Hi all. I have an 88 6 port turbo. Engine vibrates really bad when accelerating in any gear. When I press in the clutch while coasting it completely stops. It also vibrates when revving in neutral. The entire car rattles. I have hocky puck engine mounts that have been in the car for a long time. I installed poly trans bushings a few months back while the engine was being rebuilt. I feel the poly trans bushings are the culprit here because ive never noticed vibration this bad with just the engine mounts. My other car has poly trans bushings and only vibrated untill they broke in. I've tried adjusting the preload on the poly mounts but it doesn't seem to change. I'm not really sure what to do. Has any one else experienced this type of vibration with stiffer mounts? Should I switch back to oem mounts? Im currently using the car as my daily to break the engine in. I do plan to drift this car occasionally but mostly street driving. I just want to hear your experiences with stiffer mounts and vibrations and how you guys resolved it. Sorry for the long post thanks in advance.

 

Personally, I see no point to solid mounts of any kind on a primarily street driven car.
Replace both engine and trans mounts with the stiffer than stock (but still not solid) Mazdaspeed units and your problem should go away.

 

The solid mounts are the issue. There has to be somewhere for the drivetrain to flex and absorb drivetrain vibration or you will get vibration resonance throughout the car. If that's something you can live with then it will be just fine. Personally I see no point to them on a car you use as a cruiser or daily driver. A car used primarily for racing then sure. Did you turbocharge an NA engine? Just wanted to get all info possible, as the standard TII engines were all 4 port.

 

Yes I did turbo charger an na engine using all t2 components. I just replaced the trans bushings with the competition mounts but the vibration is still there. I will try to source stock engine mounts and see if that fixes the problem. On another note the car is rhd and I did accidently down shift into second while on the highway and the vibration got considerably worse. It's not even drivable now. I feel I may have damaged something in the trans or the rotating assembly. Would a loose flywheel nut cause these vibration? I will be dropping the trans in the next few days to give everything a look.

 

So just a quick update. I dropped the transmission and It turns out that the aftermarket eBay pressure plate was to blame. A few of the springs were bent. I put the stock pressure plate back in and all vibrations are gone. It revs nice and smooth now.

 

Thank you for following up with the cause of your issue. Odd that failure point would be there, but glad you found it none the less.