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View Full Version : 39 pound injectors limit is???


Motorhead350
02-26-2011, 03:39 PM
Being that I am putting a Cobra engine in the car means I need to put more boost on the car to keep the same power level... I think. So what is the limit for 39 pound injectors? I was told they are fine up to 480rwhp, Last time I made a dyno run I had 456rwhp with a boost leak. With the new engine I do not know what it will make, I do not know what it would make if I found a way to up the boost to 16 to keep the power there with the new engine.

At what point will I need 60 pound injectors?
SC Cheesehead
02-26-2011, 03:45 PM
Being that I am putting a Cobra engine in the car means I need to put more boost on the car to keep the same power level... I think. So what is the limit for 39 pound injectors? I was told they are fine up to 480rwhp, Last time I made a dyno run I had 456rwhp with a boost leak. With the new engine I do not know what it will make, I do not know what it would make if I found a way to up the boost to 16 to keep the power there with the new engine.

At what point will I need 60 pound injectors?

You already answered your own question, Dom... ;)
Motorhead350
02-26-2011, 03:51 PM
You already answered your own question, Dom... ;)

Yes, but I am unsure of what the power output will be. I have heard mixed things on the 39lb injectors. Fine to 450, some at 512. I need to know for sure.
LANDY
02-26-2011, 05:34 PM
Like I said before, not all cars will demand the same amount of fuel. You will run out of fuel in the low to mids 500rwhp. Also what FP are you running?
SpartaPerformance
02-26-2011, 05:35 PM
I had a customer make 506RWHP on an '07 Saleen Extreme, it was a near the end of it's limits on the stock 39's but the car ran strong and still in the "safe" range.
Motorhead350
02-26-2011, 06:43 PM
I had a customer make 506RWHP on an '07 Saleen Extreme, it was a near the end of it's limits on the stock 39's but the car ran strong and still in the "safe" range.

That's good to hear, but also that's a different engine. Does it make a difference when it comes to things like this?
RacerX
02-26-2011, 06:48 PM
You can have a tuner raise fuel rail pressure so the 39s will put out more fuel. Read this info and use the worksheet at the bottom of this page to get a better understanding:

http://www.rceng.com/technical.aspx
Motorhead350
02-26-2011, 06:49 PM
As long as I know I can run 16psi with 39# I'll be happy. I guess it's all in the tune.

Thank you!
FordNut
02-26-2011, 07:21 PM
If it doesn't have enough fuel system capacity, lower the rev limiter.
SpartaPerformance
02-26-2011, 09:53 PM
That's good to hear, but also that's a different engine. Does it make a difference when it comes to things like this?

Not really, the only time injector capacity differs is N/A vs SC vs Turbo