Thread: Electric fuel pump questions?

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Hey everyone, the shop that built my 383 sbc said the mechanical fuel pump was not strong enough for the engine. So they sent me an electric fuel pump regulator etc. never delt with electric fuel pumps. Questions can I still use my stock tank or do I need to modify the tank? Or buy fuel cell. Also what is the best spot too mount these pumps and the best way to wire it up? Any advice would be awsome possibly photos as we'll. thanks guys

If you're running a carb, or multiple carbs my first choice would be to switch to a high volume mechanical pump, like one from Holley or Carter, made for performance engines. Summit sells several - http://www.summitracing.com/search/b...tOrder=Default The mechanical pumps are tried & true, and provided you're not running EFI where you need high pressure, you're not relying on an electric drive that will fail at some point in time.

If you're set on running the electric then you need to follow the manufacturers recommendations for mounting it as close to the tank as possible, and below the tank to the extent possible. These pumps are made to push, and if you make them lift the fuel they will fail much quicker. You can use your existing tank, but it depends on your regulator if you have to have a return line or not. There are two types, one bypasses back to the tank, and the other simply backs the pump up on it's curve and chokes flow. There are different schools of thought on filters. Most instructions that I have seen say to install the provided filter downstream of the pump, but many people believe that having the filter ahead of the pump protects the pump from debris in the tank. This is true, but if that inlet filter plugs, or partly plugs you are going to starve the pump which is equivalent to mounting it above the tank and making it suck fuel - you'll burn up your pump, often in short order. Bottom line, you need a clean tank to run an electric pump. Mechanical pumps are much, much more forgiving, and will just keep on pumping until the diaphragm ruptures.

you can buy mechanical pumps that feed nascar engines how much steam is your engine making . i sumped stock tanks for new fuel pump setups the lowest part of fuel line close to tank leve with sump pickup point is were i allways mounted the pumps i used many of them . many fuel pumps do not self prime and will wear out faster . if street use or race a return or by pass is a good way to go as helps keep the pump from dead heading the pump and keeps fuel pump cool here a photo of my gto with a sump in a stock tank feeds over 750hp just fine but no power adders. the other port is for that.... capped off. on the tank i allway ran a filter first the fuel pump on the gto you can not see it is a line russell have used many marine filters setups but i open up the feed in and out ports to 3/8 npt or bigger

Thanks for the info and pic. Yea motor is Street/strip combo right at 500hp, 850 850 quickfuel carb, aluminum heads etc. I like the modification on your tank where can you go to get that kinda work done not much of awelder.

Originally Posted by 383novass

Thanks for the info and pic. Yea motor is Street/strip combo right at 500hp, 850 850 quickfuel carb, aluminum heads etc. I like the modification on your tank where can you go to get that kinda work done not much of awelder.

i made it i wanted the least fitting so a use male AN steel for port feed bungs . you can buy sump in a kit from moroso . i done many for guys around here by my shop over the years . that was a new tank as the old tank was on it way out . i can do a new tank up for you but cost of shipping would be alot . find a old guy around you that fixed gas tanks an radiators . for your engine build i would run a 3/8 steel or AN 8 would do .you want the least amount of fittings you can use . if you need any fast bends us hi flow fitting no hardware street L try to not use any 90 bend fittings if so look at hi flow many brands to pick from do not use much stock rubber gass/pcv hose. only were you need it to flex .on your build mechanical pump use a 110or 130 gph pumps. i like Carters brand like m6901 or m4891 do not buy some no name cheap chrome junk pump. the tank sump would not be needed . take off the filter screen off the stock sender/pick up and find a 3/8 one. if not the smaller tube on pick up in tank can be open up for a 3/8 tube welded or brazed in the new pickup in your old sender body .you do want to use a light weight fuel pump push rod made from tubing fuel pump rod like comp# 4616. cast iron cam core or #4607 bronze tip for steel core cams. make sure you have the tank vented good . this setup will work good to 500hp ez . if you do weld on your old tank have it boiled out .make sure it is very clean and you can not smell any gas

Pat thanks big time for your help and your time I'll let you know how it goes thanks again. Mark

This is all the fuel pump that any street/strip SBC motor will ever need.....
http://www.summitracing.com/parts/cr...make/chevrolet

Most of you fellows on this board have grown up with EFI, where more pressure makes more horsepower. That is not true with a carburetor. More than about 5 psi will overpower the needle and seat in the bowl and allow the pump to blow raw fuel into the intake manifold, creating a tuning nightmare for you. You do need large lines to provide good volume, but the pressure has to be limited to around 5 psi. Actually, many fellows have found that the Edelbrock Performer series of carburetor works best with a fuel pressure of 4 3/4 lbs. The Edelbrock design was taken from the Carter AFB, so the 4 3/4 lbs works well for those carburetors also. Holleys can generally stand a little more pressure before the needle unloads, but personally, I wouldn't run more than 6 psi on a Holley.......................... MORE PRESSURE WILL NOT MAKE MORE HORSEPOWER. It will only generate a nightmare for you because any tuning you try to do will be offset by the loading up of the intake manifold with raw fuel.

