...

My car is 100% stock, manual, with Sports Plus and the stock PS2s....

A more experienced guy was running his 997.2 S with PDK, Sports +, PSE, PSM.... the full monty... He ran a 49.5, the fastest time from all Porsches... Note that his tires were almost done, so i would think that on a fresh set of tires times could have been better.

The fastest times in this event were made by an EVO IX (i used to own one) and a Subaru Forester, both with worked suspensions and guys who do this almost every weekend! The were running in the 48.7 sec range...

Long story short, 997 cars can be very competitive even in stock form... Personally i knew that if i could make a couple of more passes i would go ever lower since towards the end i found better lines and i wanted to try with my tire pressure since towards the end i started experiencing more understeer...

I will do some more events and then i might consider a second set of wheels with track dedicated tires and maybe thicker sway bars to control body roll...

simsgw

Well... it is. Already. Better than the others and better than you think it is. Now as for the rest, this gets touchy. I raced for many years and I taught for almost as many. I strongly resist combining the two in a remote situation. Fast driving is not something you learn from a book, and it's not something you teach -- correctly -- by writing one. So let me keep my comments fairly generic.

First, I will confess that my own car is a 997.2 and I'm sure some changes were made from dot one to dot two cars. Despite that, I'm confident when I say that your 996 and any earlier cars you owned were nowhere near as suitable for the track as your 997 is straight off the dealer's floor. They were analog cars and unless modified they had to be designed with the goal of ultimately protecting you when you screw the pooch. The 997 is a digital/analog hybrid instead. And that design technique combines protection for someone in over their head, with glorious speed for those who are not.

Racing was my hobby, but computer control was my professional field. Many people believe they can out-brake a computer, but they are wrong. Well, with the possible exception of some early badly-designed systems. Hell, I can also do arithmetic better than a computer programmed incorrectly, but those are very old examples. Let's skip them and remember that Porsche knows this stuff. They are the ones that other car manufacturers call in to consult on such designs. Your 997 is programmed correctly.

So here we are twenty or thirty years later and some people not only are still convinced they can out-brake anti-lock systems, but they believe they can out-control the computer control system on the suspension of a car like the Carrera. You can not. The system will cover your tail until you start asking things that only a racing driver knows how to ask. Then it will handle those things better than you can, even your surname is Rohrl. I haven't looked it up, but from my own track experience with this car, I'll bet the Porsche factory drivers leave PSM engaged when they go for fast times on the Nordschleife.

I pause here to consider how specific I want to be since I can't do a few laps to show you what I mean. A quick example is all I propose to offer. Forty years ago, many of us would remove the spring from the release button on our handbrake control. That done, or with a reliable thumb, you could apply and remove the rear brakes and modulate them without affecting the fronts. Of course, we had drum brakes in the rear, so we were actually modulating the "service brake" as it's properly called, not some piddly-*** "parking brake."

That independent control of the brakes front and rear was very useful. Worth several seconds in a hillclimb or the occasional autocross. Again, we won't discuss technique, because of that whole "don't teach racing by mail" objection I have, but the point is we had flexibility that the rules deny to most full race cars. Race cars are permitted a manual adjustment in the pits, and sometimes even a balance change on track, but I don't know of any class that allows what we accomplished by simply removing a spring connected to the locking ratchet for the hand lever. Including the ones we were in at the time. They removed that freedom. Controlling the fronts and rears independently is so valuable they don't let race car drivers have that freedom. Consider that carefully. End of example.

Now here we have a modern wonder. A road car that controls all four wheels independently and some people suggest you turn off that feature? I can't speak for the mundane version you'd find on a Hyundai, but the stability system on a Carrera, certainly any 997 Carrera, is a very sophisticated directional control system. Not quite as elaborate as we put on the F-22 or F-23, but within its limited range of intent, it is excellent. Its goals are to extract the most traction from each tire up to the limit that permits balanced vectoring of the other three. (That is, if only one wheel has good grip, it won't spin the car maximizing that one while the others just idle. In other words, it is goal-directed programming, not a simple reactive loop.) You have four control vectors operating on a road car. Two more if you're in a racing class that permits controllable front and rear aerodynamics, but we'll skip that as too much to handle in real time for most of us. Let's stick to four wheels and independent control of each one. With PSM turned on, you have a computer evaluating half a dozen sensors to decide what you're trying to do, and then controlling those four vectors independently to make that happen. You have to know the track and your car well enough to know what simple physics will permit it to accomplish at the limit, but within that limit PASM and PSM will do better than you ever can. Don't turn PSM off. When you do, you're leaving yourself with nothing but the "save your ***" mode the design engineers included for the seven out of ten drivers who bought your model Porsche because the color looked cute.

