Most fuel efficient speed?
Melting Slicks
Joined: Dec 2000
Posts: 2,629
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From: Lawrenceville PA
It's how you get to that magic number that impacts gas mileage more than the cruising speed. Jack rabbit starts and and goosing the gas pedal kills your average, but then again isn't that why we bought a Corvette to begin with?
Team Owner
Joined: May 2005
Posts: 23,682
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From: Flagstaff Az.
When mine was stock(3:15's) I got 30-31 at 80 and the slower I drove the less mileage I got. I drove 2000 miles from Fla. to Az. with is and tried different speeds just to check it out. Below and over 80 produced 1 or 2 miles per gallon less. Could have been due to the fuel differences, but I used Chevron each stop.
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Joined: Mar 2004
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From: Fort Wayne IN
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75-80 in sixth got me right at 30mpg on 60# injectors. I'm happy with that.
Burning Brakes
Joined: Sep 2005
Posts: 987
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From: Braidwood Il.
I'm a retired engineer from a major US auto maker, it was my job every once in a while to check fuel economy on certian vehicles. You would go 55mph(not 1 mph more) on a straight road with NO wind for 10 miles out and 10 miles back and thats how we determined mpg.
But who wants to drive a vette 55 mph. Maybe you would do it in a taurus. Thats why I bought a vette when I retired.
But who wants to drive a vette 55 mph. Maybe you would do it in a taurus. Thats why I bought a vette when I retired.
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From: Marlton. Increasing performance one speeding ticket at a time! NJ
There's no such thing as most fuel efficient speed. What your really looking for is most efficient RPM, which i believe is somewhere around 1500RPM for a stock LS1, below that, the engine is not operating as efficiently as it could, above that pumping work and other factors require more fuel to increase RPMs.
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
Life Time NCM #2196
Joined: Sep 2004
Posts: 82,572
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From: Converse TX
There's no such thing as most fuel efficient speed. What your really looking for is most efficient RPM, which i believe is somewhere around 1500RPM for a stock LS1, below that, the engine is not operating as efficiently as it could, above that pumping work and other factors require more fuel to increase RPMs.
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
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Instructor
Joined: Feb 2007
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From: San Francisco CA
There's no such thing as most fuel efficient speed. What your really looking for is most efficient RPM, which i believe is somewhere around 1500RPM for a stock LS1, below that, the engine is not operating as efficiently as it could, above that pumping work and other factors require more fuel to increase RPMs.
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
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From: San Francisco CA
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St. Jude Donor '08
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From: . New York
So Im guessing that I'm the only one that looks at that "Instant MPG" thingie we have on the DIC ? Either that, or no one is mentioning it because it's not accurate?
Becuase I often play with that while on long trips (out of bordom on some roads).
Going by the instant mpg display, my most efficient speed/rpm on a flat road would be a lot closer to 60 than 80? (about 29-30 mpg).
When I lean on it coming out of a toll booth I can get it down to about 3 mpg
Becuase I often play with that while on long trips (out of bordom on some roads).
Going by the instant mpg display, my most efficient speed/rpm on a flat road would be a lot closer to 60 than 80? (about 29-30 mpg).
When I lean on it coming out of a toll booth I can get it down to about 3 mpg
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I've gotten my best MPG when going 75 mph/6th gear/cruise control engaged. Got 30+ mpg that way.
Intermediate
Joined: Feb 2008
Posts: 49
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From: Austin Tx
I drove about 1 1/2hrs on open hwy this last weekend and averaged 33mpg at 75-80mph
I was going 75 when i reset the average... the getting to 75 is what uses the most gas IMO
Vortex intake, long tubes, bassani x-pipe, bassani x-back exhaust
City driving i average 16-17mpg... little more if i drive the car like a granny
I was going 75 when i reset the average... the getting to 75 is what uses the most gas IMO
Vortex intake, long tubes, bassani x-pipe, bassani x-back exhaust
City driving i average 16-17mpg... little more if i drive the car like a granny
Le Mans Master
Joined: Feb 2006
Posts: 5,267
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From: Phoenix AZ
There's no such thing as most fuel efficient speed. What your really looking for is most efficient RPM, which i believe is somewhere around 1500RPM for a stock LS1, below that, the engine is not operating as efficiently as it could, above that pumping work and other factors require more fuel to increase RPMs.
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
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Burning Brakes
Joined: Oct 2003
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From: Foresters Falls(near Ottawa) Ont
Burning Brakes
Joined: Sep 2006
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From: Cumming Georgia
There's no such thing as most fuel efficient speed. What your really looking for is most efficient RPM, which i believe is somewhere around 1500RPM for a stock LS1, below that, the engine is not operating as efficiently as it could, above that pumping work and other factors require more fuel to increase RPMs.
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
So whatever speed you go in a certain gear at 1500RPM's (give or take) will determine the most fuel efficient speed. That number will be different for manuals vs automatics, and again different depending on rear gear ratio.
Going 1500RPM's in 1st gear takes the exact same fuel as 1500 RPM's in 4th (auto) or 6th (manual).
I go by average mpg, and while the mpg numbers look good on freeway mileage, I have to deal with off freeway miles too, along with a 3200 stall converter, A4 and 2.73 gears. That being said, the car seems to do best mileage wise at right around 60mph, which happens to be around 1500 rpm. Average is 24mpg combined city/highway. One week I got up to 25mpg average, but it was difficult. One thing I learned to do was turn my heating and air conditioning off, which seems to stop that flippin' air conditioner compressor from running when the outside temperature is between 35 and 65 degrees Fahrenheit.
My .02 worth,
Tim Glover