another source of confusion:race fuel system

[jenavet]

since everyone was so good at helping me understand horsepower vs torque...i have another question that has always confused me.......most cars have aprox a 5/16 fuel line from the tank to the engine...and i understand that pressure will vary at the carb or injectors,depending on the type of system/car you have...my race car is carburated and i just installed an expensive barry grant fuel system this week...they have me run #12 line from the tank to the pump /filter assembly...if you are familiar with the braided line system...that is absolutely HUGE!! then on the filter side to the regulator at the engine,they had me run #10 line....which is also very large line....then on the other side of the regulator they have me run #6 line from the regulator to both sides of the carb,which is like 5/16 or even a bit smaller......this is why i get confused......i understand in any fuel system you need both volume and pressure...you can only have so much pressure though or you will flood the needle and seat or injectors,thats why cars have a fuel pressure regulator...in my case this is about 7psi down the track...but as far as volume goes...no matter how big a pump and no matter how many gph it can crank out...your carb can only consume so much fuel...correct???.....so i guess my question is...if volume is so important...why do they have me go from huge line out of the tank...to medium line up to the front...then little tiny line to the carb??? doesent this defeat the purpose of the big lines in the back of the car?? and on top of that...only so much fuel can squeeze through the regulator correct?then, even if you could get a large amount of fuel to the carb inlet...the carb can only intake what it can utilize...right??.....maybe i am just confusing myself!!!

 

[Ken]

... #12 line from the tank to the pump /filter assembly ... the filter side to the regulator at the engine,they had me run #10 line ... #6 line from the regulator to both sides of the carb

... maybe i am just confusing myself!!!

Makes sense to me Jen. The pump needs a large line to ensure it has suction, the pump also needs a sufficiently-sized line to feed the regulator, and the #6 line is just about right for the carb inlets. Volume is thus guaranteed, and pressure of course is adjusted by you; so the carb, or rather, the engine, gets just what it needs.

Geez, I'm not making any sense now am I? :eyerole

 

[redc4corvette]

I know the laws of physics are hard to understand but to put it simple,when "G" force
is exerted on accerlation the fuel will try to return to the tank and you will also experience what is like "0" gravity and the fuel will have to catch up with the demand.
The more fuel in the lines the less bogg you will have off the line.You may also have to run a slosh tube from one fuel bowl to the other to keep fuel from spilling into the carb.