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User fuel pump survey: Mech. v Elec.

Discussion in 'The Hokey Ass Message Board' started by highlander1732, Aug 1, 2010.

  1. highlander1732
    Joined: Nov 26, 2009
    Posts: 9


    Yea though I walk through the valley of the shadow of the electric fuel pump, I am starting to wonder if mechanical ain't so bad? Holley "blue" fuel pump runs hot and shuts down. Getting rather tired of it actually. Trying to feed a 468 BBC with 780 double pumper. Do I really need all the headaches to feed a fairly mild street motor? I'd love to hear some feedback. Am thinking about a hi-po mechanical, nothing more than 80-100 GPH with no need for a regulator. Thoughts? Thanks!
  2. 39 All Ford
    Joined: Sep 15, 2008
    Posts: 1,531

    39 All Ford
    from Benton AR

    If there is room and a carb, mechanical every time IMO.

    Just better, cleaner, and more reliable.

    There are exceptions, I can't find a pump for my LYB that is less than 40 years old, so it has a Carter elec, which imo is second best to a mechanical.
  3. langy
    Joined: Apr 27, 2006
    Posts: 5,735

    Member Emeritus

    I prefer electric, I've used Holley red and blue top, Carter & Mallory, all have been fine.
  4. 61bone
    Joined: Feb 12, 2005
    Posts: 890


    Mechanical, after all this is the trad board. Mechanical will serve for 99% of your fuel needs with proper plumbing. You don't need high capacity, high pressure. If you are maintaining 7-10 psi at the carb, that is all the pump you need. Install a pressure gauge just before the carb to keep track. The 1 1/4" one look cool and will do the job.
    Use a fuel filter at the tank that has at least 1/2"npt fitting and 3/8" id fuel lines so you don't restrict the fuel flow and cause "vapor lock". I don't use a sock on the inlet. I'd rather the crap in the tank went to the filter so I can remove it. If the crap is to big to pass the inlet line, the tank needs to be removed and cleaned anyway.
    Last edited: Aug 1, 2010

  5. I'm leaning twards an electric.

    A few advantages include, add an anti theft switch and it starts better after sitting a while cause the bowls are empty.
  6. highlander1732
    Joined: Nov 26, 2009
    Posts: 9


    Great idea (removing the sock). I'm inclined to drop the tank in either case as it's a stock replacement and thus has a 5/16" bung. Holley recommends a minimum 3/8", so I'm already restricted to the inlet port on the pump...seems like mechanical is the way to go...thanks a lot.
  7. 69fury
    Joined: Feb 24, 2009
    Posts: 1,419


    for a car that really moves out (11.99 or less) i dont like to have a huge column of fuel moving rearward under launch forces while the mechanical makes slurping noises on vapors and the carb runs dry...

    keep in mind that the bigger, higher capacity fuel lines just mean a bigger, heavier column of fuel to try and suck forward right when you need it most...

    for traditional somewhat quickish cars, go mechanical...
    but if its a fast car then its no contest-electrical all the way at the back to push the fuel forward.

    Think about the traditional front mounted moon tanks, and dragster tanks--using launch forces to push the fuel back toward the mill..

    I'm all for traditional, but i'm building a gasser and wont stand for it being a pooch- and when i put the Paxton on, the last thing i want is to lean out under boost...

  8. 29nash
    Joined: Nov 6, 2008
    Posts: 4,544

    from colorado

    Mechanical. Back it up with an electric, run it only if .............(there's a dozen situations)
  9. 61falcon
    Joined: Jan 1, 2009
    Posts: 772


    i vote electric. i have been running an aeromotive inline pump for a couple of years on the falcon and will run an electric pump on whatever i build next. but i wont use holley pumps, to many bad stories about them.
  10. I'm ont the fence-have electric on the 33 and mech on the 40

  11. i use both too , and have the electric on a switch
  12. uglydog56
    Joined: Apr 8, 2008
    Posts: 331


    I used to be a confirmed electric guy, but have slowly been reverting back to mechanical. My truck can't use a mechanical, and it goes through fuel pumps faster than I can buy them it seems like. I'll never buy another holley blue. The noise makes my teeth grind.
  13. olscrounger
    Joined: Feb 23, 2008
    Posts: 3,953


    I use a mechanical on my 40 with an electric backup--use the elec when I start teh car after it has set for a while--works fine so far (4 yrs)
  14. Steves32
    Joined: Aug 28, 2007
    Posts: 1,280

    from So Cal

    Mechanical on the 32
    Ran 2- Mallory 140 electrics w/ pump controller on the 55 (big hp). Shitcanned it all & ran a Victor Jr mechanical & reg.

