1994-1995 7.4 L uses 43# injectors per turbo city. 17104288 at 30 lbs FP. i have 2 of these that i have no use for. brand new.

 

anybody have pulse width or other chip stats for that particular setup? Id like to see how they got everything metered well at idle and wot.. was it 30psi constant or vacuum adjusted or some other variable system?

good for you that you've got a couple... put em on the classified section - not here....

a good topic for someone to research though... i dont have the energy

 

i think someone else had this Q. bulldog92. if you run that 1994-1995 454 TB with injectors as it had from factory at 13 lbs FP it will possibly give you fits. GM apparently decided to go high FP with their truck TBI those years. not sure what last year was for TBI but that may be it? we could not determine the flow rate as not posted anywhere.

 

I have a 95 7.4 in my 67 camaro with the same part numbers and in the "ECM Constants" in the CATS program the injector is set to "67.90 # per hour". I have in fact changed that number and it will lean or richen across the board. If I raise the number it went lean.

So what does this mean? I dont know, I just thought I would tell you what the computer thought....

Lee

 

I guarantee those injectors are NOT 46lbs/hr @ 30psi.

The rating is most assuredly 46lbs/hr @ 10-11psi.

When you increase the pressure from 10psi to 30psi you end up with approximately 79lbs/hr.

Why they don't publish the test pressures is beyond me, as pressure is a very important part of injector flow.

The 94/95 7.4L ran a constant 30psi of fuel pressure which, with the smaller injectors resulted in approximately the same fuel flow as the earlier 7.4L's which ran 10psi.

 

but what would help is if we could design a formula to convert.... 46#ers at 13psi, and 46#ers at 30psi, we could more easily be tuning our chips settings.

 

You mean a formula like on this page?

http://www.jimsperformance.com/tech.html

 

just to repeat. the flow was confirmed by turbo city. the FP was given to me by certified GM mechanic for 94-95 7.4L. this was a injector part # that nobody had solid data on. i have a BPW calculation at home that factors FP into it. that is what i used to set BPW in constants when i swapped out 65 lbs to 90 lbs. that plus a solid underlying fuel table allowed me to hit commanded 12/1 WOT with WB02 on dyno. had eroneous values been in eprom who knows what the outcome would be.

 

If you'd have emailed turbo city you'd have discovered that they tested all the injectors, 94/95 included, at the same pressure. You would have also discovered that the 94/95 injectors flow roughly the same as the earlier units when supplied with 30psi.

Since the '93 and earlier 7.4L injector were already known to flow 75lbs/hr @ 10psi its pretty clear that they tested all the injectors at 10 psi.

 

see... this is what im talking about, here i wanted to know something and others went out and found it out for me.... gotta love you guys LOL

Im now convinced then that the 80pph injectors (or 75 if you wish) could flow and meter fuel accurately anywhere between 75 pph and 160pph. as long as you could vary fuel pressure accordingly to engine needs at particular rpms.

Thats maxing 2 tbi injectors out at 512hp. and idling nicely at 10psi.

so all we need now is a vacuum adjustable regulator spring that will allow fuel to go from 10psi to 30 - sorry, its not going to exist. (especially with the kind of vacuum you're gona get on any engine making 512hp on top.)

for anybody to want to use tbi that far, you're gona have to design an electronic fuel pressure regulator that takes a tach signal to calculate pressure. now go try to tune those apples....

Lord. Im done playing