Mechanical fuel pump

[pjc360]

which mechanical fuel pump is the best pump between the edelbrock performer rpm part number 1720 and the Holley pump part number 12-360-11 or the Quick Fuel 30-360.
All 3 pumps say 110 gph the edelbrock is the most expensive at 150 and the Holley is 135 and the Quick fuel is 127.50.
This would be going on a 300hp crate 360 magnum with a Quick fuel super street series 680cfm carb.
Running in a 91 half ton short bed 4wd pick up.
I have a cheap parts house replacement pump on it right now from oreilly auto parts I believe it's a prescsion pump, it doesn't hold a steady pressure sometimes it's at 6.5 psi sometimes it's down 3 psi and it just doesn't seem very consistent.
Maybe that's just the gauge on my fuel line though?
AnywYs I was just thinking it would be a little more consistent and run a little better with a higher quality pump on it.

 

[yellow rose]

I'd do the Quick Fuel. Looks more like a Carter. But, Holley owns QF so I'm not sure what is what anymore.

I have used and rebuilt dozens of those Carter pumps. Just did mine for my car.

 

[MoparLeo]

Lots of quality, rebuildable, clockable , high volume/pressure fuel pumps on eBay. Get a quality fuel pressure regulator while you are at it. Carter, Airtex, Holley, Edelbrock, and others from about $50. and up

 

[Mattax]

The fuel pressure will vary between maximum when the fuel inlet at carb closed and when its wide open. This is common when using a dead head arrangement (versus controlling the pressure by a releif valve to a return line). It is not a problem if it can stay around 3 psi for the length of the track. That's an indication that the pump is capable of supplying the carb with more fuel than is being consumed. If it drops to zero, that means its barely keeping up or not keeping up the volume needed.

On the other hand, if the pressure goes above 7 psi or so, then it may push the needle valve open and overfill the bowl.

A few years back I sent a few pumps up to Ryan Brown Racing to have them tested for flow and cut off pressures. At about the same time, Holley came out with new pumps and actually posted a graph of the flow rate for 4 psi or something like. I put that all into a table and spreadsheet and made my own graph. Click on my homepage and then go to the Fuel Delivery page. I think it will address your questions.

edit: At least for my browser, it looks like with the forum revamp, homepages were removed. The fuel delivery page is Mechanical Fuel Delivery for Mopar LA Engines
Its a bit old format so my apologies, but the info is there. If the Edlebrock fuel pump is a 6 valve (3 in/3out) it may have fit issues. There's photos showing that on the page. Using the bottom plate didn't solve that. (What's needed is a early style water pump.)

 

[AJ/FormS]

300hp @ 1/2 pound per hp per hour requires 300 x .5=150 pounds of fuel per hour, at WOT.
Or; 150/60 =2.5 pounds per minute. At 6.5 pounds per gallon this is ; 2.5/6.5=.38 gallons per minute, or 1.5 quarts, per minute,still at WOT. And you want a 110 because it is 289 times more powerful than it needs to be?
Mopar used to sell a P4007040 rated at 80gph at8.7 psi. I have one of those on my 367 running about 400hp.Same math says I need 2qts per minute. So my pump is only 160 times more powerful than it needs to be. I bought it in 1999. It mighta cost 60Canuck-bucks at the time. What's that in USd, maybe 40/50 dollars?
Jus saying.......

 

[rumblefish360]

Could you nutshell that for us?

 

[AJ/FormS]

Why use a ten pound hammer to drive a 2penny nail?
lol

 

[rumblefish360]

Because bigger is better. And makes the job EZ. No shortage of driving force.

 

[AJ/FormS]

That's it! no more nutshells! The vacation is over,lol

But I ain't holding the nail....

 

[Mattax]

Because it doesn't flow 110 gph when bolted up...

and of course the same is true for the 80 gpm
It just happens that p4007040 is a Carter M6270.
So you can see what its performance curve looks like since that's one of the pumps Ryan Brown tested for me.

Oh yea, these tests are done with the restriction controlled on the output and little restriction on the feed. Most types of pumps, including these, have more trouble overcoming restriction on the suction side than the delivery side. That's a reason to factor down the actual flow when installed.

 

[AJ/FormS]

Yeah, I knew that; but 289 times overkill is an awful lot of compensation. You could probably tie the line in a knot,cinch it down hard,set the car on fire,shoot it out of a cannon, with the engine screaming,and until the fire consumes the engine,it will keep running,lol. What a picture!

