Vibration while free revving - very fast vibe

[dinanm3atl]

Like a shudder. Just put in new tranny mounts that are very stiff. I could not feel this before. The car has a vibe/shudder that is very fast when you blip the throttle at while not moving. It goes away around 2500-3000 rpm. Anyone else every experience this?

[nando]

are they urethane?

if so, that's your problem. I just put in a urethane filled rubber tranny mount in my car, I can hear a little more of the tranny but it's not too bad. solid urethane would pretty much suck though..

[dinanm3atl]

are they urethane?

if so, that's your problem. I just put in a urethane filled rubber tranny mount in my car, I can hear a little more of the tranny but it's not too bad. solid urethane would pretty much suck though..

No it is rubber mount but comparing to a brand new OEM BMW dealer bought mount it is a food 2x or 3x harder rubber.

[PeaveyBassist]

Probably just the trans mounts. I have straight through bolt mounts for the engine/trans and a delrin diff mount. My car vibrates a little hahahaha.

Will

[Dibo718]

Did you touch the drive shaft at all? If you unbolted it and then attached it again, maybe it became unbalanced, my brother did a 5 speed swap on his e46 and he gets the same vibrations due to his driveshaft being unbalanced. Just a thought.

[Garageaholic]

Maybe you are running too rich.

[PeaveyBassist]

Did you touch the drive shaft at all? If you unbolted it and then attached it again, maybe it became unbalanced, my brother did a 5 speed swap on his e46 and he gets the same vibrations due to his driveshaft being unbalanced. Just a thought.

Doesn't make any sense. How would unbolting it from the trans and bolting it back up again make any difference in balance? And you dont have to unbolt it to change the trans mounts anyways.

Will

[Garageaholic]

Are you running on all 6 cylinders? I know it sounds trivial and you may have already checked it, but maybe one of your plug wires are loose and needs to be pushed back on the plug...

Is the car running like shit? or just vibrating?

[dinanm3atl]

Did you touch the drive shaft at all? If you unbolted it and then attached it again, maybe it became unbalanced, my brother did a 5 speed swap on his e46 and he gets the same vibrations due to his driveshaft being unbalanced. Just a thought.

It was out and guibo and CSB was replaced 3 weeks ago. I don't think this is a problem. It was not disconnected to replace the trans mounts.

U joints and everything felt great

Maybe you are running too rich.

This is interesting and could definitely be something... Another problem I am having someone was telling me to check my FPR because he had a similar problem and was running rich at idle

Are you running on all 6 cylinders? I know it sounds trivial and you may have already checked it, but maybe one of your plug wires are loose and needs to be pushed back on the plug...

Is the car running like shit? or just vibrating?

Um it runs good. Really good except if you free rev like that...