What you should be doing is talking to... well, me I suppose if we ever get to Willow Springs on the same weekend. But anyone will do who has full race experience and the intuition to figure out how to take advantage of the combination of PASM and PSM. Show this note to such a person and let the muttering run down (if he's been driving a full analog car.) Then let him play with yours for a lap or two and ask for a lesson when that is done.

Incidentally, I can't see PSE helping one way or the other. Certainly it's more fun with a louder exhaust, but any recent Porsche is not going to be power-limited in an autocross. My dot two was blowing off earlier model Turbos on the Streets at three-digit speeds and I never felt like the engine was strangled for lack of PSE. Catching anything in second gear is more a matter of not blowing through the redline than it is of having enough power. Just saying.

Without driving your example, I can't say much about "lag on throttle and the non-linear torque". Recent cars are much better, but it is very typical of high performance engines to exhibit non-linear torque. In fact, people object to designs that don't behave that way. I'll bet you're used to it as well, so when you say that, I assume yours is especially non-linear for some reason. Unless... did you just buy it? The dot one does have nearly as much torque as the dot two, but I found it much peakier when I drove them back to back. You could be sensing the extra height of the torque curve compared to your 996 and intuitively feeling like you want to be up on top of that peak longer.

The "lag on throttle" is related. If you're in one gear too high and you ask for full power, you won't feel much until the engine gains a few hundred or even a few thousand rpm. It's not really a 'lag' so much as being "behind the power curve" as we say of aircraft. To prevent that situation in aircraft, we put the propeller into high pitch or spool up a turbine engine in other ways. You need to do the same thing. Get the engine rpm up before you ask for that power. Unless you're going really slow in first gear, that basically means downshift before you have the need for that power.

If you're feeling throttle lag in first gear, then you're going way too slow for a speed event, at least in my own opinion. If the track layout compelled you to go that slow, then disengage the clutch while you gain rpm and then release it when you need the power. A second or so is enough time to accelerate our flat six to the useful rpm range, even without a racing flywheel fitted. Damn, this doesn't work in writing, but you'll get the hang of it after spinning a couple of times. So try it when you have nothing but pylons to avoid.

I have to say that a recent Carrera is not the optimum car for an autocross. Remind yourself you're out there to enjoy your car, not set fast time of the day. At the low speeds of an autocross, it's entirely possible for the course designer of the day to have arranged it so the faster cars are at a disadvantage. If he's in the mood, then you're always bumping into redline in first gear or too damn slow in second gear, and he won't open up the autocross set-up enough to permit third gear very long in cars like ours. They can do that, but the insurance risk goes a lot higher unless the course is laid out on a real track. So if you're essentially driving the course in first and second, you're seriously handicapped. We have a close ratio transmission. At race tracks or on fast German roads. In third, fourth and fifth in other words. First and second gears are not close to third, fourth and fifth. They are not evenly spaced, and they are awkwardly related even to each other. The competitions they designed our cars for are not conducted in first and second. Hell, even at the Streets of Willow, I never got out of fourth gear. It would take the big track at that venue and I'd be around 150 mph on turn seven/eight if I were using fifth regularly in my Carrera.

So basically, at a typical low speed autocross you're screwed for rpm in second most of the lap, and worrying about bouncing off the rev-limiter in first. Neither is optimum, so I'm not surprised that an Evo turned in a better time than the P-cars you watched.

Now if I were silly enough to care about an autocross this much, I'd put a locked rear-end in a Carrera, set up the ratios for second gear to cover the fifteen mph hairpin nonsense and make the car reach the redline in fourth at about a hundred. That would let me use three and four most of the lap and we would turn some times! Of course, for the cost of such a mod, I could build a special that would go even faster at those ridiculously low speeds and a Carrera so modified would be running in the same 'Modified' class.

We have to face it. Autocrosses are fun in anything, but serious sports cars are not built for those speeds. Our cars excel at 100 to 170 mph, and they are impressive at low speeds like 60 to 100. At parking lot speeds... well, enjoy yourself and don't resent the smaller cars having their glory.

Unless you just want to modify the car for the fun of it, don't bother trying to second-guess the engineers at Zuffenhausen as far as performance is concerned at real track speeds. I'm sure some people drive the car faster after they basically revert to an analog design that matches their driving style, but the car's own limits will be lower, not higher.

