GT3 handling problem
Discussion
Posted an earlier thread for advice on Geometry, got some good feeback.
Just had a full Geo set up for track at AMD (didn't have time to go anywhere else and the guys seem to know their stuff?) that has made the turn in much better. Understeer is now minimal.
I still have a problem with stability at the rear on high speed on corners, slow and medium there is plenty of grip and feel.
The problem showed itself at my last track day at bedford before the latest setup and only on one corner (the only high speed entry on the track, left hander before the chicane that leads to the back straight)
Just done Donnington today and what was annoying at Bedford, felt just plan dangerous through Craner! I could not lean on the car at all, example I could not stay with a standard 997 C2S on road tyres, on this section.
I thought it was me, by 3 different people have driven the car (including a Brit Car winner and ex F1 driver today) all feel the same issue.
So this is what seems to happen.
Turning into to high speed corners you feel the car weight as you get on a balanced throttle or on the power the car settles at first and then seems to roll further and snap oversteer. If you dont get the oversteer by going in slower you still get a sort of rolling sensation, i.e. yaw.
It sort of feels like the shocks may be gone, (03 car 18k miles with 4 trackdays?) but they feel tight on all other corners and the road (i.e when not fully loaded)
The other area could be bushes on the top mounts and ARB?
My instructor today said to seek some advice as I could wasted a lot money chasing a problem that may have a simple fix?
We tried lowering the tyre pressures and this did nothing to help?
Any similar issues or advice appreciated.......I really dont want to go down the new shocks and spring route just yet!!!
Jeweller
Just had a full Geo set up for track at AMD (didn't have time to go anywhere else and the guys seem to know their stuff?) that has made the turn in much better. Understeer is now minimal.
I still have a problem with stability at the rear on high speed on corners, slow and medium there is plenty of grip and feel.
The problem showed itself at my last track day at bedford before the latest setup and only on one corner (the only high speed entry on the track, left hander before the chicane that leads to the back straight)
Just done Donnington today and what was annoying at Bedford, felt just plan dangerous through Craner! I could not lean on the car at all, example I could not stay with a standard 997 C2S on road tyres, on this section.
I thought it was me, by 3 different people have driven the car (including a Brit Car winner and ex F1 driver today) all feel the same issue.
So this is what seems to happen.
Turning into to high speed corners you feel the car weight as you get on a balanced throttle or on the power the car settles at first and then seems to roll further and snap oversteer. If you dont get the oversteer by going in slower you still get a sort of rolling sensation, i.e. yaw.
It sort of feels like the shocks may be gone, (03 car 18k miles with 4 trackdays?) but they feel tight on all other corners and the road (i.e when not fully loaded)
The other area could be bushes on the top mounts and ARB?
My instructor today said to seek some advice as I could wasted a lot money chasing a problem that may have a simple fix?
We tried lowering the tyre pressures and this did nothing to help?
Any similar issues or advice appreciated.......I really dont want to go down the new shocks and spring route just yet!!!
Jeweller
Assuming you are running "trackday" tyres Pilot Sport Cup, Dunlop D01/02, Pirrelli Corsa, slicks etc then fit a new set of tyres. Never mind how much "tread" is left on them repeated heat cycles and storage cause the rubber to go off.
I assume there is nothing lose or broken on the suspension as you will have picked up on that with your pre-trackday inspection and AMD hopefully looked at everything before they set the car up.
If you`re struggling with a set up or handling issue then you must change the tyres to eliminate them. If the problem remains then you still have the old tyres to use later. If it solves the problem, and it might, then chuck them away.
Henry
I assume there is nothing lose or broken on the suspension as you will have picked up on that with your pre-trackday inspection and AMD hopefully looked at everything before they set the car up.
If you`re struggling with a set up or handling issue then you must change the tyres to eliminate them. If the problem remains then you still have the old tyres to use later. If it solves the problem, and it might, then chuck them away.
Henry
I don't know how good AMD are at setting up the car. Assuming that there are no broken/damaged components, I would be looking to either stiffen or loosen the rear (and possibly the front) anti roll bar. When I was running my RS last year a simple adjustment made a bid difference to how the rear of the car handled.
I had a bad day at both Donny and Brands, but after a quick adjustment it felt much better the following day.
Jonathan
I had a bad day at both Donny and Brands, but after a quick adjustment it felt much better the following day.
Jonathan
Having good turn in is great, but this can easily be at the peril of high speed oversteer if
not set up properly....
I would get the car set up/ checked by some guys with more Porsche Experience.....JZM or Parr...
Tell yourself you haven't got time when you're in the gravel trap!!!!!!!!
G.
not set up properly....
I would get the car set up/ checked by some guys with more Porsche Experience.....JZM or Parr...
Tell yourself you haven't got time when you're in the gravel trap!!!!!!!!
G.
Just had a full Geo set up for track at AMD (didn't have time to go anywhere else and the guys seem to know their stuff?) that has made the turn in much better. Understeer is now minimal.
