six40

Hello all, I have a few questions about the fuel system upgrade path on this platform as it's different than the DSM's I'm used to. Right now I am maxed out of my current setup and would like to upgrade (again). Currently my fuel system consists of a single Walbro 255 in tank with the MAP install kit, and FIC 1000cc injectors up front. Stock rail, stock lines, stock regulator, stock fuel pump relay.


My question is: At what point will I need an AFPR? I am assuming if I was to do a Walbro 450, an AFPR will be a must. And there's some confusion in my mind regarding the fuel pump relay. Is there a time where it would be beneficial for me to remove this? So it's no longer flipping between 9 & 14 volts, so it's running full voltage at all times? Also, what is the base fuel pressure on the Evo X? What point do the fuel lines and rail become a restriction?

STM Tuned

iTrader: (4)

If you wanted to run the pump on high voltage all the time you would want to run a rewire kit, simply removing the relay will just leave the car in low power which you dont want to do.

If you run a 450 on high voltage you will need a return kit with an AFPR, without it you will over run the stock regulator and your pressure at idle will be way to high. There isnt really a specific number where you need to run an AFPR it is more based on what what components you are running.

For example with a double pumper like the Buschur kit, that leaves one pump on low at idle, then the pump kicks to high mode and once there is enough boost pressure the second pump kicks on full blast. With that setup you can make over 600hp but dont need to have a regulator kit.

RazorLab

iTrader: (8)

You really want to rewire if you use a Wally 450. They are power hungry.

You will also want to run some time of fuel pump controller or hobbs switch so you do not run the pump at full voltage at idle and cruise. If you do, it will over run the FPR and create a ton of pressure in the return.

The OEM FPR, OEM Fuel Rail and OEM fuel lines are good for at least 600whp+.

My current setup:
OEM FPR
OEM Fuel Rail
OEM fuel lines
ID 1700cc injectors
Radium fuel pump hanger (Walbro 255 fuel pump)
Radium surge tank (Walbro 450 fuel pump)
Torqbyte fuel pump controller (0-5v MAP reference)
Custom inline SS fuel filter

This is enough for 640whp DJ and 570whp MD on E82 fuel with the ID1700's at 82% peak injector duty.

I am just now running out of fuel pump at 8,000 RPM+ as my fuel pressure starts to drop off about 5psi from 8k to 9k.

six40

That is some good information. Thank you to both for the replies. Good to know some of the stock components will last. I wasn't aware of the Buschur double pumper, or a controller for the 450 but it makes sense.


I need my fuel system to supply enough fuel to max out the stock block. E85 is not an option without really going into another country to get, so I am stuck with pump 94 and ideally would like a rage gas tune to get to that limit... "safely".


Would that be the best way to go for me?

RazorLab

iTrader: (8)

What turbo are you planning on?

Things get MUCH more simple if you aren't going to run E85. Might just be able to use an Aeromotive 340lph in your OEM pump assembly.

theblackbeast11

iTrader: (1)

If you put a walbro 450 just use a hard wire relay kit done deal.
Get a fpr but get a good one. I have seen same set up with a aem fpr work amazing no problems others fuel pressure stays kinda high.
I ran aem fpr not a huge fan of them and a walbro 450 hardwired to a relay kit and i made 505 on e85 with 1100cc injectors and then made 550 on 2150cc injectors.
As far as injectors go it depends on your end goal.

But as far as your end goal gear the hole fuel system to this. An make sure you get the high pressure 450 just to be safe.

Base everything off your end goals

six40

I thought E85 was simple, just get everything big and call it a day :P JK lol


The turbo is already on the car. It's a JB FP Black with a ported hotside, AFI tubular manifold and a 3" downpipe with the wastegate dumped atmospherically, catless 3" exhaust. 3.5" intake, UICP, 4" intercooler consist of some of the other mods. Car made about 470/345 on the current setup, stock longblock and pump 94 on a safe tune. Looking to do cams, upgrade the fuel system and push it a little further on the stock bottom end.


I'm a fan of the Fuelab AFPR if I go that route, never had an AEM one. But Bryan mentioned a 340LPH pump, would that suffice with 1000cc injectors? Would that just by itself overrun the stock FPR?

theblackbeast11

iTrader: (1)

Just do the high pressure 450 or you could do a asnu pump its around a 320 range or i have heard of a new pump out called the dw400 have not heard anything about it other then its suppose to be better then a walbro 450 but it cost more haha

six40

I will look into an Aeromotive 340 if not I will just do the Walbro 450, rewired with an AFPR if needed. Should be enough to max out the stock shortblock. Don't plan to go past that