Thread: Fuel pumps

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Do you perfer an electric or mechanical fuel pump and why? I personally like electric.

I asume your talking about older cars with mechanical pumps rather than the new cars with tank mounted pumps.

They both have their place. From a reliability standpoint, I tend to stick with mechanical pumps, my experience is that they seem to last longer.

I have always built my personal cars with an eye on making long road trips. If I'm running an odd ball engine (like my early Hemi's) where I might have a problem finding one if it goes out in Resume Speed Nebraska, I'll generally run electric.

Something I started doing with electric pumps is using the little square high volume ones. These have the ability to have gas either sucked through or pushed through when they are not running (which also makes them great as a starter fuel pump for a car that sits for extended periods of time). I plumb them in series with each other, and wire a 3 position switch (usually in the trunk) that allows me to run one or the other with center position being "off". That way if a pump does go out on the road, it's a simple matter of just throwing the switch to get going again. The off position is used when the car is parked over night as an anti-theft device. I occcasionally switch the pumps from one to the other so I know I have good pumps when I start out.

Sorry I should of been more specific i was talking about Racecars but yes i would also go mechanical for a street car.

For me it would depend on the race car..... I'm going to make a couple of assumptions here again.


Something with a reasonably small motor (400 CI or less) not turning excessively high RPMs (under 6000) normally aspirated non-NOS engine could probably get by with a good HV mechanical pump. (In my early years I dragged raced cars with the stock or HP pumps (when I could find them) with no problem). From a safety standpoint I like the idea that when the engine is not running the pump is not working and that you have less pressurized fuel line on the car.

In those instances where the engine has a high demand for fuel and it is questionable that the stock type pump would keep up (especially NOS equipted cars that can melt pistons if they lean out) I would go with a positive displacement rotary type pump. This also hold true on engines that see very high RPM as the fuel pump arm can go into a float condition and not keep up with the fuel pump eccentric.

Anytime that a fuel system is changed, safety considerations become paramount. Most sanctioning bodys have very specific rules on fuel systems to include kill switches and the total amount of rubber fuel line that can be in the system. These are an excellent (and if you race) mandatory guide on what you can and can't do.

Streets,

Thats one feature I like about them too being able to control if it is on or off.