Your highest fuel demand is up top where injectors have the shortest window to spray fuel. So 30 psi+ 43 psi = 73 psi, which is well under the 87 psi.

 

So, calculating the fuel pressure under load is around 79psi (5psi give or take for the fuel line losses). So, the pump sees around 85psi at WOT. The 267 pressure relief valve opens at 87psi so I think you are good for now. But if you decide to build the motor and give it more boost, 267 won't cut it.

Keep in mind that when we monitor the fuel pressure, the sensor is near the fuel rail (either before, or after). The fuel pump in order to send this pressure to the rail, it works at higher pressure. There was an article around the forum which calculated the losses from the pump to the rail. Obviously, the bigger lines help with those losses. I think around 10psi for oem hard lines and 5psi for larger lines? So the losses is another part of the equation and not only base fuel pressure and boost

 

Yea man exactly. I have this issue at the moment that I try to figure out. But because I have another issue with the batt voltage, first of all i have to resolve this and then swap to twin 274's and give it a try. But as I explained, 58psi + 25psi of boost + 5psi(estimate) equals to 88psi which is higher than the wally's 450 pressure relief valve. The problem however is not the wally, but the AEM which opens from 80psi. So, in WOT the fuel pump instead of sending fuel to the rail, it dampens fuel back to the tank.

I also plan to boost it to 33psi and i am certain that i will run to more fuel issues. So twin 274's which have a pressure relief valve at 112psi will hopefully resolve my issue

 

Twin 274 sounds good. The relief valve opening at 87psi on 267 is not good. I didn't check this, when I bought it. My afr was floating running 35psi to 28psi. Maybe the valve was opening/closing or the pump just wasn't able to flow more.

Read Mrfred's writing about 267 and 274 here in post #294:

https://www.evolutionm.net/forums/ev...-8-9-a-20.html

I was thinking the Aem pump as a primary but as mentioned, the relief valve opens at 80psi. At the moment, Deatchwerks 255 pump looks the most economical e85 specs pump for me as a primary. And if I do a double pumper, I will probably install another one. And the specs says, it has 100psi relief valve. And it doesn't run big Amps and flows 190L/80psi.

 

Was never truly answered is it okay to run a 255 as the main pump then have a 450 as the 2nd pump. Thinking maybe the 255 would help with drivability and the 450 would help get all the fuel needed up top.

What the power max on e for two 255?

Does it just make sense to use two 450, i just didn't want to try to drawl to much power out of the system.

Around 600HP

 

A single walbro 525 will make 600whp. Dont overcomplicate it.

 

I second what letsgetthisdone said. I went to a dual 255 setup and wish I would have just went with a single 525 for simplicity.

 

Well i ran out of pump on a 450, So what i was reading i would need to change out the lines to help with flow and move up to a 525. I didn't want to do a double pump but here we are