2009 Porsche 911 turbo - all wheel drive. At speeds greater than 85 mph, there is a low frequency vibration that gets louder as speed increases. It feels like a harmonic and the frequency does not change with speed, only severity of vibration. Appears to come from the front of the car so not in the engine. Any thoughts from folks here? In general even at lower speeds, car does not feel like a 500 HP car. Engine revs fine but just doesn’t feel like the horses are getting g to the wheels. Any advice would be appreciated.
You need 3 things 1. A dedicated Porsche 911 Forum 2. A good independent Porsche shop 3. A good credit rating for a HELOC ( Home equity line of credit ).
Maybe a loose piece of molding or shroud?
I’d suspect the front differential going bad… bearings most likely.
I need to ask, why are you posting tnis question here? Are you going to fix it yourself? Are you going to go to a shop and say “Fix xx please” or are you trying to get an estimate of how many gold bars this going to cost you?
It would really help to know.
Lots of similar complaints about the high speed vibration on Rennlist and other 997 Specific forums. If a speed balance doesn’t solve the problem then your mechanic should look at the drivetrain to make sure nothing’s worn out. We have a few very good Porsche shops where I live but I don’t know how often they see this era of 911.
A tire or rim out of balance could cause this. Suggest to start there rather than assuming it is something out of whack in the engine/trans/drive-train. I find wheel balance weights along side the road all the time on my daily walk-a-bouts. I have two coffee cans full of nothing but wheel weights. So it wouldn’t be that unusual for one or more of your wheel weights to have fallen off. Could be a a tire problem too, but less likely. You can try switching the wheels to different positions, if the effect changes, could provide some more clues.