light front end at speed
Discussion
tbv said:
hi all.
just went on the bypass in my 06 997 Carrera s, very quickly got to 100 mph but packed of rather quickly as it felt light at the front end and to me I didnt feel confident to push it any further, not often do such speeds but not a car on the road and its a long straight road, I know the engine is in the back and that may not help but as its supposed to reach 180mph im wondering if there is a problem somewhere, anyone else had this??
thanks.
lee
To be frank, you need to do some due diligence before posting a question such as this, otherwise you'll end up with million and one "suggestions" as to what may be causing the issue. And rest assured a million of them will be wide of the mark ....just went on the bypass in my 06 997 Carrera s, very quickly got to 100 mph but packed of rather quickly as it felt light at the front end and to me I didnt feel confident to push it any further, not often do such speeds but not a car on the road and its a long straight road, I know the engine is in the back and that may not help but as its supposed to reach 180mph im wondering if there is a problem somewhere, anyone else had this??
thanks.
lee
So ... Firstly check the condition and age of the tyres and their pressures. If they're ok, check all the bushes, ball joints etc in the front and rear suspension, and check the condition of the springs for either sagging or breakage and the dampers for leakage.
If these are all ok (quite unlikely in my experience) get the geometry checked and adjusted by someone who knows and understands 911s.
If after all that, the car is still wayward, it maybe be worthwhile asking the question on here again (though in all honesty, once that lot has checked and found to be ok, if the problem still exists you'll need to take the car to Chris at Center Gravity or one of the other good independents) to get it sorted anyway. But until you've addressed the basics, you are effectively wasting your time trying to second guess what the issue may or may not be.
What a great reply by slippydiff, spot on with everything suggested. Well here goes with the second of the million replies. Firstly I only drive my car in the warmer weather so some of what I say may not be accurate. I have been doing track days and the occasional sprint and hill climb for many years and even in summer, the tyre temperature makes one hell of a difference to the handling of a car and at this time of year you not only have cold tyres but there will be salt on the road making it slippery. One other point is the road surface, I too live in the Leeds area and can think of one bypass with an atrocious road surface, maybe it was the same road. My car is a 997.1 but with the aero kit and is completely stable at speeds well in excess of what you were doing but of course these speeds were attained on the autobahn. Check the tyres and find a road with a nice smooth surface and try again on a warmer day.
Slippydiff said:
If these are all ok (quite unlikely in my experience) get the geometry checked and adjusted by someone who knows and understands 911s.
If after all that, the car is still wayward, it maybe be worthwhile asking the question on here again (though in all honesty, once that lot has checked and found to be ok, if the problem still exists you'll need to take the car to Chris at Center Gravity or one of the other good independents) to get it sorted anyway. But until you've addressed the basics, you are effectively wasting your time trying to second guess what the issue may or may not be.
This.If after all that, the car is still wayward, it maybe be worthwhile asking the question on here again (though in all honesty, once that lot has checked and found to be ok, if the problem still exists you'll need to take the car to Chris at Center Gravity or one of the other good independents) to get it sorted anyway. But until you've addressed the basics, you are effectively wasting your time trying to second guess what the issue may or may not be.
As a guide my 996 does it, and it's been CGd, the main reason is that the front springs have been changed at some point in its life, but not the rears. So it has no rake on it, sits level to very slightly backwards raked when standing level, and will definitely be arse down at speed - this toes out the front wheels and makes the car flighty. A rear engine car is always going to be more susceptible to that effect than your standard front engine, rear drive motor too.
Öhlins (or exe-tc) planned for it, one day!
Measure your front and rear ride heights and report back.
Also in this weather your tyres if you have not adjusted will be at 20psi.
Not may people adjust summer to winter tyre pressures.
You won’t know the geo or can check easy or the bush's etc, hence I cannot say much about that so pointed you to 2 very simple checks.
Also if the cars done over 60k or is of an age like yours the shocks might be way past their best.
Check tyres, post your ride heights on here, then take it to one of the main geo shops.
Also in this weather your tyres if you have not adjusted will be at 20psi.
Not may people adjust summer to winter tyre pressures.
You won’t know the geo or can check easy or the bush's etc, hence I cannot say much about that so pointed you to 2 very simple checks.
Also if the cars done over 60k or is of an age like yours the shocks might be way past their best.
Check tyres, post your ride heights on here, then take it to one of the main geo shops.
Edited by Porsche911R on Saturday 2nd February 21:31
Isn't this a characteristic of the RWD cars, light ('bobbing') front end on acceleration
Doesn't mean it doesn't have some issues as well of course
Never experienced this bobbing in my C4S that was 10 years old when I sold it, the C4S has 50kg of diff over the front axle. Might not sound like a lot but if you lift 50kg in the gym it is a lot and it's right over the axle pushing it down.
