First and foremost I've scoured the forums and haven't heard of this, but I am looking at putting a s5 turbo engine in my 1980 rx7.... I found a motor and tranny for $1400... Supposedly it was taken from a running car and imported from Japan (not from Tiger), anyhow the very helpful guy at my local auto salvage yard told me that I needed to know the vin # of the car it came off to ensure I get the right computer to match since in 1986 they ran 2 different computers.

Anyone able to clarify on this? I think I'd probably rebuild the motor once I get it, and after reading on the swaps done by members... I'll use the tranny and get a custom driveshaft made. I also plan on removing every piece of emissions crap on the car as in west texas, we dont emission test.

Let me know what you guys think, I value your insight very much!

Best regards,

David

P.S. I hope this doesn't double post, I was going to post in the newbie section, but backed out before it submitted, if not, Im sorry Mods

 

Assuming this is an S4 engine ('86-'88), you need an S4 TII ECU: part number N332, N333 or possibly N340 (jspec).

ECU part numbers thread in the 2nd gen archive: https://www.rx7club.com/2nd-gen-archive-72/ecu-part-numbers-applications-873382/

 

There is an S4 engine and an s5 engine, both complete with all peripherals including ecu's, alternators, starters, etc etc all... but since the s4 was more expensive I was hoping to go for the s5... Bad choice?

 

Given the choice, the S5 is a much better stock vs stock setup. They fixed a lot of the small problems present in the S4, and the S5 makes a bit more power in stock trim.

 

If going with an S5 TII engine, you would need an N370 or N374 (jspec) ECU. N370s can be somewhat rare and expensive, but since this would not be going in an FC, the cheaper N374 would work.

An S5 engine is better is almost every way. The S5 turbocharger design is much better than the S4; it builds boost sooner and has slightly more top-end. The S5 uses an electronic boost controller to run more boost in stock form (8 psi vs. 6 psi). It also has a higher compression ratio (9.0:1), larger intake runners and a larger intercooler inlet.

But...

S5 engines use an electric MOP/OMP, which loves to fail after 20 years of service. When they fail, the ECU is usually damaged, and the car will go into limp mode (limited timing/fuel). S4s use reliable mechanical metering oil pumps.

 

So it makes sense to make sure that gets replaced with the rebuild then?

 

or block it off and get the ecu chipped by Rtek.

 

Premix for the win!

 

chopping up an original 1980 10th anniversary RX-7 would almost be a crime in most states....