Thats the price you pay for the above ! fast corner oversteer is the result you have to except it or dial in the understeer again, the better driver you become you deal with oversteer because you hate understeer even more,,,,
Russell
Thats the price you pay for the above ! fast corner oversteer is the result you have to except it or dial in the understeer again, the better driver you become you deal with oversteer because you hate understeer even more,,,,
Russell
I find my GT2 very sensitive to rollbar adjustment, so much so that at Spa i wanted a setting in between the holes on the roll bar.
You may want to post your set up to see how it compares
Also check corner weights
Even if there is break away, it should be progressive and manageable with a flick of the wheel.
I am still working with mine as funnily enough i also have reached the limit on the high speed stuff, sometimes i get 4 wheel drift (old hairpin) sometimes the rear is rocking ready to let go (Bedford chicane in middle of back straight)
I would spend time analysing other peoples settings, some are secretive (IPR), some don't give a stuff (like me)
You may want to post your set up to see how it compares
Also check corner weights
Even if there is break away, it should be progressive and manageable with a flick of the wheel.
I am still working with mine as funnily enough i also have reached the limit on the high speed stuff, sometimes i get 4 wheel drift (old hairpin) sometimes the rear is rocking ready to let go (Bedford chicane in middle of back straight)
I would spend time analysing other peoples settings, some are secretive (IPR), some don't give a stuff (like me)
I would certainly get the suspension checked over failed bushes will give you snap oversteer in high speed corners (speaking from experience here) but I also suspect that your setup is just too extreme, no turn in understeer usually means a high risk of oversteer which is fine in slow corners but not very nice in high speed corners.
JZM or Parr will get your car sorted for you they have far more GT3 experience than anyone else in the UK.
Richard.
JZM or Parr will get your car sorted for you they have far more GT3 experience than anyone else in the UK.
Richard.
Cannot really help with the camber as this is tyre specific.
You can go to a tuner of course but if you want to know what is going on and experiment then at your next track day take the appropriate spanners for ARB.
I would put the rear back to full soft and then bring it back to harder.
By doing this you should feel the balance of the car move from Understeer to oversteer
You can change the ARB in less than half hour
You can go to a tuner of course but if you want to know what is going on and experiment then at your next track day take the appropriate spanners for ARB.
I would put the rear back to full soft and then bring it back to harder.
By doing this you should feel the balance of the car move from Understeer to oversteer
You can change the ARB in less than half hour
As everyone has said before, check everything is tight and not broken. Check that you are happy with the settings put on by AMD. (They look OK to me). Then its up to you. So much depends on your driving style and lines, particularly at Craner. If other people agree that the car is oversteering ask yourself wether it is turn in oversteer, mid corner or when you get back on the power. Easy questions but sometimes difficult to answer. The corrections you need to make to the chassis will depend on the answers so make sure you really understand what is going on. It takes a long time (and I dont think I have always got it sorted) but work at it. As a complete punt in the dark I would try stiffening the front bar to full stiff and then see what happens. Dont be afraid to try things, you can always put them back. Just be careful on the first lap or so until you can feel what is going on. Another obvious piece of advice, change one thing at a time!
Its the beauty of racing, or track days, as you have a car that you can mould into what you want.
Good luck,
Richard.
Its the beauty of racing, or track days, as you have a car that you can mould into what you want.
Good luck,
Richard.
Richard hi:
When I first read this post I said to my self now here's someone who knows what he's saying! (Actually you took the words out of my finger tips
) and I checked your nick which I found suspicious but then when you signed it all made sense. Nice to have you here as well.
P.S. Jeweller, follow this gentleman's advise and you can't go wrong.
When I first read this post I said to my self now here's someone who knows what he's saying! (Actually you took the words out of my finger tips
) and I checked your nick which I found suspicious but then when you signed it all made sense. Nice to have you here as well. P.S. Jeweller, follow this gentleman's advise and you can't go wrong.
Not sure I know what I am talking about!!!
Just rather understand what is wrong. I am never convinced it is a good idea fix things if they are not broken.
Plenty of people happy to take money from you for no good reason.......RAM Air spoiler for GT3 ring any bells?
I expect I will get a reply stating the HP gain and cooler running! I would like to see the proof!
Anyway some good responses here that are appreciated.
I have the wheels off and I can see oil leaking from the right rear shock......This may be just the reason I need for the Manthey replacements!
Jeweller
Just rather understand what is wrong. I am never convinced it is a good idea fix things if they are not broken.
Plenty of people happy to take money from you for no good reason.......RAM Air spoiler for GT3 ring any bells?
I expect I will get a reply stating the HP gain and cooler running! I would like to see the proof!
Anyway some good responses here that are appreciated.
I have the wheels off and I can see oil leaking from the right rear shock......This may be just the reason I need for the Manthey replacements!
Jeweller
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