996TT geo setting possiblites

[kyepan]

Hiya,

Quick question...

Does anyone know what the maximum front camber you can get on standard bottom arms is? just trying to work out what might be possible for a fast road setup without going for GT2 or adjustable arms.

Had a good search but most of the posts are "go to parr, or CG" and spend a few hundred quid,

In searching i have found the standard 996 geo setting, then standard and fast road 996 gt3

So i can see that:

996 standard front standard tolerance 0-0.5 deg
996 gt3 front standard tolerance -1 deg +- 0.5 deg
996 gt3 front fast road setup i found was set to -1.3

Also many posts about wear on the inner shoulders, so if anyone knows the sweet spot for that too, please shout.
Failing that if anyone has geo settings for a fast road 996 on standard suspension, i'd also be interested in having a look at that.

In the mazda or peuegot world this kind of information is available pretty readily. MIQ spec in mazdas for example, perfect fast road settings that you can take to a decent 4 wheel alignment place.

Cheers
J

[Steve Rance]

You can create a set up that is as sharp as you want it to be. The restricting factor at the front end will be your abs which will trigger earlier with each negative camber increment. At the rear your restriction will be traction as the beginning camber increases incrementally.

It depends on your driving style and what you are looking for. Bear in mind that a GT3 will - by the nature of its NA engine will be set up to differently to a turbo car where the torque created during deployment can overwhelm where the GT3 won’t.

It’s all a trade off but balance is important. All 911’s (pre 991) undresteer. A bluntly (soft) set up car can - to an extent - have this dialled out but as you get towards the optimum end of the chassis set up window the driver must make up the difference in the balance of the car

[IanG1]

Front camber isn't adjustable on standard suspension and arms on a 996 Carrera/Turbo, Only adjustment on front is toe. Fitting shorter springs introduces more negative camber. The rear is adjustable via the eccentric bolt fitted to the rear coffin arm inner mounting but again not massively once lower springs are fitted and more important is the toe setting. GT cars were fitted with two part coffin arms with shims to offer wider adjustment settings.

[nunpuncher]

Isn't the front camber adjustable due to the slotted holes for the strut top mount?

[mr pg]

Front camber is adjustable, had it done at CG when I owned one. There is no caster adjustment, as you can do on 964's for instance.

[Porsche911R]

No adjust arms but a bit on the tops mounts should net you -1.2 which imo is not enough, but better than -0.5 of course.

[nunpuncher]

A Dremel will get you a few more degrees from those slots*

• I take no responsibility for anyone who takes that comment seriously and actually tries this.

[kyepan]

IanG1 said:

Front camber isn't adjustable on standard suspension and arms on a 996 Carrera/Turbo, Only adjustment on front is toe.

Are you sure?

16 90014600303 oval-head screw M 5 X 10 is shown on the parts diagram




I thought this was the eccentric bolt, and have had geo done several times without ride height being adjusted (because it can't be)

[kyepan]

seems that -1.5 might be the answer..
https://rennlist.com/forums/racing-and-drivers-edu...

It would seem that the top mounts have slots to adjust camber from the top! as stated


Cheers
J

[IanG1]

Front lower arms are definitely not mounted with eccentric bolts, slight tweak by slotted top mounting holes as noted above but again only very minor adjustment.

[Olas]

you can buy eccentric bolts and 'oval' the holes for more adjustemnt, or you can buy adustable top mounts.
either way, it IS possible to get the adjustment.


Why not make some changes and see how the car responds, make some more changes, drive it again etc, making incrememtnal changes until it behaves exactly how you wan it to.
It might take a day of your time but it will be exaclt y aas you want it to be, not how someone else thinks it should be.

[kyepan]

Steve Rance said:

You can create a set up that is as sharp as you want it to be. The restricting factor at the front end will be your abs which will trigger earlier with each negative camber increment. At the rear your restriction will be traction as the beginning camber increases incrementally.

It depends on your driving style and what you are looking for. Bear in mind that a GT3 will - by the nature of its NA engine will be set up to differently to a turbo car where the torque created during deployment can overwhelm where the GT3 won’t.

It’s all a trade off but balance is important. All 911’s (pre 991) undresteer. A bluntly (soft) set up car can - to an extent - have this dialled out but as you get towards the optimum end of the chassis set up window the driver must make up the difference in the balance of the car

If only the abs cut in more often, I really struggle with the quality of the brakes on this car, they just don't feel adequate. Was looking at 997tt discs and caliper spacers last night.... just for some extra stop.

I'm not looking for anything drastic, it's a road car for sure, a little more turn in, a little less low speed scrubby understeer. I fitted 309 front wishbones to my Pug 205 and then Citroen ZX rear training arms, bit more camber all round, little bit less toe at the rear, and that transformed how it handled completely. Granted it still wants to kill you if you take your eye off the ball.

[nunpuncher]

kyepan said:

Are you sure?

