so i'm building a motor as of right now. my plans changed from going with a larger turbo, haltech ems, and all of the goodies... but now i'm thinking of going with a straight s4 t2 swap.

the motor i'm building is a s5 t2 but i do have a s4 t2 laying around, but the irons are not usable. as well, one rotor has a gauge in it from being bit from an apex seal, but its not too major.

so my question is... can i build a s5 turbo motor and is it safe to use if i'm using a s4 turbo ecu, injectors, and sensors? or should i go with a s4 turbo rotating assembly, which will require me to obtain another s4 turbo rotor.

 

So you are or are not using the Haltech to run this? Short term you're thinking of using the stock ECU?

You can run an S5 block / rotors with stock S4 electronics just fine. I've done it, and so have others. You just have to keep in mind that you're running a higher CR, and the S4 timing tables may be slightly more aggressive than the S5 versions.

 

I've done the S5 block and S4 electrics swap many many times and actually prefer the S4 electrics more than the S5 such as the setup in my '88 rx. What kinda intake setup do you have, S4 or 5? - There are differences between those two

oh, click my turbo swap how to in my sig. I think I mentioned this kinda thing in the thread. If not I'd be happy to type it all up for you.

 

what a coincidence, i was actually reading your thread earlier today haha. yeah so i talked to a bunch of engine builders and they say they've built s5 turbo blocks and just ran it on a s4 ecu fine, so i'm planning on doing the same thing since i already have perfect condition s5t2 rotors and irons. very good information. i actually have both s4 and s5 t2 manifolds. Which would you recommend? i was planning on using s5 but would the s4 tps bolt up to the s5 throttle body? or can i just use s5 t2 manifolds with a s4t2 throttle body?

 

You can do either or. It doesnt matter. The only differance is the S5 rotors are 9.0:1 compression and the S4 rotors are 8.5:1. The throttle bodys are basically the same, but if you want, you can yse the S4 throttle body on the S5 intake.

 

yeah im thinking of using s5t2 manifolds and a s4t2 throttle body.

next question:

should i use the s5 housings... or s4? because the spark plug locations are different by approximately 5mm. im guessing this will change the timing if i use my s5t2 housings while using a s4 ecu

 

bump.. anybody ? still have many questions haha... well just that same one