Fuel Pumps

[Monster]

Does anyone know offhand, what the fuel pressure is with a mechanical fuel pump on a SBC ?
Trying to figure at what point a normally aspirated application would benefit from an electric pump, if ever.

[anotheridiot]

Pretty sure most float seats can only handle 6 1/2 pounds. That is the whole key so you don't push past the seat and just overflow from the vent straight down the throats.

We have 2 weber conversion kits on our jeeps. Those can only handle 2.5#.

If you get an electric, you will probably need a regulator, and if it is regulating too much, it heats up the pump, so a regulator with a return line would be better.

[dieselhead]

I think a stock SBC fuel pump provides around 5 psi or so. If you suck all the gas out of the card or carbs when accelerating hard you need more volume but not more pressure.

[cstmwgn]

you can get electric pumps that do not require a regulator as well. I have run small Carters on lots of things with no issues (no regulator or return line) and very good longevity.
Lots of reasons to run a electric as well as lots of reasons to run a mechanical.
One of the benefits I like with electrics is it primes the system up to the float needles.
One of the downsides to electrics is they need to be mounted close to the tank and preferable below the fuel level as they don't suck all that well.

The Fairlane has a mechanical on it and if it sits for extended periods of time takes a bit to get the gas pumped back into the carb.

[Monster]

I saw an advert for a Pro-Cam 7.5 PSI mechanical fuel pump that will flow 130 GPH (requires 1/2" inlet & output lines), rated for up to 1,200 HP on gas and I started wondering about stock specs.

[cstmwgn]

there is a whole bunch of VODO bullshit when it comes to fuel pumps. 1200HP on the dyno is a different animal than the same engine in a 6 second drag car that 60s in under a second. I ran a little carter on the wagon for years - probably in the 600 - 650hp range - but it never hooked so there wasn't as much demand on the pump.

[Monster]

there is a whole bunch of VOODOO bullshit when it comes to fuel pumps.

I'm beginning to understand that ...

[squirrel]

The fuel pump has to work hard at the top end of the strip, not the starting line, so traction has little to do with it.

There's a direct correlation between gallons per minute and horsepower. Do the math

[cstmwgn]

There's a direct correlation between gallons per minute and horsepower. Do the math

I have done the math - multiple times and the math does not seem to match up to what the fuel pump companies say. They SEEM to be adding a rather large factor for something. When talking with a friend of mine that has a super stock car his opinion varies from yours in where the difficult part is for his combination.

[Monster]

There's a direct correlation between gallons per minute and horsepower.

This makes sense like you need larger fuel injectors to accommodate increased flow when power increases in fuel injection systems. They increase delivery size to handle larger volumes, rather than increased pressure.

[anotheridiot]

every tuning problem I have ever had has been too much fuel, so I will stick to the mechanicals