I have a s5 TII shell. I think its a 90s model. I will be getting an S4 TII engine. The engine will come with complete engine,harness ecu intercooler brand new clutch. Can I basically put the S4 engine in, using its harness, its ECU and not connecting any S5 sensors. I do have a tranny but the shell has the whole drive train. I have went to Rotary Resurrection.com and the way the explain a similar swap like this, is if I already have an S5 engine. They explain that I need to make the car still think it has an S5 engine. I figure this method is only when using an S5 ECU. thank you for all your comments.

 

No, you can't just stick an S4 engine in. S4 and S5 wiring and electronics do not mix without extensive modifications to multiple harnesses. Search the 2nd gen section if you're bent on doing all the necessary rewiring. This question gets asked all the time.

 

The easiest way to do this is like the rotary resurrection website states. You must use the bare s4 block, and then mount all the s5 electronics/manifolds onto that block. Also, it will neeed the s5 oil metering pump so that needs to be swapped out with the front cover too I believe.

It needs to think its an s5 engine. If you need more information, there are a ton of these questions that always get asked.

 

Thank you for all your guys advice. helped out much.