Discussion
Hi all,
I'm wondering about various geo set-ups; ride height, toe, camber, tyre pressures etc,
I seem to have a lot of understeer at speed and would like to sharpen it up a little.
The transaxle is running a plate LSD.
Currently my tyre pressures are 17 front 24 rear (cold) running Pirelli Corsas.
Standard rims and tyre sizes.
I would normally let a bit of air out of the front or put a bit in the back but 17 psi seems low enough and 24 psi high enough.
I'd rather keep my geo to myself for the time being so as not to influence any answers.
Also any experience with Protech shocks (dual damping) settings would be welcome,
I have a bit of pogoing going (eh?) on at the moment, bumpy roads get the car out of shape very easily.
One more thing, I'd like to get the throttle pedal a bit higher for heal and toe,
it is a manual throttle and there is slack to take up, is there any reason I shouldn't wind the outer cable out a bit, or is this a problem with long throttle cables?
I'm wondering about various geo set-ups; ride height, toe, camber, tyre pressures etc,
I seem to have a lot of understeer at speed and would like to sharpen it up a little.
The transaxle is running a plate LSD.
Currently my tyre pressures are 17 front 24 rear (cold) running Pirelli Corsas.
Standard rims and tyre sizes.
I would normally let a bit of air out of the front or put a bit in the back but 17 psi seems low enough and 24 psi high enough.
I'd rather keep my geo to myself for the time being so as not to influence any answers.
Also any experience with Protech shocks (dual damping) settings would be welcome,
I have a bit of pogoing going (eh?) on at the moment, bumpy roads get the car out of shape very easily.
One more thing, I'd like to get the throttle pedal a bit higher for heal and toe,
it is a manual throttle and there is slack to take up, is there any reason I shouldn't wind the outer cable out a bit, or is this a problem with long throttle cables?
Tony,
Have you checked your bump steer. I did mine years ago and it made the biggest difference on bumpy roads.
I only recently, while having instruction at Silverstone, learnt how to vastly reduce front end understeer in most corners. I think the term is trail braking, ie holding on the brakes right to the corner apex before excellerating out. That way you keep the weight transfer towards the front, without upsetting the balance into the corner. It means the turn in is so much more precise and the front hardly washes out at all. Give it a try (and I don't mean stand on the brakes, just hold them on. You will still have lost most of the required speed prior to turning! It goes against the grain for a while, having been tought to do all your braking in a straight line etc.
Have fun
Have you checked your bump steer. I did mine years ago and it made the biggest difference on bumpy roads.
I only recently, while having instruction at Silverstone, learnt how to vastly reduce front end understeer in most corners. I think the term is trail braking, ie holding on the brakes right to the corner apex before excellerating out. That way you keep the weight transfer towards the front, without upsetting the balance into the corner. It means the turn in is so much more precise and the front hardly washes out at all. Give it a try (and I don't mean stand on the brakes, just hold them on. You will still have lost most of the required speed prior to turning! It goes against the grain for a while, having been tought to do all your braking in a straight line etc.
Have fun
F.C. said:
Hi all,
I'm wondering about various geo set-ups; ride height, toe, camber, tyre pressures etc,
I seem to have a lot of understeer at speed and would like to sharpen it up a little.
The transaxle is running a plate LSD.
Currently my tyre pressures are 17 front 24 rear (cold) running Pirelli Corsas.
Standard rims and tyre sizes.
I would normally let a bit of air out of the front or put a bit in the back but 17 psi seems low enough and 24 psi high enough.
I'd rather keep my geo to myself for the time being so as not to influence any answers.
Also any experience with Protech shocks (dual damping) settings would be welcome,
I have a bit of pogoing going (eh?) on at the moment, bumpy roads get the car out of shape very easily.
One more thing, I'd like to get the throttle pedal a bit higher for heal and toe,
it is a manual throttle and there is slack to take up, is there any reason I shouldn't wind the outer cable out a bit, or is this a problem with long throttle cables?
