Marco Polo

The following factors have been identified as significantly affecting the steering behavior of the MkII GT3:

1. Tramlining - Due to front end geometry and width, compound, and tread design of front tires, the car will tend to follow or be diverted by irregularities in the road surface.

2. Lift-off turn-in - This is most noticeable in a turn: when the throttle is reduced from a relatively steady-state application, the front end will "tuck in." Conversely, when throttle is added, the car will tend to track out.

3. Reduced re-centering - The GT3 has less re-centering effect than the conventional 996 cars. If a driver is accustomed to the level of effect in these other cars, the influences of 1 & 2 will seem even more pronounced. The driver must more conscientiously center the wheel and hold it so. One of the manifestations of this combination is a sense that the car wanders under hard straight-line acceleration or upon lift-off afterwards. Drivers accustomed to cars with more re-centering effect may be unconsciously relying on this effect to hold the vehicle straight during such maneuvers; a more affirmative effort is required.

4. Tire pressure variations.

5. Tires with undocumented manufacture parameter differences - Beware of mixing tires from different manufacturing lots even though published specifications are identical. This may be more likely to be a factor when tires original to the car (from early manufacture lots) are involved.

Note that items 1 - 3 are also features of the Cup cars.

Dirt Track Racer

Just cup cars?

You're right, no other cars are affected by throttle lift, tire pressure, tramlining and re centering (whatever the hell that is).

DTR

Radar

Oh, come on, DTR. He did say GT3 and Cup Cars...

Dirt Track Racer

Whats the difference?

mds

Tramlining can be minimized with an accurate wheel alignment. Toe is critical. The factory's acceptable toe variation range of +/-2' is less than half that of the regular 996.

Lift-off turn-in when turning far from the limit at low side g-loads is apparently due to the LSD. This occurs even with perfect wheel alignment.

Reduced re-centering, I have not noticed this. If you want to feel truly senstive steering, try driving a Formula Mazda.

Tire pressure variations. Pressures vary greatly as the tire heats and cools across periods of aggressive driving. Try monitoring and adjusting them during your drives. A 1psi change is noticable at the limit, a 3psi change has a huge effect.

Marco Polo

The post is accurate. These are factors that affect the steering in ways that people new to this level of performance find perplexing. I correlate to the Cup cars to demonstrate that these are not defects, per se, but inherint in the design of the rear-engine race car.

Alignment can be perfect and the car will still tramline and tuck. Perhaps some of you do not particularly notice these or the re-centering aspect because you have a lot of time driving other track-ready vehicles. Being the first Porsche of its kind (street-legal track car) to be imported to the U.S., it is being driven by many who do not have this level of experience.

Sloth

Hey Mark, I found your post useful and informative. I have several years of track experience running race built Porsches (including a 75 911 w/ 935 suspension, 3.8L 993RS) and was still surprised at how sensitive the GT3 is... nothing a little time behind the wheel has not resolved.

Its ashame that this particular forum has gotten so arrogant that people do not appreciate posts for the sake of the information they provide.

Dirt Track Racer

Your post is accurate - accurate for 99% of the cars on the road. I will grant you that the GT3s low speed turn in issue is probably related to solely to the GT3. But even the way you worded that was ambiguous as most cars will tighten their turning radius if you lift off the throttle.

But the rest is certainly not aimed at the GT3. If you think the GT3 is the only car that

then your GT3 must be the only car you have ever driven.

Heres another:


Ever hear of torque steer? Even Honda Accords and Toyota Camrys exhibit this behavior.

And then you have tire pressure listed as a separate instance. Do you really think the GT3 is the only car affected by tire pressure?

Finally, I am pretty sure that most car manufacturers recommend against combining tires from different tire companies.

So I ask, who really are the arrogant ones here? Me, who points out that most cars produced today exhibit these traits, or you, who think your Porsches are the only ones that do?

DTR

Sun Ra

"This person is on your Ignore List. To view this post click [here] "

that's what i see when dirty track racerette posts.

try it; it saves alot of wear and tear. God bless you dirty.

Dirt Track Racer

Edit:

Hey Marco, what happened? Did you delete your own post that this was a direct response to?

And you have missed my point in so many ways.

If GT3 drivers spent more time driving and less time trying to figure out high performance vehicle dynamics which is beyond the comprehension of most people, they would grow more accustomed to the "unsettling" (your word, not mine) nature of a real drivers car.

Come on, is it really that hard to keep the GT3 on the road? Because thats how you and a lot of others are making it seem. I know I don't have any problems with this stuff when I drive a GT3.

DTR

PS - Hi Watt. Its funny that you are actually on my Buddy list so that I am informed each and every time you make a post. I just learn so much from you.

Bob Rouleau

Dear Dirt Track Racer,

How long have you had a horrible self-image problem?

Was it when you noticed the other kids in the locker room were better endowed that you?

Are you obese and upset about it?

There must be some underlying reason that forces you to try and build yourself up by putting other people down.

I'm sorry if Marco is guilty of posting what you already know. Must have wasted what.. ten seconds of your time? Way less time than you invested posting even more pissant prose.

Seriously, a lot of us would like to help you. The forum would be a better place. As a start you should lose that juvenile avatar which tells us at a glance that whatever you post is bull****.

Signed

A friend who would like to help you ...

Dirt Track Racer

With friends like you Bob...

Bob Rouleau

Uh was that B.S. the meter says man the lifeboats. I guess that means it's BS. Darn.

macfly

Wow, for my first look on the site this certainly is a fiesty group!

This post is a huge boon to me, as after picking my car up this weekend, and doing my first 150 miles up in the San Gabriel Mountains I'm not alone in my wondering about the nervous, rather odd steering vaugeness. On day one this car reminds me of the old Kawaski 750 two stroke triple, goes like stink, but doesn't like corners. I was wondering if I'd make a huge mistake, and what are all these journalists are on about, so it is good to see I am not alone. This is obviously a car that takes some learning!

So, yes, indeed it's my first Porsche, the only rear or mid engined cars I've driven before are Formual Fords at racing schools here in CA and NV, and this sure doesn't feel like those!

I am looking forward to seeing if it is as good at the track as promised, and that is mainly why I bought it, it was the next logical step from my heavily track modified M3smg. Are any of you in the LA area, and going to the POC event at Willow Jan 31- Feb 1?

MetalSolid

I'll be at Willow on the 21st...