fuel pump s50b32

[backspring]

hi guys ive searched and got more confused.
ive got a s50b32 in my m3, its got a fuel pump in the tank and a external.
i know the b32 uses a 5 bar pump and my stock one isnt up to the task.
i was gonna replace it with a walbro 255 or bosch 040 in tank and remove the external, just leave a filter there.
can i do that or do i need to keep both? should i replace internal pump or external or both
thanks

[UweM3]

Do you have any issues with the pump? or running issues?

I know some guys with M3's running Alpha-N on S14's running with 5bar but can't remember if they used the M3 pump or another.

Keep in mind, it's not the pump which is rated at 5 bar, it's the pressure regulator.
As long as a pump can supply the AMOUNT of fuel required at a certain pressure, it will be fine.

[staley_turbo]

Keep in mind, it's not the pump which is rated at 5 bar, it's the pressure regulator.
As long as a pump can supply the AMOUNT of fuel required at a certain pressure, it will be fine.

Exactly.

But if you do need to upgrade, I have a walbro 255 fitted in tank and it works well and fits fine.

[DanThe]

I would recommend keeping the intank pickup pump and fitting an upgraded external, it would also be a good idea to fit a small swirl pot next to the external pump.

I used a walbro pump in the tank before and had terrible fuel starvation at anything under 1/2 tank of fuel. The original pickup is an important part of the tank/pump design so its best to keep it.

[backspring]

thanks guys it doesn't go as well in the top end of the rev range, just trying to eliminate the 20 year old pump. plus i have future mods im thinking ahead for..
so if i were to change just the external, would this effect the performance of the internal? (would it keep up)
what do you recommend for external walbro? bosch? /(best/easiest fit)
is the swirl pot necessary?

[jaistanley]

An upgraded external and swirl pot is the best bet. The swirl pot will more or less garauntee you wont have fuel starvation during cornering or on a low tank.

Bear in mind though: I used an M3 (M-Coupé to be precise) pump cut off an E36/7 cage and fitted to an E30 one. I then bought a sock filter very similar to the E30 one with a push on brass connector for the pump from FSE. Never had any issue with fuel starvation at all on my S50B32...

HTH

Jai

[RoadHazard]

What external pump do you guys recommend for upgrading the stock one?

[backspring]

i used a walbro 255 intank, bracket needed to be modified a little. (shorten supply line on bracket, cut mounting bracket for old pump off, secure with steel cable ties.) this was because the walbro pump was taller than the original unit.
i removed external pump, replaced with a 12mm to 8mm reducer and a length of fuel line.(new filter)
runs much better i think my old ones were on their way out

[RoadHazard]

Out of curiosity I was looking at E36 M3 fuel pumps on Ebay because some people use these in their conversions. Seems like there are several versions, 1 pipe and 2 pipes. I know the E30 intank has 2 pipes so that's probably what we can use. But can the 1 pipe version be used as well? How does it work?

[backspring]

on the intank pump bracket (e30) one is for a feed to engine and the other is a return. i dont know about the e36 pump/bracket.

[RoadHazard]

Never mind my ignorance. I took apart the feeder unit last Sat and found out the motor itself had only 1 outlet which connected to one of the pipes. The other pipe was the return pipe. So I recon if I am to retrofit the M3 fuel pump, either one would work, as long as it can build enough pressure.

[backspring]

update on walbro.
it didnt generate enough pressure on its own so i had to use the stock inline pump aswell.
need to find a better solution for the pump

[HenryM3]

In answer to your origional question, Yes, you can run with the E36 EVO pump in the tank on a modified E30 cradle out to the standard filter. Mine has been running like that for 8 years and never a problem.