Is this enough fuel pump?

[Chargerguy74]

I'm looking at the Mallory 110 gph electric pump, deadheaded, Part Number MSD-29256. It's rated at 110 gph free flow, max 7psi. My 440 put out a max of 536.6 hp and 541.2 ftlbs, but the way I'm gonna run it in the car it put out 520.2hp and 541.7 ftlbs. The BSFC (brake specific fuel consumption) is 0.541 @6000 rpm, so by my math it requires 93.8 gph. Carb is a Holley DP. Looking at the pump curve, looks like it would flow enough at 6psi, and Holley recommends a minimum of 4 psi at redline. Anyone have an experience with the 110 and similar HP? I'd prefer not going with the 140 and bypass regulator if I don't need it, but if I do....I do. It's nice to save some money where I can, but I'm also getting very sick of buying twice, sometimes thrice.

I have a Carter Super Mechanical Street pump (M6903) but the last time I ran it I lost 1/4" of fuel pump pushrod. Don't know if it was the pump that caused it, or a bad pushrod, but I'm not willing to chance it again so I'm pretty set on an electrical.

Thanks  

[myk]

I had heard there was a bad batch of fuel pump pushrods.  Maybe yours was one of them?

[BSB67]

so by my math it requires 93.8 gph.

Consider re-doing your math.

You cannot look at the pump in a vacuum from the rest of the fuel delivery system.   The 110 could work, depending.  The 140 does not necessarily need a by-pass regulator.

[1974dodgecharger]

man I was using the carter 120gph and I was fine and my little 383 was only 505hp....and then I added the blower and 10lbs of boost using the same carter fuel pump and I was fine also at WOT...maybe im missing something......

then again I blew my piston....you haven't done that yet 

[firefighter3931]

I'd go with the 140 and run the bypass regulator...especially if you plan a lot of street driving. Circulating the fuel will keep it cool and be easier on the pump. The pump will also be quieter and less annoying.  

Vapor lock is a big problem these days with junk gas and anything you can do to keep the fuel cooler is a bonus.  

The 110 gph pump is marginal at that power level, inmho  


Ron

[chargd72]

man I was using the carter 120gph and I was fine and my little 383 was only 505hp....and then I added the blower and 10lbs of boost using the same carter fuel pump and I was fine also at WOT...maybe im missing something......

then again I blew my piston....you haven't done that yet 

So I guess it wasn't fine at WOT with 10 lbs of boost.  Blown piston is a classic case of running lean with forced induction.  Bet that motor is a screamer when it's getting fuel though 

[Chargerguy74]

I had heard there was a bad batch of fuel pump pushrods.  Maybe yours was one of them?

I bought it last year. I heard about the bad batch. This was a comp pushrod made by Trend Performance. Not sure if those were affected or not, if so it could be the case.

so by my math it requires 93.8 gph.

Consider re-doing your math.

You cannot look at the pump in a vacuum from the rest of the fuel delivery system.   The 110 could work, depending.  The 140 does not necessarily need a by-pass regulator.

Redid my math. Yup 93.8 gph

man I was using the carter 120gph and I was fine and my little 383 was only 505hp....and then I added the blower and 10lbs of boost using the same carter fuel pump and I was fine also at WOT...maybe im missing something......

then again I blew my piston....you haven't done that yet  

Ouch. I blew 3 pistons in an engine before, probably not having nearly as much fun either.

I'd go with the 140 and run the bypass regulator...especially if you plan a lot of street driving. Circulating the fuel will keep it cool and be easier on the pump. The pump will also be quieter and less annoying.  

Vapor lock is a big problem these days with junk gas and anything you can do to keep the fuel cooler is a bonus.  

The 110 gph pump is marginal at that power level, inmho  


Ron

Yeah, I knew of the bonuses of circulating the fuel and keeping it cool, but I guess this is why I sometimes buy twice lol. Yeah, marginal, is not what I'm looking for, I'll pick up the 140. Thanks  

[1974dodgecharger]

Better safe than sorry.......im moving to electric fuel pump also....

[BSB67]

No, your math is wrong. 

If you have a motor that consumes 600 lb/hour (93 gph) of gasoline, you should be over 1000 hp.

Would you like me to show you how to do the math?  Here is a hint, it's about 47 gph, about half of your number.

Everything that Ron said is pretty good advice.  Those charts do not speak to the specific dP in your system and those details are what what makes or breaks the actual fuel volume at the carb.

You can hypothesize forever if a 110 Mallory will work, but you simply won't know until you try it.   I totally get why you want to use the 110.  The question you have to answer yourself is simply this:  Do I want to try the 110 and see if it works okay, and if not, change it for the 140?, or just go 140 now, and skip the 110 test/cost/effort.

[Chargerguy74]

Well actually it consumes 226.2 lbs/hr at 6000rpm. Where I get my number from is by using a formula for calculating fuel pump requirements, 2 * (flywheel hp * BSFC / 6) = gph which takes into account g-force, friction loss, etc. My math is correct, maybe my formula is wrong...

Thanks for your help.

[BSB67]

The multiply by 2 is a silly factor as the g-force and friction loss have nothing to do with fuel demand. 

[Chargerguy74]

So the multiply by 2 is at silly factor as the g-force and friction loss have nothing to do with fuel demand.

Demand? No. Meeting that demand, yes. Looking at the original post I shouldnt have used the word "requires" without elaborating. I knew exactly what it required for fuel, but I was referring to what it needed for a fuel pump.

[1974dodgecharger]

Mat does seem off quickfuel told me at 800hp I needed only 80gph boased on math but not all pumps are 100 percent efficient so u always go bigger on pump.....

