Where to mount an external fuel pump?

[importracr317]

All -

I bought a FF 2G fuel cell, bolted it up and decided I needed to run all new fuel lines. Then things went a little nuts... -6AN fuel lines, new rail and while I was laying it all out, I also decided I wanted to only run an external fuel pump, for ease of use, I guess. I'm not pushing a ton of HP, nor do I intend to, so I thought an in-tank and an external pump would be overkill. So I bought an in-line Walbro 255lph pump.

My question is, where should/can I mount the external pump? Does it have to be higher or lower than the pickup? Right now I have it mounted to the underside of the car, directly where the rear passenger side footwell is. It makes me nervous having it mounted so low to the ground, so I was thinking of moving it to where the spare tire well it - I removed mine and replaced it with sheet metal, so I have a lot of mounting space, but that location would be higher than the fuel pickup on the FF cell.

Thoughts? Or is it good underneath the car as is? Off the top of their head, does anyone know if the "under car" mounting will pass a tech inspection?

EDIT: NM... can't upload a picture right now for some reason...

Thanks for the help.

 

[dsmcurse]

if it were me personally id put a stock dsm fuel pump in the tank, then mount the high flow in-line pump in your engine bay, AFTER your fuel filter. The pump wouldnt work from a dead stop, it'd be working off a head start given from the stocker in the tank. this is called "compound" fuel pump, the 255 would deliver a true 255lph to the engine. super easy to do and very effective

 

[importracr317]

if it were me personally id put a stock dsm fuel pump in the tank, then mount the high flow in-line pump in your engine bay, AFTER your fuel filter. The pump wouldnt work from a dead stop, it'd be working off a head start given from the stocker in the tank. this is called "compound" fuel pump, the 255 would deliver a true 255lph to the engine. super easy to do and very effective

Thanks, thought about that when I bought the cell and had to decide on a sending unit... I went with an autometer unit which doesn't have a hanger for the OEM pump. At this point, I'm trying to run with what I have or modify the hanger to accept and in-tank pump.

I suppose I could leave it, but having it mounted so low to the ground makes me nervous... one large speed bump and bang! ... dead car (or exploding car ) ...

 

[LandSpeed-DSM]

I've had them mounted under the car, tucked into a safe recess, as well as in the engine bay.

Bosch 044 mounted under the car, plumbed "in-series" with a 190lph(?) Walbro in the tank

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Magnafuel 4303 mounted on the passenger shock tower, drawing from my surge tank in the passenger front fenderwell.

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[importracr317]

Thx Landspeed. I guess my answer is it doesn't matter where the external pump is mounted as long as it's in a "safe" location.

That said, I guess most people only ever run external pumps in series... doesn't seem like many people only run externals. Hmmm....

 

[dsmcurse]

compound 'em buddy

 

[LandSpeed-DSM]

Thx Landspeed. I guess my answer is it doesn't matter where the external pump is mounted as long as it's in a "safe" location.

That said, I guess most people only ever run external pumps in series... doesn't seem like many people only run externals. Hmmm....

I'm setup now so I can drain the main tank, cap the line and the feed to the surge and run just my 4303 off the 3 gallon surge tank.

There are plenty of folks running just an external or two externals off a sumped tank. Some will delete the in-tank pump and just plumb a pick-up tube through the stock hanger.

Some externals are not rated to prime themselves and need to be mounted low.

Running in-series does help keep flow up at higher combined fuel pressures. Some pumps have high pressure by-passes though so depending on your systems needs it may not be needed.

 

[PieEyedPiper]

Say a guy ran an OEM in-tank and simply added an external like you guys are mentioning, series/compound, what happens if the old stocker dies? Would you know it immediately or would it only exhibit itself under high load?

 

[importracr317]

I'm setup now so I can drain the main tank, cap the line and the feed to the surge and run just my 4303 off the 3 gallon surge tank.

There are plenty of folks running just an external or two externals off a sumped tank. Some will delete the in-tank pump and just plumb a pick-up tube through the stock hanger.

Some externals are not rated to prime themselves and need to be mounted low.

Running in-series does help keep flow up at higher combined fuel pressures. Some pumps have high pressure by-passes though so depending on your systems needs it may not be needed.

You answered my question - and I think I'll call Walbro directly and ask if their 255 in-line primes itself. If so, I'm going to move it up to the old spare tire well - better safe than sorry. If not, I may have to buy a different pump that works in my intended mounting location. Thank you all.

 

[T is for TURBO]

if it were me personally id put a stock dsm fuel pump in the tank, then mount the high flow in-line pump in your engine bay, AFTER your fuel filter.

Wouldn't you want to keep it pre-filter? That way if your external pump ever decided to grenade, you won't get shit in your injectors.

 

[3kgt2nv]

mine is right on the side of the tank

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nice and safe out of the way of anything that moves

 

[dsmcurse]

Wouldn't you want to keep it pre-filter? That way if your external pump ever decided to grenade, you won't get shit in your injectors.

How many fuels pumps have you seen "grenade"? If they fail, %99.9 of the time they just quit working when they die. I've never seen, nor even heard of a fuel pump exploding or imploding so I don't know...?

 

[LandSpeed-DSM]

I have my setup like this:

Stock Main Fuel Tank -> Fuel Pump Sock -> Walbro GSS342 -> 8AN Filter and Line -> 3 Gallon Surge Tank

Then:

3 Gallon Surge Tank -> MagnaFuel 4303 -> 10AN Filter and Line -> Rail -> 6AN Line -> Aeromotive AFPR and Gauge -> 6AN Line -> Surge Tank

The Surge Tank has an overflow line using the stock return hardline back to the main tank.

This lets me carry ~18 gallons for extended street driving, or 3 Gallons at the track for keeping weight on the front axle

 

[dsmcurse]

I have my setup like this:

Stock Main Fuel Tank -> Fuel Pump Sock -> Walbro GSS342 -> 8AN Filter and Line -> 3 Gallon Surge Tank

Then:

3 Gallon Surge Tank -> MagnaFuel 4303 -> 10AN Filter and Line -> Rail -> 6AN Line -> Aeromotive AFPR and Gauge -> 6AN Line -> Surge Tank

The Surge Tank has an overflow line using the stock return hardline back to the main tank.

This lets me carry ~18 gallons for extended street driving, or 3 Gallons at the track for keeping weight on the front axle

very clever. i like

mine is a stock mitsu fuel tank with a high flow 255 in-tank, pushes through a custom short route 3/8"s fuel hose (not the factory lil piss tube) goes through a nice fuel filter thats mounted on the fire wall, then i have a in-line 255 thats mounted about 10"s away from the fuel rail. this set-up has been working awesome for me.
i also have a fuel pressure gauge mounted ontop of the filter BEFOR the in-line pump, then another fuel pressure gauge mounted on the fuel rail AFTER the in-line pump.

at 42psi at the rail, i see about 8-10psi at the filter. i know my in-tank is SUPPLYING to my in-line.

i REALLY like landspeeds set-up

 

[importracr317]

mine is right on the side of the tank

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nice and safe out of the way of anything that moves

If I had access to a tig, I'd add a panel just like this to mount the pump. THanks for the help guys.

 

[dsmcurse]

That is a sweet set up for sure