Doesn't mean it doesn't have some issues as well of course
Never experienced this bobbing in my C4S that was 10 years old when I sold it, the C4S has 50kg of diff over the front axle. Might not sound like a lot but if you lift 50kg in the gym it is a lot and it's right over the axle pushing it down.
Porsche911R said:
Measure your front and rear ride heights and report back.
Also in this weather your tyres if you have not adjusted will be at 20psi.
Not may people adjust summer to winter tyre pressures.
You won’t know the geo or can check easy or the bush's etc, hence I cannot say much about that so pointed you to 2 very simple checks.
Also if the cars done over 60k or is of an age like yours the shocks might be way past their best.
Check tyres, post your ride heights on here, then take it to one of the main geo shops.
how would I check/measure the ride height?Also in this weather your tyres if you have not adjusted will be at 20psi.
Not may people adjust summer to winter tyre pressures.
You won’t know the geo or can check easy or the bush's etc, hence I cannot say much about that so pointed you to 2 very simple checks.
Also if the cars done over 60k or is of an age like yours the shocks might be way past their best.
Check tyres, post your ride heights on here, then take it to one of the main geo shops.
Edited by Porsche911R on Saturday 2nd February 21:31
thanks.
lee
just checked my tyre pleasures and there were 40psi in each one, probably due to the wheels getting re done a few week ago and them putting the air in, I now have 34psi in the front and 40psi in the rear, just been out for a drive but a bit wet to be giving it some, however I did reach 112 without even knowing,
and it felt better than it did the day before,but surly not through 6spi of air pressure in my front tyres?? and can I just say in no boy racer who just thrashes his porsche up and down the bypass all day, (well, not every day
and it felt better than it did the day before,but surly not through 6spi of air pressure in my front tyres?? and can I just say in no boy racer who just thrashes his porsche up and down the bypass all day, (well, not every day
tbv said:
Slippydiff said:
To be frank, you need to do some due diligence before posting a question such as this, otherwise you'll end up with million and one "suggestions" as to what may be causing the issue. And rest assured a million of them will be wide of the mark ....
So ... Firstly check the condition and age of the tyres and their pressures. If they're ok, check all the bushes, ball joints etc in the front and rear suspension, and check the condition of the springs for either sagging or breakage and the dampers for leakage.
If these are all ok (quite unlikely in my experience) get the geometry checked and adjusted by someone who knows and understands 911s.
If after all that, the car is still wayward, it maybe be worthwhile asking the question on here again (though in all honesty, once that lot has checked and found to be ok, if the problem still exists you'll need to take the car to Chris at Center Gravity or one of the other good independents) to get it sorted anyway. But until you've addressed the basics, you are effectively wasting your time trying to second guess what the issue may or may not be.
Hi, thanks for the detailed reply, I will get them things you mentioned checked out, when I bought the car 5-6 week ago I took it for a 111 point check, here are some of the things that came to light,both rear toe arms have excessive play, N/S antiroll bar D bush heavily swelled, alignment out on road test vehicle feels lose at rear end,both HBA rods seized, I have planned to take to a garage and get these looked at but its finding the time,So ... Firstly check the condition and age of the tyres and their pressures. If they're ok, check all the bushes, ball joints etc in the front and rear suspension, and check the condition of the springs for either sagging or breakage and the dampers for leakage.
If these are all ok (quite unlikely in my experience) get the geometry checked and adjusted by someone who knows and understands 911s.
If after all that, the car is still wayward, it maybe be worthwhile asking the question on here again (though in all honesty, once that lot has checked and found to be ok, if the problem still exists you'll need to take the car to Chris at Center Gravity or one of the other good independents) to get it sorted anyway. But until you've addressed the basics, you are effectively wasting your time trying to second guess what the issue may or may not be.
thanks,
lee
Work through and address any issues in the checklist I've detailed, and you'll sort the issue. It may not be cheap to do, but with anything worn replaced, and anything wrongly adjusted, set correctly, along with decent tyres, correctly inflated, the car should feel totally planted at the speeds you've mentioned.
There's little point in measuring the ride heights at this stage (a quick visual check will suffice, and if the rear of the car looks lower than the front, you'll need new springs either because the springs have snapped or sagged with age) it'll most likely be the latter.
Regrettably the spring seats aren't adjustable on the C2/4 997S, so the only way to correct incorrect ride heights will be to fit new springs, hence why I suggested you get the springs checked for corrosion and breakage initially.
Some will disagree, but the Pirellis frequently don't find favour with many on here. Michelins seem to be considered superior.
My experience of Pirellis is that they're incredibly pressure sensitive, both under and over inflation can and does cause handling inconsistencies. Put bluntly, as you've now found out, they need to be spot on.
My experience of Pirellis is that they're incredibly pressure sensitive, both under and over inflation can and does cause handling inconsistencies. Put bluntly, as you've now found out, they need to be spot on.
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