981 GT4 Suspension Geometry set up recommendations

[Andy OH]

Hi all,

I want to get a suspension geometry set up on my 981 GT4, I've had the car 6 months and it's had a couple of owners previously, as most of these have had. I'm not after an out and out track set up as the car will be predominantly used on road but I would like to dial out the understeer these suffer.

I'm based on the Herts/Essex border and don't mind travelling to get it done. I am aware of Centre Gravity but a few other GT4 owners have recommended other places to go to. There is also a company near Brands Hatch called Precision Alignment which I've heard good reviews for them.

Can you guys recommend anyone and if so I'd appreciate your thoughts on who you've used.

Thanks.

[BubblesNW]

Try RPM Technik, they know what they're doing. HP23 4QR.

[Twinfan]

It sounds like you have two options already, I'd go with either of them. You just need someone with an accurate alignment machine e.g. Hunter and some settings to dial in. Either take their recommendation or do some research and ask them to dial in your own (as I did on my car).

Good luck!

[FTW]

Center Gravity did a great job on my R, I would recommend them from my experience. RPM too.

Have you tried stiffening the rear anti-roll bar? They do change the balance of the car considerably.

[TDT]

Depends on where you live primarily…

Center Gravity
RPM Technik
JZM
String Theory
Ninemeister

Have all done geos for people on here recently.
Ultimately you will be limited by whether or not you have extra parts one the car to allow wider adjustment ranges.
If you’re just looking for a road set up, it can be done quite well with stock car as it is.
For handful of track days at moderate pace for fun it will be ok also but you’ll have more tyre wear and have to drive around front understeer dependant on your pace.

Anything more, and you’ll likely start to need a few extra bits to help keep the car stable at pace and to manage tyre life.

Edited by TDT on Thursday 20th August 12:16

[Andy OH]

FTW said:

Center Gravity did a great job on my R, I would recommend them from my experience. RPM too.

Have you tried stiffening the rear anti-roll bar? They do change the balance of the car considerably.

Yep rear ARB is set to stiffest setting and front ARB is medium and yes that has helped.

[Andy OH]

TDT said:

Depends on where you live primarily…

Center Gravity
RPM Technik
JZM
String Theory
Ninemeister

Have all done geos for people on here recently.
Ultimately you will be limited by whether or not you have extra parts one the car to allow wider adjustment ranges.
If you’re just looking for a road set up, it can be done quite well with stock car as it is.
For handful of track days at moderate pace for fun it will be ok also but you’ll have more tyre wear and have to drive around front understeer dependant on your pace.

Anything more, and you’ll likely start to need a few extra bits to help keep the car stable at pace and to manage tyre life.

Edited by TDT on Thursday 20th August 12:16

Thanks that's basically who is on my list too.

Closest to me is RPM. I would like to dial out the understeer, changing the rear ARB to the stiffest setting has helped a little. My racing days are long over, did 15 years racing karts, single seaters and saloon cars in my teens and early twenties and did a few years of car track days years ago now. To be honest the car will probably only see a track day once maybe twice a year. We have something else that we can use as a track car which is in the process of being built, just need suspension and a cage for it.

So basically I would like a fast road set up for the GT4 and I wouldn't have thought I would need adjustable toe arms or anything like that as I don't want to compromise road driving for an aggressive track set up which will only be used once or twice a year.

Edited by Andy OH on Thursday 20th August 12:44

[Twinfan]

Minimal if not zero toe up front, rear toe to taste, max camber front and rear. Job done, no parts needed. Any geo place can do that for you.

[Pauloamore]

Similar topic....

If anyone comes across a means within warranty to adjust the suspension to avoid so much front left tyre overheating / damage on clockwise tracks.

OP - suggest you try and dial that into your spec for geo.

Thanks in advance

[Porsche911R]

Twinfan said:

Minimal if not zero toe up front, rear toe to taste, max camber front and rear. Job done, no parts needed. Any geo place can do that for you.

An expert now after 1 geo and no track use :-),

The issue with that is in the cold, zero toe up front will not put any heat in your tyres if you drive like a nanny, CUP's need a bit of heat.
So you put in zero toe, you get no heat build up and then have understeer, the very thing you were trying to avoid. !

Zero toe for a road car imo is a NO NO a bit of scrub makes heat, the CUP's friend ;-)

you also cannot MAX camber front and rear that would be daft, you could get -4 up front but the oem setting only allow -1.5 at the back. !!!

You want a bit of toe in at the front, to generate heat and stop the car wandering off/tramlining etc, about -2 up front with some shims, and adjustable rear toe links at the back to get about -1.7 ish. you can go -2.2 front -1.8 rear that's what I had on my GT4 and it was great but maybe too much on the road only, but that worked for me hooning about and gave ok tyre wear across the tyre.

then you can put the rear ARB back to the middle, as imo it's too stiff maxed out one you have a better geo. Max rear worked ok on the oem geo to help the car.

no good having zero toe up front, -2.2 front camber than -1.5 at the rear !!! that's not a good setup imho !!