Wow. here are my observations:I'm wondering about various geo set-ups; ride height, toe, camber, tyre pressures etc,
I seem to have a lot of understeer at speed and would like to sharpen it up a little.
The transaxle is running a plate LSD.
Currently my tyre pressures are 17 front 24 rear (cold) running Pirelli Corsas.
Standard rims and tyre sizes.
I would normally let a bit of air out of the front or put a bit in the back but 17 psi seems low enough and 24 psi high enough.
I'd rather keep my geo to myself for the time being so as not to influence any answers.
Also any experience with Protech shocks (dual damping) settings would be welcome,
I have a bit of pogoing going (eh?) on at the moment, bumpy roads get the car out of shape very easily.
One more thing, I'd like to get the throttle pedal a bit higher for heal and toe,
it is a manual throttle and there is slack to take up, is there any reason I shouldn't wind the outer cable out a bit, or is this a problem with long throttle cables?
The LSD will cause understeer, maybe its worth getting that removed - unless you are hammering it on track I don't think its worthwhile. We dont have one on our race car and its not a problem at all.
Is the understeer as you first turn in or mid corner? Adjusting the toe slightly will help with this.
The tyre pressure seem odd to me - we run them much closer together. I cant remember off the top of my head what Ultima recommend.
If it is at speed (what speed?) try increasing downforce (will help at 80mph+) by adding a splitter or increasing the size if you already had one.
The best way to resolve this is by increasing the amount of rubber at the front - increase the front rim width by an inch and go up to something like 260's on the front - this will have a huge effect.
As mentioned bump steer will have an effect on country roads, though if you are running at standard ride height this should not be a problem. Your issue on country roads is most likely that your damping is too stiff. We have not tried Protech shocks so cannot really comment.
You can fix the throttle easily as you suggested - or of course drop the brake slightly as that is easy to do.
HTH
Jonny
Pb3 said:
....I only recently, while having instruction at Silverstone, learnt how to vastly reduce front end understeer in most corners. I think the term is trail braking, ie holding on the brakes right to the corner apex before excellerating out. That way you keep the weight transfer towards the front, without upsetting the balance into the corner. It means the turn in is so much more precise and the front hardly washes out at all....
+1. Best 'eureka' moment for me too.Pogoing, nice terminology!
It occurs to me that this could either be it's to stiff and bouncing around on its tyres, or too soft and therefore not enough damping.
Both conditions could cause you to have understeer depending on where in the corner you develop it.
An lsd wouldn't normally cause high speed understeer, it's normally low speed high steering angles that lsd's effect.
I'd start around half way through the damping range of adjustment, if you are much stiffer than this then i'd suggest its too stiff and vice versa. If you are any where near Canterbury bring it down one afternoon and we can have a play with it and sort it out.
If it's understeer on initial turn in, or power on, or over a bump then i'd say it goes hand in hand with your pogoing problem.
D
It occurs to me that this could either be it's to stiff and bouncing around on its tyres, or too soft and therefore not enough damping.
Both conditions could cause you to have understeer depending on where in the corner you develop it.
An lsd wouldn't normally cause high speed understeer, it's normally low speed high steering angles that lsd's effect.
I'd start around half way through the damping range of adjustment, if you are much stiffer than this then i'd suggest its too stiff and vice versa. If you are any where near Canterbury bring it down one afternoon and we can have a play with it and sort it out.
If it's understeer on initial turn in, or power on, or over a bump then i'd say it goes hand in hand with your pogoing problem.
D
Edited by dozracing on Wednesday 27th July 12:54
k wright said:
To achieve the settings recommended for track time you will have to trim about .25 inches of the upper a-arm in the front. After you've done this aim for -2 degrees front and -1.4 degrees back and your understeer will improve greatly.
Don't forget to readjust the toe after you have changed the camber.Gassing Station | Ultima | Top of Page | What's New | My Stuff