Loud gearbox vibration
 

Recently i stripped all my subframes and fitted energy suspension bushes everywhere.. including Diff Mounts and mazdspeed engine mounts

After the car was back together with a newer and lower mileage 93 1.6 and stage 2 F1 racing clutch (older 90 gearbox still in place) i took it out for a drive.

I noticed a lot of quite loud and heavy vibration coming from the middle of the car on deceleration (at about 3200 down to 2500) and it feels like the vibrations are travelling up the gear stick.

I torqued the clutch plate and the old gearbox slid into the new engine like a well lubed chinamans penis into a old fat woman. (ie. very well) so id say thats fine..

I did notice a small amount play in the input shaft of the gearbox before i installed it.

Are these vibrations a normal side effect of all this harder rubber in my suspension?? or have i lined something up incorrectly??

any advice on this would be apprciated

I noticed alot of vibration after installing the diff bushings, i noticed that they eventually "break in" and the harsh vibrations fade alot, either that or im just used to it now. I would imagine with the harder engine mounts its would make the vibrations that much more noticable.

Is the new clutch disc sprung or solid? If solid, that's your cause.

I'd say this is normal and expected from upgrading your mounts.

no theres springs in the clutch plate. inwas told it could be an alignment between the ppf and gearbox?

^ unpossible.

Matthew nailed it. Add a lightweight flywheel and it gets even worse....

In my experience that helps the noise that the gearbox and/or diff makes when you're on decel, generally due to lightweight flywheels and other random phenomena that I don't understand about the Miata drivetrain.

Does not help vibration.

Well if you do have a sprung clutch disc then that's not it. Could very well be the stiffer mounts not dampening a harmonic/vibration in that rpm range that you otherwise did not feel with the softer bushings.

This makes sense considering its a vibration that I can repeat.. I have a spare gearbox just in case.. I'll drive the stones off it till it softens up or explodes..

Thank you very much