Hi im looking for an external fuel pump to put in my hot rod that im building and i was wondering if anyone had any suggestions for a good pump. I was told about an old diaphragm style electric fuel pump that some people called a thumper fuel pump from delco but no one seems to have heard anything about them that i ask. Has anyone heard of this kind of fuel pump?
Hi, the external pumps that are out there come in three types. 1. Cheap pile of crap that is noisy. (Ebay looks like Holley or Mr. Gasket) 2. Not so cheap pile of crap that is noisy. (Holley or Mr. Gasket) 3. Expensive. But really, you give us more to go on as far as pump performance. What kind of fuel delivery system? Carburetor or Fuel Injection? How much Horsepower do you plan to make, now and the future? K Sent from my iPad using Tapatalk
Need more information. What carb, 6 or 12 volt ect? The Holley red pump would meet almost any street car needs but you will need a regulator for carbs needing less than it's discharge pressure. Using a pump with too much pressure will flood the carb and be a fire hazard.
Running a regular mechanical? I was talking to my motor guy and he was saying that its possible that it won't deliver enough fuel cause the the motor is a build up 350
Those are also called a pulse pump. A delco would have been a good pump 20 years ago I can't say about now. Actually of all the crappy Lucas electrical components their pumps were a pretty good product too. of course this has nothing to do with the thread. Most of us use a positive pump these days, they are noisey as hell but they work. For a mild or stock motor if you go this route the Holley red pump works real well. I use a blue pump most of the time myself, it is their intermediate pump. But for a disclaimer I also carry a 50 year old airtex pulse pump for backup. OK no help for ya. Sorry I just wanted to make myself sound intelligent, which is an illusion at best. How built up is your 350? The reason I ask is that the 355 that we run in the roadster makes about 400 give or take and we have run it on a carter high performance mechanical ( 120 gph) and it ran just fine. Fuel line size has a lot to do with pump performance.
I usually set one up but with the red and the blue holley says it is not necessary. I run one anyway because it is just easier on the pump. A quick bit if useless information while I am at it, I always try and run my return line the same size as my supply. I used to think it didn't matter but I was chatting with a Mallory tech (I like Mallory regulators better then Holley) and he said that you will receive a more accurate and consistent fuel pressure if the lines are sized the same. mallory makes a real sweet regulator that uses a vacuum line from the carb to adjust fuel pressure according to need, you set your initial @ whatever the carb recommends, I run my Holleys @ 6-6.5 then off idle the regulator will actually supply more fuel. It is a crap shoot, a mechanical doesn't make so much parasitic drag that you will notice it, its not like turning the AC on in a '64 Galaxie. it may make the difference between winning and loosing at a pro stock level where thousandths of a second count. What I started to say is that actually an electric makes drag as well only more indirect, if your alternator has to make electricity to run it than it is making drag. On a dragster that doesn't run a charging system this becomes a moot point of course.
Yah, I ran a stock pump on my Z28 302 in my race cars and winged them as hard as possible on 1/4 1/2 and 1 mile tracks with an 800 holley and never starved for fuel. If you think they rob some power they do, but what do you think your alternator does with extra electrical load? Gary
They ran fine with the mechanical pump from the factory didn't they. I know that the '69 I had in my '64 Chevelle was more then enough for that car.
I prefer stock type mechanical pumps for SBC's usually but a little searching at the parts store and you will find numerous inline electric pumps like this one (this one happens to be for 6V but there are numerous models like it in 12V and various pressures and flow rates) http://www.summitracing.com/parts/atx-e8011
only reason I would run a electric with a hungry motor is more of the gas issue of vapor locking , not supply , but thats for us who have to have the spiked fuel ( ethanol ) a holley red should work good for your app so will the carter eqivelent , the old pulsers other than the small facets ( very low flow and pressure ) do they still make a big one anymore ?? I haven't seen one since Giant auto was in business .. as for return line , for a better regulator control its one 1/8 larger return than feed so there is no restriction on the return . a street car can do with a equal size , but might cause creeping problems at the regulator when low usage occurs .
A 3/8 line can support 600HP with a sufficient GPH fuel pump. Theoretically, a big enough pump with 3/8 line could support 1000HP. https://www.lmengines.com/fuel-line-calculators/ Holley RED electric pump is rated at 97gph with a preset pressure of 7psi. Good for stock to mild engines. A regulator is not required when used as a stand alone unit. Holley BLUE electric pump is rated at 110gph with preset pressure of 14psi. Good for performance (Street/strip) use. It requires a regulator per carburetor. If using an electric pump you will require a low pressure unit mounted near the tank. The typical output pressure of a mechanical fuel pump is only 4psi to 10psi, not a lot of pressure is actually required to supply a carburetor with fuel! If using a electric fuel pump you will require an oil pressure safety switch (5psi) that shuts the engine down when oil pressure is lost, a common sense safety issue. You still need to run a fuel filter before the electric pump to keep any contamination from entering the pump and causing damage. A typical mechanical fuel pump siphons fuel from the tank and pushes it towards the carburetor. If using an electric pump you will be pushing fuel towards the mechanical fuel pump; it will not be drawing fuel, hence the requirement for a low pressure pump. I'm no expert however I'd use a regulator prior to the mechanical pump if going the Holley Red route.
Mechanical pump takes a tiny amount of power to run, like 1/100 HP or less. Electric pump takes more. Stock pump should be fine for the street, no matter how powerful your motor. If you want extra capacity over stock you can get a Holley fuel pump.
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