stock injector size (96 3.4DOHC)

[pontiacjeff]

Anybody know?

UPDATE... THEY ARE 23#@50PSI.

[dohcfiend]

i have heard alot of differences in opinions be4 on this subject.

i have heard it is 21 for 91-93, 23 for 94-95, and 24 for 96-97.

but one person deals with the ecms and i think he says they all have 23's in them.

so either way it is 23 or 24(i would guess 23).

i know this isn't exactly the answer u are looking for but it is a step closer than u were hopefully.

why are u asking anyway? i have also heard that the dohc injectors have a specific spray pattern on them but i have seen non-dohc injectors in them be4 and run good so i don't know about that.

[SappySE107]

91-93 are 23#, and im using 94 injectors now with no difference inthe computer between injectors that I saw. Would be best to have some injectors flow tested so we know for sure. I have a brand new 94-95 injector I can have done but nothing for 96. Im sure someone has a set of 96 injectors that we can get to have it tested out.

[pontiacjeff]

Turbocharging. I need to know where I'm starting. Trying to decide if I need injectors or just use an FMU.

[SappySE107]

Judging by how GM chooses their injectors, I don't see them going more than 1# more for 5 hp...if they even bother doing that. Its all just a guess though really. Going to 55psi is only going to make them 30# injectors, which is probably gonna fall short on what you will be ending up with for power. Im not sure how much pressure is safe to put through the injectors, so I would look at getting another set. I have heard the saturns got a similar spray pattern and are rated higher but I dont recall the exact amount they flow. Its still in the high 20s from what I remember though. With boost though, does spray pattern even make a difference?

Brian was using L67 injectors, which I believe are 36#. Are you using mpfi or sfi? SFI will be easier to deal with for tuning idle on larger injectors, so if its mpfi I would consider using larger injectors and have the fuel pressure upped under higher boost conditions. Just my thoughts on it anyway.

[Anonymous]

So I know this isn't for a forced induction system, but I also need more fuel. Do you think I could get away with just bumping up my fuel pressure a little on my factory injectors? I have a set of 96s, but I am not sure whether I'll use them or mine. Mine are a lot louder, but at least I know all of mine work, and work well. I can't say the same with these cuz they are junkyard pieces. I will be using an aftermarket FPR. What is our factory FP? And what would be your best guess as to the max that the 3.4 stock injectors can handle?

I was also thinking of trying out the ones off of my firends 2.4L Z24, since they are a bit bigger than mine.

[dykz34]

All I know is that the 96/97 injectors are infinitely quieter than the early style ones. I didn't notice one bit of change when swapping to the newer style ones besides less ticking (ie: idle quality was the same, etc.).

[Anonymous]

I will swap them before I build my mani to see if they help the idle any. Does your car stall Dyk? If you havn't felt a car or driven one that does, it is sooo annoying. And dangerous too, cuz you lose power brakes and steering liek instantly. Thank god I slow down with it in like 3rd and the clutch in, so if ti does die, I can just release the clutch real quick. I have had more than a few close calls however.

[pontiacjeff]

Just cleaned and flow-tested the stockers... they ARE, in fact, 23#@50psi. The stock fuel pressure regulator is set a 50psi with no vacuum and IS boost referenced at a rate of 1:1. The injectors start shutting off at 75psi f.p. and are all shut by 80psi. So, even a 4:1 FMU will basically shut off fuel at as little as 8 pounds of boost.

[SappySE107]

Hmm, they are supposed to be 23# at 43 psi, which is what they run at idle. That would make them 19.7# at 43, which is how GM rates their injectors. That would be too little fuel for the stock motor. 3.1 are rated 16.6# at 43psi.

[dykz34]

I will swap them before I build my mani to see if they help the idle any. Does your car stall Dyk? If you havn't felt a car or driven one that does, it is sooo annoying. And dangerous too, cuz you lose power brakes and steering liek instantly. Thank god I slow down with it in like 3rd and the clutch in, so if ti does die, I can just release the clutch real quick. I have had more than a few close calls however.

No, my car doesn't stall by itself.

[Anonymous]

I will swap them before I build my mani to see if they help the idle any. Does your car stall Dyk? If you havn't felt a car or driven one that does, it is sooo annoying. And dangerous too, cuz you lose power brakes and steering liek instantly. Thank god I slow down with it in like 3rd and the clutch in, so if ti does die, I can just release the clutch real quick. I have had more than a few close calls however.

No, my car doesn't stall by itself.

Ok it has been established that my car is a POS.....No need to rub it in