Superchargers, Blowers, & Gas Milage?
03-16-2006, 10:28 PM
#11
Originally Posted by treyZ28
Performancetrucks.net: physics and logic need not apply.
03-16-2006, 11:42 PM
#12
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Originally Posted by 1slow01Z71
Personal experiences from numerous members dont count due to someone who can pull some numbers out of their *** that obvioulsy according to numerous members posts does not apply. Please you bore me
http://www.fordmuscle.com/archives/2...Line/index.php
Engineers have termed the volume required by an engine as Brake Specific Fuel Consumption, or BSFC. BSFC is the amount of fuel (in pounds) required to make one horsepower for one hour. A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at wide open throttle. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient.
The following are some general guidelines when choosing a BSFC number:
Low to medium performance street engines: 0.50
Performance engines with good cylinder heads: 0.45
Race engines with very efficient cylinder heads: 0.40 - 0.45
Supercharged and Turbo-charged engines: 0.55 - 0.60
Low to medium performance street engines: 0.50
Performance engines with good cylinder heads: 0.45
Race engines with very efficient cylinder heads: 0.40 - 0.45
Supercharged and Turbo-charged engines: 0.55 - 0.60
http://www.motorsportsdigest.com/tech/perform1.htm
# BSFC (Brake Specific Fuel Consumption) varies with application. Normally aspirated cars use between .45 and .55,
# Supercharged cars use between .55 and .65
# Supercharged cars use between .55 and .65
Conservation of energy also said "nay"
03-16-2006, 11:44 PM
#13
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Originally Posted by mjhoward
I understand what you say about drag with a blower and not increasing. i don't see how an increase in efficiency could happen by any means but with a properly sized turbo the entire efficiency of an engine increases. You have less pumping losses by being able to use more of the heat produced by the engine. We all know that an engine is basically a device that converts heat energy to mechanical energy.
Additinally, you have extra coolant flow, oil flow etc.
Think about it this way, how could it get better? Nevertheless 20% better!
20% increase in gas milage is insane.
03-16-2006, 11:49 PM
#14
Like I said bro obviously they dont mean **** to these people that are picking up mileage. Once again quit while ur ahead. You can talk it to death but the cold hard facts are that, many people INCLUDING blower people have experienced a gain in mileage. Have you ever had an s/c or turbo? I suggest you do a search on this site and see what alot have to say abotu mileage and FI when in lower boost settings.
03-17-2006, 12:01 AM
#15
don't wanna really get in the middle of this but it did say at wot in your post up there and maybe i'm wrong but we are talking cruising not drag strig mileage. or are we lol. i know in trucking magazine i think it was there 4.8 gained like 3mpg by going to the sts kit. if the thing can pull itself more efficiently by that i mean not haveing to floor it to go up a little hill like my little 4.8 did then wouldn't it yeild more mileage i know for a fact that my highway mileage shot from like 15mpg with the 4.8 to 20 mpg with the cammed ls1. now around town and racing yeah it sucks bad but highway is where i want the mileage anyhow. jmo, carry on lol
03-17-2006, 12:05 AM
#16
Pulled from one of your quotes, these numerical values apply only at wide open throttle.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
03-17-2006, 01:12 AM
#18
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Originally Posted by j's01silverado
Pulled from one of your quotes, these numerical values apply only at wide open throttle.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
With my Magnacharger and 5 speed I was only getting 15.5mpg babying it. I had a 3.0 pulley on it that pulled more drag on the engine and 1 bar tuning. With the 4.8 and that pulley it was almost imposible to accelerate at all without going into PE which was an instant 11-11.5:1. No my mileage didn't increase with it of course. Now with 2 bar tuning and a 3.7 pulley there might be a chance of it on hilly highways. On flat road I would doubt there would be any gains. This same goes for a turbo.
03-17-2006, 01:18 AM
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Originally Posted by j's01silverado
Pulled from one of your quotes, these numerical values apply only at wide open throttle.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
"A typical naturally aspirated street engine has a BSFC of 0.5, meaning it will consume one-half pound of fuel per horsepower per hour at WIDE OPEN THROTTLE. The BSFC goes down as engine efficiency rises. BSFC tends to go up with super and turbo chargers as they are not as efficient."
It only makes sense that as more throttle is applied, you are going to use more fuel and adversely affect your fuel mileage with any forced induction.
I think we are talking about gas mileage at cruising speeds not under boost.
its fuel usage per hp made. not mpg. very different.
my point was that they are less efficient, they use fuel.
aside from additional mass, if something is moving (like a pully that isn't even connected to anything) it is using energy. Its gotta come from somewhere!
03-17-2006, 01:32 AM
#20
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I experience the same as JamesB and agree I'd do it again. I can merge or pass effortlessly on the road where as before I would follow pissed but getting good mileage. Tuning helps but really more horsepower and torque is gained at the expense of mileage.