Well, I just finished my exhuast from the turbo back, put in my apexi AVCR, autodream E-prom ECU chip, RB25 MAF with intake pipe and apexi filter. I don’t have my front mount intercooler in yet so I am running 8psi of boost. The car has great low end torque and mid range pull feels good, but I don’t have much top end pull. I realize the stock SR turbo behave a little like that, but it seems to have less top end than when I was running stock. And the more major problem, The apexi AVCR can dispay my injector pulse width, I realize it’s not perfect but close. At only 8psi(maybe spiking to 9psi) I have hit 100% and in the high RPM’s at full throttle it runs in the 90% area. That means my injectors aren’t closing when I am doing 7000rpm at full throttle and boost. NOT GOOD!! But the stock injectors should be able to handle 15psi I thought. and my engine is only supposed to have 60-70,000km’s, shouldn’t be failing injectors right? So I figure it’s either the fuel pump or the fuel pressure regulator. Well, i don’t know how to test if these are working right and at what PSI they should be opperating at. The car was originally a non-turbo so I am thinking maybe the fuel pump wasn’t swapped like it should have been? or the fuel pressure regulator is failing?
What do you guys think, and how can I check?
Please help, I don’t want to detonate my SR so it’s not much fun driving it right now!
Thanks
when you say you’re hitting 100% are talking injector duty cycle? if you’re injectors are hitting 100% the fuel pump is doing its job. but I would check that fuel pump, see if its an aftermarket pump or the stock KA one (which flows around 70cc/min which is WAY too low flow for a turbo setup).
which injectors are you running?
It’s a silvia, started life as a Q model, (ca non-turbo).
So it now has stock SR injectors. And if the injectors are at 100% duty then that means they are wide open, and not closing. that will burn them out, and means I can’t deliver enough fuel at wide open throttle in higher rpm’s.
So I am wondering if the stock non-turbo fuel pump is still in there if that would cause this problem.
what kind of fuel pump are you running?
I don’t know. That’s what I tryed to say!
It could be a stock non-turbo CA. or it could be a turbo SR. I was told it was switched for the SR, but how do you know? If this could be causing my problems, then I am going to take a look, but then I would need to know how to identify which is which.
just wondering, are you running an aftermarket FPR? If its the CA18DE FPR, you might want to switch that over the SR20DET FPR.
Gauges, my son. Why guess, when they can tell you what you need? This is the one I made for my 240SX. I still have it.
http://minimopar.knizefamily.net/quickfpg.html
no, the FPR mounts onto the SR fuel rail, so I don’t think it could be a CA FPR.
But I think I have it figured out. I talked to the owner/head mechanic at autodream and he said:
that’s just the way the factory does it. They max out the injectors at high RPM’s under load, but doen’t max out the pressure unless it’s really needed. So I thought I was running lean when my injectors were maxing out, but the stock fuel pressure regulator is probably just letting some fuel slip by to regulate the air/fuel ratio.
Anyway…nice to know I am still OK!! Now I need to throw my intercooler on there and crank the boost
but I still want to get it onto a dyno and check out the air/fuel ratios to make sure it’s all OK.
AND…I would check my fuel pressure, but I don’t know what it’s supposed to be at for a SR???