High Perf. Mechanical vs Electric Fuel pump

[JMB340Challenger]

Well, I went dragracing Saturday night. The Challenger ran good! Drove about 25 miles to the track, ran 5 times and drove home! My issue is this; every single run, about 80 feet before I crossed the 1/8 mile mark, it seems I ran out of gas. Excellent pull through first and second gear to about 6000 RPM, but as I approached 80 mph, I think my fuel bowls were empty. I literally "cruised" through the 1/4 mile finish line at 14.6 @ 81 mph. (My 1/8th mile was 9.0 @ 79mph spinning like mad on BFG Radial T/As). As you can see from those numbers, I did not gain any mph in the last 1/8 mile of the track because I had to let off and just drive through.  Assuming I am diagnosing the problem correctly and it is an old worn-out fuel pump,  what would you recommend as a replacement? Mechanical vs electric? Regulators? Thanks in advance!

[70chall440]

I would upgrade to a better mechanical to begin with.

[cudabob496]

5/16 fuel line may be too small

but there could be other issues restricting fuel delivering

An electrice fuel pressure gauge is very helpful

[70chall440]

5/16 fuel line may be too small

but there could be other issues restricting fuel delivering

An electrice fuel pressure gauge is very helpful

  BTW you can run a gauge with a mechanical pump (just in case you were/are wondering). If you are racing, you might think about running a gauge to the cowl (outside the car) so you can watch it. You can run them inside, but you need some special parts to keep from a fuel leak inside the car. 5/16 is pretty small if you are pushing the car.

[cudabob496]

BTW you can run a gauge with a mechanical pump (just in case you were/are wondering). If you are racing, you might think about running a gauge to the cowl (outside the car) so you can watch it. You can run them inside, but you need some special parts to keep from a fuel leak inside the car. 5/16 is pretty small if you are pushing the car.

Actually, my electric fuel pressure gauge comes off a small diaphram/transducer attached to the fuel line by the carb.
So all I have is a wire going to my dash area.

http://www.summitracing.com/parts/sww-412m

[70chall440]

Actually, my electric fuel pressure gauge comes off a small diaphram/transducer attached to the fuel line by the carb.
So all I have is a wire going to my dash area.

http://www.summitracing.com/parts/sww-412m

Yea I have one of those too on my Cuda.

[Chryco Psycho]

+ or - to both  I like the quiet simple HV mechanical pumps. Electric can be noisy but a good Mallory 110 pump works well .
 there could be a number of issues though , 5/16 line can be too small upgrading to a 3/8" line may be nessisary but do not forget about the pick up tube , it needs to be 3/8" as well  , if the filter is before the pump that can be a big problem too .
 I assume this is a 340 small block so the fuel pump pushrod is not an issue as it can be in a big block ?

[70chall440]

"I assume this is a 340 small block so the fuel pump pushrod is not an issue as it can be in a big block ?" Correct, no push rod on a SB, there is the eccentric on the cam.

[JMB340Challenger]

Thank you for all the input. I'm thinking of trying a HP mechanical like this Edelbrock http://m.summitracing.com/parts/edl-1720 . It has 3/8 connections so I can adapt to it on the inlet and use 3/8 to the filter and carb. If I'm still having issues I'll upgrade to 3/8 from the tank.

[cudabob496]

won't make any diff, since the tank is 5/16.
Need a 3/8 sender that goes in gas tank.

sure your filter is not clogged
also, there is a sock filter inside tank that might be clogged. Inspect it first.

Dont open tank near gas water heater flame.

had a neighbor blowup and burn to death, not to mention his house burned down.

[dave73chally]

Sorry to hijack but relevant to what I was about to post...I have a 440 with the stock 5/16" fuel lines. Plan to upgrade line size later but not yet. Anyone have a part # for a good hv mechanical fuel pump to work with my line size? The only one I see is a Carter that puts out 4-5psi which is not high volume...

[dfrazz]

Sorry to hijack but relevant to what I was about to post...I have a 440 with the stock 5/16" fuel lines. Plan to upgrade line size later but not yet. Anyone have a part # for a good hv mechanical fuel pump to work with my line size? The only one I see is a Carter that puts out 4-5psi which is not high volume...

I would not invest money in a hv pump for your current lines if they are just temporary.  I installed a 3/8 line from Dave at Roseville, kept the 5/16 line as a return, and went with this 440source pump.  http://store.440source.com/High-Volume-Mechanical-Fuel-Pump/productinfo/138-1013/

[GreenFish]

I'd stick with a Mechanical if i were you. I ran a Carter mech pump before switching to EFI and I was running 11's. Like others said,  Run 3/8 lines, get a gauge, and make sure there are no clogs

[JMB340Challenger]

Good advice; thanks!

[rUNCHARGER]

With my second Challenger, I pulled 7000RPM in high gear with a dual AFB Hemi with a stock Hemi fuel pump and 5/16" line. So, I don't believe a 3/8" line is necessary. If you want to change to a 3/8" it won't hurt but I don't think it is a must do.
I prefer mechanical pumps however the electric pumps are nice for filling up the carbs when this new gas evaporates at rest in hot weather. I hate the noise of an electric pump though. So I would try a larger mechanical pump with regulator first.

Sheldon