fuel pressure with 60lb hr injectors?

[turbojitsu85]

On E85 what fp is everyone running especially if you have 60lb injectors stock fuel lines and a walbro pump?

 

[jasjamz]

Run what your chip maker suggest. Running a higher base won't really help because the higher the fuel pressure the less the pump can flow after certain point.

 

[turbojitsu85]

I ask because I'm running rich and and at WOT I'm washing out spark. I put the car on a dyno this weekend and somewhere between 88 and 92 mph I loose spark. It's a turbo tweak 5.6 chip and if I remember correctly he recommends setting it at 42psi with line off which it's set at. Now to correct my problem should I turn fuel pressure down or should I adjust it in the chip parameters. I was logging the run with the power logger but didn't save the log file properly all I have is the file of it at idle on the dyno before the run.

 

[jasjamz]

How much boost are you running?
What is the a/f ratio at WOT and the injector duty cycle?
What fuel pump?

 

[turbojitsu85]

20psi of boost with a walbro 340 pump. Not sure of a/f ratio or idc because I didn't save the file but I would guess 100% duty cycle.

 

[turbojitsu85]

Here is the dyno print out sorry for the poor scan if need be I can rescan it and mess with the contrast some.

 

[jasjamz]

I would start by turning the boost to 14-15psi and gather your wideband reading at wide open throttle in 3rd gear and the duty cycle. . I know, I know low boost ain't fun but you need this info to see where you are. I bet you run out of injector before 20 psi keeping the air fuel under 11.5. That would explain the lack of performance.

 

[Hot Air]

I would also check out the fuel pressure under boost. Running E85 will challenge a Walbro since it takes 30% more fuel to duplicate energy in gasoline. As pump volume goes up, the available pressure goes down so BE CAREFUL! Plus most folks increase the boost since E85 has higher octane and better latent heat of vaporization (cools the incoming air charge) so it is "safe" to crank-it-up but fail to realize that higher boost requires higher fuel pressure which just keeps working the pump all the harder! Take the time to read all the E85 Stickies.....there is some good info there!!!
Conrad

 

[strokethis]

Just food for thought. i was always told with a 340 pump you have to use a bigger return line than stock because it can not return the fuel fast enough through the stock line under boost.

 

[Boost231]

Just food for thought. i was always told with a 340 pump you have to use a bigger return line than stock because it can not return the fuel fast enough through the stock line under boost.

not with a 340. Some have issues with the DW but thats only some.

To the OP, what plugs? what plug gap?

 

[turbojitsu85]

Autolite 25's gaped at 30. A buddy has talked me into getting an xfi (like he really had to twist my arm) and to start over with the tune once that's installed.

 

[Chuck Leeper]

^^^^^^????

 

[turbojitsu85]

^^^^^^????

I don't understand. Are you asking why I'm getting an xfi?

 

[jasjamz]

An XFI wont fix your problem. I see you're local. Let me know if I can help you. You have all the equipment to find the problem already.

 

[turbojitsu85]

An XFI wont fix your problem. I see you're local. Let me know if I can help you. You have all the equipment to find the problem already.

I don't think it will fix the problem but it's a lot less things that I'll have try and tune. No more MAF, Translator, ECM, and chip. the thought behind me getting it is to simplify things.

 

[jasjamz]

Well, I can understand your train of thought, however I will look it over with you before you decide to change it for free. I may spot your issue and you can go from there. I'm the one who keeps the other 4 GN's that came later up and running. One is a E85 car.

 

[turbojitsu85]

I appreciate the help but I've already started selling off parts. I'm sure once I get the xfi and get it up and running I'll need some more.