I just picked up a S5 jspec engine from a guy who bought someone's failed S4 to S5 TII conversion. Has I think a stuck seal on the front rotor and I think blown coolant seal cause nasty coolant came out of the front rotors spark plug holes, so he's going V8 and I bought the rotary for the turbo parts. Anyway upon looking at the T.B. it has a tps with a single plunger and no cam for the second plunger. My initial thought was that it has aS4 T.B. on it. Is this correct or was the JSPEC S5 use a different T.B. and TPS? I was under the impression they were the same.

A second question. If it is a S4 T.B. can I still modify it to us the FD TPS like some people have done on their S5 T.B.? Thanks.

 

Within series (S4 or S5) and within type (NA or turbo), the JDM and USDM throttle bodies & TPS sensors are essentially the same, with a few minor differences. I have a spare S5T2 JDM throttle body and my USDM TPS sensor bolted right up to it. Only difference I recall on the JDM TB is that it has a spring loaded adjust screw for the base idle/throttle stop adjustment (just like the TPS adjust screw), while the USDM TB uses a set screw & jam nut for that. So the one you got must be an S4 TB.

 

Thanks. I had a feeling it was a s4. Add that to the list of things the person that started the conversion did that makes no sense. At this point if my S5 N/A TB and TPS can't be made to work it would probably be cheaper to convert to the FD UIM and TB. It would look and function better anyway.

 

Yes, the tps you have is a s4. If the s5 engine is going in a s4 car, it is wise to use s4 throttle body and electronics on the s4 car. Much easier than wiring the s5 harness to a s4 car. I ran the same setup.

 

Therein lies the problem. It will now be going back into a S5. The confusing part is the original owner( not who I bought it from) was trying to transfer all the S5 wiring from a JDM front clip into the S4 shell and run it with a N374 ECU, so he needed the S5 TPS anyway.