Annoying vibration

[sebby1982]

Hi guys I was wondering if anyone could help with my vibration I'm getting through my steering.
 When I put down the power hard I get a slight vibration through the steering, than it goes away, and if I am on the motorway it's fine up too 90mph than the vibration comes in, once I'm at 100mph and above its fine until I back off the power than at 90mph it comes again feels like it is coming through the drive shaft, or the exhaust which I got the Miltec de cat pipe and cat back exhaust coming,  it's exactly on 90 anything above and below on the motorway is fine. I have recently changed from duel mass fly wheel to single with vr6 clutch also had the box rebuilt, the problem was there before, I've changed the drive shaft and the driver side wheel bearing, I changed my wheels from 18 to original 16 inch Montreals, I have got to the stage were I am tired of throwing money at the car with guess work, so if anyone has any ideas please let me know, many thanks Seb

[dom]

Wheels not balanced correctly?

[golfyste]

Does sound like a wheel balancing problem!

one of the weights may have fallen off.
have a look if you can see a spot where there was a weight or just go and get them balanced anyway 

[sebby1982]

I work at Kwik fit so that was the first thing I done when I had the 18 inch wheels on now i have 16 on and I balanced them myself. I was told it could be the single mass flywheel. But I had. The Same prob when i had the duel one on. If somone holds the revs on about 3500 i can feel the vibration through the drive shaft while I'm under the ramp.

[xxChrisxx]

Was it in gear? Try it in two gears and see if the vibration on the driveshaft changes.

Be careful, don't want you doing yourself an injury.

[golfyste]

Was it in gear? Try it in two gears and see if the vibration on the driveshaft changes.

Be careful, don't want you doing yourself an injury.

How can you hold the driveshaft while its in gear 

[xxChrisxx]

Was it in gear? Try it in two gears and see if the vibration on the driveshaft changes.

Be careful, don't want you doing yourself an injury.

How can you hold the driveshaft while its in gear 

You don't put your hand on it, Jesus Christ. I guess the warning needed a after it to show it was meant in jest, though I thought that was obvious. EDIT: I'm rather worried that my advice was interpreted like that, I should have been more clear about it.

You just feel out for the vibration through the steering wheel and seat rails. If it still occurs at 3500rpm, it's engine related. If it occurs at a different rpm (varying by the ratio of the two gear ratios) it's wheel/driveshaft speed related.

The simplest way to do this would be to run it on the road in two different gears at the road-speed (because you have load, but it's dependent on finding a good testing road), but if the road speed is too high you need the wheels free whilst it's in the air.

[golfyste]

i was joking dude, i know thats not what you meant .......
its just thats how it read 

[Granta Gti]

What mileage has your dual mass fly wheel done??

[sebby1982]

The dule mass done about 90000 miles before this I put a second hand gear box in and changed the cluch. Than when I went to take the box off to recon it and change to a single mass the cluch that only done about 5000 miles was nackerd. I got the box done thinking this might be we're the vibration is but it was still the same. I can feel it woluthout the car being in gear on the drI've shaft