Sorry if I'm posting this in the wrong section, but it's definately a swap, but I haven't managed to find a section for rotary swap into a rotary... so... yeah.

I just (as in two days ago) bought a '90 N/A motor from a guy in Texas. Now, I have an '87 GTU with, yep you guessed it, the original S4 motor. All this is fine so far I hope, my question is, in order to do this swap, what may I need to buy, what will bolt up, etc. So far I've figured that the exaust should bolt up, the mounts should be the same, and my tranny should follow suit (oh, kinda important I guess, I have a five speed). I'm thinking that it's should be plug and play for fuel lines and electrical plugs with some minor splicing, but truthfully, this is about as far as I've gotten. So if anyone with some experience could clue me in to what I've just gotten yself into that'd be great. Thanks again.

-Todd

 

Bump.

 

get the harness for the new motor and the ecu to go with it. then just swap the motors ecu's and harnesses and the body harness from the s4 should work with the s5 ecu. it will save a lot of thime and frustration if you just swap out the ecu's and harnesses

 

Ok, so like I am getting everything from the guy, harness and such, but not an ECU, is it impossible to use The S4's ECU, and if so, are S5's pretty easy to find/distinguish from an S4's unit?

 

Read This.

 

You can just swap engine harnesses. The body harness wont work with that computer you would have to re wire the whole car. You would have to make the S4 harness work on S5 engine. There are a few componets that would need to be swapped as well. The oil metering pump is the biggest issue.

 

Ok, so like what I was thinking is swap in the motor, then use the S5 ECU/engine harness, and then cut the S4 plugs off the dash/body harness and mate them to their appropriate place on the S5 harness (i.e. put the S4 dash plugs from the engine side of the harness and put them on the S5 engine harness, then just flat out plug them into the dash harness), wouldn't that work?

If that is not actually the case then I was also thinking I could just use the S5 block, UIM, and LIM and then just adapt the sensors over, and scratch the entire harness idea. Or taking that a Step further, just putting the S5 block in for the higher comp and saying **** it to the S5 UIM/LIM.

Thoughts?

 

http://www.rotaryresurrection.com/2n...o_s4_swap.html
I plan to do this very soon aswell. If I'll let you know of any problems I run into. And the S5 intake is a little better than the S4, thats why you see people putting them on S4 motors. The plugs are different, as the above links have said.

 

You cant just cut the plugs off the s4 haness you have to use it. Other wise you will be rewiring the whole car. The S5 computer will not adapt to the s4 body harness.