Hi Guys,

So I fitted on of these on the weekend, it replaced a Walbro 400, NON E85 version.

Anyways they arn't really 400 lph, more like 450lph.

When fitted I found my idle fuel pressure jumped 5psi, and I couldn't dial it any lower.

Rather than redrilling the return I began thinking about pump voltages.

Does anyone know (roughly of course) what the lowest voltage a fuel pump will reliably pump at?

I am thinking about putting another 0.55 ohm resistor in series with the current fuel pump resistor.. If my calculations are right then the pump should see about 5-7Volts...

Thoughts?

 

yikes. i have this pump too. sounds like i need to get a fuel pressure gauge ordered TODAY.

what is your return currently drilled to?

 

Interesting! I'm still rocking my standard 400, it's holding up fine.

I'm sure you could get it to run fine at a lower voltage; it's just a turbine and it will just spin slower.

Let's do this.

 

i'm guessing it runs at 12V and jump to ~14V under load by means of fuel relay?

 

i havn't logged my battery volts in a while, but normally its around 13 when the engine is running...

with the resistor, which I think is around 0.65 ohms, that will drop the voltage down to like 8-9 ish...

next time I go down to my local shop I will use their DC supply to test out different voltages, and see what pressures I get... should be interesting... if it can supply the amps...

 

Would the standard 400 still work ok for a high hp E85 application?

 

yep... until it fails

for the $200 odd its not worth ruining 10k worth of motor/turbo

 

Thanks for the info!

 

i'm not good with resistor math but wouldn't the resistor run hot and possibly fail?

what did you use for in-tank fuel hoses for this setup?
i used the white/clear plastic flex hose.... that was a PITA to install on the pump.

 

Yeh, you need to run like a 50w resistor...

 

What happens if the $0.50 resister fails?

 

so drilling the siphon isn't a option or?

I just bought this pump too.

 

actually they are about $8...

you could run 2 in parallel if you wanted a backup.

but remember it only controls low loads, above that the resistors are taken out of the equation as the relay flips over to full voltage...


I am already drilled to 2.5mm, i dont really wanna go bigger...

But if it works, it means I can run 45 psi (to get a good pattern) but at low flow, so it doesn't overrun the return or injectors themselves

 

Is the standard Walbro 400 part number WLB-F90000262 and the E85 version WLB-F90000267 (last 3 digits different)? And the E85 version has a higher flow rate?

 

I think you could run it down to 9v