I am not sure I need one, but am looking into it.
Motor is around 475-500hp or so.
I am currently running a mechanical high volume pump. My question is, when do you know you need an electric pump?

That is a good question Dave. When I had an issue with fuel delivery at the first time out this season, I thought my Mechanical pump was going away, turned out to be the fuel pump pushrod was getting shorter (long story). I installed a complete electric system that maintained 6.5 psi at the top end. The result was no difference in ET or MPH from my Carter 172 mechanical that would give me 3.5 psi at the top end.

What happened when I ran out of fuel was a bog, it coasted for a few seconds and then when the pump caught up I was able to run at WOT again. I did not notice any slow down until a moment after the gauge read 0 psi.

If you have a fuel pressure gauge where you can read it at WOT the car is pulling hard and you have at least 3 psi at the fuel log, you will be fine. But if you feel like the car is dying off and the fuel pressure is low, you may have an issue. Just don't be too quick to jump to the conclusion the pump is bad. there can be many other factors involved individual to each vehicle.


I have run 10.78 and 125.1 mph with the Carter 172 mechanical pump.

11.36 at 117 with a stock 3/8 line, stock sending unit and the Carter pump.

There has been discussions about certain cams needing more fuel than others, but I just don't see how that is possible enough to warrant a different fuel system. The difference in fuel requirement just cannot be that different.

Hope this helps.

If your engine is not bogging & maintainig
fuel pressure I would not switch to an
electric pump. If you plan on getting into the 10's then I would think about it, although I
know plenty of people running 10 second cars
on manuel pump's. I called Barry Grant awhile
back & there story is your pump needs to pump
a gallon of fuel of thirty seconds to run 10's.
I have a 69 Chevelle with a 454 that run's 11.20
to 11.40's depending on the weather & in a 1 1/2
weeks at Super Chevy I'm going to get this thing
in the 10's. I Hope Hope Hope.
Larry

Thanks Tom, that helps alot.
I think I'll just leave mine alone.
The reason I was asking:
I had a bog, or so I thought, just off the line. The track was so sticky, I was getting zero wheel spin launching. The car was dead hooking, even with a 5000 rpm launch. :eek: The car would move about 10 ft or so and the rpms would drop to about 2000 and then slowly climb (seemed slow) until I hit around 3500 and then the car got going. I couldn't tell if I was running out of torqe or fuel. I think now it was torqe. :(
Sixty foot times were still nothing special @ 1.8ish.
Since then I have advanced my initial timeing and decreased my total to keep it around 36 deg.
Going to the track next wednesday to see if it will help.

thanks for the info.

Hope you make 10's Larry, thanks

Dave

Dave,

No problem, Fatten up your accelerator pump circuit before you go, you likely had a lean bog

Thanks for the tip, I'll give it a try. :D