    I hate electric pumps on the street.
  15. brad chevy
    Joined: Nov 22, 2009
    Posts: 2,627

    brad chevy

    I have always preferred mechanical pump,if you use a electric pump put it back by the tank to push the fuel,not hung on the firewall or fender working its ass off to draw the fuel.,Holley quality has gone downhill on all their products, adjust,adjust,adjust,it never ends and the fuel pumps just don"t last very long.
  16. fridaynitedrags
    Joined: Apr 17, 2009
    Posts: 402


    Use 1/2" line throughout for a street/strip motor. Mount the electric pump and a good quality filter right at the tank/cell, then the supply line to the carb. Run another line from the carb back to the tank with a regulator in this line, set at 5 psi max for a Performer/AFB/Quadrajet, 6 psi max for a Holley carb. The return line will allow circulation of fuel and eliminate the heating of the pump resulting from dead-heading the pump against a regulator in the supply line.

    When putting your creation together or when changing pumps/systems, mount a mechanical 0-15 psi pressure gauge onto the cowl of the car with duct tape, tie wraps, whatever. It's only gonna be on there temporarily. Use a 2-way or 3-way tee at the carb inlet and run a pressure line back to the firewall, up the firewall to the hood lip, then on up to the cowl to hook up with the gauge. The point is to be able to see the actual fuel pressure at the carb inlet with the vehicle in operation. Only then can you adjust the system to work properly for you. Oh, and by the way, I think the max pressure for the early Strombergs was around 2 1/2 to 3 psi.

    Most young folks have been raised on EFI and the fact that if they want to go faster, it will take more fuel pressure. This is not the case with a carburetor. More pressure will simply over-power the needle & seat and blow raw fuel into the intake manifold/head ports, causing you a tuning nightmare.
  17. carbking
    Joined: Dec 20, 2008
    Posts: 2,858


    On a daily driver, either can work well.

    I use electrics on my performance collector vehicles because of the volatility of modern fuel. Pumps are (as per federal law) permanently wired on oil pressure switch; but have a manual override (pushbutton) on the dash. When I go to start the vehicle after allowing it to sit for a week or more, push the pushbutton until the carburetors fill, then start the vehicle and the pump will then energize from the oil pressure switch.

    Takes a lot of stress from the starter, and battery.

    On the one collector vehicle without electric pump, I remove the air cleaner, and prime the carb through the bowl vents. Not nearly so handy. Just no place on this vehicle to mount an electric pump.

  18. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,428

    Von Rigg Fink
    from Garage

    less is more with me when it comes to this choice.

    No wires, No relay, no switch,no fuse, no drain off the battery, not noisy,easy to replace, redily available in the exact size and make for my engines.
    Never have to wonder if it was left on, KISS
  19. I have nothing against mechanical pumps, HOWEVER, I do like to have a spare pump and spare ignition when travelling.
    Those are the most common repair items if something goes wrong on a long trip.

    In the event of any failure, if I want to flip a switch and keep on driving instead of being stranded at the side of the road, the backup pump must be electric no matter what the main pump is.

    A quiet electric pump with the safety shut-offs etc has almost always been the easiest to use, for me at least.

    It is also very easy with an electric pump, to unplug a hose and pump out a gallon or so to rescue a stranded motorist or refill an ATV. Can't do that very easily with a mechanical pump.
  20. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,110


    A lot of mechanical fuel pump failures are due to a ruptured diaphragm, which usually results in some fuel being pumped into the crankcase. If you have this kind of failure, and use an electric pump to back it up, then you are eventually going to have a crankcase full of 2-stroke fuel, which isn't a good thing.
  21. Another good reason to be leery of mechanical pumps. I have had a few dump raw gas into the crankcase oil. It is always undetected until it is past the "very dangerous" point.

    The danger of an electric is the continous running after an accident. ALWAYS ALWAYS use some sort of shut off such as a Ford impact sensor ($5 at a junkyard) that kills the power to the pump after an impact and can be reset by pushing a button.
    PLUS (a good idea but not essential) an oil pressure sending unit that stops the pump from running on and on if the engine stalls when you are away from the car.
    Last edited: Aug 3, 2010
  22. RABrods
    Joined: Dec 12, 2007
    Posts: 20


    Go with a mechanical... I just finished my 65 Nova end of last summer. I was running the BG 220HR pump which is meant for street use. It is one year later and have been through 3 of them. All my routings were correct I used both -10 supply and return lines. First and last had bearing issues, the second issue was undiagnosed by BG. They all run really hot, you need extra wiring...why spend the money?

    Two weeks ago I went back to a Carter high flow (forget the model) with clockable inlet/outlet. It works great! No noticable difference, no starting issues, I even kept the return setup.

