In spite of knowing better, I autocrossed my SE30 car a few weeks ago and broke the RH motor mount. I’ve replaced them with way-cool poly mounts and urethane trans mounts. However, during 1st and 2nd acceleration I’m getting a floorpan/chassis reciprocal vibration that is rather scary. I jacked the ass end up today and it only does this under load, so could not find anything running it like this in the garage. U-joint appears tight, guibo was new only a few months ago and still looks like new. Has anyone else experienced something like this or have a good guess as to the cause?
Disconcerting vibration during accel
Patton
#2
Leave the poly mounts under the engine, but change the transmission mounts back to BMW rubber.
That solved a similar problem with one of our racers.
Regards, Robert Patton
ddavidv
#3
Swapped back. It’s better, but it’s not cured. Seems to be 3000-4000 rpm in 2nd gear where it’s most apparent (I’m going up hills to try to find the cause). On the track at speed it probably won’t matter, but I sure would like to know what’s causing it.
edavidson
#4
We had a similar problem and it turned out that the clutch disk had lost about a third of the friction surface, and hence was out of balance. We thought the tranny was going bad and found the problem when we went to change it out.
Ed