I also would not use RPM !! unless you want 1/2 a job doing and a bill 3x your quote ... maybe I was unlucky !

[robj4]

A vote for String Theory, one of the few places I've experienced over the years that really did put the effort in as if it was his pride and joy, very good price too and no lecturing at you like he's doing you a favour. He also has info for settings from a well known very quick Pro. whose business developing parts for porkers is gaining a reputation for high quality.

We all have our favourites I suppose, having tried an awful lot he's up there.

And a shout for CGR in Leicester, they did some brake work on my car recently and what a great find. The owners experience is worth a book deal and really nice to deal with. Again no interest in rushing you in and out with BS.

The settings on my beetle have made is so much more enjoyable, track and road.

Good luck

Edited by robj4 on Thursday 20th August 21:34

[Porsche911R]

robj4 said:

A vote for String Theory, one of the few places I've experienced over the years that really did put the effort in as if it was his pride and joy, very good price too and no lecturing at you like he's doing you a favour. He also has info for settings from a well known very quick Pro. whose business developing parts for porkers is gaining a reputation for high quality.

We all have our favourites I suppose, having tried an awful lot he's up there.

And a shout for CGR in Leicester, they did some brake work on my car recently and what a great find. The owners experience is worth a book deal and really nice to deal with. Again no interest in rushing you in and out with BS.

The settings on my beetle have made is so much more enjoyable, track and road.

Good luck

Edited by robj4 on Thursday 20th August 21:34

yes I am going there to get a proper one for 1/2 of the price RPM charged. Gutted to have to have another geo though i'll go the full way this time and have it corner weighted also.

[LennyM1984]

Porsche911R said:

An expert now after 1 geo and no track use :-),

The issue with that is in the cold, zero toe up front will not put any heat in your tyres if you drive like a nanny, CUP's need a bit of heat.
So you put in zero toe, you get no heat build up and then have understeer, the very thing you were trying to avoid. !

Zero toe for a road car imo is a NO NO a bit of scrub makes heat, the CUP's friend ;-)

you also cannot MAX camber front and rear that would be daft, you could get -4 up front but the oem setting only allow -1.5 at the back. !!!

You want a bit of toe in at the front, to generate heat and stop the car wandering off/tramlining etc, about -2 up front with some shims, and adjustable rear toe links at the back to get about -1.7 ish. you can go -2.2 front -1.8 rear that's what I had on my GT4 and it was great but maybe too much on the road only, but that worked for me hooning about and gave ok tyre wear across the tyre.

then you can put the rear ARB back to the middle, as imo it's too stiff maxed out one you have a better geo. Max rear worked ok on the oem geo to help the car.

no good having zero toe up front, -2.2 front camber than -1.5 at the rear !!! that's not a good setup imho !!

I also would not use RPM !! unless you want 1/2 a job doing and a bill 3x your quote ... maybe I was unlucky !

Having run various different geos on different cars, I would probably agree with the sentiment here.

zero toe (or even toe out) up front is awesome on track but can be a bit of a pain in the arse on the road. Every bump or rut in the road has the car wanting to turn. It makes crappy b-roads "entertaining" and even subjectively better roads will have the car wandering around a bit.

After a bit of experimentation I settled with 2' total toe up front (on my 987 Cayman... not the same thing I know) and it's still good on track without being quite so tiresome on the roads near me.

If you are happy to experiment a bit I'd say try what 911R says above and if you don't like it or feel that the front toe settings are dulling the turn in, try a little less etc. Adjusting the front toe is super simple and any competent garage will be able to do it without charging you a fortune (I've now got a string setup at home but last time I paid for just the tracking it was about £30).

If you can't be bothered with all that, take it to somewhere like CG and get them to recommend a setting for you

Edited by LennyM1984 on Friday 21st August 11:29

[Andy OH]

I had quite a long chat with Ben from String Theory this morning and I'm probably going to get booked in with Ben in the next few weeks. From the conversation we had he certainly knows what he's talking about.

[julian987R]

Andy OH said:

I had quite a long chat with Ben from String Theory this morning and I'm probably going to get booked in with Ben in the next few weeks. From the conversation we had he certainly knows what he's talking about.

Check out these videos on Centre Gravity
https://www.youtube.com/watch?v=1E67LiYQkrE

https://www.youtube.com/watch?v=VU5EJ5Asr5M

They seem the subject matter experts.

[TDT]

Andy OH said:

I had quite a long chat with Ben from String Theory this morning and I'm probably going to get booked in with Ben in the next few weeks. From the conversation we had he certainly knows what he's talking about.

Nice one. Be sure to post up afterwards.