Ok so i have a 11lb flywheel right now with a s5 auto counterweght. my question is if i get the Fidanza 8lb one do i still use the same counterweight? I have to change the tranny anyway thats why. Its a 90 n/a 5 speed. thanks

As long as the counterweight matches your engine (correct series), you're fine. Meaning yes, you should use the same counterweight.





(someone correct me if I'm wrong) Reason being is that it matches the front counterweight. The stock flywheel included the counterweight as all one piece, so it doesn't matter how much your aftermarket flywheel weighs, as long as the rear counterweight matches the front (S5 to S5, and S4 to S4), you should be good to go.

correct on the weights , need to match serise to series of the rotors inside the engine.

yes, that is correct.

the counterweight must match the series of the engine...but beyond that, it's all open game on the type of flywheel one chooses to use.

I dont think that is factual I used S5 TII front counter weight and flywheel on an S4 TII and it worked perfect so?

Did you balance the motor to see if it was "perfect"



You may not feel a small imbalance but your bearings sure will



Kevin.

you should not see any changes in the balance of your engine if all you are doing is swaping your aftermarket flywheel with another afremarket flywheel assuming both flywheels were in balance to begin with

good luck with the swap. If your car starts to leak oil from the rear main seal you might want to invest in a new counter weight.

well i would not say perfect but there wasent even slight vibrations from the engine. It had new mounts all around engine, tranny, diff, but i think if they where out of balance you would deffinatley feel it. I had the key on the flywheel brake and it turned on the e shaft mabey a 1/16 inch turn and the car felt like a jackhammer.

Very true. I got a rebuilt engine once that was supposed to be S5, so I used my stock s5 flywheel. Pulled the motor apart for porting 20k miles later, and the main bearings were SHOT. The rotors were S4, and the slight misbalance, while I never felt it, wore the main bearings way out of spec in the short time i had the engine in the car.