Where To Mount An External Fuel Pump?

[cybernck 403 1 Cars]

I may be converting my 205 to use an external fuel pump, so I am wondering where would I mount it?

 

Is there enough space on a RH side of the tank, between the tank and the sill?

 

Or should I move it all the way to somewhere in the engine bay?

 

Any other ideas?

[GilesW 41]

Injection pumps don't pull 'very well' and their efficiency drops dramatically the further away you are from the tank, especially when you add a head to it as well.

That's why oe injection pumps are always in/very close to the tank and Lego or even below the fuel level.

You'll also get drain back unless you use a one way valve.

 

So in short- NO to engine bay, yes to under floor ( weather it fits beside tank I don't know).

[jdt 6]

why an external fuel pump?

Carb conversion?

[cybernck 403 1 Cars]

405 has an external pump and no problems whatsoever. Can't really remember where is it located exactly, but it's somewhere under the car.

 

No, still injection, but a high flow pump.

[welshpug 1,666]

Behind the fuel tank.

[GilesW 41]

405 has an external pump and no problems whatsoever.

 

Many many cars have an external pump, (I didn't say you couldn't).

Behind the fuel tank.

Ie close and at the level of the tank.

 

 

If you really wanted to mount it above the level of the tank and further away then it may well work. But it would run dry every time yiubstopped (injection pumps use fuel as a lube), it would take a few turns (at least) to prime itself at each start, and if you got any fuel starvation whilst driving- ie a long corner - then it would take longer to pick the fuel back up.

[welshpug 1,666]

I was saying where the 405 pump was mounted...

[GilesW 41]

I know Mei.

And I was saying that is normal (and the reasons why).

[Tom Fenton 1,548]

The standard pump in good order will support 250-odd bhp. Fit an equivalant uprated Walbro or similar inside the tank for 500-odd bhp.

Why make things difficult? Just put an upgraded pump in the standard position. Job done.

[Anthony 1,003]

The standard pump in good order will support 250-odd bhp. Fit an equivalant uprated Walbro or similar inside the tank for 500-odd bhp.

Why make things difficult? Just put an upgraded pump in the standard position. Job done.

This - the in-tank pump works, is simple and tidy.

 

The only reason I can see for an external pump is if you've got a swirl pot or similar and hence need both a low-pressure in tank pump (to fill the swirl pot from the main tank) and high-pressure external pump (to fuel the engine from the swirl pot)

[cybernck 403 1 Cars]

The reason for it is that I've already got an external Bosch Motorsport pump that's proven to work fine

with the planned setup and I have also recently purchased a brand new Bosch OE in-tank pump, so I'm not

really hot on idea of purchasing yet another pump. But what can you do, plans change. I supposed I should

sell both then and get an uprated standard-fit one.

 

What about a fuel filter? What kind of a filter would one use with an uprated fueling setup? And can it

be fitted alongside the tank, instead of under the bonnet? Is there some obscure reason not to do it?

[GilesW 41]

You should have an initial filter before the hp pump to stop crap from the tank into the pump, and the a finer one post pump to ensure no crap gets to the injectors.

 

You can get replaceable element filters with push on or jic connectors, but an oe one is actually fine.

[cybernck 403 1 Cars]

I meant with the in-tank setup. Why haven't they fitted the filter under the car instead of above the exhaust manifold.

 

It would have saved C_W's car from engine fire years ago.