S4 to S5 engine swap (check list)
 

Okay, I apologize if there are already a million of these threads, but this is my quick rundown to make sure I have everything I will need. I was originally going to upgrade the S4 NA to around 200whp, but I quickly realized the cost of doing so would make it more affordable to get a turbo engine and keep it 90% stock. I have never swapped an engine before, and I am looking to get the bulk of this done in a week, I have two other people helping me and we will be working in tandem for up to 8 hours per day.

Okay, so here's what i have ordered:

S5 engine (complete w/ turbo, stock IC, accessories & injectors, etc)
S5 Transmission (comes w/ clutch and flywheel attached)
ECU
Wiring harness
Downpipe
Cat back exhaust
K&N Cone filter kit
Aluminum S5 drive shaft
4.30 LSD Rear end for an S5
Silicon hosing

Okay, it is my understanding from reading how tos on rotaryressurection and fc3spro that the S5 13BT will bolt into my existing engine mounts for an '87 NA RX7. I know cooling will be an issue (both for the turbo and engine), but it's still winter, so it's not a primary concern yet.

Now please correct me if I am wrong, but I am under the understanding that I can reuse parts of my existing S4 wiring harness. Is this true? Would I be better off wiring in the S5 harness? And finally, if I wire in the S5 harness am I looking at gutting the car completely or can I just do the engine harness?

I apologize for the redundancy of this thread, but I just need some verification I have everything in place before I put my car on jack stands and pull the engine out.

Thanks for your time and patience!

im on the same boat you are on this car is giving me a headache and i want it done. i instead am using the n/a rear end, then plus i still have to get the sensors

I couldn't find the point in using the NA rear end because it's an open differential. Some of the sensors you can reuse..

Advanced search this section of the forum. The topic has been beaten to death. The wiring is up to you whether you want to doing a lot (S4 harnesses & S5 electronics), a little (S5 EM harness & S5 ECU) , or none at all (S4 harnesses & S4 electronics).

you know that 4.3 only comes on the super rare GTUS. not on (a) GTU(s)

do you already have it, or planning on finding one?

I was planning to find one. I am going to go ahead and buy the S4 engine setup to save time because I really need this car back on the road asap, soooo yeah, if I can find the 4.3 I'll buy it, but if not, the stocker will do.

which ECU do you have? an actual N370?

and let me tell you right now, if you think you're going to get this thing done reliably in a week you can just forget it. You'll most likely be hunting down some part. Find another means of transportation.

My opinion is that you'd go with whatever harness goes with the ECU - engine matters a lot less then ECU when it comes to the harness.

Since I assume you're using the S5 TII ECU, I'd say use the S5 TII harness :)

And it's just the engine harness, you don't have to gut the car.

In the interest of time, I am going to buy the S4 swap. Which SHOULD work with 90% of my existing engine harness

Good choice. Adapting an S5 harness and ECU to an S4 car is much more complicated than just plugging it in and forgetting about it. Totally not worth it either.

change anything S5 on your list to S4.

Exactly. Plus it's almost February and I have an unheated garage, so it is not easy to re-wire a car. I was thinking of doing the Microtech once I get the $ for upgrades. Hopefully, the engine I get will be in decent condition and not need too much work.

looks like a lot of misinformation in the thread, first of all, it's not so easy to use an s5 engine harness on the s4 car, not even worth the effort. You can use an s4 harness on the s5 engine if you swap front covers (unless you plan to disable your OMP system), and use s4 injectors, actually you can use s5 injectors, but it's a little more work. Yea, definitely do more research before you dive in, and expect more than a week's worth of work unless, your a professional mechanic with lots of experience, or you want a hacked up car that you'll regret every minute of until it's redone correctly. Also, the cooling system is essential even in the coldest parts of winter, get that shit right or you risk blowing the new motor.

As I've said several times, I am ordering an S4 engine.

good choice.. i did an s4 t2 motor into an s5 na for my friend and it was a pain. The harness is completely different. I pretty much ended up makin the car an s5 shell with all s4 harness and motor.

but i did end up gettin a free s5 na motor in the end haha

The turbo motor won't bolt up to the NA transmission by any stroke of luck will it?

Also, is there a place to get a custom drive shaft? I can't find a reasonable price on a T2 rear end ANYWHERE..

ur going to have to swap flywheels if u want to use the na trans on the turbo motor. If i remember right the center is bigger on the t2. I know they sell the na trans to t2 rear end driveshaft. Not too sure bout the other way around tho.

do you know who sells it?

Mazdatrix has a TII to NA driveshaft.

I am finding the most costly part of this (besides the engine) is the exhaust! wow, $900-1200 for a full exhaust is asinine! Maybe I can get a downpipe and have the muffler shop make some tubing for me

well u could use the na trans for a while on the t2 motor. I know Aaron used his na trans for a while tho i remember him sayin it blew on the highway. But it lasted.

Yeah, well, I shot Mazdatrix an e-mail inquiring about their TII->NA rear end shaft, if it's cheap enough I'll pick it up. I like the T2's gearing a little better and I will be out of money once this swap is done, so the car needs to last :)

I can re-use the NA throttle cable, right?

If money is an issue why not use your na drivetrain?
Bolt on na starter and flywheel with no wiring issues and use na trans dshaft axlees and rear.

-lonewolfrx-- Aaroncakes trans came apart with 400whp and multiple track rapes. :)

Return the s5 engine, it makes no sense unless it was free......and get an s4=saving you the price of a microtek.

Makes a potential suicide inducing headach...into a very doable "project".

That is unless you like a challenge, but personally i would want to spend all of that time driving the car.

Throttle cable can be modified, but i would just pay the 40.00 with the money you just saved.

Oh...only japan2la and atkins for engine....unless you inspected it yourself, too.

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john ny