A lesson on how much fuel pump volume (GPH) you actually need......
Most any internal combustion engine will consume fuel at the rate of .5 (1/2) POUNDS of fuel per each horsepower hour at MAXIMUM power.
So, a motor under full power and making 500 hp will consume fuel at the rate of (.5 x 500 = 250 lbs of fuel per hour). Since fuel weighs roughly 6 lbs per gallon, we can divide the pounds of fuel used by 6 to determine the gallons used per hour (250 / 6 = 41.66 gallons per hour at max power). So, theoretically, a fuel pump that flows 42 GPH would supply enough volume of fuel to support 500 hp on a continuous basis. Most street motors will spend 99.9% of their life running between idle and 3000 rpm's, so don't let anyone talk you into more pump than you need. Most of you fellows don't have 500 hp motors and even if you do, how often do you ask the motor to generate 500 hp?

Sometimes us hot rodders are inundated with all the razz-matazz of the latest double-throwdown, cadmium-plated, triple-adjustable whiz-bang whatchamaycallit and buy parts that far exceed the actual requirements of good, sound engineering.

Math will never lie to you. There are no gray areas. I'ts all either black or white. It's either right or it's wrong.

Now, as far as installing electric fuel pumps.....
NEVER bolt an electric fuel pump directly to any metal part of the automobile. Always isolate the pump from the vehicle with rubber isolators or suffer the penalty of droning sheet metal which will make you crazy in short order.
http://www.summitracing.com/parts/wl...FcZZ7AodiXoAUg
Also, use short pieces of non-metallic fuel-rated hose to connect the fuel lines to the pump. Connecting metallic lines directly to the pump will make the aforementioned droning sound that you will not like.

I like to install a fuel filter before and after the pump. Of course, you have to keep an eye on the filters and keep the elements changed on a regular basis to prevent burning up the pump. This type of inline filter wil work well and allows changing the filter element with little mess.....
http://www.ebay.com/itm/High-Perform...-/190924601803


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he did say holley carb thats is what a quick fuel is . i would like to see that list of most guys grew up with EFI??. AFB aluminum four barrel. used them yup they do not like anything over 5psi sink the floats but as your carb id much the same as a holley 6psi is fine with out a by pass if you go to electric pump can get psi creep were the fuel can climb with out a by pass . you can work the math i will say a stock setup with what i listed will work fine with the pump i listed and fuel line size .if you doing all mostly drag racing with good hookup you may want the sump in the tank can a pump like 110/130 you do it one time as you may go more power you want a pump that drives fuel to carb that may not work the best with a small tick ..tick pump. the new holley gerotor pump is very quiet rubber stud isolators for mouning the pump work very good. but do not help with the holley blue pumps much they make alot of sound . rubber isolators harley davson use them i think on the oil tank if you have a dealer in town . can be found with may sizes threw mcmaster carr

Originally Posted by pat mccarthy

Can be found with many sizes through McMaster-Carr

I'm glad you made the reference to McMaster-Carr. Man-oh-man, if they don't have it, you don't need it. And talk about SERVICE!!!!!!!!!!!
I recently ordered a stick of 6mm stainless allthread from them. It was 7:30 PM when I ordered it. Next morning at 11:00, here came the big brown truck with my stick of allthread. UNBELIEVABLE SERVICE.
McMaster-Carr


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Thanks again guys! The car will see some track time but more of a hi performance street machine. Fuel pressure now is at 6.5, engine company sent me all the electric fuel pump parts. Said the pump that's on the motor now causes it too run way too lean?

Originally Posted by 383novass

Thanks again guys! The car will see some track time but more of a hi performance street machine. Fuel pressure now is at 6.5, engine company sent me all the electric fuel pump parts. Said the pump that's on the motor now causes it too run way too lean?

well i posted on how i would do it. two ways that will work fine..... BUT..... i do not see the engine build sheet. as i do build engines and have a engine machine shop i build engines for all kinds of racing .i not going to get between you and your engine builder .i had guys that i told them what to do. and did not...or should of called and never did . guess how much help a pist off engine builder can be when you do not do what they say and things go wrong