Electric or Mechanical fuel pump?

[aarvig]

Hey guys, I'm running a 427/351 DART by Smeding Performance in my Cobra. It has a Quick Fuel carb on it. On the dyno it put out 607HP and 585 ft/lbs of torque. There is a set up for a mechanical fuel pump. Will a hi volume mechanical fuel pump be sufficient for this set up or would you do electric pump with fuel pressure regulator?
I am assuming that with a mechanical pump I can use lo pressure fuel line fittings and with the pump I will need to do hi pressure fittings with flared fuel lines...correct?

[edwardb]

There are numerous mechanical fuel pumps that will handle that much power. And a lot more. I'm a big believer in the simplicity of mechanical fuel pumps for carb'd setups. Get the right GPH rated pump and the right size line and you will be good to go.

I don't know that there's a huge difference in fuel line requirements for a mechanical vs. electric pump setup. At 6-7-8 PSI vs. 40-50-60 PSI they're both relatively low pressure. In both cases you want them (obviously) properly installed and leak free. High pressure is 1000 PSI like for power steering and even higher in brake lines.

[NAZ]

Depends on your planed use for the car. If it's a street car then go with simple & low cost. If you plan to race the car and that racing requires acceleration such as drag racing or road racing I'd recommend electric. Consider this, pumps push fuel much better than they pull fuel. Mechanical pumps are typically mounted up front on the engine and the fuel tank is in the rear. Gas weighs ~6lbs per gallon and that has to be sucked or pushed against the resistance in the fuel line and the g-forces of acceleration. It's easier for a pump to push against this resistance than pull against it. So many will use a rear mounted (or tank mounted) electrical fuel pump on race cars. You can set the fuel pressure a bit higher from the pump to the carb mounted pressure regulator which will help overcome the g-force of acceleration. Another benefit if you live in high temp climates, pressurized fuel will resist vapor lock. If your suction line on the block mounted mechanical fuel pump runs near your exhaust it can heat soak at shutdown and cause vapor lock (fuel pumps won't pump vapors). Not as likely with a rear mounted pump as even if the fuel line ran near the exhaust (not a typical routing for electrical pumps) the pump would simply push any vapors through the system where they would exit through the carb fuel bowl vent.

[edwardb]

I agree intended use should always be considered. Not sure it matters in this case though. That's a potent powerplant for sure. But NASCAR ran mechanical pumps until just a few years ago when they switched to EFI. With even more power and a higher speed / higher G environment than any us would ever see with our cars. The originals worked pretty well with mechanical pumps as well. I haven't had any vapor lock issues with my two carb/mechanical pump builds.

My take is pretty straightforward. Electric fuel pump is mandatory for an EFI setup. No discussion there. Just finished installing one in my Coyote build. There may be some cases where it's not possible (no provision for a pump on the engine, no eccentric on the cam, maybe others) but mechanical will always be my first choice for a carb setup. They're relatively inexpensive, easy to install, and just work.

[GoDadGo]

A high-quality mechanical pump should be A-Okay for an old school carbureted power-plant.
The good news is that it's an easy upgrade should you find yourself dealing with fuel starvation.
I'm running a mechanical pump, but likely have far less horsepower than you. (383 SBC / ZF 6-Speed Trans)

[aarvig]

Alright guys...mechanical fuel pump it is. So does anyone have a recommendation for make and model for a high volume mechanical pump? Also, could I use the aeroquip socketless fuel line fittings with this or do you have another recommendation?

[CraigS]

As long as that hose is good for 10# it will be fine. Can't recommend a specific pump but will say to try to get one that you can clock the top in relation to the base. That can really help w/ fuel line runs.

[edwardb]

I've used Edelbrock fuel pumps in my two carb'd builds. I've been happy with them. My 450+ HP DART 347 has the 110 gph Edelbrock Performer RPM 1725. According to the calculator in this article (http://www.onallcylinders.com/2013/05/16/what-size-fuel-pump-do-i-need-your-top-tech-questions-answered/) that would be plenty for your engine as well. There are several other brands that offer similar capacity pumps. Often when getting into higher volume pumps they also have higher pressures, so would need a regulator for your Quickfuel carb which is supposed to be 6.5psi / max 7psi. Personally, I would avoid that additional complication if you can.

I haven't used those specific fittings. But anything from Aeroquip I've found to be first rate. I'm sure they're up to the task. Not sure if you're asking about the complete fuel lines being flex though. Personally, I would avoid that. Expensive, plus many instances of them breaking down over time resulting in fuel smell, leaks, etc. I would recommend a hard fuel line with flex only at the ends.

[Blue MK3]

As usual, I agree with Mr. Ed. A decent mechanical pump will be fine with your setup. And it will eliminate all the extra wiring and return tubing required by an electric pump. I have a similar engine setup and it works fine with the mechanical pump, although a pressure regulator has been installed. KISS.

[Avalanche325]

You will still need a regulator with most high performance pumps. I am using an Edelbrock pump and Quickfuel regulator on mine.

[GoDadGo]

I'm Running An Edelbrock Street/Strip High Volume Style Pump.

Mine is the Performer Series Pump that requires no regulator; however, the Victor Series do.

[aarvig]

Edwardb, and all the others, I really appreciate your advice. I checked into the mechanical pump from Edelbrock that you recommended and I am going to go with that. I agree with the KISS practices...