16 90014600303 oval-head screw M 5 X 10 is shown on the parts diagram




I thought this was the eccentric bolt, and have had geo done several times without ride height being adjusted (because it can't be)

Number 4 on that diagram is the bolt that holds the coffin arm in the subframe. It's non eccentric (m12 I think). I'm currently refreshing my suspension and have just replaced those bolts.

Number 16 looks to be a bolt related to the litetronic level sensor which attaches to the subframe and the coffin arm.

I'm not sure how easily you could slot the holes in the subframe at the front. The head of the bolt passes through a sort of tube like area and I think it would be considerably weakened by removing metal. Access to the bolts/hole is awkward. Forking out for adjustable arms or more likely top mounts to avoid issues with the driveshafts on a turbo would probably be best.

[kyepan]

Thanks for all the helpful replies, especially Nunpuncher, i've never managed to do anything productive with a dremel, it always ends in crying tears.

kyepan said:

Failing that if anyone has geo settings for a fast road 996 on standard suspension, i'd also be interested in having a look at that.

Olas said:

Why not make some changes and see how the car responds, make some more changes, drive it again etc, making incrememtnal changes until it behaves exactly how you wan it to.
It might take a day of your time but it will be exaclt y aas you want it to be, not how someone else thinks it should be.

I'm game for this, but i think there is a more complex relationship between camber and toe, as you adjust camber it's going to affect toe. So toe would need adjusting each time, which i can do.

Also i'd need marks on the strut tops (like you have on adjustable cam pulleys) to work to so i know how much i'm moving each adjustment.

If only 4 wheel alignment rigs weren't thousands, which makes me think, how did they do it back in the day on old f1 cars and alike... someone must know

[IanG1]

kyepan said:

If only 4 wheel alignment rigs weren't thousands, which makes me think, how did they do it back in the day on old f1 cars and alike... someone must know

With string,stands and patience. Something like this

https://ralphhosier.wordpress.com/2010/12/28/setti...

[tobie]

IanG1 said:

With string,stands and patience. Something like this

https://ralphhosier.wordpress.com/2010/12/28/setti...

My understanding is many race teams still do use string - it's a bit time consuming but with pracise (and a few handy rigs) you can get pretty good with it.

[nxi20]

kyepan said:

If only 4 wheel alignment rigs weren't thousands, which makes me think, how did they do it back in the day on old f1 cars and alike... someone must know

String, plumb line & a ruler. That's all a Hunter does, it just does it with lasers & draws pretty pictures.

[nunpuncher]

I used string and a couple of axle stands to do the alignment on my 205 last year. Surprisingly worked quite well. Although admittedly there's not as much adjustment as with a 996.

I'm going to try a similar technique on the 996 but set the camber using a length of wood on the wheel face and a level app on the phone. Should do until I get it up to a proper alignment place.

[kyepan]

nunpuncher said:

I used string and a couple of axle stands to do the alignment on my 205 last year. Surprisingly worked quite well. Although admittedly there's not as much adjustment as with a 996.

I'm going to try a similar technique on the 996 but set the camber using a length of wood on the wheel face and a level app on the phone. Should do until I get it up to a proper alignment place.

A fellow 205 owner! Hi there

There is an inexpensive tracking tool that sealy sell I think, my mate paul uses two lengths of wood and string too. Seems to be able to get it quite accurate for zero toe.

What kind of 205 do you have? I've got a black k reg Mi on bodies! It's currently hybernating, but will be out to bring induction hammer to the world soon.

[mikep240]

I run a 996T and have extensively exhausted the standard suspension set up. My car now runs Ohlins R+T and a few other goodies, but it could be made to handle very well indeed with the stock suspension, soft springing was the limiting factor though.

As for a set up, as Steve Rance said above, it is very much a case of tailoring the geometry to suit your driving style. This was where I got to with a totally stock set up;
Front camber: Max available was 51 minutes!
I replaced the coffin arms with slightly adjustable caster pucks: 8'15" was the number that worked the best with the above camber.
Front toe: zero

Rear camber: 1'50" worked pretty well on Michelin PS2
Toe: have run the following... 10 minutes TOTAL (drove like a mk2 Escort, sideways everywhere, no understeer at all)
16 minutes TOTAL, reasonable stability but lacked rear cornering grip on corner exit
24 minutes TOTAL, better grip, reasonably agile, good stability
30 minutes TOTAL, super stable, monster rear grip, but pushed the front if too early on the gas.

The car needs to be heavily trail-braked to get the front to stick with all of the above. Ran 1.43.2 at Anglesey with PS2 tyres on the 24minute toe settings, set by CG.

Bought the Ohlins, fitted Cup 2s (a revelation in terms of both comfort and grip), car set to GT2 ride heights. Runs 1 degree front but screaming out for more, zero toe. Rear 2'05", 30 minutes toe. Massive slow corner grip, but washes the rear in higher speed corners. Set up by Fearnsport, who did an excellent job.

Ran 1.40.38 at the same track. The car is in need of a lot more camber at both ends now.

Hope this little lot helps fella.

Mike.