I am getting a S5 TII motor & trans. for my S4 vert. What do I need to modify to make this work. I am assuming that I will need an S5 harness and ECU of course. But can I use a NA S5 harness and just add a few wires here and there. Will the NA ECU get me by for a while if need be. I am asking because I know where I can probably get a S5 harness for almost free where the S5 TII will cost a lot.

Also since it is a jspec, does anyone know what things are different. For instance what emission things are missing, what little hoses go to different things than in the US models, etc.

.....or any other advice from someone who has done this swap before.

 

I'm not totally sure on whether or not the harness can be used. But I am fairly certain that the ECU cannot. That is, N/As don't have nearly as many things going on as turbos do, at least that need to be monitored.

For safety and security you would be better off getting turbo ECU and harness.

 

Yeah, due to funds I may have to wait a month or so on the real TII ECU and I was thinking of the quickest way to get the thing running so that I can at least get it to running condition. Also it may have the engine part of the harness chopped at the firewall so a NA harness may only have 2-3 extra wires or something or to save costs that part of it may have been the same, with differences at the sensor plugs. My S4 NA harness has about half a dozen unused plugs here and there. I know a couple are test connectors but some must just be unneeded on a NA motor.

Also does the TII S5 harness just plug into the car side (under dash) or do I have to do a custome point to point on wires? That is what I had to do on my Conquest when I did a similar type of EFI swap between years.

 

if your using a s5 turbo harness on a s4 na you'll have to do alot of splicing. the s4 plug won't fit in the s5 ecu. also the s4 pin placement to the ecu isn't the same as an s5. some people get the actual harness from behind the dash and the driver side of the car from a s5 to do this conversion. this eliminates all the splicing you would need to do.

 

I REALLY hope you can read and fully understand car wiring diagrams. you will certainly have to get both of them (s4 is online, S5 is not). you will be cuting alot of wires. then having to find where the wire now goes by comparing the 2 different year diagrams.

have fun! I wouldn't.

also good luck finding a S5 turbo ecu and decent wiring harness.

I would save up for a standalone ecu. it shouldn't be too much more $. like haltech or mircotech.

 

I don't plan on keeping my S4 engine/ECU harness, I plan to use a S5 harness with a S5 ECU, I am just looking at my options, in case I have problems finding a turbo harness versus a NA harness.

 

I am an electronic field tech, and I have also worked as an accessories installer (pwr. windows, locks, cruise, remote start, alarms, etc.) I have also done a ECU/harness and EFI system swap on my last car (a Conquest TSi). But what really helped me with that swap was finding someone else who had done it before to save me a lot of time with trial and error since the engine and dash harness wire colors and circuits had chaged drastically on that car. I needed to custom wire it in for the gauges to work and having someones advice who had done it before was a real time saver.
How much would one run, I think they are about $1000 right? That is a little out of my budget right now.

 

Well,
If you want to swap the engine and interioir harness to S5 then you shoudln't have much problems. You'll need the ECU Harnesses and Gauge cluster.


I'm going to opposite way. I am keeping my S4 ECU/harness AFM etc. I will just put S4 injectors in and use a S4 Throttle body and TPS on the full S5 block.

 

You only have a few options?? There is an easy way to do converson or the HARD route. Easiest way to do conversion would be to use the s4 TII harness with s4 TII computer (n332, n333). These parts are easy to find and plus you don't want to go through the HEADACHE of taking out the dash harness and all that bull!##$.

Find those s4 parts and just run with a N318 pressure sensor and afm. done!

One problem you might find is the OMP. You can either eliminate the electric OMP you have on right now and just block it off (like i did!) meanwhile runnin premix. Another option is to switch front covers off of an s4 with the whole mechanical OMP and TB. Me personally, i would eliminate the OMP and just run premix.

If you do get s4 parts, just remember to change TB/TPS and might have to mess with injectors if harness has s4 harness has solenoid resistor box. Other than that everything else on motor is plug and play. Trust me you want to find the easiest setup that will be compatible with both your year of your car and year of your motor!

Chris
87 GXL
s5 TII motor conversion with other goodies!!!! haha!

 

Yeah. That's why I am trying to stay with the most S4 parts I can. I'm having the front covers swapped so I can use the Mech OMP.

I heard the injectors have a different plug style on them. Is that true?

Also my Car will be like the Initial D AE! I'll have a tach going to 7-8k while my SUPER DUPER engine can go to 8-9k! lol.

 

I heard the injectors have a different plug style on them. Is that true?

Digi7ech- Yeah, that is correct; the s5 motors bring oval style injector plugs meanwhile the s4 motors have a square style shape. If you use the s5 injectors you would have to make sure the harness is rigged up for high impedence injectors.

In your case, if you have an 87 TII harness (with solenoid resistor box) than just buy some good used low impedence injectors and it'll be plug and play. Matter of fact, this would be even better if later on you decide to upgrade the injectors since bigger injectors only come low impedence.

Then again, you "could" still use the s5 injectors but this would require more work for them to function properly.

Chris
87 GXL
s5 TII motor conversion with other goodies!!!! haha!

 

What about the VDI intake?

 

I don't know what about the VDI? Isn't that on NA's?

 

There is no VDI on the turbo mdels?

John