Staged fuel pumps

[Norbie]

Has anyone done this? Two fuel pumps in parallel, with the second one only coming online at high engine load. I'm considering this option because a single pump won't be enough for my needs (unless I buy some mega $$$ monster) but a pair of pumps will be ridiculous overkill 99% of the time.

Any thoughts/opinions?

[MS-75]

I can't see why it won't work dude.

You'll just need to make sure the second pump has a good one-way valve so it doesn't just vent the line pressure.

044's have an external check-valve, wereas it's internal in a lot of other pumps. You'll just need to test the check function of any second pump and add a check-valve if required.

Will you be using an ECU output to switch the second pump? (sounds like a good idea actually)

[Norbie]

Yeah I'll use an ECU output (assuming the E6K has something suitable, have to check) otherwise a Hobbs switch set at say 5psi?

[brett_celicacoupe]

how about running them both in series and then switch to parallel when load = X?

would require maybe 2 DPDT relays

provided they actually work on 6V


might actually keep them a bit quiet too

[brett_celicacoupe]

planning on using a fuel reg about this big?

[Norbie]

I've already ordered a Sard fuel rail and "racing" fuel regulator so yeah hopefully that will be up to the task.

Trawling eBay now for good deals on external Walbro pumps. Damn my car is going to be loud with 3x Walbros buzzing away!

[brett_celicacoupe]

[MWP]

What the...

ECU off = fp2 and fp1 running in series.
ECU on = fp1 running at 12V, fp2 running at 12v but in reverse polarity??

[30psi 4agte]

Had this prob a little while back too. I run both of my pumps at the same time though without any issues.

I have wired them seperate too with two fused relays. The positive thing about this setup is ..........Should one pump fail you can just pull the fuse from the relay and drive home still.

[30psi 4agte]

planning on using a fuel reg about this big?

My malpassi copes no prob... Its the return system that needs to be upto scratch

[brett_celicacoupe]

What the...

ECU off = fp2 and fp1 running in series.
ECU on = fp1 running at 12V, fp2 running at 12v but in reverse polarity??

yep, im on crack

all fixed now

[SillyCarS]

I've already ordered a Sard fuel rail and "racing" fuel regulator so yeah hopefully that will be up to the task.

Trawling eBay now for good deals on external Walbro pumps. Damn my car is going to be loud with 3x Walbros buzzing away!

be very careful with walbro'son the net there are many fakes

forunately there arn't any fake 044's or 040's getting around yet and they are a very good pump too

[MWP]

yep, im on crack
all fixed now

Yup, better
Thats a good way of doing it.

[Devils]

be very careful with walbro'son the net there are many fakes

forunately there arn't any fake 044's or 040's getting around yet and they are a very good pump too

Actually a few months ago (i was a manager at a performance shop in Perth), we had to stop sale of our Bosch 040s and 044s due to there being a lot of fakes been brought into the country.

There was an outbreak on eBay not so long ago (last year) but there was luckily a way to tell the difference between genuine and fake thanks to the serial id's and some stamping.
The more recent ones appeared to be exact copies in the sense that the average person buying online wasn't able to tell from pics, the difference being internal. The copy pumps were failing in just a few months of being installed!

brett_celicacoupe's way of hooking them up is probably the best way for performance, but 30psi 4agte's is a very 'safe' way to hook them up and still get the same performance!

[Kyosho]

Just run them both wired in parallel all the time.

BUT, run some appropriately sized resistors that you can switch in and out of being in series with each pump.

If you want a picture, ask me...
Basically, it's to kill the voltage down a touch to the fuel pump, slows them down in pumping.

The skyline guys are having issues around town with just a SINGLE Bosch 044 when idling around, to the point that they're starting to boil the fuel in the fuel tank, and are REQUIRING, either a cooling system on the return line, OR, having to slow the 044s pump speed down...