Fuel systems for FI motors

[neildrake]

Greetings

My last car had an injected R1 motor and I chose to use a Mallory 4060 pump and it worked great with the exception of the one time with low fuel level and hard braking the car would stall. The setup had no external feed tank just the FI pump extenal to the fuel cell.

Do most people run a scavenge fuel pump to another small tank to avoid having the fuel pickup uncoverered during hard braking or cornering?

I've thought of using my return from my pressure regulator to fill a small tank with a feed to the pump and another return to fuel cell with a one-way valve.

For my new project I'm using the same Mallory 4060 and will first try without an external tank but what has worked well (or poorly) on your projects?

The Mallory has a third "purge" line coming off the pump but obviously it doesn't purge air sucked from the tank.

Thanks
Neil

[RussMcB]

My opinion: Yes, you will want an auxilary tank that will always have fuel in it (up to the point of your car being completely empty).

The best design I've seen has a low pressure pump from the fuel cell to the aux tank. That pump needs to flow at a volume greater than the engine needs.

Your FI high pressure pump will get it's feed from the bottom of the aux tank. If the aux tank has a cone shaped bottom, that's better.

The top of the aux tank needs an overflow hose routed back to the car's fuel cell. If your FI system has a return line, route it to the aux tank.

The aux tank is not under pressure. Any excess fuel pumped into it will simply be pushed back into the car's fuel cell.

I think if you do not have a set up like this then your engine may occasionally get air instead of fuel, which could cause lean conditions and problems.

[Stan Clayton]

Use of a "header tank" external to the main fuel cell may violate the GCR's fuel cell requirements, so I urge caution with this approach. Our Ralt has a header tank contained within the main fuel cell which otherwise accomplishes the aims laid out in Russ' post, and the engine runs flawlessly until there is less than a cup of fuel in the cell.

Stan

[formulasuper]

According to the sports racer forum there are currently some XSRs (Ds & maybe Cs) running with external cannisters.

[neildrake]

I suppose an appropriately sized/shaped "fuel filter" with feed and overflow ports might be an approach to any rules stipulation.
Thoughts?

Neil

[Dave Gomberg]

I run my DSR with a Kawi ZX-10R using just an external Bosch fuel pump. It seems to work just fine without a "lift" pump or make-up tank.

Dave