Questions:

1) Can I plug a S5 into a S4 ECU and wiring harness?
2) Should I get a S4?
3) Should I get a S4 with a S5 exhaust manifold & turbo?
4) Whats involved with replacing the water/oil seals. Compression is guaranteed but what if the seals are bad?

Roto Gurus help?

Im thinking of putting a JDM in my 87 T2.

Flame me if you want, I don't care as long as someone knowledgable with experience sets me on the correct path.

 

you may find this helpful. http://www.jaked.org/8ball.html?

 

you will need to swap out the indash harness (pita). the ecu plugs on s4 and s5 are different. replacing seals requires you to tear the engine down and rebuild it. if you are going to plug and play, the manifolds don't really make all that much difference.

 

You're probably gonna get scolded for this later, but don't put people's names in your thread title.

 

1) Can I plug a S5 into a S4 ECU and wiring harness?

No.

2) Should I get a S4?

Yes.


3) Should I get a S4 with a S5 exhaust manifold & turbo?

If you want, nothing really special about the s5, just port your s4 wastegate and you're just as good.


4) Whats involved with replacing the water/oil seals. Compression is guaranteed but what if the seals are bad?

Pretty much a rebuild, even if the apex seals/etc are all good, it's best just to replace it all while it's open.

5) Im thinking of putting a JDM in my 87 T2.

Is this because your current engine is dead? Why not rebuild that one? The JDM one serves no purpose other than being a complete engine readily available.

 

After doing the mod im sure others will agree if your motor is in good condition right now talk to SonicRat about his NA turbo kits being that the turbo is what your after. There is a chance you get a good JDM engin but personaly I feel I should have listend to evryone ells and not get into the posible headach and get a rebuilt USD engin you know is good from like "kevin landers - http://www.rotaryresurrection.com " Insted of rolling the dice.

I balive the S4 13bT has lower compreshion than the S5 and will swap much easyer then a S5 will for you.

 

I think he's got a TII already and is just considering putting a JDM engine in, which leads me to believe either A) it's blown or B) he thinks the JDM engine is better? But, as you said, if it is blown, getting it rebuilt for the cost of a jspec is the best bet (if it is a tII engine, at least), no guess work required!

 

NO.
Why would you want to do that???
With no OMP, the S5 stock ECU will go into limp-home mode and have crappy power.


-Ted

 

Wow, i read that wrong, I thought he meant a s5 ecu into a s4 harness or something, lol. Thanks for the requote Ted, wouldn't have noticed!

Back to question #1: (if you mean plug a s5 engine into a s4 harness/ecu, otherwise, follow previous answers, lol)

Simple answer, no.

Long answer I don't feel like discussing, yes. (think intake swap, front cover swap, injector swap, etc)

 

He's talking about putting an s5 motor into his s4 tII. Yes you can, you just need to swap out your old front cover and injectors(since yours are low imp). But if you block of the omp and certain other things, then yess you can just drop in the s5 motor and run it with the s4 ecu.

 

Hard to say...
I just reread it three times, and it could mean either.

I assumed it's S5 ECU into S4 harness.
The engine doesn't matter.

Even vice versa, the engine harness cannot plug into an ECU that is not the same group - i.e. S4 versus S5.
If you looked at the connectors, you'll understand why.


-Ted

 

He stated an S4 ECU also..

 

He could use the injectors off of his old tII motor, and use his intake manifold to use his acv and bac( dont remember if they use the same connector as the s4). THats if he wants to use it. But I blocked off everything and removed the rats nest.

 

What kind of IC piping is that Martin?

 

2.5" alu.

 

Hmmm...

"a S5" - assuming (S5 engine)?
..."into a"...
"S4 ECU" - ok, pretty obvious
"and wiring harness" - I guess this is where the confusion is...the typical would be to assume it's an (S4) "wiring harness" also

More confusing are the initial words "Can I plug..." - this would normally imply something electrical or mechanical coupling.

More accurately, I think it would've been better to ask "Can I install an S4 ECU and S4 wiring harness on an S5 engine?"
That would've made it easier.

Excuse my rambling... :P


-Ted

 

What he said.

I have a 87 T2, 99k miles, with absolutly no compression on the front rotor. I think all the apex seals, front housing, front rotor and turbo need repair/replaced.

Being the typical cheap 2nd gen owner It seems alot cheaper to get a good Jspec and repace the water seals.

I was wondering about installing a S5 using my S4 harness and ECU just because S5s are a little newer and I've heard the odds of getting a good S5 JDM are better.

 

I have also heard that the S5 OMP defaults to pump at its highest rate if its not conected to a S5 ECU, if so that should not be an issue.

 

I dont even know if that is true, but being an s4 theres not even a clip for it. If I were you I would just block it off, or since you are taking the motor apart, then just swap front covers...

 

If you have a S4 Turbo engine already, why don't you just swap the S4 front cover and MOP onto the S5 motor (much like I would do with the engine harness, but that is another issue).

 

I was thinking of that, but a rotary mechanic told me I didn't need too. Mabey I do. Another rotary mechanic told me it defaulted to %50, too high at idle and too low at WOT.

(Just like the mechanic I asked to use a S4 front cover on my rebuild to go with my lt8s standalone told me he would and then made my lt8s a piggyback and left the S5 cover on, but that is another issue and my other car).

 

lt8's as a piggy back??? IF the motor is in the car already, the easiest way is to block of the omp and run premix. Or youll have to remove the oil pan bolts along with water pumphousing and alternator

 

Im not trying or wanting to premix. And yes the lt8s install on my 89 is hosed. It was done by Hayes. Thats another issue. Im just trying to formulate a plan to fix my 87 here.

 

Ok, Im getting a S5. I know it hurts for the "pro" to condesend and give a straight answer but can someone tell if I'm doing this right?

Remove front housing off S4 core and put on S5
Remove UIM & throttle body off S4 core and put on S5 - low impedance injectors
Parts needed = front cover & UIM gaskets, plus high temp gasket sealer for oil pan. Clutch, pilot berring, pressure plate. Port WG. Remove air pump and ACV.

Im still not sure if there's an issue with connecting the S4 tranny to the S5 engine.

 

Sounds about right, but I would probably keep the S5 UIM on the S5 engine and just swap the injectors, and throttle body to S4 versions.