Mechanical fuel pumps

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Ironmike

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Hey guys! If anyone here running a mech. fuel pump with a 550+ HP smallblock, I'd sure like to know which one.

Have tried the Edelbrock, Holley HP, and both show a pressure drop at 5500RPM and above. Both drop to 4PSI or so.....

I ordered a Clay Smith pump and it's just too big! Hits the water pump bottom outlet, gotta send it back.

I'm tring like hell to find the Carter "strip" pump that needs a regulator, but nobody lists it anymore.

Also, although the pressure dropped on the dyno, the motor never went lean. But I just think I'm giving up some power with a pressure drop that low.

Sure hope you guys can point me in the right direction. This is getting frustrating!
 
I was running the Carter mechanical pump with 3/8 rubber hose and a Autozone fuel filter on my 394 small block that made 662 hp and I never had a problem. I was only running 1/8 mile shifting at 6800 rpm. I change to the MagnaFuel electric pump with the built in filter and -10 lines and it did not make any difference.
 
Running a Carter M6270 with 1/2 fuel sender, fuel line with 900 cfm on a 550hp with no problem.
Showed no leaning at all on the Dyno, with a rev limit of 6200 and shifting at 5800.
 
I bought the Carter M6270 at Summit for my 408. Should be making north of 500 hp when done. It seemed to be what everyone was recommending when I ordered it.
 
running a 416 that made 583 at 6800 using the same carter street strip pump works its the one you would want:blob:
 
Ironmike said:
Hey guys! If anyone here running a mech. fuel pump with a 550+ HP smallblock, I'd sure like to know which one.

Have tried the Edelbrock, Holley HP, and both show a pressure drop at 5500RPM and above. Both drop to 4PSI or so.....

I ordered a Clay Smith pump and it's just too big! Hits the water pump bottom outlet, gotta send it back.

I'm tring like hell to find the Carter "strip" pump that needs a regulator, but nobody lists it anymore.

Also, although the pressure dropped on the dyno, the motor never went lean. But I just think I'm giving up some power with a pressure drop that low.

Sure hope you guys can point me in the right direction. This is getting frustrating!
Click to expand...

I might have what you are looking for. it looks just like the one in the summit add posted here.

http://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=M6270


it was on my 73 dart when i bought it and was working fine when i took it off. the owner threw in a brand new chrome one.
It is yours free if you want it. it has been stored in my parts room in my house for the last 2 years. the number stamped on the side of the mounting boss is 62704C23A
 
Does this carter pump require or does it benefit by using a regulator?
 
Same question as Rocket. I heard these pumps can go north of 8PSI at times. Don't mind a regulator if It would benefit.

Hey there AJ! What do 'ya mean by a fuel delivery test?
 
I bought that Carter. Mostly stock HP 360,Thermoquad,still had fuel starvation at high rpm. Installed a electric pump at tank 4-7 psi to push fuel to the mechanical pump. It helped. No regulators.Fuel pressure is about 5-6 psi at carb. I also checked inside of thank,changed all hoses and blew out fuel lines.Just a thought.
 
Well its been reported that it takes 1/2 lb of fuel to make 1 horse power per hour, as a general rule.
So if you do the math a 450 hp engine requires 225lbs/hr,which is 3.75 lbs/ minute.And IIRC gas is about 6lbs/USG, so that 3.75lbs is .625gallon which is 20oz. So if your pump puts out more than 20oz (2.5 cups)per minute, at point of full hp you should be good to go.The formula is linear so if you have 20% more power you need 20% more fuel.Therefore 540hp would need 24oz.(3 cups)
The few pumps I have tested put out in the neighborhood of 2cups(16oz) at idle, nevermind at 5500rpm.Who cares about the 2psi pressure drop, its the volume thats important.
Lets say you had a pump capable of dead-heading 10psi , but you forced it to pump through a tiny orifice of .030.And it deliveres just 8oz of fuel at 5500rpm.Would you want that pump? Of course not.
And then lets say you had a pump that dead-heads at 4psi, but delivers 30 oz at 5500 rpm.Well no thats not what we want either.The pump would be very large and consume quite a bit of power.
No we need, 20 oz at 5500, and just enough pressure to lift the fuel from the bottom of the tank, up into the bowl.The pump also needs to be able to draw the fuel from the back of the car to the bottom of the pump.
So, in my mind the volume test is paramount.
 
