Gransport Set Up

Zep

Zep

Moderator
Messages
9,336
porsche girl said:
Thanks All.

I have a set of rear toe links on their way (thanks Drew) and when they arrive i will decide where to go for the set up. I am tempted towards TDi in Lakeside. Sam Borgman there is a proper chassis guru and he know's a heck of a lot more than i do about vehicle dynamics. They will match the geo to the tyres (Pirelli) and hopefully will be able to give me more of what I am looking for. The only problem will be parts. I doubt they have any maser bushes in stock so it might be cut and come again. The other option is Roberto in Halstead. Good guy though he most certainly is, he is not a chassis master.
Click to expand...

If you are looking to change the bushes then you will be there a while as they take a bit of work and a 10 tonne press to get them out of the control arms.

For the geo set up you can substitute the Ferrari / Maserati shims for washers with a slot cut so they can slide over the bolts which will allow adjustment of the castor at the front and the camber and castor at the rear. To adjust front camber you need a Maser only shim for the upper front ball joint, I bought a few from Superformance before I went for a set up. I didn't need them so passed them on to Catman, not sure if he still has them or threw them in with the sale of his car.
 
drewf

drewf

Member
Messages
7,159
Felonious Crud said:
I'm watching this thread with interest, as a novice watches in wonder as someone who knows what the h3ll they're doing does something impressive. I'd like to take my car for a proper geo setup but fear I'd fall at the first hurdle. "What's your driving style like?". "Er. Erratic? Inept?"

Regardless, I'm pretty sure the slight rear skip on gearchange under hard acceleration suggest something slightly out of line.
Click to expand...

Have it set up for grass OB. You know it makes sense :)
 
CatmanV2

CatmanV2

Member
Messages
48,949
Zep said:
If you are looking to change the bushes then you will be there a while as they take a bit of work and a 10 tonne press to get them out of the control arms.

For the geo set up you can substitute the Ferrari / Maserati shims for washers with a slot cut so they can slide over the bolts which will allow adjustment of the castor at the front and the camber and castor at the rear. To adjust front camber you need a Maser only shim for the upper front ball joint, I bought a few from Superformance before I went for a set up. I didn't need them so passed them on to Catman, not sure if he still has them or threw them in with the sale of his car.
Click to expand...

I did indeed pass them on to the honourable Wack61

C
 
Felonious Crud

Felonious Crud

Administrator
Staff member
Messages
21,288
It's the fear of ******* up rather than the actual ******* up that causes the issues. I may well have made it, God-like, round that right hander at the end of the straight, but the image of all the spin-offs I'd seen before and the fact that those old Modena-spec brakes would be of little use made me head for pastures new instead. I thought the whole episode had a certain pastoral beauty.
 
P

porsche girl

Junior Member
Messages
35
I had my GS set yesterday at Grimaldi. It turns out the rear toe links were totally shot - which is why it wasn't handling. Just need to get the supplying dealer to reimburse as the links were shot when I bought the car.
...As the Geo had to be done anyway, we decided to go for some Porsche Girl custom settings:

Front
Camber = -1.25 degrees
Caster = 5.10 degrees (would have liked to go to 4.5 but couldn't be done)
Toe = -0.50 degrees (so half a degree of toe out each side)

Rear

Camber = - 1.5 Degrees
Toe= 0.16 degrees (more or less factory toe in)

Sorry to put the numbers in decimals rather than degrees and minutes but it's not easy to find a 'degrees' symbol !!!

The turn-in is much sharper and I can really lean on the front outside corner now. i've gone for a much more aggressive set-up on the front but am running the rears a touch more upright. It's made a huge difference to rear end grip I can tell you. PM me if you want hear more about the rationale and work that we did at Grimaldi.

I am tempted to try more front negative camber but i don't think it will give me what I want all the while I am running the factory from ARB. If I decide to upgrade then I would expect to get a bit more understeer so may try dial that out with more negative camber and toe and also might start messing around a bit with tyre pressures too. It would have been nice to run factory levels of caster but it could not be done with the camber settings that I wanted to run.

What I have now seems like a pretty good compromise. The car is a bit more nervous under high speed braking (to be expected) and the car will now oversteer when pushed to the lateral grip limit at higher speeds as the rear ultimate grip (for higher radius turns) has probably gone down a fraction. if I was going on track I would run another degree of negative camber at the back and probably another .5 at the front too. But i'm not !!!

So there you go !
 
mjheathcote

mjheathcote

Centenary Club
Messages
9,046
Formula Dynamics recommend a toe value of 1/64" out front, and 1/64" in rear....don't know how this equates to degree's though.
Then front camber -0.75 to -1.00 degrees, and rear -0.5 to -1.00 degrees.
So in comparison, yours look very aggressive.

What's the standard figures?
 
P

porsche girl

Junior Member
Messages
35
mjheathcote said:
Formula Dynamics recommend a toe value of 1/64" out front, and 1/64" in rear....don't know how this equates to degree's though.
Then front camber -0.75 to -1.00 degrees, and rear -0.5 to -1.00 degrees.
So in comparison, yours look very aggressive.

What's the standard figures?
Click to expand...


Someone else will know exactly but from memory it's something like:

zero toe - slightly toe in at the front.
about 1/2 a degree of negative camber at the front.

The rear negative camber from FD is less that stock - stock is about 1.5 degrees of negative camber for the rear. I went for just a bit less.

1/64th of an inch is about 0.4mm so I have more like about .75mm I think.

996 turbos like to run loads of front toe out....

Yes, I agree that I have gone quite aggressive at the front and it won't do the tyres any favours but then again I drive almost entirely on Essex 'b' roads so lots of twisty bits.

oh, and the reduced rear negative camber at the has reduced camber thrust and I think there is a bit less bump steer (although I might be imagining that).

I have a lot more confidence in the front getting key'd into the corner now. I can come in on a trailing throttle and then really lean on the outside front and go progressively to full throttle as soon as I passed the apex. Lifting off mid bend just tightens the line. Even on damp roads today it was pretty reassuring. I would like to run a bit more toe on the front and get the roll reduced and get a bit more front -ve camber because I still can't quite feel when I reached the end of the front grip. It could just be:

a. I need to get used to carrying a bit more speed into corners. It will stick it's just no 911 or 360.
b. The excess of frontal roll could be causing a lot of ground level geo/ contact patch changes so that is making the front grip a little bit inconsistent.
c. I haven't actually got it understeering since the set-up yesterday. I realise that I have a very much rear engine'd driving style and perhaps I need to just get on with it ;-)
 
CatmanV2

CatmanV2

Member
Messages
48,949
Please, miss. Are you planning on coming to Bruntingthorpe? I think you owe it to the public!

C
 
You must log in or register to reply here.