Originally Posted by
captain stacker
thanks to all the guys who made suggestions regarding tweak.
on mine, it's 100% the motor mount. As soon as I tighten up the screws to the motor mount brace, it tweaks the chassis. Seems like I can only leave it not tightened all the way, might need some shimming under that brace. It really is a stupid mounting system, never seen it before on a touring car. The mount should be completely flat.
edit.....even though with the motor mount screws done up tight and tweak is there, once the top plate is tightened up properly, the tweak is gone. So all is good now.
I had this same issue; the motor mount was causing tweak. I isolated the problem to the layshaft mount that the motor mount bolts to. This mount wasn't dead straight on the chassis, so when I bolted the motor mount between the layshaft mount and the chassis, the chassis tweaked.
My solution was to bolt the two layshaft mounts together using 19mm standoffs. Then bolt the mounts to the chassis, then remove the standoffs. This got both mounts dead square (which is good), and meant I could bolt the motor mount on without tweaking the chassis (which is very good).
Your car needs to be 100% tweak free without the top-deck. Using the top-deck to force it into a given position will just make it more likely to tweak on track as the chassis will be trying to pull it back into the tweaked position.