That Carter took my 367 to 93mph in the 1/8th, and it is sucking hard through a 3/8 line with a great big EFI canister-filter at the back, that,tho nearly new at the time, has by now accumulated about 80,000 miles and the engine still pulls like it ever did. That is,IMO, a heck of a pump, and a heck of a filter.
Before I installed that pump, I ran her on an old 340 pump. That factory pump took this 68 Barracuda to 106 in the Qtr, with a different cam. Also a pretty good pump for the street.It was easier on the float valves making only about 5psi,as I recall.

Here is some more math.
In the Magnum example 300 hp requires about .38gph@WOT. this is about 1.5 qts or 48 ounces per minute. In 12 seconds say, this would be 48/60 x 12 =9.6 ounces.Any pump that can pull 9.6 ounces, through the installed fuel system,under the duress of acceleration, is just adequate. If you add 20% for a safety margin, that would be 9.6 x 1.2=11.5 oz per 12 seconds.This then becomes 1.8qts per minute. And this needs to occur over an operating range of; from stall rpm to shift rpm. Lets say 2800 to 6200 on that Magnum. This is an average rpm of 2800+6200/2=4500. So; go hook up a Tee to the Magnum's fuel system, at the carb, rev it up to 4500 for 12 seconds and see if it will pump at least 11.5 ounces. No don't do that. Just imagine doing that.

The factory test is to pump 1 Qt in 1 minute at 500rpm.You can't compare this directly. But it doesn't take much imagination to see that the factory pump can probably keep up. It did for me; car went 106 @ 12.9 seconds with a 2.2 60ft.
I'm not trying to push the factory pump;no way. I'm just saying, it worked for me. I had a box of old pumps sitting in the shed. I just rigged up a pressure gauge and started pumping arms; I stopped at the first one that made more than 5psi, and bolted it on.I ran the volume test, was happy, and went racing.

 

[Mattax]

I figured you knew but many others reading the thread would not.

It depends on the pump, some have performance curves that drop off after 2000 rpm (as even Holley showed in their own graphs). Some of the the factory pumps are (were) better than the aftermarket. This is why I did the testing. Too much marketing BS. (and that's the reason I made a webpage with the results)

At least as important is the feed line. Having been in the situation where the car was running out of fuel at the top in the quarter mile made me very interested in all of the relevant factors. I put a pressure gauge on the cowl to confirm what was going on.
A new stainless steel 3/8 line and pickup made a big difference. And the lower cutoff pressure of the new Holley resolved the occassional flooding with the M6270.

 

[AJ/FormS]

Goodonya Mattax
I hope you get a lot of traffic to your webpage.
I only put the big pump on, cuz I thought it was the thing to do, to hit the track with.I was totally green to the track.The 340 pump was working fine on the street.
On the street. Zero to 60mph is usually a one , or maybe 1.25 gear blast. It usually starts at about 30mph.And it's all over in 2 or 3 seconds. I keep it to that, so that the good guys have to see me being bad,lol. Hearing don't count.
Per the above example the 300hp fuel requirement, at WOT, is a tic under 1 ounce per second. So a short little burst, barely empties the bowls. Just about any old pump can keep up to such tomfoolery,lol.Occasionally,the blast goes into third gear; I'm no saint.....

 

[Mattax]

I think that gets back to the O.P.'s 300 hp truck. A stock pump would probably do fine even pulling on 5/16" line - if its in good condition.

 

[yellow rose]

The fuel pressure will vary between maximum when the fuel inlet at carb closed and when its wide open. This is common when using a dead head arrangement (versus controlling the pressure by a releif valve to a return line). It is not a problem if it can stay around 3 psi for the length of the track. That's an indication that the pump is capable of supplying the carb with more fuel than is being consumed. If it drops to zero, that means its barely keeping up or not keeping up the volume needed.

On the other hand, if the pressure goes above 7 psi or so, then it may push the needle valve open and overfill the bowl.

A few years back I sent a few pumps up to Ryan Brown Racing to have them tested for flow and cut off pressures. At about the same time, Holley came out with new pumps and actually posted a graph of the flow rate for 4 psi or something like. I put that all into a table and spreadsheet and made my own graph. Click on my homepage and then go to the Fuel Delivery page. I think it will address your questions.

edit: At least for my browser, it looks like with the forum revamp, homepages were removed. The fuel delivery page is Mechanical Fuel Delivery for Mopar LA Engines
Its a bit old format so my apologies, but the info is there. If the Edlebrock fuel pump is a 6 valve (3 in/3out) it may have fit issues. There's photos showing that on the page. Using the bottom plate didn't solve that. (What's needed is a early style water pump.)

Very good web page. Hope more people see it.