TBI High Pressure Injectors

[Nasty-Z]

I didn't the marine engines ran such high HP numbers!

Where these 17104288 injectors any special design from the original 13 psi injectors or were they simply regular TBI injectors with the pressure amped up to 30 PSI? Would this allow for safe operation of any GM TBI injector to be operated at these higher pressures?

Steve

They were essentially a 4.3 injector ran at a higher pressure, if you do the math , the 45 pph 4.3 injector @ 13 psi would be around 70 pph @ 32 psi , GM's thought was it would fight vapor lock by using a higher fuel pressure , aside from designing a new injector , what they already had was used and the pressure increased to fuel a BBC . Anyone who has dabbled with a TBI BBC though finds out quick enough that the injectors at that pressure were marginal for fueling at the factory settings , one of the first things I did to the stock 454 in my '94 Dually when I bought it was to revert to the earlier injectors (5235231) and ran them around 15 psi , woke the otherwise stock engine up .

If you are going to be raising pressures , especially on the BBC injectors , I would stay with the 5235231 platform , these are much more tolerant of higher pressures than the 17104288 injectors .

I as well as many others have run the 5235231 injectors upwards of 70+ PSI with no adverse effects on cone shape nor spray pattern.

TOM

[sfara002]

Awesome, thanks for the info Tom. 70+ PSI, that's so much higher than the original 13 PSI as designed. So are they just relabeled 4.3 injectors? Any changes in spray pattern between the two? I assume a 4.3 at 28-32 PSI would accomplish the exact same results?

I was thinking of running the 17104288 injectors in my mild 350 truck. I was seeking better atomization and cleaner burn through higher pressures. I had concerns about being able to get the fuel psi with the injector set right with a pressure regulator spring for a 350; as well as, minimum pulse width optimized from a 7427 PCM for low enough for idle/fueling conditions on the 350 vs the 454. I already have a pump capable of 30 PSI and Spring on hand but I don't have the injectors yet.

[buddrow]

Remember, when you change the injectors and/or the fuel pressure, you change the base pulse width needed and should make accommodations for it in the .bin.

Buddrow

[sfara002]

Right, just to confirm for the $0D mask, the BPW function is a mater of setting the injector flow rate in lb/hr. and the cylinder volume. In the case of the 17104288 at 30 PSI, should be set to 74lb/hr. I am assuming the 7427 PCM will be able to compensate enough at idle going from 61 lb/hr from the stock set up to 74 lb/hr with the 17104288 at 30 PSI. If not I would have to reduce fuel pressure from the 30 PSI on those injectors.