Hey guys, I have a buddy with an s5 auto and an s4 engine he want's to swap in. Someone told him there were going to be balance issues having to do with the hub in the transmission if he didn't use the s4 hub... can anyone shed any light on this? Thanks

 

as log as he uses the S4 Engine and flywheel,there will be no issues.
The s5 engine's rotating assembly is lighter than the s4,so you can't use the flywheel as it would throw the s4 engine's balance off..Using their respective flywheels and installing the engine and flywheel will alleviate any "parts swapping" and THEN you are good to go!

 

Thanks for the clarification. Is there any difference between the flywheel that would be on an engine mated to an auto compared to one on a 5 speed? (Sorry if this is a noob question don't actually know anything about auto trannies.

 

I may be wrong, but yes. Usually auto's use a flexplate with a counterweight.

 

Thank you

 

He will need an S4 counter weight to bolt the S5 flexplate to..

 

He'll be using an S4 engine, so he'll need the flexplate and counterweight.

 

Ok..if you are staying AUTO then you just need the S4 Rear Auto counterweight to hook up to the flexplate,to run the s4 engine in the car.
The Rotating assembly must Match the ENGINE..(s4 counterweights for s4..s5 counterweight for s5) The Transmission has ZIP to do with the Counterweights.
IF you are gonna stick a Manual s4 engine in there,then you will keep the rotating components all s4. then seek out the pedal assembly clutch assembly,master,slave etc..
The Flywheel of a Manual setup engine has the Counterweight Built IN To the flywheel.(hence just one piece ,,not a flex plate and counterweight,)..and the s4 and s5 flywheels can't be used on the "other" type engine.(no s4 flywheel on an s5 engine.and vice versa).

 

Sorry, I went retarded for a minute haha.

 

ok so am I getting this correctly? you are telling me we can pull the s4 manual, use the counterweight that is on it, and keep his s5 flexplate? (he is staying auto but we are using an engine previously mated to a 5 speed) I'm a little confused by you saying all we need is "the rear auto counterweight" but your also saying the counterweight has nothing to do with the transmission...

 

You will need the counterweight off an S4 auto if the car is going to be in an auto.

 

ok, thanks guys.

 

So he wants to put an S4 engine that had a manual transmission into an S5 car with an automatic transmission? You only need an S4 counterweight and S5 flex plate in order to bolt it up to the transmission but you won't be able to get the engine to start unless you plan on installing the S4 ECU and wiring harness.

 

Or rig all the S5 parts onto the S4.

 

Oh crud - forgot about that.... The bolt and loop on the back plate of the S4 engine will need to be removed and some metal will have to be filed down on a plate to fit the S5 UIM

http://homepage.mac.com/carldavis/in...s/p6240006.jpg