    On my coupe with the Cad motor I am definately going with a mechanical.
  23. nutajunka
    Joined: Jan 24, 2007
    Posts: 1,466


    I use mech. I always figured thats good enough for the street. I also think alot of electric failures are due to over heating, thats why most oem stuff is in the tank to keep them cooler. A good mech. pump will supply enough gas for most engines, but alot of mech. pumps these days are made who knows where if you know what I mean?
  24. I have a Carter electric now. Just got a mech. Pump for the Rocket and rebuilding it now. Keepin' it simple and it looks good on the motor. May keep the Carter installed as a backup.
  25. Francisco Plumbero
    Joined: May 6, 2010
    Posts: 2,536

    Francisco Plumbero
    from il.

    I have found that a lot of electric pump failures are from improper wire size, improper ground size, using an inexpensive pump, improper fuel line routing, or pump placement. The pump should be at the rear, below the tank to create a siphon, it should be redundantly grounded, it should have a filter of good quality protecting it, it should have isolation valves to service it, it should have a high quality line of the proper dimension that is correctly attached, it should have a collision cut out switch, a regulator and a gauge. I have seen a lot of pumps mounted in the engine compartment, under the car by the exhaust, tiny tubing, and some god awful cheap pumps are out there.
    An electric pump is a system, if you don't go faster than a 13 quarter on the street and pull less than 400 horses, you most likely do not need to invest in that system. If you are pulling serious ponies or are running a power adder you should look into the system, in most power adder situations it is required, and anything over a 100 shot I would say absolutely no matter how many HP the net total amount is. Keep in mind, system, if you only run half the parts you no longer have a proper system and you will have troubles. The manufacturers are very specific about this, especially pump placement.
    Have fun.
  26. I've never really had any problems with an electric pump, of course I still have a few good years left. But I've run both and if you don't have mega fuel requirements a mechanical will do just fine.

    I have a carter street/race pump that I have been running for awhile. Feed it with a large line (3/8-1/2") and you should live real well with your single carb.
  27. AnimalAin
    Joined: Jul 20, 2002
    Posts: 3,417


    A long time ago (three engines ago), my coupe had an electric pump only. Decision was based on the space around the engine powering the car at the time. It worked pretty well, until it didn't work at all; this caused a couple of episodes generating compressed vocabulary, long-term storytelling potential, and possible bragging rights that I got the damn thing to go again, eventually.

    Currently, I run mechanical pumps on all three vehicles. The coupe has an electric pump as secondary; sometimes helps in the heat of the desert, when the tank is getting low.

    Modern in-tank pumps require some work to adapt to our old cars. Lots of them are designed for high-pressure systems and need a regulator to get the seven psi needed for a carb, but I think they have the potential to be as effective as anything. Just as a rhetorical question, how many miles have you put on your late-model whatever between changing fuel pumps? Not sure that that's enough to make me change the system over, but worth considering.
  28. GothboY
    Joined: Feb 12, 2007
    Posts: 214

    from SoCal

    I tried to go easy on a car and NOT cut a cup into the frame to make room for a mech pump because I was trying to rush the project. Since I got that car on the road I have had nothing but trouble with fuel issues. Multiple brands of fuel pump, different locations, etc etc. When that engine goes bad, Im cutting into the frame to make a pocket for a mech fuel pump. One of my dodge darts had an electric on it, and i had nothing but trouble with that too. This is the second car that has made me HATE elec fuel pumps (when being used in a daily driver). Performance, I dont know. -GothY-
  29. mrpowderkeg
    Joined: Mar 11, 2009
    Posts: 178


    Unless you are pulling some decent 60ft times I'd stay with a mechanical pump. I doubt most street cars will hook well enough to push the fuel back to the tank, and I don't think most of us need to fuel a 500hp monster at WOT for extended periods of time.

    A 170 GPH mechanical pump, and the correct size fuel line such as a 3/8 line, including the pickup in the tank will be more than enough for most of us.

    What I see and I have to say WTF is when people feed a duel inlet carb off of one side of the pressure regulator, and have a pressure gauge in the other outlet. They're limiting themselves to 1/2 the volume of fuel flow through the regulator. I have a few friends that are trying to feed their "drag" cars like this, and they constantly bitch about not enough fuel on the top end, even when they step up in pumps.
    Joined: Jun 3, 2005
    Posts: 8,056


    I ran one of those holley mechanicals on a 468 powered C-c-camaro (had a hard time typin that!) with a super power shot N2O system on it. Had a gauge to monitor pressure and at WFO sprayin with the 150hp pills in high gear we had 5PSI. I think you'll be just fine if you have the room. Also, those pumps are rebuildable and can be "clocked" to whatever position you need the inlet/outlet to be. With a 2500 stall convertor, 8.5" slicks, 3.73 gear, the all steel bitch ran 11.40s all day long. Plenty of fuel. It also started life as a BBC car so it had a 3/8 line front to back. Yeah, do it.

    BTW, I see you're a highlander?

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