996 smoothness at speed
Discussion
Not certain. That is fairly fast. My experience of problems at somewhat lower speeds is wheel balancing. It might also be that your tracking is off a bit. Are your tyre pressures correct / consistent? Do you have any kind of abrasion / problem with any of the tyres? Possible road surface / cornering issue? People sometimes have problems on constant radius turns with tyres unwinding due to the slight difference in radius inside to out. This is a subtle point but some contributors have experienced / raised it and it is well recognised and disconcerting.
It is also conceivable that you have set up a resonance in the suspension due to steering inputs. This is a dreadful problem as you think the steering is failing but it is fine. At the time this is very hard to identify and can occasion you very quickly. There are youtube videos of people having a similar problem when over-correcting in slides and the car oscillating due to steering inputs and then sliding off the road. My little lad did something similar today on his balance bike at rather lower speeds...
Frustrating and a bit worrying!
It is also conceivable that you have set up a resonance in the suspension due to steering inputs. This is a dreadful problem as you think the steering is failing but it is fine. At the time this is very hard to identify and can occasion you very quickly. There are youtube videos of people having a similar problem when over-correcting in slides and the car oscillating due to steering inputs and then sliding off the road. My little lad did something similar today on his balance bike at rather lower speeds...
Frustrating and a bit worrying!
Elaborate on "sounds buzzy" and do you correlate with the instability or are they separate?
Instability is usually tracking, if it's not correct the car can be very nervous indeed even at much lesser speeds.
Obviously the usual suspects such as tie rod ends, and also coffin arms, must be checked.
Important to note that the sensitivity of the steering will always mean a lot of feedback from variations in the road surface. These cars are not really "cruisers", insulated from the world outside.
Instability is usually tracking, if it's not correct the car can be very nervous indeed even at much lesser speeds.
Obviously the usual suspects such as tie rod ends, and also coffin arms, must be checked.
Important to note that the sensitivity of the steering will always mean a lot of feedback from variations in the road surface. These cars are not really "cruisers", insulated from the world outside.
Thank you so much for the suggestions. The car has done c86,000 miles and its service was at 911 Excellence. It received new rear disks as well as a new clutch in its recent annual service. The drive was on German autobahns to the Innsbruck area and back, and the issue began rearing its head at 130mph plus which occurred often enough during the trip. It was a worrying but the car did reach 160+, just, without falling to bits or leaving the road.
The buzzy vibration was not attributable to any one source. hence the original question. I'll go through the list, starting with the tracking and wheel set up. Thanks again for all the replies.
The buzzy vibration was not attributable to any one source. hence the original question. I'll go through the list, starting with the tracking and wheel set up. Thanks again for all the replies.
I had by the sounds of it the same issue on a Cayman of mine, once it got to 111mph the thing was shaking everywhere.
The wheels and tyres were perfectly balanced and I couldn't solve the issue so I sold the car, but if I could guess I would say the issue started happening after the front discs were changed.
The wheels and tyres were perfectly balanced and I couldn't solve the issue so I sold the car, but if I could guess I would say the issue started happening after the front discs were changed.
Indeed - my 99 996c2 with 88k on it was not stable at speed at all, but got front dampers, mounts, bumpstops and drop-links done last week, followed by a proper four-wheel alignment and it's absolutely rock solid now
Rear dampers were done a couple of years ago and all four coffin arms last year - no old parts left on there now - handling and stability are bang-on!
Rear dampers were done a couple of years ago and all four coffin arms last year - no old parts left on there now - handling and stability are bang-on!
Agreed on the tank of fuel thing. Interesting one about brake condition - makes sense.
Veyrons were heavy for a reason. My 996T seems more planted than my previous 996C2. Heavier, bigger front tyres and 4wd gubbins contribute I imagine. It's also a bit wider.
I hope you get it sorted.
Veyrons were heavy for a reason. My 996T seems more planted than my previous 996C2. Heavier, bigger front tyres and 4wd gubbins contribute I imagine. It's also a bit wider.
I hope you get it sorted.
I saw 175 on the clock shortly after I got mine around 10 years ago and it was stable Ina straight line - though it did feel a bit uncomfortable over a long bump mid bend!
Haven't done near that speed since, but regularly see 130+, and it's perfectly stable at that speed, even on shocks that have done over 160k miles.
Anywhere with the proper 4 wheel alignment gear can track it... if that doesn't fix it then you'll need to go to a specialist.
Haven't done near that speed since, but regularly see 130+, and it's perfectly stable at that speed, even on shocks that have done over 160k miles.
Anywhere with the proper 4 wheel alignment gear can track it... if that doesn't fix it then you'll need to go to a specialist.
nebpor said:
Indeed - my 99 996c2 with 88k on it was not stable at speed at all, but got front dampers, mounts, bumpstops and drop-links done last week, followed by a proper four-wheel alignment and it's absolutely rock solid now
Rear dampers were done a couple of years ago and all four coffin arms last year - no old parts left on there now - handling and stability are bang-on!
>>>>>>>>>>>>Rear dampers were done a couple of years ago and all four coffin arms last year - no old parts left on there now - handling and stability are bang-on!
Interesting points. Thank you.
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