Duke

Believe it or not I have bought 70 injectors from Racetronix since last October. They have always been very pleasent to deal with. Which is a very good thing for me since I am located in Sweden

Matt H

John, I was joking with you! No offense, I was making a joke, sometimes that doesnt come across on the internet.

www.racetronix.com for the injectors

I agree with Duke, I am not saying it is not possible, I am saying that it is no where near ideal.
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Duke

All this reminds me of reading a post a couple of years ago from Alan C. about duty cycles and power levels at about 370 rwhp and wouldn't you know it...

I found the thread and here's what Alan C wrote:
"I run 83's with 370 at the rear and hit about 80% duty cycle."

Alan runs TEC 3 so dutcy cycle was taken from the logs.

toddk911

Well, 4.5 BAR is 65.25 psi. There are plenty of fuel pumps out there that will handle up to 80-100psi. I know as I researched a bunch of them for use as a pump for water injection.

But I agree, if you can just send a little more and get bigger injectors to run less duty cycle that is the better way to go, but not always feasable to all of us on this board

OriginalSterm

it's not the pressure that is a major concern, but the capacity of the pump at that pressure. how much can it flow as the pressure increases.

Matt H-
you can run static, but like i mentioned before, not for long. the coil gets very hot from a constant current (100% duty cycle). fuel flowing through the injector does help to cool it, but that only prolongs the inevitable (real word?). 80% is a target number thrown around to keep coil temps down to a reasonable operating range.

tazman

Well I can tell you guys that I see around 68% duty cycle with my 75 lb/hr injectors and my dyno chart showed around 285 RWHP. That was with 2.5 bar fuel pressure.

Duke

That's interesting.

I calculated you're BSFC and it's around .50
For Alan's car it's around .55 and a stock care is also in the lower .50's
I assume the fuel consumption per HP goes up with more and more power.

So now that we have the BSFC set straight when can calculate once more..
For 470 bhp (note brake horsepower) with 0.50 BSFC and 3.0 bar fuel pressure and maximum 80% duty cycle we need 73.86 lb/hr or 776 cc/min injectors.

With a higher BSFC the engine needs more fuel per hp and that results in 81.35 lb/hr.

With 100% duty cycle it needs 59 lb/hr injectors at 3.0 bar base fuel pressure.

But to be honest, not many will hit 470 real brake horsepower!