I don't understand why people are re-doing Evo fuel pump wiring. I would keep the stock wire routing scheme and upgrade the wire gauge if you want to run more voltage.

The stock wiring is setup to keep fuel pressure manageable at idle.

 

Im on a Walbro 400 with e85 and rewire. I ran into issues with it over running my stock fuel pressure regulator. Just gave me a reason to buy a STM Return kit which is a very nice/clean setup!

No problems now.

 

The E85 version has a longer overall length than the standard 400.Has anyone installedd the Walbro E85 Combatible fuel pump in an EVO VIII fuel pump hanger?

 

running with walbro 400lph on fp red with rc 1000 injectors with stock wire with no issues

 

stock fpr btw, but the pump by my self, if you interesting pm me for pics

 

I run the 450lph pump on my 9mr... Took some modifying beyond what the 400 requires... But whatever. I actually had to dent the bottom of the tank cause i clipped the pump outlet as short as it can go and it was still to tall...

As for the 400s the are far from e85 compatible and when the fail, not if but when, i pray you guys arent at 36psi like i was. Ethanol is a positively charged ion that happens to happily react with negative carbon ions... Which happen to be the ground terminals for the motor inside the pump. First pump died at idle and i thought it just went bad. Took 3 months. The second was during tuning and it last 9 days. Thats when i researched the chemistry. Luckily the detonation only scarred the cylinder wall a tad and the piston ring handled it after a few days. Anyway. The 450 is worth the safety. Oh im not sure yet if its the pressure of the pump or the age of the grommet but my pump to hanger grommet tore after getting on the car a couple days straight.

 

So you cut the piece that the rubber grommet goes on as short as you could and the assembly still hit the bottom of the gas tank?

 

I cut it down to where the tip was just long enough to fully seat in the grommet. I didnt wanna have a sealing issue. And when mounted in the hanger and the hanger in the tank there was about 1/8-1/4 inch gap at the seal. So i dented the bottom of the tank where the pump itself sits... Only about a 1" circle area in the bottom. That allowed enough room for it to fully seat the hanger and i was done.
Maybe im a scardy cat... But i dont suggest using tools that can spark when doing this. I wrapped a brass punch in a shop towel and used a rubber mallet. Sparks and ethanol dont agree with each other when outside of a combustion chamber...

 

An aftermarket rail and FPR make no difference, because the problem is the return system itself, and more specifically, the tiny plastic 'T'-shaped orifice at the fuel pump assembly that causes the restriction and resulting uncontrollable pressure increase.

The factory wiring is inadequate for a single pump, much less two. When the pump is under load, voltage will drop. Getting full rated flow out of any aftermarket pump in an EVO requires upgraded power and ground wiring. Only then will a steady 14.3-14.5V be maintained at the pump under load. Pump performance drops significantly with a decrease of even 1.0V.

A simple fix for the return line issue is both easy and free, which allows one to have his 'cake' and eat it too:
https://www.evolutionm.net/forums/ev...ould-know.html



FYI

 

have you compared side-by-side? if yes, any photos or measurements?

 

yes see pictures

 

Thanks. Looks like all the extra length is in the outlet nozzle, and if I measure from inlet nozzle to the base of the outlet nozzle, I get the same length for both pumps. Did you happen to measure that length on both pumps?

 

Yes that dimension on both pumps is actually 3.94". I'm going to post a bunch more dimesions in a few minutes.

 

Many more dimensions here:

https://www.evolutionm.net/forums/ev...fuel-pump.html

 

so after seeing a few articles on custom double pumper setups. I've decided to figure out how to modify the pump hanger to accommodate the 450/416lph pump. if anyone can help me find a 90* -6an to barb bulkhead connector that will pass thru the top of the pump hanger i will figure out all the odds and ends to get these installed without back pressure issues of the factory setup and without having to dent the tank.
THE PLAN
with the hanger out i plan to cut it down to the point only the return and saddle feed line are left on the cover along with the sending unit bracket inside. removing the tank "thingy" and all other internals. then drill an appropriate hole to fit the bulkhead connector. i plan to run a -6an line directly to the fuel rail. and use the stock feed line as the return line instead. i have been told its slightly larger in diameter and should allow the proper amount of flow to reduce back pressure. once i find the bulkhead connector i need i should be able to get started and get a write up out to the community. I know the connector exists because i have seen it used on a customer double pumper but the guy who built it hasn't gotten back to me. hopefully all this goes well and i dont end up needing a new pump hanger.