FC turbo injector sizing
 

Hey,
I'm trying to put a butcher'd FC back together. The car is a 1990 jdm stock turbo. Someone put a megasquirt in it and did a BAD job. I have gotten a harness and all that was missing, minus the injectors. I want to go to a Rtek 1.8 chip upgrade with 720cc or 750cc injectors all around. I also have a turbo setup from another car I was hoping to add. I'll post specs below

My Questions:

How do you choose the size of injectors to use? I was hopiong to use 720 or 750 so I could stay with the 1.8 chip.

Would a Rtek 1.8 work ok with a upgraded turbo or do i have to go to a 2.0 or 2.1?

I will be running 7psi, will the stock s5 motor handle this?

Specs:
Car is stock 1990 jdm Turbo II
60mm turbo with 0.62AR cold side and 0.82AR hot side
Turbonetics evolution wastegate with 7 psi spring
front mount intercooler
stock motor (no porting or upgraded apex seals)
have not bought injectors yet.
N374 ECU

I have a stock s5 turbo but it is questionable.

Thanks for any help.

Also the leading coil has 3 wires coming from it, 2 go into a connector and the other one (black) is cut. Is the cut one a ground?

I think I have heard the stock motor can handle 12psi could be more not for sure but can't go over 9 if u still have fuel cut but with the rteck has built in fcd

The black single wire on the leading coil doesn't need to be hooked up to anything. You could use that for a tachometer signal if needed.

My engine runs with up to 14psi with 4 750cc injectors and they aren't maxed out. The engine internals are still stock.
I don't think you would get problems if you use a 1.8 chip with only 7psi.

Cool, thanks for the info guys. That put my nerves to rest.

Past about 12psi to the TMIC can no longer cool efficiently.

More info on this turbo is needed before anyone can give you a real idea if a simple non-programmable rtek chip & 4x720cc injectors will work alright as a temporary solution. What compressor wheel is in it? By 60mm do you mean it has a 60-1 wheel? For any aftermarket turbo, a programmable computer is strongly advised. If it is a 60-1 compressor, running only 7 psi is going to make for a slow, laggy setup. A stock turbo would make for a faster car.

Thanks, I'm not to conserned about the lagginess of the turbo. It was in another car that I had the chance to drive and it pulled good with a large range. That setup only ran 7 psi. My main issue is the fuel and fuel management. They had a megasquirt and they didn't tell me what injectors they ran. So I'm trying to decide what to use myself. I think I have decided on 750cc injectors and think I'm going to spend the extra $$ on the rtek stage 2 upgrade.

I'm pretty new to the turbo scene and probably made a mistake by not getting more info on the turbo but thats all the info I was given. The guy I bought it from was the one who butchered the car and hooped me big time for it, so him and I are not exactly on speaking terms to ask for more info.