I just did a 400lph Warlbro and a stainless 8an line before the rail, and was thus wondering if this will create too much fuel pressure for the stock regulator.

At what point does the stock FPR need to be replaced with an aftermarket unit?

Thanks all!

 

Yes you will if you rewire it. If you stay on stock wiring, on my dw300 pump I believe it overran my stock one. I'll double check my logs for you

 

I don't have a problem with my stock FPR. I am running Dual Bosch 044s and steel lines as well. The only time I ever upgrade the FPR is if you are trying to make your 1250cc injectors act like 2150cc injectors and need to bump the base. 9 times out of 10, most people don't need to upgrade their FPR.

Mikey

 

+1

 

I upgraded mine chasing a low fuel issue (ended up being a fuel pump "kinda" going out).

 

I have rewired 255 lph wallbro. do I need to upgrade fpr as well ?

 

No you do not!

 

Mikey,

It has been my experience that when you use a rewired/stock dw301 or bigger fuelpump that it has changed my fuel trims as well as making me make changes to my maf table to "trick" the maf into getting the trims back in line (one way to do it at least). And any deviation from before the pump install is the cause of an overrun fpr? Again, just from what I have seen on dsms and evos. Have you seen this?

Thank you,

Josh

 

I'm guessing you have one of your pumps on a hobbs switch or the like, or are they on all the time? I'm jealous of this setup

 

It really all depends on how the car is setup. Most of the time you don't have to touch the FPR. It is all dependent on voltage 11-15v. I'm not going to sit here and say you don't ever need to change the fpr but I have run 301,400 etc. You just have to control the voltage so you don't overload the fpr/injectors at idle.

Yes, that is why my second pump is on a 11psi hobb switch.

Mikey

 

A rewired 301 most often overruns the OEM FPR... however the fuel pump test Mrfred just did with the 255, 301 and aeromotive pump pretty much negates the need to waste your money on a 301...

 

Stock rail, stock FPR, twin 044s and 2150s-

 

as long as you don't bypass the low to high voltage relay that the evo has you dont need an aftermarket fpr.. the only reason the stock fpr gets overrun when you rewire, is because the car is delivering constant full voltage to the fuel pump and it gets overrun just idling..

this is why you see dual walbro 255's being ran on stock fpr.. its still using the relay and running that single walbro in low voltage mode at idle/cruise.. if you rewire that single walbro you will overrun the stock fpr..

thats why one of the best setups is the double pumper with a hobb switch that activates the 2nd pump via pressure

mr fred just did a big write up on this how it works at: https://www.evolutionm.net/forums/ec...ion-table.html

 

Davids bad bish is on stock FPR also. theres lots of high hp evos on stock fpr.

 

Thanks for all of the info, guys! Makes perfect sense tscomp.

And Mikey, yeah I hear you on that. On the last Mustang I built I ended up making the 22.5lb injectors act like 36lb injectors .