mazdadrifter

I'm using a walbro fuel pump with 3/8 fuel line from the pump up to a aeromotive high flow fuel filter to stainless -6 line, that Y's so each rail gets its own line. Out the opposite end of the rail, into an aeromotive rising rate fpr.



I'm planning on putting down high 200's to low 300's to the wheels, but I would like it to also be an efficient setup as well.



I understand that on low fuel pressure the fuel doesn't atomize as well (not mixing as well= less power/efficiency), and at too high fuel pressure the injectors can leak (causing untuneable conditions = less power/efficiency)



I'd like to run the highest fuel pressure that I can reliably also not decreasing the efficiency of the walbro fuel pump.



What would you guys suggest for my scenario?? Keeping in mind that my fpr is pressure controlled 1lb boost / 1lb fuel pressure.



Thanks in advance!!!

mazdaspeed7

The spray pattern starts to degrade around 65-70 PSI. Id set it to the fuel pressure at max boost is around there.

mazdadrifter

K thanks a lot. I was thinkin around 60-65. If I set ambient pressure at 50psi. then at 15 I'll be at 65psi max boost.



And if I decide to crank it a touch more w/ race gas at the track or something, I'll still be under 70psi.



I like the fact that it reduces pressure under vaccum too so even if i set it to 50 psi, the injectors will only see approx 43psi during normal driving.



Any more ideas?

j9fd3s

in leu of having no concrete numbers, i was gonna say not to go crazy. um where are you expecting the gains to show? cruise? wot? both?

mazdadrifter

I don't want the injectors to see too much pressure for normal driving, but I want the best atomization when I'm really trying to make power.



I'm using 4 - 720cc secondaries.



I'm not sure exactley what you mean by concrete numbers I was hopeing someone would know what kind of pressure you want to be at for best atomization.



The rising rate fpr is a cool idea, and since I've overdone my fuel system I'm trying to find ways to use it to my advantage.



I figure If i can make some power using little tips and tricks like that, then that's less boost I have to run to be at the power output I'm looking for, which will keep my motor bangin longer. like viagra, but not

j9fd3s

by concrete numbers i mean, i cant say 'bump it up to xx and it will magically be perfect'



personally id think you'd see the gains at cruise, because at wot stuff happens so fast it sorta doesnt matter

mazdaspeed7

Higher pressure also makes the injectors flow more fuel. You can find out how much with a simple formula. Take the square root of (new psi^2)/(old psi^2) and multiply is by the injector flow rating at the old psi. Injectors are rated by their flow at standard pressure or 43.5 psi.



720 cc injectors at 50 psi fuel pressure(65 psi-15 psi boost) will flow 827.5 cc/min.