Fuel Pump selection - Electric / Mechanical

Hi Andre,

Got a 2JZ powered supra - Want reliability and really hate having to run multiple electric fuel pumps to deliver the power on E85. Thinking of moving to a mechanical system - Weldon 34706 based.

Ben said you have some experience using mechanical pumps. How have your experiences been with them? Would you use one on the road with E85 (4000km a year max so not much)? Anything you would recommend to watch out for?

Would be great if you mentioned it in the upcoming webinar as I guarantee I am not the only one having to consider a 3rd electric pump to keep up and considering other options.

Many Thanks,

Llewellyn

Mechanical pumps traditionally are more often used for drag cars with huge fuel requirements, although depending on where you are with power levels, they aren't unheard of on the street.

Mechanical pumps have a few downsides that need to be considered though. The biggest is that they usually don't produce sufficient pressure at cranking speed and need to be augmented with an electric primer pump to get the engine running. Secondly the fuel flow is a direct relationship to engine speed which in itself isn't necessarily a bad thing, however at high rpm off throttle your FPR will need to bypass large quantities of fuel in order to maintain stable fuel pressure. There are a few FPR manufacturers that make products specifically designed for mechanical pumps. I've used this before with good success - http://www.aeromotiveinc.com/product/belt-drive-pump-efi-regulator/

Lastly I'm not sure how well a mechanical pump would work in a street car with a fuel tank mounted in the rear of the car. In the drag applications I've been involved with we've always used a fuel cell mounted in the engine bay so the mechanical pump would be gravity fed. In a street application you'd still need to run a lift pump, surge tank, and a feed pump to supply fuel forward to the mechanical pump. Essentially I see this configuration adding complexity and cost to your fuel system without really giving you an advantage.

If it was me, I'd retain an electric pump personally. There are some really large electric pumps on the market that will support pretty serious power levels on E85, particularly in twin pump installations.

Very detailed reply!

Thank you!

Imo, this is all you need:

http://www.weldonracing.com/#!store/r0nxr/!/Pumps/c/14136041/offset=0&sort=normal

1 Pump, 1 speed controller, 1 regulator, 2 filters..choose the right inlet / outlet AN-fittings size.

Lifetime warranty on the pump!

I ran a Weldon 2345A coupled with a 16 volt booster on my drag car which supported 1100 whp on methanol. It's a pretty noisy pump though and that needs to be a consideration for a street car.