boqueron

Following the advise of different members of the forum I have aligned to ( nearly ) Roland Kussumaul's numbers my GT3 ( I could not get more than -1,5 camber in front) . I also have soften the rear sway bar to -2 and front to -1 as advised .... By the way, the second alignment in 25 days and 2 track days, with...DIFFERENT initial numbers !!

The same GT3 that was throwing me out of the tracks ( 4 spins in 2 track days) and was DANGEROUS - yes, DANGEROUS - to handle on bad roads. WHAT A CHANGE !!!!: Is just like driving a new - and MUCH MUCH more efficient car !!!

The car has become predictable has you would ( and should ) expect from a GT3. It has lost part of the very strong understeer and now is much more neutral, I have been able to recognise the limits, sliding and recovering it . I have been able to drive the car from pot hole to pot hole, jumping, with predictable ( not really confortable or enjoyable ) results... . The terrible behaviour when touching a pot hole has changed.... A PLEASURE TO DRIVE !!!

THANK YOU ALL !!! My 3rd track day has been a pleasure !!!!

GT3 Chuck

boogie on boqueron

john0719

Can you kindly share the numbers you aligned with? Thanks

boqueron

Here is the thread https://rennlist.com/forums/996-gt2-gt3-forum/262321-which-alignment-for-my-gt3.html with the suggestions received from different members. I used the ".Roland Kussumaul's" numbers recomended by Bob Rouleau ,911 Silverback and Pilma , BUT with Rear -2 and Front -1 ( as suggested by Bob Rouleau ). I couldn't get all the front camber recomended and got "only" -1,5 Front. It REALLY has made a difference ......

Here are the settings copied from 911 Silverback reply..

GT3 settings

Front axle:
Camber: -2.5º
Max camber difference, left/right: 5'

Toe total: +5'
Toe difference at 20° lock: -1°20' +/- 30'

Caster: 8° +/- 30'
Max caster difference, left/right: 30'

Front height: 115mm
Swaybar – 1 from hard

Rear axle:
Toe total: 35’ +/- 2'
Max toe difference, left/right: 5'

Camber: -2.3° +/- 5'
Max camber difference, left/right: 10'

Rear height: 128mm
Swaybar – 1 from hard

DavidNR

Excellent news! My car was upsetting but not that bad. You are fortunate nothing bad happened.

If you would like the info on how to get -2.5° camber or more I can post the details if you don't have it.

Enjoy!

boqueron

David NR, thanks for your help. Your advise will be higly appreciated..

I have been told by Bob Rouleau and others that there are different ways to get the -2,5 Front: enlarging the holes, swaping the struts, turn the tup of the struts, install camber plates ( which seem to be the "safest" and, by far, most expensive way). I have not been able to convince my shop to - slightly - enlarge the holes on top of the shock mounts, which was my chosen alternative... Here is the thread : https://rennlist.com/forums/996-gt2-gt3-forum/271806-help-have-you-swaped-strusts-for-more-camber.html

Thanks again,

DavidNR

boqueron,
I don't remember exactly where I got this but I am sure it was somewhere on this forum:

Quote:
Best solution if you know you don't want less than 2.5 neg front camber is to rotate the struts. There is another set of holes on the struts to use to do this (the alternative holes are color coded and are about a 60 degree rotation - just jack a front wheel up and you will see what I’m saying). Then you have a range of 2.5-4.0/5.0 neg. btw - this is how the cup cars are delivered (all you need to do is to remove the upper strut mounts, press out the 3 pins and place them in the other set of holes, and then re-install the mount, rotating it 60 degrees from it's original installed position. There are no "pre-punched" holes in the sheet metal)

It's easy to see the pins in this pic as well the factory service manual also has these instructions. Just seemed like the simplest way to do it, and since Porsche does it...

Holger B

I just had this done by the dealer during my last alignment. It's as simple as it sounds since they didn't charge me any extra to do it. Front camber is now -2.5 and rear is -2.1. I'm very happy with this setup.

HerrRennSport

I´m stealing the thread a little, do anyone have the alignment numbers for a 996 Gt2?.
I would like to have my car more neutral.

