Put the two pumps in and then get an EFR. I know a guy who might be getting a bigger EFR soon

 

Your setup is awesome, but I could never afford it. I'm sure there will be people busting down doors to buy your setup. Unless I happen upon $5K, I'm gonna have to be happy with my HTA Green.

 

Mr. Fred, please post when you have an idea how the higher base pressure changes your fuel economy. Better off boost torque would have to mean a more efficient burn!

 

I am thinking the same. I definitely got better on my first full tank at higher base pressure. I'll post after I get more concrete numbers.

 

LOL. So I was looking at my latest WOT log today and realized that AFRs were at 10.5-10.8:1 instead of my target 11.5-11.8:1. The higher base pressure if flowing a lot more fuel than realized. When I rescale my injectors properly, I suspect that the Walbro 416 may actually be able to handle 500 whp at 60 psi base pressure. It will likely be right on the edge of what it can handle though.

 

Quick update - I've been through two tanks of E85 now, and it looks like I'm getting about 10% better mileage. Went from 160 miles per tank to 177 miles per tank (usually about 12.3 gallons). Its pretty lame mileage either way. I used to get 200 miles to the tank when I lived in a flat area.

 

Your not thinking your at the limit of the fuel pump already are you?

What's your IDC's at currently?

I'm curious if this will help with getting 2150's to idle better on stock subaru ecu's.

 

After a bit of tinkering, I determined that the pump is at about 85% of the limit. If I richen AFR to below ~10.5:1, pump pressure will start falling off from where it should be.

Higher base pressure pushes more fuel through the injectors, so while spray pattern may improve, more fuel is going to get pushed through for a given pulse width, so an even lower pulse width would be required for idle on the 2150s likely cancelling out any potential benefit. Best solution for the Subie guys (if they have to run hi-Z) will be to wait for FIC and ID to come out with mid-size hi-Z injectors. Both companies are likely only months away from a release.

 

It's ID1300s.

Didn't know fic planned a knock off already?

 

Is the fuel return line an issue when running higher bfp? I was looking at doing either the Wally 450 or a double pumper to satisfy my car (fp black, 35lbs., fuelab afpr) either would be rewired. Won't the stock return line, or even the stock feed line be a problem when more fuel is needed (when the second pump kicks on, higher in the rpm's).

Thank you

 

The stock supply line is definitely an issue for more than 450 whp on E85. Back pressure from the return line can raise the fuel pressure. A larger return line is one way to deal with it. Another way to deal with it is to set full voltage on single pump applications or set the second pump on double pumpers to engage only when needed. This will minimize the return line causing fuel pressure overrun. If you look at some of my Walbro 416 logs (other threads), you'll see that I set full voltage to engage at about 5-6 psi. With the stock FPR, I got virtually no overrun, but with the AEM regulator, I initially get about 4 psi of overrun. This indicates that the overrun issue was due more to the AEM FPR than it was the return line.

 

So a double pumper setup with a Hobbs switch will overrun the fuel return line if it's set at anything higher than stock bfp? I like the idea of 50+bfp but I don't like the idea of replacing lines if I don't have to.

Thank you

 

Its not the base fuel pressure, its just the amount of flow when both pumps kick in. If anything, having higher base pressure will reduce the possibility of overrun because higher pressure against the fuel pump reduces the pump flow rate.

 

I called FIC today and they gave me some info regarding this. They said that their low impedance they reccommend no more than 60psi bfp, and the same goes for their high impedance injectors. He did say that lots of people have been using the high-z injectors up as high as 5 or 6 bar with amazing results, but on paper, they reccommend no more than 60psi base for both. I asked about the "rupture" or "burst" limit, and they said theres no problem with their injectors with this, and they put a limit on the bfp not because of the "rupture" limit, but because any more than 60psi base and the injectors will not operate properly.

Thought I'd add to the thread a little instead of just asking questions like usual lol.