What about fuel consumption how much does a charger affect over a NA eng. 454mag.

Nova,

The correct answer is it depends on how the engine is configured.. This thread should be able to point out some of the reasons why it depends on hte setup..

Hope it helps,

Richard

hte??? can't figger that one out, little slow.

So are my fingers.... ;)

R

Whats hte stand for?

It was a transposition of "the"...

What I mean is that there re a million ways to setup an engine. In theory, a properly setup engine can produce more power, and use less fuel than an improperly built one.

Simple example.. If 2 engines are exactly the same size... Displacement... And engine A has a BSFC of .41, and engine B has a BSFC of .61 and produce the same amount of power, then engine B will use 50% less fuel to do so....

BSFC is Brake Specific Fuel Consumption.....

R

semi-dyslexic THE

Engine fuel consumption is directly commensurate to power output. If a properly tuned engine uses X gallons to generate 500 horsepower, one that generates 1000 horsepower will use 2X fuel.

Depends-in theory a supercharged motor should be more effiecient BUT in the real world,less then perfect marine engine enviroment it won't be neccesarily true. At very light cruising speeds (just short of making boost) if your fuel curve is tuned correctly you will get decent mileage cruising,better then stock. My 272 baja stock (if I can rember that far back for that BRIEF time frame:D) got around 1.5-1.7 mpg cruising at 45-50 mph with a 23 pitch merc 3blade. After getting the tuning righton my 502 with the blower it would cruise nice at 50 mph at a lower rpm turning a taller prop getting about 2.2 mpg. However,these mefi efi systems are crude,batch fire with no feedback to the computer as to what the afr is so unless someone very carefully water tunes the boat with a O2 sensor and a laptop your fuel at part throttle often ends up rich wich kills your mileage.
As far as once into the boost,it takes fuel to make hp,for example-if its going to take 30gallons a hour to make 350 hp N/A and you add a blower with enough boost to add 350 more horse power,your fuel use will be double (add another 30 gallons per hour),now your at 700 hp using 60 gallons per hour,now add in the extra hp your making to turn the blower,lets say it uses a 100 hp,add another 28% of 30 gallons-8.4 gallonsper hour,your at 68.4,now add some extra fuel to get the afr from what used to be a safe 13-1 to a more blower safe 11.5 afr,another 13% -8.892 gallons per hour,now your at 77.29 gallons per hour. My math is crude and might not be exact but I know I'm close. Now,keep in mind though,your boat that used to go 55 mph w/350 hp using 30 gallons per hour is now going 78 mph at wot using 77 gallons per hour (assuming your hull picks up 1 mph for every 15 extra hp and is propped correctly) so your using more fuel but your covering more water faster-and impressing all your buddies with how damn fast your boat goes!!! Smitty:D

You better check your math and re-read what you posted-
IF engine A has a BSFC of .41 and makes 500 hp-youll use 205 lbs per hour of fuel
If engine B has a BSFC of .61 and makes that same 500 hp-you'll use 305 lbs per hour of fuel,approx 50% MORE -NOT LESS.
Typically blower motors show a bsfc of .6 to .65 vs .5 to .55 on a N/A application because of the parasitic loss from turning the blower and the fact the afr is adjusted to run lower=richer to keep from burning holes in the pistons/detonation from extra work going on in the cylinders,of course I'm sure you already know this,Smitty

I measure mine by dollars per day. It SUX!