Bob Rouleau

Herr - the specs I got from Roland Kussmaul (above) worked fine on my GT2. I also found that running the rear sway bar one hole softer than the front helped a lot in high speed corners.

Harry - congratulations. I am very happy to know that your car now performs the way it should.

Best,

boqueron

Thanks BOb.

ltcjmramos

Here's a posting from the PCA.org tech site. Has anyone heard of this "solution?"
PCA.org Technical Q&A Section


Classification: Suspension
Subject: 2004 GT3 alignment
Model: GT3
Year: 2004
Total Mileage: 15000
Car Use: Street use only

Question:
Hi Joel, great job moderating BTW. I have had the lucky opportunity to recently trade my 1996 C4S for a 2004 GT3. I was going to wait a few years, but decided that the reasonably strong air cooled market coupled with the 993s mileage (just under 30000 miles) warranted the change. What an amazing car! I am lucky to own one of the cars that justifies any financial decisions Porsche makes to stay profitable. While I still love the air cooled cars (still have one), I realize after a week of driving the new car that it sets entirely new standards.

My intention is to use the GT3 mainly for the street. I will probably take it to the track (DE) to figure it out, but not regularly. I have no intention of turning it into a track car at this point. I have read about the potential factory alignment woes and the edgy handling characteristics as a result. We looked it over pretty well and it doesn't look like it has ever been adjusted since delivered. It feels incredible right now on the street, but you can't really push it hard enough to know. I can tell already that it could pretty easily oversteer.

I drove a student's GT3 on the track last year and my overall impression was that it can easily overpower street tires and that caution was necessary, although I am not used to street tires on track anymore. Should I have it aligned/adjusted (without lowering from stock) to make the car safer both on the street and the tra ck? If so, do you recommend settings for this? Are the factory (street car delivered) settings ok as long as the car actually matches them? Was the issue more that they fell out of these factory settings somehow and that is what made them tricky near limit? I know quite a few have been balled up on track.

Thanks,

Kurt in Chicago
1987 Carrera Coupe Club Racer
2004 GT3


Answer:
Yes some have fallen out of factory specs, possibly due to settling of suspension components.

But mostly I have traced the edgy handling to the motor mounts, they are very soft and compliant, and they permit the engine to move around a little too much. I install the 993 Euro RS mounts, or the X73 mounts, and the cars are transformed. Much improved handling at the limit. The clue to this is that the 996 Cup cars don't have this problem, and they have solid race mounts. So I tried to find an available solution from Porsche that fit correctly yet still takes up some vibration. The solid mounts are not suitable obviously for a street car, but the other two I mentioned are excellent.

I would do the motor mounts first, and have the alignment settings read and recorded, but I would not change it unless it is definitely and clearly out of spec. And in that case, I believe your dealer may even help you under warranty, not sure, but worth a phone call.

Apart from these issues, I think your stated approach works well in your favor. Take it a step at a time, because as you correctly observe this is a LOT of car, and must be handled accordingly. It is easy to get "sucked in" over one's limit if one is not careful, and it sounds like you have this part well understood. These cars are so good they can communicate a sense of invincibility, however the laws of physics still apply, so using good judgment is the best plan of attack.


Joel Reiser - PCA WebSite - 6/3/2006

DavidNR

Thanks Joe, very interesting.

I would have thought the Porsche would have used firm enough mounts. With the firm suspension and too soft mounts... Not the first time motor mounts imporved handling.

datax

Interesting. I had polyurethane (not solid) mounts for tranny and engine on my M3 and they make the thing vibrates like a WW2 fighter plane for first few months. Just as already mentioned, even though solid race mounts are definitely NO NO for a street car, those some none-rubber mounts can be still harsh for some for few months (actually more like 6 months) until it broken in (or, you get used to it). Never tried the X73 or Euro RS ones tho. But, I'm curious now. Since it's a Porsche part, it cannot be too hardcore.

roberga

Porsche did build a street car for Americans. All of the changes we talk about are taking the car where the track rats would like. Austin can speak to the motor mounts. I did the Wevo when putting on TRG bits. Not much more noise and the car rocks in the right hands. --not mine as I am still slow