ok, so im not new to FC's i have 2 already, one 10th AE, so im pretty rotary savvy. but i was selling my jeep and someone with an FC who knew NOTHING about rotary or cars in general offered me a trade. its a 1990 GTU (CLEAN) with supposedly a 13b-t swapped in running a NA ecu... is what he told me but he said he had no idea and thats what the last guy told him. here is what i know

good compression
no smoke
doesn't overheat
factory turbo and manifold
non turbo tranny (only 1 drain plug)
full hard pipes with a front mount
turbo oil filler (elbow to go around top mount)(i say this because it has crossed my mind that its a n/a motor with a turbo on it)
the ecu says n351 on it and only has 3 plug clips

heres what it does wrong

start and run fine when engine is warm
hesitation under 2500 if you try and get on it
it will run out clean untill 6000 (never took it past didnt want to lean out hard)and actually is pretty fast
when you push in the clutch to come to a stop the car wants to die then kicks back up to idle (tps?)

my friend had a s5 turbo ecu laying around, so i plugged it in, it had 4 clip ports not 3 and it just turned over and didnt start, there was fuel though

if anyone can help me determining what i have going as far as if it is actually a turbo motor or an n/a motor with a turbo, im no dummy im just confused because i have never owned an s5 and cant compare it strictly to my 10th AE because its a S4

 

I bet the correct ecu for a turbo motor would be a good start.

 

if you read about 3/4 of the way down my friend had a s5 ecu, i plugged it in, it turned over and you could smell fuel, but it wouldnt start. plugged the n351 in and it fired right up.

do s5 turbo ecu's have 3 or 4 plug holes, the ecu i tried has no label on it

 

I guess i just skimmed it.

Im no expert on s5 but I thought within series they had the same plugs.

If I were you I would download the FSM for the s5 turbo and NA and see what is different. My guess is that someone neglected something when they did the swap.

 

you need a n370 ecu, sounds like your buddy has a FD ecu. turbo computer wont help without a turbo pressure sensor. then on top of that who knows if you have a turbo fuel pump and injectors.

 

oh wow, FD ecu must be why the clips are different... haha it has the pressure sensor that runs the factory dash boost gauge, what sensor goes on the intake elbow? because it looks sketchy like it might be broken.

 

can you run a n/a tranny with a turbo motor? i know there is one spline difference on the clutches and the turbo one is like 1/2" bigger in dia, could you use a n/a clutch disc with a turbo flywheel and turbo pressure plate? kinda a jank way to do it if you didnt have a turbo tranny? i can take pics tomorrow.

 

you can run a NA transmission with a turbo engine. you have to use a NA flywheel from the same series along with the NA clutch disk and pressure plate.

 

ok, so next step would be grab a REAL s5 ecu (not FD like i tried under false info from my friend) see what happens. i'll keep you guys posted, i'll snap some pics tomorrow too

 

er, my s5 turbo ECU (n370) has 3 clips... not four. Try a series four ECU?

 

i can pull the ecu out of my 10th AE but i only want to if it will work in a s5, will it? or would i be wasting my time?

 

Get the Engine series Right THEN get a Correct series ECU and take it from there

a TURBO Series ECU

 

the engine is a s5, i know that. what i am not sure of is if someone just put all the turbo stuff on the n/a motor or if that is possible, and how to tell if someone did that. i wouldn't think a s4 (10th AE) ecu would work, but please correct me if i am wrong.

 

No, it wont. The pinouts are different from a series 4 to series 5 ECU. If someone were to go through the trouble to strip down an N/A motor to the shortblock then you could technically (but why?) put all turbo stuff on there. It really doesn't matter though, except for the higher compression rotors on an N/A and the sleeves in the exhaust ports for the N/A as well. The wiring harness would be different as well. Maybe someone frankensteined a N/A to a turbo when re-building it? It's hard to tell if this is the case. Just get a confirmed N370 ECU and find out if it works.

 

gotcha.... i'll be on the hunt, unless that is someone here has one lying around....

 

take some pics and post them.