Ok guys i got an 87 rx7 tII. I have a RPM related vibration that occurs from 2300ish RPM and up. Its not constant, its on off but very fast. I thought it was driveshaft so i replaced driveshaft. That didnt do it. Its pretty bad too. Any ideas?

 

Check your accessories, especially the water pump and clutch fan assembly. Also check the engine and transmission mounts.

 

Will do, thanks.

 

Also, check to make sure that no part of the exhaust system is in direct contact with the chassis....








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if you get a "new" driveshaft, that doesnt necessarily mean its balanced either. dont assume it is.

 

Well the draveshaft came off anouther 87 tII rx7 that was bone stock and had no vibrations lol

 

ur still assuming, can u see that?

 

If it is the driveshaft, try rotating it 90 degrees and check for further vibration.

 

have u tried just slowly revving it while sitting still? that will tell u if it's drivetrain related or not.

 

If there is any chance this might be a tire balancing issue, swap the wheels front to back as well to see if that changes anything. Or, could be motor mount, tranny mount, and the list goes on.............

 

I know for sure its RPM related, becuase when i sit still, and rev it up it still does it, im pretty sure its motor mounts now becuase i gave it a hard launch the other day and now its constant threw RPM range