kalli

some wonderful pictures there :-) and that black thing looks scary alright!

for what it's worth it was getting dark outside so I put a stop to my work, but gave it a quick test just running the pump. way different behaviour. The fule lines jumped and with that pumping a swishing noise and pressure at carb, fuel filters between tank and pump was cleared of any bubble there was.

I might sneak home for lunch and start the car to see that running. Much quiter and much better so far :-]

urban_cowboy

Fake, thanks a bunch for your opinions! I always love talking with people who have used and broken parts so that I know what way to go. My Holley Black is hanging tough, but it sounds like I may switch to a Mallory when something happens. I am currently running a deadhead regulator, most because my BG pump with return crapped out, and I have been fixing other issues with little time to run a return line correctly (greasing squeaky wheels as they say).

One last question on this before I step out. Is there a good formula for determining what gph flow you need for a given engine? I think my Holley is 140gph and the Barry Grant was 220gph. I assume 140 is plenty for my naturally aspirated small block, but just curious to confirm.

Thanks again for the education and information.

Adrenolin

Kalli.. have you installed an inertia cutoff switch for your electric fuel pump? For that matter.. how about the rest of you? I'm adding one under the dash on the passengers side above the kick panel in case of an accident.

Norm Peterson

Yes. You need to know at least what your engine's HP and BSFC are. BSFC is typically 0.5 lb/HP-hr for NA engines, so 300 HP needs ~150 lb/hr. Assuming a (low estimate) gasoline density of a little over 6 lb/gallon, you need 150/6 = 25 gph.

Linky


With respect to the pumps themselves, I've got a Holley 12802 (blue?) that's noisy but pulls enough suction to prime itself and flows enough to keep about 350 HP or a bit more happy. This pump actually feeds an intermediate tank that an EFI pump draws from, and the EFI pump has only had a supply issue twice at autocross when the main tank fuel level was low.


Norm

Gary H

A good read here
http://www.enginebuildermag.com/Arti...l_systems.aspx

urban_cowboy

So gas weights about 6.25lbs/gallon. If .5lbs of gas per hour are needed per horsepower, then a 500hp motor needs 250lbs/hr. That is 38.5gallons/hour of gas for a 500hp motor. Interesting that so many pumps are rated at 140+gallons/hour. So technically a 1000hp motor could still run on a Holley Black or Mallory 140...

Good to know that what I have is sufficient. Thanks for the info. I learned something on this one.

Gary H

Most pumps are rated free flow. Fuel line size, fuel filter and pressure regulator restrictions etc all have a big deal to do with it. Better to much than to little. :-)

kalli

nothing installed yet, but what I'm planning to do in the next weeks is to install an oil-pressure switch. i know there's prefab kits, but the idea is:
only deliver "when ignition is on AND oil pressure is there (engine running)" OR "when key is in start position"
maybe i'll opt for such an option:
only deliver "when ignition is on AND alternator stat has 12V (engine running)" OR "when key is in start position"

i think it's a good idea to have something like this with electrical fuel pumps

kalli

I've officially given up on mounting the pump in front. I fabricated a bracket that sits just forward of the tank. I re-installed the summit (holley) fuel pump in such a way that pertrol would run down into it fro tank. about 1" or 2" drop, no longer than 4" hose. from there the pump pushes the petrol all the way forward. steady 6 psi at carb now. all sorted.