injector power limits

[DriFt3r]

what are the Highest HP you can get with 50/hr and 72/hr injectors?

[andrave]

I'd imagine it would be like 400 and 500 hp or so.

[Nathan]

According to JWT when I had my ecu programmed, 72#'ers are good for 520hp, I'm 99% sure that was a 3 bar fuel pressure program too.

[andrave]

oh yeah, "500 or so" means +/- 20lol

[zachosz]

There's an approximate formula for this. This applies for cc/min so you have to convert the flow rate.

Injector size / 5 = hp supported per injector

For example, one 550cc injector can support 550 / 5 = 110hp, so on a 4 cyl engine that would be 110 x 4 = 440hp, on a 6cyl it would be 660hp and so on.

That assumes "stock" fuel pressure at a 80-85% duty cycle.

[95_240sx]

I found a website that did the calculations for you, But I dont remember what the URL is. I do remember thought for 625 crank hp you would need 72lb injectors with a peak pressure of ~100psi.

Rick

[Structure240sx]

nathan it should be the 3bar program. i jsut got my jwt ecu back tuned for 740cc's and its the 3 bar program. rick, 95 240sx, says his 72# injectors we at about 75% duty cycle at 25psi with a to4s i believe. he was running race gas at that boost if it matters to u

[95_240sx]

No no, I was running pump gas on 72lb or 756cc injectors with the stock FPR. At 18psi at 6000rpm in 5th gear WOT it was about 60-65%. I never ran it at 25psi long enough, or I didnt have the laptop datalogger going to get a reading on the duty cycle. But, as you increase the pressure at the same spot your duty cycle will go down.

Rick

[95_240sx]

http://www.rceng.com/technical.htm

Theres some good stuff on there.

Rick

[Structure240sx]

sorry got a lil confused thanks for clearing it up

[MarkEmark]

95_240sx: 18 psi at 6000 RPM?!? I bet that feels AWESOME, eh? I bet first second and third are useless under full boost at high rpms...

What are you making for whp?

Sorry for the post whore.....