At an autocross, just have fun. Or buy a track car like a 1974 turbo or the like and put Hoosiers on it if the rules allow that. Meanwhile, if you catch me at Willow some weekend, I'll show you how to take advantage of PASM and PSM to blow off any earlier analog Porsches and also any current ones whose owners turn off PSM.

Gary

simsgw

Actually, it was bad phrasing. I was thinking of the sight picture from the cockpit and even that is sloppy thinking because you're too high up and sitting in a seat, not a cockpit. What I meant was that I might have used a particular crack in the pavement as my braking point in a Formula Ford going that same speed, so instead I passed that point and gave it a heartbeat longer before starting my braking.

The tires are amazing, I agree, but still not producing the grip levels of a dry racing tire, even the ones we had in the early nineties. What makes the difference is the ability to carry a more effective blend of braking and cornering in the trail braking phase that connects the straight braking section to the turn's apex. The Porsche can do that better than an analog car, even a race car, because in the racing classes you are not allowed independent control of each wheel even if a driver were able to split attention that way.

Come to think of it, I wonder if they permit that in the American Le Mans series and events like that, or if the Porsches and Ferraris must disable their stability control systems. (Which means 'remove' in a race version. You don't carry the weight of anything you disable unless the rules require it. Some people bitch about the weight of paint.)

Gary

db

Gary - wow, another great lesson from the instructor. You've given me some interesting points to contemplate in preparing for getting my C2S on track. Thanks for taking the time to share, as always.

Looks like the next POC Streets of Willow event is Sept 10-11. We'll have to try to meet up there and put theory into practice.

ADias

Right on. It has been proven on the track that a good driver of the latest generation PSM does not feel it, because it does not intervene... I do not have to explain why PSM intervenes...

Correct again. So many people blame the hardware these days, when they should blame themselves. Lack of smoothness in throttle, brake application is often the culprit, not to mention incorrect gear (even though they say they know how to drive a stick).

PASM is not an issue either, especially PASM2 in the latest cars, which is just about perfect. I see so many people tweaking their suspensions - they always think they know better than Weissach - and essentially compromising them.

utkinpol

only 'lag' stock 997.1 motors have is a bit of a dive down of torque curve in the area of 5800 rpm. it feels very well on a stock engine. look at bright blue curve below darn blue curve. DFI 997.2 motors have much much better torque curve.

DMoore

At PSDS in Alabama, the instructors were clear - never disable the PSM. Their comment was that it's only there to save your rear if you're screwing up, so why on Earth would you ever turn it off? That makes a lot of sense to me. I'm willing to turn it off occasionally to play without it on an AX course (low speed, nothing to hit but defenseless cones) but on a track I always leave it on.

ADias mentions that people tweak their suspension - "essentially compromising them." I'm not entirely sure I agree with that. My GTS destroyed its original set of PS2 tires (and front pads) in five track and 2 AX days. With stock suspension settings I corded the outside edge of all 4 tires. I've now adjusted the alignment to maximize the negative camber, but you can't dial in very much with my stock (SPASM) suspension.

I can definitely feel some handling improvements. With only one track day and one AX on the new settings and Pilot Super Sport tires, improved tire wear remains an unresolved question.

There does seem to be general agreement that putting more negative camber into the front can be beneficial for both tire wear and handling on the track. I recognize it makes the car less stable on the street (tramlining, etc) but IF YOU TRACK the car I suspect that some suspension changes (e.g. GT3 LCAs) really are beneficial.

If my car was for street use only, I wouldn't change a darned thing on it. I do believe that the car is totally dialed in for the street, which is after all the primary purpose for which it was designed.

Just my $0.02.

DMoore
'11 GTS
'10 Panamera 4S

Yomi

I'm autocrossing a 996 C4S, but reading your original post sounded like some of the thoughts I had before my first autocross with it as well.
I heard the same thing. I took some runs in a 1995 993 a number of years back and some of these comments brought that to mind -- back end always wanting to go it's own direction. Plus, I went and bought a C4S, which while it looks great and has nice options for DD use, has been pretty roundly trashed for autocross on the internet.

a) Autocrossing a factory stock 996 C4S is fun. Yes, the car is heavy, but I autocrossed a not-too-much-lighter STi before so it wasn't a big change. Yes, there's weight in the back but the suspension changes really have tamed a lot of the nastier aspects. There is some oversteer just due to the weight, and some understeer (perhaps more so in the AWD C4S) -- it just means thinking ahead more. It's nowhere near as bad as some of the comments I've read. It's not like you don't have to think about how weight shifts under manoeuvring with any other car. With about 100 or so runs in it so far this year, I have not yet felt like it was an exercise in futility. I've wished it was faster. I've wished I could drive better. But I've also had runs with non-stop grins, and runs where I get out shaking and full of adrenaline and no thought but how much I want to go out and drive the course again.

