So im swapping an s5 motor into my s4. My question is will my lightened flywheel off my s4 work on the s5? What would i have to do about the counterweight?

 

The counterweight must match the enines rotating assembly.

 

i see.. so i can use the lightened flywheel but would have to use the s5 counterwieght instead. I just figured since it was lighter the counterwieght would be different. The old s4 motor came with it so i figured i might as well use it again.

 

In reality the flywheel should be balanced to itself, and then the counterweight is used to balance against the engine.

 

Looking for source for lighter than stock flywheel for 86-88 altho I suspect 86-90 would all be same for NA. Thanks Weaver

 

So just find a s5 auto counterweight.

 

The only difference between light flywheels is NA/Turbo. You bolt a stock automatic rear counterweight to the aftermarket flywheel. The auto counterweight allows you to bolt the assembly to the eccentric shaft. The auto counterweight must be the same series as the rotors in your engine, turbo or NA doesn't matter.

 

so i need to get an automatic counterwieght?

 

How many times has this been discussed before............................*

Yes, all you need is a S5 counterweight. That S5 counterweight can be used on a S5 NA or S5 Turbo engine.

*It is amazing the amount of knowledge that is available about RX7's in this forum. And the Search function is your key to the door to access all that knowledge, but ONLY if you USE IT!!