Rocket said:
Does this carter pump require or does it benefit by using a regulator?
Click to expand...

Ironmike said:
Same question as Rocket. I heard these pumps can go north of 8PSI at times. Don't mind a regulator if It would benefit.

Hey there AJ! What do 'ya mean by a fuel delivery test?
Click to expand...

I run the Carter 6270 on my 340. Works great, although I'm probably only making 420-430 hp. I also run a 3/8" pickup and fuel line with -6AN fittings from the pump to the regulator and carb. All probably overkill, but I needed a new pick up/sender and line so why not.

I do run mine with a regulator, and it's probably a good idea. Mine was cranking out almost 8 psi without one. Maybe not all of them will, and maybe you can get away with it, but it's easy enough to install one and then you know exactly what you're getting.
 
I'm at work, now. My dyno sheets have the fuel usage, I'm checking them tonite...just can't remember right now, BUT are you saying if I'm making 576HP with no signs of fuel starvation(lean) clear to 6800RPM, I'm OK. Even though PRESSURE drops to 4.1PSI?

Oh. 3/8 pickup with 6AN line.

I do NOT want to go electric. Too many issues!

About AJ's day job, I believe he's a rocket scientist.
 
"BUT are you saying if I'm making 576HP with no signs of fuel starvation(lean) clear to 6800RPM, I'm OK. Even though PRESSURE drops to 4.1PSI?"
Reread my post. NOWHERE did I say that.If you have a melt down dont put it on me.
My post is about fuel volume delivery, and how to determine if you have enough.
BTW; how often, and for how long is your engine required to put out its, full load, full rpm,maximum dyno hp?
I tell you what though, if I had your power level, I would get an electric pump.That engine is just too pricey to risk on something this easy to prevent. I would, however, get a pump that is designed to be draw-thru, and run them in series. I would turn the electric pump on with a Hobbs sw and a rpm relay to come on at the time when the engine needs it. Say at around peak torque rpm and 6 inches vacuum. Then you never have to hear that thing. And I might use 1/2" aluminum line,armored where required, if I planned to go racing.. No A/N for me. If I could put the pump in the tank I would, but as a part timer and a street car, I wouldnt lose sleep over it not being in there. If you have serious traction a sump is more than just a good idea.

I am just a man.Semi-retired.With a lifetime of learning and a headful of junk thats dying to get out.I just want to help.
 
I did not use a regulator. At the time my best 1/8 mile ET was 6.29 @ 109 mph.
 
My car went 93 in the 1/8 one time.I thought that was pretty good.
But 109. Now thats hoofing.And 6.29 is really cooking
And on a 6270 pump too.
Whats 109 at your scale work out to, hp wise
 
Yeah. I'd love to go electric. But I've been there done that. It's not uncommon for me to go Test n Tune Friday night, then Saturday me and wifey go take a 60-70 mile cruise somewhere. Too many electric pumps fail. I don't wanna be 50 miles from home on Saturday at midnite and be stuck. They never give a warning. They just die.

My car's mostly a street duty Demon, but seems like someone's always "testin' ya" at stoplights. Me and wifey are always happy to ablige if it's safe. So, it's run pretty hard, but not to the "strip only" catagory forsure.

I'd sure as hell NEVER blame anybody from this forum for a melt down, blow up, whatever. I don't know how i'd have done it without you guys' advice. I joined the day I got this car, and used members info and advice to completely restore the thing. Me and Mopars were brand new in 2009.

I think I'll run the Carter, try and monitor it and see how it goes.
 
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