I know noone does this, and maybe for good reason. Just throwing it out there.

I've found with 1200-1600cc injectors even on e85 idle/cruise is rough to get diled in for a street car. That being said if I drop my fuel pressure down to 25-35psi (or lower) I can get a much cleaner idel/cruise as I can increase the DC of the injector.

So my idea would be using a fmu to ramp up the pressure faster than our standard 1:1 FPR's.

On the same note back before all these fancy piggy back systems we use to use fuel pressure alone for enrichment and trying to tweak the most power out of a factory fuel pump/system. My pont it most injectors are rated to max pressure of around 100psi. So why not use it? (assuming the pump can keep up)

Unfortunately I see no 2:1 FMU's, fully adjustable FMU's are around $300-400 and would work best. The smallest I found at a reasonable price is a 6:1. Which I'm sure could be altered.

So say we have some e85 and 1600cc injectors. Base fuel pressure was dropped to 25psi for a good idle. @ 3psi you'll be at 43psi. Obviously at any amount of decent boost your regulator would just be closed and you would see max pump fuel pressure. Depending on how hungry your motor is and what the pump can keep up with you may not make it over the max pressure ratings of 100 psi'¦. or maybe you would.

I could see the low idle/cruise pressures causing poor atomization. Even with my 1000's I notice a much cleaner idle around 32psi base pressure. Problem is I need the extra pressure up top for the power I'm making. Some sort of return line shutoff may be cheaper. Does anyone have any experiance with this? Will the walbro chew them selves up with no return at high pressures?

Anyway... just an idea.

 

What injector driver are you using?

 

There was a guy on here with an LSx powered Nova on E85 that did just that. Used a 2:1 FMU (but he did it so his injectors could keep up with the demand, as he was marginal).

 

Subscribing. It would like to see how far I could go with my 42 pound injectors.

Jess

 

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

Don't forget to subtract boost from your max fuel pressure. Also most injectors either hang (won't open) or split around 120 PSI.

 

Using the factory Ecm at the moment, which is HI-Z and using a resistor pack. (93 eclipse turbo). Not sure what the drivers are capable of.

Do you have a link? I'd like to know where to get a 2:1 FMU. -thks!

So this calculator says my 1000cc injectors could roughly put out 1500cc at 100psi.

Problem is fuel pump flow drops like crazy with the pressure increase. So I think some type of surge tank with a low press, high volume woudl have to be used with posible two inline pumps to get the 100psi of pressure.

 

This guy

https://www.theturboforums.com/smf/the-builds-board-hall-of-fame-builds/gigantic-turbo-ls1'ish-motor-custom-kit-and-a-nova/

 

After going over the thread, it looks like this FMU:

http://www.holley.com/512-505.asp

 

That is the reason your idle is poor. Get a low impedance driver.