I have read a lot on here about the different harnesses, and what is best to use with a swap, and everything, btu my application is different (and so is my question). I am using this in a sandrail, not a car, and have no need for any controls that go to the car other than to run the ECU for the fuel injection and turbo. I am going with a JDM S5 turbo engine and ecu and am trying to figure out what harness I can use for what I need. I know for a turbo swap people say to use the NA harness, but I have nothing to start with and am wiondering if i can still just use an NA harness, or if it's easier with the turbo harness , and if I can use an S4 harness on my S5 engine (again I have read all the difficulties of doing this in a car and am wondering if it is any different since i don't need/ use a lot of the same harnesses and stuff a car would, nor do I have the whole left side/ right side problem). Any help would be appreciated. I have found a guy who will build me a custom harness to hook everything into once I get a stock harness and ecu to power it and everything.

 

It would be in your best interest to use an S5 turbo harness. Not sure why you're using the stock wiring and ECU on a buggy though. I'd get an inexpensive standalone and make your own wiring harness, because deep down inside you know you're going to want more than 190 hp.

 

I know that I might want more down the road, but I was already popping wheelies with a stock NA engine and I'll be pushing the limits of my transaxle with the stock power from the turbo. If I get the extra money for a $2-3K transaxle then I'll be looking for more power, but right now I'd just be asking for it to blow up. Thanks for the response though. Can I use an S5 NA harness, or would that be to big a pain? I've been looking in the for sale forum on here and ebay trying to find a turbo one for a descent price, but have yet to find one (but I found a lot of NA ones for $100 or less).

 

Yeah, an NA harness will be fine. You just have to get the matching sensors for the ECU. Some wires will have to be extended in certain places, but you said you searched and found the threads that explain it, so just follow that. You'll just have to omit whatever auxiliary crap there is. Keep in mind that you'll have to chop the harness anyways to add power/ground wires, so brush up now on basic electrical stuff.

 

OK, I managed to find someone with a matching ecu and harness for my engine and I now have another question. How hard is it to get power to the ecu ( might sound like a dumb question, but remember that this is for a buggy and not a car that has existing wiring to just plug into)? I found a guy that said he could do a custom harness to power it for $250, but I still use the wiring harness as well and it seems like all he's doing is adding a few wires that I would hook to power and it's an otherwise stock harness I think (he said it would hook to the coils, ecu, and power).

 

Nevermind the above post, I talked to the guy and he helped me understand it. I didn't realize there were 2 harnesses that plug into the ecu.

 

The "front harness" on the FC also plugs in to the ECU.

 

This is important.

 

yeah, that's what I learned, I'm new to the fuel injection stuff since I've been running a carbureted setup and thought the engine harness was the only one I would need, but have since been educated by a fellow forum member.

 

I've been trying to figure out what the front harness looks like and if they're the same between S4 and S5 and NA verses Turbo. I haven't been able to find any pictures of this harness and I just received my ecu and engine harness and it included part of the front harness with it (plugged into the ecu but it was cut).

 

The S4 and S5 front harnesses are different, with different plugs. If your ECU came with the cut plug, that works out for you. All you have to do now is look through the FSM and figure out what pins need +12v and ground, and which ones go to different outputs. You'll want to get a 4 wire shielded cable, and ground the shielding at the same ground the ECU uses. The 4 wires are for the crank angle sensor, it's a very small signal that can get corrupted by other things in the engine bay, such as the injectors or coils.