Fuel delivery vs consumption

NoMoore

Pro Stocker
May 26, 2006
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Rochester, Pa
A recent episode of horsepower sparked my interest.

They were doing a rerun, it was the one the put the engine dyno in the shop. They dyno tested a nice small block and the big block out of that race car nova.

One of the things it showed on the screen was the fuel consumption. The big block used 53 GPH and the small block was like 33.

So that got me to thinking. Where is the line to be drawn on pump size? Naturally overkill is good to avoid lean conditions, but when does usage and maintaining pressure become an issue?

For example a holley blue pump looks like a great choice for a healthy motor. But what real world factors make it too small? G forces, actual consumption, pressure losses?

Discuss.
 

Goob

Top Fueler
Jun 6, 2003
3,641
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Indianapolis
The Holley Blue delivers fuel well enough, most of the time, but are noisy, unreliable, and can leak.

The 6 valve Super Speedway block mount mechanical pump will supply anything up to and including more HP than you'll ever have, without mechanical alky injection and power adders......

I'm at "overkill" with my Holley block mounted street/strip pump.
 

jbaker

Weekend Racer
Oct 3, 2005
82
0
0
kewanee,il
ever been inside a "six valve superspeedway pump" ?
i assume you are referring to the barry grant (carter) mechanical "superspeedway". with the cast aluminum housing.
its nothing more than a carter pump with larger inlets and outlets
with AN fittings.............nothing else appears different internally, IMO.
 

Goob

Top Fueler
Jun 6, 2003
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Indianapolis
Carter, Holley, B.G., all the same internally, the last thing I'd want to do is promote sales for B.G.......and yes, I've been inside lots of 'em.

The $23 Carter pump that Scoggin-Dickey sells was good enough for 10.70's @ 123 in my ride, back when it had the stock tank and lines. I only bought the Holley so I could move the inlet/outlet around.
 

NoMoore

Pro Stocker
Thread starter
May 26, 2006
1,833
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Rochester, Pa
I mentioned holley blue just for an example. If 53 GPH will feed that nasty big block, how do we rate what pump we buy for given combination?
 

Goob

Top Fueler
Jun 6, 2003
3,641
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Indianapolis
The GPH figures are merely marketing.....and are measured in static conditions, with free flow.
The only place I can find a need for an electric pump is on an auxillary system for NAWS, or when space or block limitations require some other sort of pump.....in that case I would opt for a belt driven mechanical pump.

And yes, I've had to hack an engine front mount plate for pump clearance for a 355 engine in a light chassis car running 5.90's in the 1/8th mile.
 

eldabo

Pro Stocker
Aug 10, 2006
1,811
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Mobile,Alabama
I would like to hear more on this allso. I have the Aeromotive street strip part # 11203 be rated for 200-750 hp on gas ,Will be enough to support over 600 hp on e85 ?
 
Here is my "rule of thumb" that has not let me down yet.

Take the GPH AT THE PRESSURE you are running times 4 for a dead head system and x 5 for a return style system.

In my case, the engine dynoed at 625hp. I am running a Comp 140 pump which many a person has told me is too small.

Comp has a dyno graph of the pump, at 7.5# is puts out 125 GPH.

125x5= 625

This assumes a properly designed system with no sharp 90 degree fiitings, proper filters and line size.

In my case I have 2 #8 lines with mesh filters before the pump, a large paper filter before the regulator (hi pressure side),#8 to the carb and very few turns/fittings.

So far it fed the motor on 10 flat run.

I admit I am running right on the edge and will most likely be stepping up to thier 250, just in case.
 

Bar50

Pro Stocker
Jan 31, 2009
1,870
2
38
Tulsa, OK
One of the things to ponder is the whole brake specific fuel consumption, the bbc vs sbc rates, add in some rules of physics(law of conservation of mass & energy), you can only make a certain amount of power for a given amount of fuel. Or, look at it like this, gasoline can only support a certain amount of power given the amount of force it can expend in an explosion like combustion. Sort of like 93 octane fuel can only support 25 hp at 1 gallon per hour(just a number, I can't recall the value they actually use). Now, don't get me wrong, temperature of the fuel and the air, humudity, barometric pressure air from under the hood(static) or scooped(dynamic) all play into the role. Just like it has a given weight/specific gravity, boiling point, melting point and so forth. Considering a static volumetric efficiency of any motor.
 

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