I was checking out Corbin's site to figure out fuel pressures and such for this kind of fuel set up,but before i dive into the math, i was wondering if anyone is using this set up now, and what disk/spring you are using for proper fuel pressures. For some reason, i have this great fear of maxing out my stock injects at 8 psi, so i want to go this route, and have some more peace of mind. Anyone have any suggestions for this? I want to stay away from the SAFC for now, so the 30lb injects are the limit for now. Thanks for any info.

I don't have the HRC kit but I'm running mine at ~42 psi static and using the 2.72" disk (4.4:1) I think. I get like .88-.92 A/F at 10 psi. Easily 1550-1600 WOT in 3rd. If you are worried about blowing the motor you might want to run a little more pressure.

>I don't have the HRC kit but I'm running mine at ~42 psi
>static and using the 2.72" disk (4.4:1) I think. I get like
>.88-.92 A/F at 10 psi. Easily 1550-1600 WOT in 3rd. If you
>are worried about blowing the motor you might want to run a
>little more pressure.


Really? you are using that disk? Thats the same one i'm using now with stock injectors. My static is around 60 psi now, but it really should be around 55, but i'm running about 7 psi, which was a little to lean when my static was down to 55 psi. I guess by lowering the static with the larger injects, it will give a lower fuel pressure at each pound of boost, because the sfmu rise rate goes from the static pressure on up..right? I guess i'll just have to play around with it. Also, Hahn sells only 310cc injects, will there be much difference with only 5 cc/min, compared to the 315cc's?? I was thinking with 315 injects, i would need to use the 2.4" disk..maybe not i suppose..i'm gonna have to use my voltmeter to see what my o2 voltages are at..damn blinky light A/F gaguge..

Yeah every pound of boost you still have 18psi more fuel than me because of where you start. But when I get to 10 psi I have 86psi fuel pressure while you are running ~91psi @7psi boost. You'd have 104 psi w/ stock injectors w/ that disk and 10psi of boost.

Oh and w/ the 310's you might want to run a little higher static pressure. I'm pretty lean w/ the 315's at the static pressure I'm running.

>Yeah every pound of boost you still have 18psi more fuel
>than me because of where you start. But when I get to 10
>psi I have 86psi fuel pressure while you are running ~91psi
>@7psi boost. You'd have 104 psi w/ stock injectors w/ that
>disk and 10psi of boost.
>
>Oh and w/ the 310's you might want to run a little higher
>static pressure. I'm pretty lean w/ the 315's at the static
>pressure I'm running.


So basically, my fuel pressure rise rate will stay the same? I thought that by using larger injectors, it would change the rise rate of fuel pressures that i would need. I know that by running larger injects, it flows more fuel, and you need to lower the pressures to get the same fuel flow as with smaller injects. So i guess i'm just a little confused about the whole rise rate thing with larger injectors..

Well....(someone step in if I'm wrong)

The 315's aren't a whole lot bigger than stock since the ECU can still control them w/ the 25% fuel trim. I have my static pressure lowered to ~42. That makes it idle at ~26psi. That is about the lowest pressure you want to go that your injectors will spit out fuel properly. Lets say I had 440cc injectors. I could still use the same static since it yields about the minimum idle pressure that I can have. But of course the will provide the same fuel that my 315's will but at a lower pressure. NOW you will use a smaller gain disk. You have the minimum static pressure but you're still too rich at idle (idle is pretty good at ~26psi w/ the 315's but won't be w/ the extra fuel of the 440's) so you use the AFC to trim the idle fuel and make it idle good. So basically the only reason we are using the same disk right now is because you have stock injectors and I have ones a little bigger but small enough for the ECU to control idle. Get it?

Yeah, that makes sense. I was kinda thinking that was it, just not 100% sure. Thanks for the help man :)

Cool, glad I could help. :)

Wow. No wonder I am getting a system too rich code. I was running 39psi idle fuel pressure. Guess I need to turn that down hu?

Yeah that's about where your static should be. Between like 40-44. Whatever works best.