MAX HP w/ 39# Injectors
#16
Thats why I'm doing the tuning myself, I trust troyer and them, but I just want to do it myself, I'm tarded like that.
Well my thinking was, Cobras had 39lb injectors on a smaller motor making less power then what you make now. While a GT500 has a 5.4 with a little less power then what you make. I thought I was one upping myself by going GT500 injectors.
Well my thinking was, Cobras had 39lb injectors on a smaller motor making less power then what you make now. While a GT500 has a 5.4 with a little less power then what you make. I thought I was one upping myself by going GT500 injectors.
#20
here is a site that will tell you what size injectors you need for the
hp you want. 2nd chart down is where you enter the size of the fuel injector to get the estimated hp.
http://www.injector.com/injectorselection.php
hp you want. 2nd chart down is where you enter the size of the fuel injector to get the estimated hp.
http://www.injector.com/injectorselection.php
#21
So according to that, guys with 420-450RWHP who make about 525-550 at the crank are having 39lb cobra injectors go static at WOT.
Well assuming thats HP @ Crank and not ground. At ground 450RWHP is fine with 42lb injectors.
I would still recommend a bigger injector though, being as you should keep duty cycle at alteast 80.
Well assuming thats HP @ Crank and not ground. At ground 450RWHP is fine with 42lb injectors.
I would still recommend a bigger injector though, being as you should keep duty cycle at alteast 80.
#22
So according to that, guys with 420-450RWHP who make about 525-550 at the crank are having 39lb cobra injectors go static at WOT.
Well assuming thats HP @ Crank and not ground. At ground 450RWHP is fine with 42lb injectors.
I would still recommend a bigger injector though, being as you should keep duty cycle at alteast 80.
Well assuming thats HP @ Crank and not ground. At ground 450RWHP is fine with 42lb injectors.
I would still recommend a bigger injector though, being as you should keep duty cycle at alteast 80.
* NOTE: Unless otherwise noted, all injector flow rates are calculated at a fuel pressure of 43.5 PSI (3 BAR).
Pretty important note. Just about any decent fuel pump can support 50 - 60 psi at the rail at those power levels. If you are going to go to bigger injectors then look for 55#'s as they would support nearly 700hp @ 80% duty cycle and 60 psi of fuel pressure. That is assuming you have a sufficient pump (and you do). I think you can get by with 39# injectors with enough fuel pressure. 55's would be very safe.
Last edited by justjames80; 04-20-2009 at 02:32 AM.
#23
The only reason I'm sticking with the 39# cobra injectors is because I didn't know that the JDM fuel pumps were going to cost me $1500 and that the GT500 injectors wouldn't fit. But they will be upgraded in about a month, after I put this nice white 10lb bottle in the back of my truck Maybe I'll spray enough so my floor boards fall out....
#25
In a Mustang with a manual you can get 470-525rwhp out of 39's before they give up at standard 39psi delta P. You can of course get some more overhead out of them by upping the delta P. Otherwise get yourself some 60lb injectors and you should be fine. Not sure what the drivetrain loss is like on these trucks but I am sure it is well above 20%.
#26
#27
#29
Just got off the phone with my tuner. 463 RWHP at 14 pounds of boost. My truck ran out of turbo before it ran out of injectors. I get to go pick it up tomorrow. So..next step is a gt70 turbo, the nice white 10lb bottle sitting in my room, the troyer E-fans I'm waiting on, and some bigger injectors. I can wait to go drive it tomorrow
So I'm trying to figure out crank hp. Talked to my mechanic, who said my tuners dyno reads 10% lower than most others. What is our drivetrain loss on these mastodons? 15%? 20%?
So I'm trying to figure out crank hp. Talked to my mechanic, who said my tuners dyno reads 10% lower than most others. What is our drivetrain loss on these mastodons? 15%? 20%?
Last edited by eckomaninred; 04-21-2009 at 09:43 PM.