BritishV8 Forum

General Category => Engine, Transmission, & Rear Axle assy. => Topic started by: roverman on April 08, 2010, 08:35:22 PM

Title: How much Fuel ?
Post by: roverman on April 08, 2010, 08:35:22 PM
SBC, boat, approx. 550hp, gas, 4bbl. 1,200 ft. elev. "Carb Shop", is saying a 200 gph. mech fuel pump is neccessary. Biggest "Carter" is 172 ? How much is enough ? Max power should be no "fatter" than 12.8/1 afr. ? Thanks, roverman.
Title: Re: How much Fuel ?
Post by: ex-tyke on April 08, 2010, 09:51:35 PM
Per the "Tech Tips from the Professor" article in a typical Summit Racing catalogue, his fuel pump sizing method is based on the following:
At WOT, an engine requires 1/2lb fuel per hr per HP and 1gal gas =6lb.
So, for a 550HP engine,
fuel pump gph=550x1/2lb/hr
=275lb/hr
=275/6gph
=46gph
Based on this method, your carb shop recommendation seems high but you might want to have an independent look at this logic.

Math correction made...must have been that last beer.
Title: Re: How much Fuel ?
Post by: hoffbug on April 08, 2010, 10:05:40 PM
The old standby is ... Hp x 0.23 + GPH

Use more if using a bypass style regulator or planning on drag racing.
Title: Re: How much Fuel ?
Post by: alana on April 08, 2010, 10:05:58 PM
You sure they didn't say a 200lb/hr pump?
Take a look at something like this - which is plenty for a 550hp carb'd engine:

http://aeromotiveinc.com/products-page/fuel-pumps/11103-tsunami-fuel-pump/

Look at the flow charts.
A 200 gallon pump would be 1200lbs/hour!
Title: Re: How much Fuel ?
Post by: hoffbug on April 08, 2010, 10:36:00 PM
I was thinking something like this..
http://aeromotiveinc.com/products-page/fuel-pumps/11213-ss-fuel-pump-orb-08/
With a deadheaded regulator.
http://aeromotiveinc.com/products-page/regulators/carbureted-regulators/13201-ss-adjustable-orb-06-regulator/
Title: Re: How much Fuel ?
Post by: roverman on April 09, 2010, 11:15:01 AM
Thanks all.  I'm thinkin, they we're thinkin, Donald will be makin more like 500 hp, of which 200 lbs/hr. would be right there. Graham, when I do the math, 550 hp. X .5,(1/2), I get 275 ?  Tony,  HP X .23 + GPH. ?  I don't know the GPH. How do I add an un-known ? Thanks for the refresher.  roverman.
Title: Re: How much Fuel ?
Post by: ex-tyke on April 09, 2010, 12:32:01 PM
Art,
         Damn, you caught me with a math error...sheepishly corrected above.
Title: Re: How much Fuel ?
Post by: hoffbug on April 09, 2010, 06:53:05 PM
Sorry Its been a long week.. formula should read
HP x 0.23 = GPH
Title: Re: How much Fuel ?
Post by: roverman on April 10, 2010, 08:35:32 PM
Ok, with "Graham's" formula, 45.8 gph/550 hp. "Tony's" formula, 126.5 gph./550 hp. Anybody else want to dable in the mistyque ?  roverman.