cab91089

iTrader: (3)

First off, I tried searching multiple times and looked through the second gen archive and frequently asked questions section and didn't find exactly what I was looking for. Ok so I have an 87 N/A engine, a full rolling shell 86' base model N/A Rx-7, and soon to be a mint 90 Vert full rolling shell (by full I mean everything is there but the engine.) I also have 2 extra N326 ecu's and 1 extra N327 ecu. I want to know what I am going to need to do to swap the S4 N/A engine into the S5 Vert? I know the S5 has an electric OMP vs. S4 mechanical OMP, the air pump differences and a few other engine differences between S4 and S5. Thanks for the help

RotaryRocket88

iTrader: (7)

2nd gen FAQ, section on turbo swaps between series. The process is very similar. You either use all S5 electronics & ECU with the S4 block + S5 front cover/MOP, or you strip the chassis of almost all S5 wiring & replace it with S4 equivalents so you can use S4 electronics and ECU.

cab91089

iTrader: (3)

Thanks for the response RotaryRocket, Im going to look at up right now. I think I will go with the first route you suggested with the S5 Front Cover/MOP swap over. I cant wait to buy the vert and get it home to start! I am planning on doing a series 5 turbo2 swap at the end of summer so I want to keep as much of the S5 wiring as possible.

misterstyx69

iTrader: (142)

you will have to shave a piece off the center iron to get the S5 Upper manifold to fit flush on the Engine..remember that,or you will get a vacuum leak.
Look up: s5 upper manifold on an s4.

cab91089

iTrader: (3)

That is a good write up on the Rotary Resurrection site. Thanks for the tip misterstyx69, in the write up I think it actually covered that though but one pretty major problem I see is that I have only an s4 block with all s4 manifolds. The S5 Vert has the wiring harness, ecu, exhaust manifold and starter to work with but no manifolds or anything as its just a rolling shell. Would it work with the S4 manifolds with S5 wiring harness,ecu, and front cover/MOP?

RotaryRocket88

iTrader: (7)

It's the rear iron that has to be ground down to use an S5 intake manifold on an S4 NA block. http://homepage.mac.com/carldavis/intake.html

You can use the S4 intake manifold, but you'll need an S5 TB to use the S5 TPS. The black plastic S4 TB spacer should be used with it to keep the vacuum ports active.

cab91089

iTrader: (3)

So I am going to need an S5 TB, S5 TPS, S5 Frontcover/MOP, with S5 wiring and S5 electronics. Now for the fuel injectors, am I going to need to add in a resistor for the higher impedance? I may end up not buying the vert now because of the extra money I will need to spend just to put the s4 engine in the s5 vert just for the summer. I have nearly everything needed to put the S4 engine in the S4 base model coupe besides a clutch and other minor parts. I really want the S5 vert though so I guess I have to decide soon, like today.

RotaryRocket88

iTrader: (7)

You will need S5 injectors if using an S5 EM harness, or you can buy S4-style injector clips / cannibalize an S4 EM harness for clips.

'86-'87.5: Low impedance, rectangular plug
'87.5-'88: High impedance, rectangular plug
'89+: High impedance, oval plug

cab91089

iTrader: (3)

I might sell the S4 base model with the S4 13b engine and just buy an s5 engine and drop it in.

cab91089

iTrader: (3)

I have decided to sell the shell with or without the engine and depending on how the sale goes and my paycheck I will swap the s4 engine in if I have it or put an s5 n/a engine in OR do what I intend to do eventually now and do a S5 Turbo2 swap into the vert. Thanks for the help guys

cab91089

iTrader: (3)

Bought the vert and got it home. I intended to just s5 turbo2 swap it but my step dad wants me to put my s4 n/a engine in the vert. he is being stubborn with MY car ha. I do not want an s4 n.a in my s5 vert...

misterstyx69

iTrader: (142)

then ask your Step Dad if he wants to pitch in money for parts!..seeing he is the one that "wants" the engine in there!/kiddin man,,don't start a feud!
The s5 TII project in the long run would be cheaper!

cab91089

iTrader: (3)

Yeah he complains about every little thing too. He seriously pisses me off sometimes with my Rx-7s. Its not 1970 anymore and my car is not v8 powered... I took the s5 EM harness and ECU out today and went to swap over the N326 ECU for the S4 engine and realized that the interior wiring plug still in the s5 is not the same as the s4! AWESOME. just spent all that time removing harnesses and hit a brick wall. I wanna know what I should or can do here, should I take the dashes apart in both my cars and swap over all the harnesses just to get my s4 engine to work in the s5? or is there a way I dont have to remove the dashes just for that one plug at the end of the harness where it plugs to the ECU. Im going with a N326 ecu in 1990 vert. Im in a rough spot here and I want to get one of my rx7s running asap. I am seriously considering saying F it and just putting the s4 engine in the s4 and letting the vert sit til I have the money for what I want to do to it.

cab91089

iTrader: (3)

The harness I left in the series 5 vert is for the interior accessories Im pretty sure since it runs towards the left and up under the dash. Im sure someone knows what I mean, the EM harness is 2 plugs on the ECU and that leaves the 1 Im talking about left. Since it doesnt fit my s4 N326 ECU at the plug I was wondering, does it run to another plug where the s4 interior harness would clip in? Or would I have to strip both chassis like RR88 said? Anyone with advice would help because I am trying to figure this out by later today (6/23/11.) so I can move forward with one of my 7s. I dont want to put the s5 harness back in and then find out the s4 harness would work with some adjustments. I can always do what I said last in the post above and just let the s5 vert sit for awhile and work on the s4 coupe to get it running.

cab91089

iTrader: (3)

Although I had no help other then misterstyx69 I decided to go with MY original plan and put the s4 n/a in the s4 coupe base model and save the s5 vert for a turbo2 swap or ported s5 n/a engine to do the turbo conversion.