b) I still think it can be decently competitive in regional SCCA events, based on how I'm doing vs. the national trophy winners in my region (I'd feel more confident if I went to a NT, drove well, and looked at how I paxed overall, but that's not in the cards for me). The competition at SCCA autocrosses is going to be higher than most marque events (going by local Corvette autocrosses where the SCCA members spank the non-SCCA people, local PCA autocrosses where it's not been quite so bad but still hefty margins, and lots of anecdotal comments from other areas). The 997 in SS is certainly a stiffer competition than AS sees, so if you have good Elise / Corvette / 996GT3 cars+drivers then not quite as much. However, classing could be very different at other events, so who knows.

Just speaking for autocross I think that's a decent plan. Brakes and cooling should be a non-issue for autocross. Driver and tires.

Can't really say on this, I'm sure others have informed opinions. One driver here with a 2009 Cayman S on Hoosiers is a bit faster than my stock 996 C4S on street tires. Putting R compounds on my 996 should easily make it faster than him. A nice 997 should be faster than my 996. With only one sample of random drivers and cars this doesn't mean much however.


Remember when reading comments on forums that lots of variables are unspoken or assumed. For instance, competitive to one person may mean beating the 70 year olds that bring their cars out of their garage twice a year and never use full throttle. To others it may mean beating the Big Names at SCCA national events, and anything less is no good. Getting FTD at some regions isn't terribly hard, at others it is nearly impossible in any street legal car (think F125, AM, or BM car with good driver -- they will be raping a GT2/GT3/Elise/Vette/etc. in raw time on most autocross courses -- though it's quite possible to beat them in a car if they're not well driven or on certain courses / surfaces).

db

Great stuff, Yomi. You're right, it's all relative. Posts like yours really get me excited to get the car on track!

utkinpol

regarding to how 'good' porsche sticks at AX compared to other vehicles - here are results from 5/30 AX NER event. They stick pretty well. My base 997 is on 10th position, right above 2 M3 cars. 1st position was '10 gt3 rs, 3rd - '07 gt3 rs, 4th - 914 with V8 motor, 7th/8th is a 996 car with EVO charger. All those cars were on r-comps, non-street. '07 cayman did not run on r-comps thise event, or he would be around 5-6th place probably.
So, once again, it is much less about a car than about a driver.

1m 1 8 522B Jake Moreau GT3 RS 62.435 0.000 0.000
2 1 12 481A John George Challenge Car 62.998 0.563 0.563
3m 1 9 887A Stephen Lefebvre 997C2S 63.436 0.438 1.001
4m 2 9 75A Mark Skala 914-6 64.298 0.862 1.863
5m 2 12 240A Jon Cowen BMW Supercar 64.329 0.031 1.894
6m 1 7R 1A Oliver Lucier Boxster 64.830 0.501 2.395
7m 3 9 793A Gerard Mauvis 996C4s 65.610 0.780 3.175
8m 4 9 793B Chris Carter 996 C4S 66.502 0.892 4.067
9m 1 2R 44B Joe Kraetsch 924 S 67.192 0.690 4.757
10m 2 7R 333A Paul Atkin 997 67.435 0.243 5.000
11m 3 12 356A Ash Perkins M3 67.548 0.113 5.113
12m 4 12 963A Brian Light 05 M3 68.113 0.565 5.678
13m 2 8 115A Thomas Pelton 04 GT3 68.342 0.229 5.907

MagnusB

Where to start ...

It doesn't really matter how much magic electronics you put into the car. The springs and the sway bars are just not that stiff. This causes a fair amount of body movement. It just isn't up to par with the suspension I had in my 996.

Lag: The time between throttle input and reaction. It is not instant in a 997. Has nothing to do with torque curves.

Choke at start: When I "floor" it in first (really at ~80% so as not to spin in the gravel) the car chokes with PSE on via button but is ok if I pull the plug.
Has nothing to do with my speed.

Non-linear torque: The amount of torque is not corresponding to the amount of throttle given. An easy example of this is in first gear at just above 3000 rpm when it just takes off. Makes the car annoying to drive in city traffic.

PSM on or off: Don't think it would have mattered. I just turned it off since I'm used to not having PSM and didn't want to have to second guess if it was me or PSM.