996tt understeer. Comments??
Discussion
Have just completed my first time on track. Short session of about 20 laps.
It seems to me that the 996tt predominately understeers once on a balanced throttle or under power. I found myself turning in later and harder in order not to drift too far wide too soon on the exit.
Any comments on this. What effect tyre pressures, amount of fuel in tank or even additional weight in front boot?
It seems to me that the 996tt predominately understeers once on a balanced throttle or under power. I found myself turning in later and harder in order not to drift too far wide too soon on the exit.
Any comments on this. What effect tyre pressures, amount of fuel in tank or even additional weight in front boot?
I'm not a TT owner...but...
My old (classic) 911 understeered in exactly the conditions you describe. In fact - this is a characteristic of all 911s. Weight over the rear wheels gives monstrous grip and drive under acceleration but a light front end means understeer.
Porsche will have got better and better at setting up the rest of the car to create a well balanced vehicle but all the same this is how the car should behave.
Slow in (to allow turn in), fast out (use the huge traction from the drive wheels).
Now the TT is 4WD - which will make it better balanced again despite the weight distribution - but the characteristic should be the same.
Given that oversteer on turn in is going to be real pain to deal with in comparison to light understeer to my mind its no surprise that Porsche set the car up to do it.
Even my 2WD mid engined Boxster S will understeer gently under power on turn in. Sure you can get it to oversteer...by whacking the power down after the apex instead of feeding it in.
Not sure what the point of the above is - other than to be unsurprised at what you have found based on my experience of other Porsche vehicles.
Enjoy yer lovely car!
My old (classic) 911 understeered in exactly the conditions you describe. In fact - this is a characteristic of all 911s. Weight over the rear wheels gives monstrous grip and drive under acceleration but a light front end means understeer.
Porsche will have got better and better at setting up the rest of the car to create a well balanced vehicle but all the same this is how the car should behave.
Slow in (to allow turn in), fast out (use the huge traction from the drive wheels).
Now the TT is 4WD - which will make it better balanced again despite the weight distribution - but the characteristic should be the same.
Given that oversteer on turn in is going to be real pain to deal with in comparison to light understeer to my mind its no surprise that Porsche set the car up to do it.
Even my 2WD mid engined Boxster S will understeer gently under power on turn in. Sure you can get it to oversteer...by whacking the power down after the apex instead of feeding it in.
Not sure what the point of the above is - other than to be unsurprised at what you have found based on my experience of other Porsche vehicles.
Enjoy yer lovely car!
Ditto - the simple solution to this is go in a little hot and then lift off to get the back swinging and then hold it out on the power. You have to be very quick with the opposite lock though.
You may get it wrong for the first few times, unless you're used to 911 dynamics and/or know your car very very well, but when you get it right it's like poetry.
I've had my 993tt for four months and can get consistent 2nd and 3rd gear slides in the dry (given ideal conditions, i.e. no other traffic!), too snappy in the wet to do this on purpose though - I have caught quite a few wet slides but none of those were intentionally provoked!
Oh, and fun though it is, be prepared for tyre bills...
VS
You may get it wrong for the first few times, unless you're used to 911 dynamics and/or know your car very very well, but when you get it right it's like poetry.
I've had my 993tt for four months and can get consistent 2nd and 3rd gear slides in the dry (given ideal conditions, i.e. no other traffic!), too snappy in the wet to do this on purpose though - I have caught quite a few wet slides but none of those were intentionally provoked!
Oh, and fun though it is, be prepared for tyre bills...
VS
Same on my 964! Porsche these days will always build cars with inherent understeer for safety and as a compromise between comfort and fun.
If you want less understeer then you can change your driving style (as you tried on the track) or make changes to the suspension / wheel settings. However, you might find you don't like the changes to the on-road behaviour.
If you want less understeer then you can change your driving style (as you tried on the track) or make changes to the suspension / wheel settings. However, you might find you don't like the changes to the on-road behaviour.
My test drives of later machinery (4wd turbos) suggest that Porsche have dialled in more understeer to the basic equation since the 965 - but push significantly harder and a new handling envelope opens on the 993tt where safe-ish oversteer is on tap, and the 996tt is just stunning when you let the car help you.
