Jspec S5 turbo engine with Aspec ecu
10-20-04, 01:53 AM
#3
Epitrocketeer
Join Date: Mar 2002
Location: Virginia, US
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Actually it will work fine IF you can source out some S4 parts - I would recommend getting an S4 LIM / UIM and TB since the J-Spec TB / UIM is different (notably the brake booster hookup)
The trailing timing will be slightly off due to the rotors trailing plug position, but its also mostly emissions related and will not effect performance, boost control is PWM solenoid controlled on S5 and the turbo doesnt have that "twin-scroll" flapper junk so the S5 turbocharger will work fine but you would need to block off the S4 control system for that.
You might need some type of external boost control since the stock wastegate spring is about 10psi - it will open and wont be able to prevent spikes - especially if you add a free flowing exhaust and intake to the engine you will definitely hit stock fuel cut (around 6-7 psi on an S4) which can kill an engine because it turns off fuel to the rear rotor, under boost, which can lead to detonation.
Also you need to be sure the 550 cc injectors that you use are the correct impedance for the ECU that you are using, I am not sure exactly if they changed the impedance for the turbo models at the same time but sometime in 1987.5+ they swapped all injectors and ECU's to control them to the higher impedance injectors (12-14 Ohm). You can check which one you have by looking at the VIN# but the exact number VIN and higher is probably somewhere on this forum.
Also the VE of an S5 is better due to the higher compression rotors (9:1 versus 8.5:1) something to keep in mind if you want to overboost (lower is better, generally, but depends on your engine tuner).
S5 engines use 2 TPS sensors 1 off idle, one full range - S4 uses 1 full range TPS I believe... So use an S4 TB if you use a S4 ECU or rewire at your own risk.
To address the Oil Metering - you would have to swap the front cover from and S5 to and S4 because S4 uses a mechanical Oil Metering pump and the S5 is Stepper motor driven from the stock ECU.
The very easiest swap is to change the front cover and OMP and take all the accessories / "Vacuum Rack" / Fuel Injectors/ UIM / LIM / TB / Turbocharger unit/ PS / AC from an S4 Engine - and put them all on the S5 short block.
If it were up to me I would just get the S5 longblock + aftermarket EMS + a tunershop and premix my Oil/Fuel and be done with it. That would ensure any future upgrades to the engine will be adressed and easily remedied.
The trailing timing will be slightly off due to the rotors trailing plug position, but its also mostly emissions related and will not effect performance, boost control is PWM solenoid controlled on S5 and the turbo doesnt have that "twin-scroll" flapper junk so the S5 turbocharger will work fine but you would need to block off the S4 control system for that.
You might need some type of external boost control since the stock wastegate spring is about 10psi - it will open and wont be able to prevent spikes - especially if you add a free flowing exhaust and intake to the engine you will definitely hit stock fuel cut (around 6-7 psi on an S4) which can kill an engine because it turns off fuel to the rear rotor, under boost, which can lead to detonation.
Also you need to be sure the 550 cc injectors that you use are the correct impedance for the ECU that you are using, I am not sure exactly if they changed the impedance for the turbo models at the same time but sometime in 1987.5+ they swapped all injectors and ECU's to control them to the higher impedance injectors (12-14 Ohm). You can check which one you have by looking at the VIN# but the exact number VIN and higher is probably somewhere on this forum.
Also the VE of an S5 is better due to the higher compression rotors (9:1 versus 8.5:1) something to keep in mind if you want to overboost (lower is better, generally, but depends on your engine tuner).
S5 engines use 2 TPS sensors 1 off idle, one full range - S4 uses 1 full range TPS I believe... So use an S4 TB if you use a S4 ECU or rewire at your own risk.
To address the Oil Metering - you would have to swap the front cover from and S5 to and S4 because S4 uses a mechanical Oil Metering pump and the S5 is Stepper motor driven from the stock ECU.
The very easiest swap is to change the front cover and OMP and take all the accessories / "Vacuum Rack" / Fuel Injectors/ UIM / LIM / TB / Turbocharger unit/ PS / AC from an S4 Engine - and put them all on the S5 short block.
If it were up to me I would just get the S5 longblock + aftermarket EMS + a tunershop and premix my Oil/Fuel and be done with it. That would ensure any future upgrades to the engine will be adressed and easily remedied.
10-20-04, 11:56 PM
#5
Full Member
Thread Starter
Join Date: Sep 2003
Location: victoria
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
Racerxxxx, thanks! Helped me out alot what you had to say. What happened is I had a s4 jspec blow up on me with an s4 aspec ecu which I was told was fine, I think it blew do to boost creep since I have 2.5 straight back and I didnt port my wastegate. So I have stripped the s4 jspec down and I now have a s5 jspec that I want to put in, so I guess I can swap the injectors, manifold etc.. from my s4 jspec onto the s5 block?
10-21-04, 12:04 AM
#6
Mountain Rotary Mod
Join Date: Nov 2003
Location: Freaking Poland!!
Posts: 2,411
Likes: 0
Received 0 Likes
on
0 Posts
Go to http://www.rotaryresurrection.com and go to tech.
It WILL work, just do a search it's been done before.
It WILL work, just do a search it's been done before.
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
armans
3rd Generation Specific (1993-2002)
5
08-15-15 09:08 PM
KAL797
Test Area 51
0
08-11-15 03:47 PM