[Chargerguy74]

Ordered the 140 this morning.

[BSB67]

So the multiply by 2 is at silly factor as the g-force and friction loss have nothing to do with fuel demand.

Demand? No. Meeting that demand, yes. Looking at the original post I shouldnt have used the word "requires" without elaborating. I knew exactly what it required for fuel, but I was referring to what it needed for a fuel pump.

You still don't understand.  The fuel pump does not need to deliver 93 gph.  It needs to deliver 47 gph.  There is nothing else but the motor using fuel.  Friction loss and g-force (system losses) have nothing to do with the volume capability (gph) of a pump.  

A 300 gph pump might not supply enough fuel for you motor in the car, but a 50 gph pump might.  It depends on the delivery pressure.  Its the other axis of the graph that is important and you need to understand why. It is what needs to be accounted for in the system to overcome g-force and friction loss.

You cannot look at the volume rating of the pump without understanding the system and pressure needs.  Rated pump volume has nothing to do with overcoming the system losses, and yes, the formula is bad, actually stupid.

[Chargerguy74]

So the multiply by 2 is at silly factor as the g-force and friction loss have nothing to do with fuel demand.

Demand? No. Meeting that demand, yes. Looking at the original post I shouldnt have used the word "requires" without elaborating. I knew exactly what it required for fuel, but I was referring to what it needed for a fuel pump.

You still don't understand.  The fuel pump does not need to deliver 93 gph.  It needs to deliver 47 gph.  There is nothing else but the motor using fuel.  Friction loss and g-force (system losses) have nothing to do with the volume capability (gph) of a pump.  

A 300 gph pump might not supply enough fuel for you motor in the car, but a 50 gph pump might.  It depends on the delivery pressure.  Its the other axis of the graph that is important and you need to understand why. It is what needs to be accounted for in the system to overcome g-force and friction loss.

You cannot look at the volume rating of the pump without understanding the system and pressure needs.  Rated pump volume has nothing to do with overcoming the system losses, and yes, the formula is bad, actually stupid.

[Chargerguy74]

BSB67, I understand my engine was using 38 gph at 6000 rpm. I'm not saying it needs 93 in real life or due to g-forces or friction loss, but needs 38gph. At a minimum of 4psi let's say??? Like I said, I shouldn't have said that it requires 93gph, what I was referring to was a safe size of pump required to supply this amount because I know the friction losses caused by many factors will affect the discharge head and performance of the pump. I also know that as the pressue decreases, the velocity increases, and vice versa. In my original post I stated that the 110 gph was a free flow rating, and questioned if it could actually supply the engine with what I needed. The formula I found online, I have been looking at other resources and no one else is using the 2* fudge factor in calculating more than adequate fuel pump ratings. But explained in the article, the formula was a rule of thumb that took into account flow losses. It was not calculating fuel consumed, but an adequate pump capacity. Stupid? Maybe. I know you know what you're talking about. I'm here to learn. So I'm not sure what point you're trying to make here other than that I'm wrong (with no offer of any real explanation to help a guy out). Also, I made reference to the other axis of the graph in my original post, so it was't something I was overlooking.

[1974dodgecharger]

That's how 'B' offers advice.....he is a cold dude no worries just listen to advice take it or leave it......just like mine... 

[BSB67]

BSB67, I understand my engine was using 38 gph at 6000 rpm. I'm not saying it needs 93 in real life or due to g-forces or friction loss, but needs 38gph. At a minimum of 4psi let's say??? Like I said, I shouldn't have said that it requires 93gph, what I was referring to was a safe size of pump required to supply this amount because I know the friction losses caused by many factors will affect the discharge head and performance of the pump. I also know that as the pressue decreases, the velocity increases, and vice versa. In my original post I stated that the 110 gph was a free flow rating, and questioned if it could actually supply the engine with what I needed. The formula I found online, I have been looking at other resources and no one else is using the 2* fudge factor in calculating more than adequate fuel pump ratings. But explained in the article, the formula was a rule of thumb that took into account flow losses. It was not calculating fuel consumed, but an adequate pump capacity. Stupid? Maybe. I know you know what you're talking about. I'm here to learn. So I'm not sure what point you're trying to make here other than that I'm wrong (with no offer of any real explanation to help a guy out). Also, I made reference to the other axis of the graph in my original post, so it was't something I was overlooking.

I understood all that the first time.  The question is did you?  If you knew all this to begin with, your questions and statements should have been different.  If you did not understand this to begin with, you did learn something.  I did not spoon feed you, but gave you plenty of information to think about.  It seems like you pondered my statements, and thought about them, probably read, or re-read stuff, and you now have a better understanding.  Maybe not.

You should have learned that you cannot overcome system losses by increasing the pump volume?  Hope so.  You clearly did not know this when you started.  And it is still not clear to me if you understand the significance of the rest of the fuel system, as you still have not shared anything about that, which is critical in trying to make a decision on a pump.

You bought the 140.  It will work. 

[BSB67]

That's how 'B' offers advice.....he is a cold dude .....

Ouch.

[1974dodgecharger]

That's how 'B' offers advice.....he is a cold dude .....

Ouch.

lmao....my phone auto corrected for it meant to say, 'he is a cool dude' 

[cdr]

That's how 'B' offers advice.....he is a cold dude .....

Ouch.

lmao....my phone auto corrected for it meant to say, 'he is a cool dude' 

                                       

[myk]

That's how 'B' offers advice.....he is a cold dude .....

Ouch.

lmao....my phone auto corrected for it meant to say, 'he is a cool dude' 

Eh, he's here to lay down the truth to these cars.  I don't think he cares to soothe any aching manginas...