718 GT4 geo settings
Discussion
Having just got my GT4 back from its second PADM failure and the car now having a second geo, I’m wondering what the preferred settings are for a fast-road (track use but not too compromised)…??
I might get the car set up properly for the summer…. Also interesting that my cars geo seems to have changed hugely after the first geo setup and the “before” readings on my second setup…… only about 1k miles driven in between setups, no track days, just boggo poodling around town.
I might get the car set up properly for the summer…. Also interesting that my cars geo seems to have changed hugely after the first geo setup and the “before” readings on my second setup…… only about 1k miles driven in between setups, no track days, just boggo poodling around town.
If you go to the Rennlist GT4/Spyder section, at the top there is an excellent sticky (second one down).
I believe that the 981 and 718 GT4 suspensions are substantially similar (bar the difft suspension model for the active dampers) so it provides a really good resource. The guy that compiled the data with other track rat Rennlisters was a PCA instructor (sadly he died of cancer).
But he sets out a series of decent options from bets set up with standard, fast road, etc.
R - his words below on stock and next stage up.
Light Track Use:
We have learned that there is quite a bit of variance in how much adjustability folks are getting out of the oem equipment between different cars.
Align for the maximum of the range that the oem equipment on your car allows:
Front: Camber -1.6 to – 2.0; Toe zero, or slightly toe in
Rear: Camber -1.4 to -1.6; Toe in.
Caster: Whatever the oem setup falls onto based on the above should work and not present any issues.
TIP: On the oem equipment toe adjustability will become the limitation for adding camber, especially in the rear. Add as much camber as you can within toe limitations, leaving around -0.5 difference between front and rear camber. (You might be limited with what your car's oem hardware allows you)
Moderate Track Use:
Recommended settings are:
Front: Camber -2.5 to – 2.75; Toe zero, (or maybe very slightly toe out)
Rear: Camber -2.0 to -2.25; Toe in.
Caster: Center the front wheels in the well in order to minimize potential rubbing. For most this will be around a caster of about 9. Rear caster should not be a problem at these settings.
Notes:
In order to overcome the oem limitation for adding camber while maintaining appropriate toe and caster settings, aftermarket parts will need to be installed.
You will need shims to add camber, rear toe links to adjust rear toe and either front caster bushings, or adjustable thrust arms, to adjust front caster.
I believe that the 981 and 718 GT4 suspensions are substantially similar (bar the difft suspension model for the active dampers) so it provides a really good resource. The guy that compiled the data with other track rat Rennlisters was a PCA instructor (sadly he died of cancer).
But he sets out a series of decent options from bets set up with standard, fast road, etc.
R - his words below on stock and next stage up.
Light Track Use:
We have learned that there is quite a bit of variance in how much adjustability folks are getting out of the oem equipment between different cars.
Align for the maximum of the range that the oem equipment on your car allows:
Front: Camber -1.6 to – 2.0; Toe zero, or slightly toe in
Rear: Camber -1.4 to -1.6; Toe in.
Caster: Whatever the oem setup falls onto based on the above should work and not present any issues.
TIP: On the oem equipment toe adjustability will become the limitation for adding camber, especially in the rear. Add as much camber as you can within toe limitations, leaving around -0.5 difference between front and rear camber. (You might be limited with what your car's oem hardware allows you)
Moderate Track Use:
Recommended settings are:
Front: Camber -2.5 to – 2.75; Toe zero, (or maybe very slightly toe out)
Rear: Camber -2.0 to -2.25; Toe in.
Caster: Center the front wheels in the well in order to minimize potential rubbing. For most this will be around a caster of about 9. Rear caster should not be a problem at these settings.
Notes:
In order to overcome the oem limitation for adding camber while maintaining appropriate toe and caster settings, aftermarket parts will need to be installed.
You will need shims to add camber, rear toe links to adjust rear toe and either front caster bushings, or adjustable thrust arms, to adjust front caster.
In order to fit the PADM parts they have to remove part of the rear subframe I believe, so the “before” settings will be after it’s been bolted back together, not how it actually was delivered back to the OPC for the warranty work.
If the front settings are also miles out from first to second geo, then that would suggest that the issue is with the person/people doing either the first or second geo, or the accuracy of their equipment.
Personally, I just had my car set up to max OEM settings by Sports and Classic, who I trust implicitly to get it as close as possible using the OEM parts.
As per Snowy’s post, getting much beyond OEM camber is limited by the rear OEM toe links. To get a more track biased setup you will need to fit adjustable rear toe links.
If the front settings are also miles out from first to second geo, then that would suggest that the issue is with the person/people doing either the first or second geo, or the accuracy of their equipment.
Personally, I just had my car set up to max OEM settings by Sports and Classic, who I trust implicitly to get it as close as possible using the OEM parts.
As per Snowy’s post, getting much beyond OEM camber is limited by the rear OEM toe links. To get a more track biased setup you will need to fit adjustable rear toe links.
richyd said:
Having just got my GT4 back from its second PADM failure and the car now having a second geo, I’m wondering what the preferred settings are for a fast-road (track use but not too compromised)…??
What do you mean for fast-road use? Everyone says this but how do you like your car to feel?
For me, having a car that is planted, that doesn't tramline everywhere and a back end that doesn't kick out at every opportunity allows me to carry far more speed that a car with more aggressive track settings.
Now for me that means quite aggressive rear camber with quite a lot of rear toe in.
While at the front I keep negative camber pretty low with a smidge of toe in.
This will give you are car that weights the steering up nicely off centre, and gets heavier as you press on into fast corners so you can feel when it gets close to letting go at the back. It also means steering wheel is not juggling around and following our crappy roads all over the place.
You will find that you have to provoke the car very aggressively to get the rear end out, and it will make it feel incredibly planted.
For me, these setting are a bit numb on a track, sure it doesn't get the back end to swing round easily, but it is absolutely what I want on the road and will allow me to take corners at much, much higher speeds than a car with no toe in and aggressive negative camber at the front because I'm know when the back end will let go, you can feel it.
Other bonus is it is far more comfy.
I can't give you my settings as I do them at home, so don't actually know, but last time I did have them checked out of interest they were...
Front Camber -0º39
Front Toe In 0º01
Rear Camber -1º89
Rear Toe In 0º14
So, just be careful what you ask for, you may end up with a car that is a twitchy mess on the road and not actually that much fun.
Gassing Station | Boxster/Cayman | Top of Page | What's New | My Stuff