mpg
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From: Santa Monica-SoCal
mpg
going the speed limit for faster = bad mpg
In a typical family sedan, every 10 miles per hour you drive over 60 is like the price of gasoline going up about 54 cents a gallon. That figure will be even higher for less fuel-efficient vehicles that go fewer miles on a gallon to start with.
http://finance.yahoo.com/family-home/artic...ve-a-Lot-of-Gas
In a typical family sedan, every 10 miles per hour you drive over 60 is like the price of gasoline going up about 54 cents a gallon. That figure will be even higher for less fuel-efficient vehicles that go fewer miles on a gallon to start with.
http://finance.yahoo.com/family-home/artic...ve-a-Lot-of-Gas
it costs to be cool.
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From: Sewell, NJ
What do you drive Brock? If its the Z28 Camaro in your signature it could be a few things. I don't know if it has the ridiculously low ratio GM overdrive that sips gas, but sometimes they lug if you aren't going fast enough and the older computers increase the fuel thinking you are going to stall. This you would be able to notice though and 65 is certainly fast enough.
If its an automatic, bracket racers like those, the converter may not be locking up at 60, or the clutches are slipping and not allowing full lockup until higher in rev band. In a 11 year old car this would be my pick.
Poor atomization of the fuel is another possibility. Under light load the fuel pressure may not be high enough to get proper air/fuel mixtures and thus flame propogation inside the cylinder, but with a little extra throttle and more fuel pressure it may atomize and burn better, basically dirty injectors. The bad burn inside the cylinder gives poor readings on the O2 sensors in an open loop type injection system.
I know my S does worse the faster I go, at 50-60 I can get over 30mpg, but at 70-80 It drops to 27. I checked this a couple times on highway only runs.
If its an automatic, bracket racers like those, the converter may not be locking up at 60, or the clutches are slipping and not allowing full lockup until higher in rev band. In a 11 year old car this would be my pick.
Poor atomization of the fuel is another possibility. Under light load the fuel pressure may not be high enough to get proper air/fuel mixtures and thus flame propogation inside the cylinder, but with a little extra throttle and more fuel pressure it may atomize and burn better, basically dirty injectors. The bad burn inside the cylinder gives poor readings on the O2 sensors in an open loop type injection system.
I know my S does worse the faster I go, at 50-60 I can get over 30mpg, but at 70-80 It drops to 27. I checked this a couple times on highway only runs.
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http://en.wikipedia.org/wiki/T-56
3.42 rear end + the gear ratio's in the link above.
one word, sixth gear. 5th gear at 60 is around 2000rpm, @ 70 its around 2350, and at 75 its around 2600rpm. At 70mph in sixth I can chug along at 16XXRPM, and even at 80mpg, I am at 1800rpm.
The best part is during stop and go traffic, the gas milage drops to well under twenty to the mid teens.
Basically this article assumes you have a 4 speed automatic 4 cylinder that makes no torque, and has to work overtime as a result of drag going up with the square of ones speed. I bet a 4 cylinder in a ubiquitous civic or camry is at almost 3000rpm if not higher between 70 and 80mph, because the gear ratio's are spread out for more torque for city driving. It does not take into account larger displacement motors with more torque and 6 gear ratios.
3.42 rear end + the gear ratio's in the link above.
one word, sixth gear. 5th gear at 60 is around 2000rpm, @ 70 its around 2350, and at 75 its around 2600rpm. At 70mph in sixth I can chug along at 16XXRPM, and even at 80mpg, I am at 1800rpm.
The best part is during stop and go traffic, the gas milage drops to well under twenty to the mid teens.
Basically this article assumes you have a 4 speed automatic 4 cylinder that makes no torque, and has to work overtime as a result of drag going up with the square of ones speed. I bet a 4 cylinder in a ubiquitous civic or camry is at almost 3000rpm if not higher between 70 and 80mph, because the gear ratio's are spread out for more torque for city driving. It does not take into account larger displacement motors with more torque and 6 gear ratios.
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From: Sewell, NJ
For a stick it would be the highest gear at the lowest revs without lugging or bogging. On flat roads in the S2000 that is around 40 in sixth, but that is highly impractical and will probably get you more than a few dirty looks on the highway. In an automatic it would be the highest gear a few miles an hour over the speed at which the converter locks up.
For efficiency there are formulas but they aren't the best for MPG calculations as they are typically peak power at 3/4 throttle or WOT. Full throttle tends to dump too much fuel to avoid possible lean conditions but 3/4 allows the throttle body to be most of the way open but still using a decent fuel mixture. So depending on how good your tune is it is typically one or the other.
http://www.heumann.com/m5/hp_torque.html
An article on how leverage effects acceleration. Transmissions, rear ends, tire circumference, etc. In one of the charts towards the bottom it has force in pounds at the rear wheels assuming 15% drivetrain loss. If you weren't confused before you are now.
For efficiency there are formulas but they aren't the best for MPG calculations as they are typically peak power at 3/4 throttle or WOT. Full throttle tends to dump too much fuel to avoid possible lean conditions but 3/4 allows the throttle body to be most of the way open but still using a decent fuel mixture. So depending on how good your tune is it is typically one or the other.
http://www.heumann.com/m5/hp_torque.html
An article on how leverage effects acceleration. Transmissions, rear ends, tire circumference, etc. In one of the charts towards the bottom it has force in pounds at the rear wheels assuming 15% drivetrain loss. If you weren't confused before you are now.
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Optimum RPM doesn't really have anything to do with it. I mean engines are most efficient at a specific RPM and load, but thats really minimal. Things like internal resistance of the engine, rolling resistance from the tires, don't really scale with speed. What you're overcoming primarily at highway speed is drag, and power increases with the cube of speed.
It takes more than twice as much power to over come the drag at 80mph than it does at 60 mph. Rolling resistance of the tires also goes up as you travel faster, but it isn't as drastic. Finally theres the drivetrain loss - varies from engine to engine, but in the range most people cruise at (60-100 mph) its not going to vary much.
It takes more than twice as much power to over come the drag at 80mph than it does at 60 mph. Rolling resistance of the tires also goes up as you travel faster, but it isn't as drastic. Finally theres the drivetrain loss - varies from engine to engine, but in the range most people cruise at (60-100 mph) its not going to vary much.