S4 to S5 engine, Do I do S5 ECU???
 

Hey guys, if I go from a series 4 TII engine to a series 5 engine, will I need the series 5 ECU or any other wirings?

you need everthing, the ecu, wirring harness, pressor sensor, AFM, all manifolds, injectors, etc.

or nothing. by using the bare series 5 block, with all the series 4 stuf bolted onto it. manifolds etc.

Yes, you can put the series 5 ecu and wiring harness in with it but that is a pain in the ass. Just swap all the stuff off your s4 engine on to the S5 block, or get a haltech.

beat me to it

If I use the bare S5 block with all the S4 stuff, I wouldn't be able to use the S5 turbo, right? Is it worth it to upgrade to the whole S5 setup or am I better just sticking to a rebuild/use S4 engine? Thanks

you are better off to stick with the same year block. the 89-91 turbo and manifold will bolt on and is an upgrade. recommanded if you plan on doing any mods. it has a much better wastegate.