Doriman

how to i get the ecu to work w/ a car that was an s4?do i have to rewire the whole car or can i splice it in?

nillahcaz

iTrader: (2)

you need to change tha MAF, injectors, and some other stuff. and and use a S5 wires.

Doriman

i have everything for the car to run its just that it was an s4 and the motor is an s5 so the plug thats inside the car that plugs into the ecu doesnt fit into the ecu

J-Rat

iTrader: (2)

Make this swap easier on yourself.

The S5 ECU has been proven not to run an S4 car. So if your going to put an S5 motor on an S4 car, its better to retain the S4 ECU, and ECU harness. It will run that S5 motor just fine.

Jarrett

seventhgear

but s5 plugs are different than s4 plugs on the engine harness. why would you use the s4 harness when you would have to splice plugs right on to the harness in order to fit the s5 engine... makes no sense to me ... is there any way that the plug that doriman is talking about could be spliced in any way possible in order to make the s5 harness and engine work properly?
thanks
jack

5 point whoa

I dont know,I think you should go ahead and put the s4 one on,and see how it will work. check how hard it'll be, and then decide whether or not to do it.

AW11Rkt

I'm failing to see why a full S5 engine harness , AFM , ECU ,and motor can't be run on an S4 car .

We have everythign S5 except the car , why wont it work ? I am failing to get this much .

Makenzie71

The plugs don't matter. The only ones that are different on an S5 are the Injectors, OMP, and TPS. There for you don't use the S5 injectors, OMP, or TPS. Use the S4 injectors, run premix or swap the front case with an S4 front case and use the mechanical OMP, and use the S4 throttle body and TPS.

Makenzie71

Why won't you just use the S5 block and intake manifolds? Everything is the same between the S4 and S5 performance wise.

seventhgear

DAMNIT steve u got rid of your s4 harness didnt you ? damn ! im sure we could dig up some s4 t2 injectors. or buy some new.... either/or
jack

J-Rat

iTrader: (2)

https://www.rx7club.com/forum/showth...t=run+the+dash

Doriman

no i still have the s4 t2 harness ecu and afm

Doriman

Why cant we use the mechanical OMP off the 13B 6 port ? Is the actual front plate different ?

Makenzie71

Yes. Front plates for S4's are different from S5's.

hypntyz7

<sigh...>

http://www.rotaryresurrection.com/series5swap.html

http://www.rotaryresurrection.com/series4swap.html

Templeswain

Doriman,

I read all the write ups I could, and everyones opinion for some weird reason seems to very.

I am currently about to do exactly this:

Last night I put on a s5 front cover on to my s4 motor. I Am going to use, that's right use, my s5 ECU harness, and fuel delivery system to connect to the s4. I also have to block off the egr valve.

For some reason, I read that the VDI throttle body won't fit on the s4. It fits just fine.

The other difference is that on the intermediate housing there's a square port that's fed into the s5 ACV. No problem, I'm installing a block of plate with my down pipe and shelving the ACV anyway.

As far as this actually working. Like I said, everyone has their opinion.

So place your bets.

If it works I can give you some tips.

Doriman

Would it be possible for me to just wire up the S4 dash harness into the S5 ECU ?

Then just use my S5 harness/ECU/AFM . I'm a pretty compitent wirer so I think I could do it easily , just get the plug off an S5 dash harness adn wire the plugs correctly form teh S4 wires .

Then I would just be able to use the S5 things correct ? electrical OMP etc .

Need help ASAP , trying to get started today

Templeswain

Would it be possible for me to just wire up the S4 dash harness into the S5 ECU ?




I doubt it.

I think the s5 harness that comes from the ecu etc. also plugs into the electrical omp. The s4 harness does not, so there could be a difference between the ECUs like not getting the correct electrical signals to the s5 omp.

And as someone else said before, the front cover will not accomodate the s4 mechanical omp only the s5 electrical one.

hypntyz7

Nobody here said it can't be done, including myself.

Templeswain, you got a lot of conflicting views on this because you got a lot of replies from people who don't know their ****, and I can guarantee you that *they themselves* had never done such a swap. People just like to say whatever pops into their heads to sound like they know what theyre talking about.

I have posted up links to my writeups about these topics. I tried to go over things in the simplest way, however there are harder or "more rigged" up ways of doing these swaps.

What I really want to say, to those of you who ask these questions and then actually *do it*...

1) how well does your engine run? smooth idle? easy start? good power throughout the rev range?

I ask this because I bet you will not have good answers to all those questions. IT is possible you will, but I bet you won't. IT's hard enough to get a rotary running smoothly with all the stock parts on it, much less what you have rigged up.

2) WAS IT WORTH IT??? You may answer yes, but if you looked at it from an objective point of view, you probably wouldnt. You will have spent several hours/days swapping parts around and getting yourself confused and asking the guys here all kinds of questions. All to wind up, if you're lucky, with the same thing you could have had as a plug-and-play operation if you had just used the right friggen engine to begin with.

J-Rat

iTrader: (2)

Ahhh Kevin,

Blunt and to the point as usual...

FWIW, I have done the S4/S5 swap.

Jarrett

hypntyz7

Well, I know you have Rat, and I know you wouldnt have given him bad info like most of the others did (according to him).

What bothers me is that more and more people are asking about this/doing this, instead of just using what they need and having things be so much simpler. Then when people start telling them that this and that won't work, they seem to get pissed off. IT makes the problem worse when some people come on here saying things that aren't even right, but they just said them to sound cool or whatever.

Templeswain

2) WAS IT WORTH IT??? You may answer yes, but if you looked at it from an objective point of view, you probably wouldnt. You will have spent several hours/days swapping parts around and getting yourself confused and asking the guys here all kinds of questions. All to wind up, if you're lucky, with the same thing you could have had as a plug-and-play operation if you had just used the right friggen engine to begin with.


Its always worth it to me, even if it doesn't work.
I would love to just swap out an s5 for an s5. But right now I have three s4 motors available and one s5.

So I figure that I'll have a fun and hardworking experience trying to swap em.

If it works, then that's great. And while it's running I'll rebuild the s5 and punch it in later.

If not, I can to some authoritative extent talk about my experience doing it.

I am kinda strange. If it were up to me, I'd live in the industrial warehousing districts in a huge shop and rebuild, test, tune and **** up all day long.

Templeswain

Well, I know you have Rat, and I know you wouldnt have given him bad info like most of the others did (according to him).


Its not necessarily the Bad info like people don't know what they're talking about. Its the quality of the info.
Someone might have done 10,000 of these swaps. However if they're more proficient in working on the rotary than they are the english language.... sometimes this can make their info "bad". No blame or anything. Its just a communication problem sometimes.

Makenzie71

I'm going to come in and ask why you're insisting on wanting to use the S5 ECU? Just use what's in the car...

Doriman

did you read the whole thing

we are doing a s4 n/a to s5 t2 swap
we were wondering weather or not it would be able to splice an s5 clip where the s4 was so i can work w/ the s5 ecu