neektar

iTrader: (2)

Looking to upgrade from the stock SE twin injector set-up to the fc quad injector set-up.

I know there's tons of write-ups but when I search I only get the TII swaps, which I'm not lookig for right now.

So which ECU should I keep? I'm guessing it's the FC one. But how about the wiring harness? Codes? Plugs?

Any input is def. apriciated.

Rx-7Doctor

iTrader: (13)

Well, there are many ways to go about this.

You could keep your Se ECU to run the main injectors and use a mega squirt to run the secondaries. Or bypass the whole system and run a stand alone such as hal-tech.

The best stock system between the S4 and S5 is the S5. It has The MAF instead of the flap door AFM which is restrictive on air flow. The S5 has a better flowing intake system with shorter runners. The stock S4 N/A made 146bhp versus the S5 N/A with 160bhp.

You could run the S5 ECU and harness. Running the harness from the ECU to Engine and the components in the engine is the easiest part. Wiring the ECU for power is a different story.
You need to figure out what you are really trying to accomplish before you decide to do this.
Using the S5 intake on the Se motor only requires minor mods.

There is a member in my area that is running a S5 ported motor in his SE with a mega squirt system. I recommend pming him. rrluthi is his forum name.

neektar

iTrader: (2)

I can handle using the s5 intake with the s5 ecu.

What I do want to know is where everyting should plug in power wise with the s5 harness.

I have s3 s5 and s4 harnesses,ecu, injectors, intake everything I need. What I want is avaibility to change injector sizing for tuning purposes. Having four injectors helps a hell fo a lot. The engine is street ported btw and I don't wanna use an after market ecu.

It seems the best option I have right now is the s5 set-up. Has anyone ever tried using the s5 ecu with the stock se wiring. write-up perhaps?

If I can't find anything I'll just end up goin with a 650 holley. lol.

Thanks for helpig me clarify doc.

Rx-7Doctor

iTrader: (13)

Well to get the best Hp and tuning ability you will need to use either a SAFC or a mega squirt. The stock S5 ECU is not going to be able to do much for you by just adding larger secondary injectors. The only way it would be beneficial is to send the ECU out for remapping and i have not heard any good results that way.
I don't ever remember anyone using a S3 harness to tie into the S5 ECU though.

I still say pm rrluthi and see what he has done on his Se.
And no you are not going to use that holley,lol.

blwfly

iTrader: (4)

spend the xtra bucks and get a 48 ida TB from tweakit and use the mega squirt

im sure this will pay off in the long run

neektar

iTrader: (2)

So it sucks that there's no way to tie the s3 and s5 harness. Searching brings forth nothing.

I'm 100% not going with an aftermarket ecu for $$ and technical reasons. I just can see myself trying to program an ecu that cost me X amount of dollars on top of larger sized injectors.

So the 650 is a go!. lol.

At least I'm not spending any money on the 650. There's like three I can choose from all in working condition.

Thanks for the help guys (I hate webbers on everything except toyota's too, sorry >.<)

Unsupa

iTrader: (2)

in that case ya lookin to get rid of the s5 stuff? that's my plan for the winter: rebuild s4 block with s5 ecu/injectors/manifold and throw it back into my SE.

fcdrifter13

You could always run everything S4 and then get the MS plug and play unit from Tofuball and all those guys.

Rx-7Doctor

iTrader: (13)

Mega squirts are not alot of money and they can be programmed for you to just plug and play. And a holley 650 is too much carb for your motor.

You would be better off getting a used Mikuni 44phh set up.
Or you could just swap manifolds to A S4 system with the larger T/body and use the existing Se injectors and do not run secondary ones. I have done this with good results.
You can do the same thing with the S5 intake system.

fcdrifter13

Dont forget though, the S5 intakes have the VDI system that needs to be hooked up so it funtions properly.

steve84GS TII

More importantly,the S5 ECU will go berserk if the electric OMP is not plugged in.There is no known way to bypass the limp mode caused by having a deleted or unplgged S5 OMP.The S5 OMP will not bolt straight up to any 1st gen front cover,so that issue has to be resolved before trying to run the S5 computor.....

I agree that the S5 ECU is a great way to go.Its twice as fast as the S4,has the better air flow meter,a real check engine light and the VDI intake is pretty slick too.But the S5 ECU is smart,you cant just leave a bunch of stuff unplugged and expect it to work like you can with the SE or S4 engines.The S5 has pretty tight control over the engine and it will protest if critical parts are not intact.

Ive run both S4 and S5 controls in my car and speaking from experience,its quite easy to wire them up for power and everything.It doesnt matter if its N/A or TII,its all the same wiring and work to swap in any FC engine controls.

The most troublsome part to each swap was.....
Putting up with the EFI operation quirks of an old design(S4)
Getting around the factory safety quirks of the new design(S5)

BigJim

yea ive been planning on doing this for awhile actaully. I have the full s5 intake at my house, the VDI thing is what stopped me. I wonder how much of a gain i would see by putting the s5 intake on and getting a microtec or something

Rx-7Doctor

iTrader: (13)

Steve, You can avoid the omp situation by hooking up the harness to one and just leaving it mounted somewhere off to the side. You do not have to have one in the front cover when you do this. As long as the ECU is getting a signal that it is hooked up it should not go into limp mode. This was done on a friends GTU that had a bad OMP and the guy that owned it before him didn't make the effort to replace the bad one.