reddevil

So, I am running a 3-1 rising rate fuel pressure regulator. This worked great for up to 16 or so psi combined with the 550cc injectors. 16 * 3 = 48 psi + 43 = 90ish psi fuel pressure. When you combine this with stock 550 injectors, they come out to be 800 cc equivilents.....

But, when I modified the 550s to be 820s, and raised the boost to 22 psi, my fuel pressure jumped to about 110 psi! This makes the 820cc equivilent to 1300 cc injectors!!!! WAY TO MUCH.

So I pulled ALOT of MAF signal.... This helped but, still ran way way rich.

I didnt want to pull out the rrfpr, just get it to run less.... What to do, what to do....

So I installed the extra Greddy Manual Boost Controller I had in the vacumn/boost line to the rrfpr! Then I was able to simply turn down the boost signal till I got a better fuel rate. Pretty simple cure!

Bone1

find short rope and a tall tree!

drunkinmaster1

or just swollow this

Hitchhikkr

First off, what the ---- are you talkin about?

Im not sure what kind of car/engine your speaking of, but anytime you crank up the fuel pressure to compensate for injector size, ITS NOT A GOOD THING!!!! Not an acceptable method of tuning.

INjector FLOW IS NOT LINEAR TO FUEL PRESSURE@!!!!!

ANything past 75psi on a fuel system not designed for it (street car) is dangerous and down right ignorant. Hince the "get a rope" comment. :1

reddevil

I was using this

http://www.witchhunter.com/injectorcalc1.php4

to do the injector sizing...

And my point was on how to bring the WAY TOO MUCH pressure down to an acceptable level so everything worked together. And its adjustable, a feature that is cool.

Donald125

you need to understand how an RRFMU work at the first place.

Hitchhikkr

I get how you figured those flow rates. Thats not what im talking about.

MY point is that using excessive fuel pressure to make up for the lack of injector flow is a **** poor method to control fuel on your car. I dont care if its a brand new civic or an 87 mustang. Not only are you NOT acheving your "calculated" flow, but you are putting your life and engine in danger by having too much pressure on the fuel system...Fuel leaks DO happen, and cranking up the pressure is a damn good way to achieve that.

Engine fires are not pretty.

Im not trying to run you down, but you must understand ive seen far too many engines scatered across the track because some retard was running a rising rate regulator or FMU and blew the ****** to hell just because he wanted to skip out on buying injectors.

Injectors+tuning=cheap engine insurance AND more power.

Have fun.

reddevil

i have 820 cc injectors, I don't think I am lacking.

And my point is how I am turning down the pressure, not up.

Why the hell do people install fuel pressure regulators anyway if not to adjust their fuel.

AJxr

whats the setup here? pics?

tealcherokee

a FPR and FMU are 2 completly different things

FPR's are 1:1, if fuel pressure is 49 psi, at idle its say 39 psi due to the vacuum
the right way is to put a check valve in, and have it NEVER exceed 49psi, and buy the correct size injectors for your turboed app

FMU's are avail in 2:1 up to 12:1 or more. this means you have your stock 49 psi and depending on your FMU your adding 2-12 more psi of fuel per psi of boost, so 15psi of boost into a 12:1 FMU your now adding an additional 180psi to the 49psi of fuel pressure you started w/. now doesnt 229psi going through rubber hose and your fuel rail and crappy injector o rings sound bad?