Injector size and fuel pressure

[eclipsegst1990]

Ok, I understand the concept of the following site and calculator: 

http://www.rceng.com/technical.aspx

I just need to know what is the maximum PSI an FIC1150 injector can handle if I set my base higher.  I'm noticing with E85 I'm starting to run out of injector pretty quickly, so I'm going to turn up the base fuel pressure past the 43.5 mark.  Naturally, when I do that the WOT pressure will be much higher too and I was wondering if the injectors can handle the WOT pressure with the 1:1 ratio.  What if I chose 80psi as a base hypothetically?  Idle might need some work. 

I also understand that I will be past the capability of my Walbro 255 real soon as well and that I need to research how high of a BASE I can run before I run out of pump at WOT.  I have the figures somewhere, just gotta find it or crunch the numbers. 

[eclipsegst1990]

The only reason I'm asking this is because I seem to be running out of injector already at the top end.  I'm running 25psi on a E316g and hitting 100% in some areas.  Didn't think I'd be running out of injector yet on straight E85 since others have been relatively fine with 1150 injectors and a 255lph walbro running an E316g. 

Anyway, like I stated above, I was going the raise the base pressure to compensate and allow the injectors to flow more.  How high a fuel pressure can I go on this pump?  Say I raise the base to 60psi, I'm assuming at WOT, the pressure would now be 85psi, right?  Therefore, this 255 walbro would fall on its face at that pressure nonetheless bumping it up to 70psi base. 

Maybe I'm doing something wrong here, I dunno.  Or maybe my pump is already substandard and needs to be replaced since it may not be putting out the pressure necessary for these injectors and boost pressure.  Symptoms of a bad pump -- maybe putting out less pressure/flow than rated?  Might look for a Walbro 400lph kit (if there is a kit) or dual 255lph Walbro drop in kit so I'm good up to 500hp in the future.

Anyway, I lowered the boost at about 22 and upping the timing instead, maybe up to 26* if the car seems to like it...we'll see.  A degree at a time

Any ideas?

[snapc33]

I'm not sure what the spec is on max pressure but as with most injectors they will start spraying in a less efficient manner at high pressures.  I think you will run out of fuel flow from the pump at the higher pressures before you damage an injector. 

As for running out of fuel, if you are truly maxing out the 1150's you should be making pretty good power.  What AFR's (gas scale?) are you tuning the top end at. 

EDIT:  Do you have a fuel pressure gauge?  Have someone keep an eye on it when you make a pull.  This will tell you if your pump is keeping up or not.

[eclipsegst1990]

I was thinking the same thing regarding the fuel pressure gauge.  I have one under the hood, but I'm going to tap that fitting and put one in the car as well.  I'm also kinda confused because I'm making good power, but NOT the power I should be getting when maxing out 1150s.  I'm tuning on a gasoline scale with the AEM stand alone gauge for 11.5:1 AFR.  The car seems to sputter a little around 12:1 which what was recomended by a lot of sites for E85. 

Furthermore, I was thinking of tuning for 11:1 and adding timing to bring me to 11.5:1 for more power.  I don't understand why the injectors are in high duty cycles since my last log was lean at the top end, about 12.8:1 so I had a little knock 5-7 counts there at 100% duty cycle.  Yesterday I did a pull after bumping up the fuel pressure and now my top end is around 10:1 and at the top end I got hella power, but leading up to the top end through the RPM band under boost the car was popping at 10:1 from being too rich. 

I'm thinking my fuel pump isn't putting out the needed flow at the my former base pressure of 43.5psi.  Meaning at WOT at 25psi boost, I would be smacking the fuel pump with 68.5psi where it may also have been fading the flow which is why I've been running lean at the top end and I've been compensating by adding more and more and more fuel whereby taxing the injectors when I think it may be the pump not flowing enough.  I dunno, I guess the answer here is to watch the gauge while making a pull. 

Looking into these:

http://www.maperformance.com/full-blown-1g-dsm-dual-walbro-kit.html

http://www.maperformance.com/deatschwerks-dw300-300lph-high-flow-in-tank-fuel-pump-w-installation-kit-mitsubishi-evo-x-dea-9-301-map-evox-fpik.html

http://www.maperformance.com/walbro-high-pressure-400lph-in-tank-fuel-pump-f90000262.html

^^^^^^^^^  any luck with the above mentioned??

[snapc33]

Get the fuel pressure gauge so you can see whats going on during a pull.  Did you install the Walbro?  E85 will also knock a lot of crap loose in the system so check your filters.  Ive seen pictures of the in-tank filter sock getting pretty gummed up.  Check out the filters before you go throw money at it.