Just a little bit to add, the rear tyres will come up to temperature before the fronts unless you alter your style, which creates understeer.
If you are confident that the fronts are definetly up to temp and it still understeers, then try reducing toe in and add a little more negative camber.
I had chronic power on understeer on corsa's with my 993TT until a geometry change, then it was brilliant, still a little bit understeery until the fronts warmed up but after that - you could have understeer or oversteer based on how you turned in, great stuff
If you are confident that the fronts are definetly up to temp and it still understeers, then try reducing toe in and add a little more negative camber.
I had chronic power on understeer on corsa's with my 993TT until a geometry change, then it was brilliant, still a little bit understeery until the fronts warmed up but after that - you could have understeer or oversteer based on how you turned in, great stuff
We had a little play together at Bedford - actually, I was going flat out and you were playing and leaving me for dust! I've never seen anyone do as many laps as you did.
After you came past me down the long straight I booked the car in for an immediate service and suspension alignment! Still trying to adjust the nut behind the wheel though.
Does your wife know you drive her car so hard?
After you came past me down the long straight I booked the car in for an immediate service and suspension alignment! Still trying to adjust the nut behind the wheel though.
Does your wife know you drive her car so hard?
Well not really, we tried the husband and wife thing, but when i drove she wanted to throw up after half a lap and when she drove i suffered severe angina, even after 5 years i can still see the gravel trap coming to meet us at Macleans.
Its my daughter i am really worried about.....she gets a licence next year.
Got a GT2 now in lovely slate grey, its even faster than the 993TT, bit scary though.
Its my daughter i am really worried about.....she gets a licence next year.
Got a GT2 now in lovely slate grey, its even faster than the 993TT, bit scary though.
porsche4life said:
ahh, Mr Ace i remember the reg, yes what a great day out at Bedford and what a fantastic cct, although a bit heavy on tyres and breaks.
Off to Spa next wed and thurs if you're around
You don't need a GT2 - you were quite fast enough in the 993TT. I thought I was up to speed around bedford in a 993tt, you were on a different level altogether. Still can't believe your car is standard though; the way you came past me down the back straight!
My track day wheels have been clamped due to the imminent arrival of a baby.
I may have to email you regarding suspension settings.
Keep it shinny side up.
Alan
Good luck with that, hope it does not intrude too much into ph life.
Don't think you were on corsa's. when hot you do carry much more corner speed and can get on the power early with corsa's hence the extra speed down the straight.
The extra camber was to allow the corsa's to work better, toe was about zero from memory, 9M has the settings its about an extra degree negative all round.
See you soon.... and good luck again with baby.
Don't think you were on corsa's. when hot you do carry much more corner speed and can get on the power early with corsa's hence the extra speed down the straight.
The extra camber was to allow the corsa's to work better, toe was about zero from memory, 9M has the settings its about an extra degree negative all round.
See you soon.... and good luck again with baby.
Take the car to Parr or JZ and get a semi track set up put on it. Most road cars have understeer dialled into the geometry because it's easier to control than oversteer and 911's are no exception. That will give you more turn in. There is a technique to driving the 911 with will also help turn in but that's another story. A set up should largely sort the problem.
Steve R
Steve R
steve rance said:
Take the car to Parr or JZ and get a semi track set up put on it. Most road cars have understeer dialled into the geometry because it's easier to control than oversteer and 911's are no exception. That will give you more turn in. There is a technique to driving the 911 with will also help turn in but that's another story. A set up should largely sort the problem.
Steve R
interesing.. but for those who have to live with the normal set up.... when will that 'driving that 911' story be told ?
On clear attempt to tackle understeer I intend to fit the 235/40 in the front (instead of the 225/40) since its still within the 3% rolling diameter rule of thumb on AWD and dial some more negative camber on the front axle and converge to near zero toe, I believe this will make a world of difference and if you're conservative with the camber and toe you'll increase tyre life on spirited driving.
Regards
Francisco
Regards
Francisco
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