To those with 4.56 or 4.10 gears
#22
08-04-2010, 07:54 PM
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#23
08-05-2010, 08:02 AM
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Okay, I averaged everyone highway/city mpg's and then took those averages and compared the two gears and the 4.10's are averaging 14mpg h/c and the 4.56 averages 12mpg h/c. I know this is not extremely accurate due to different tire sizes, engines, location etc, but it may give a ballpark of how the two gears compare. I would still like to see more numbers....
#24
08-05-2010, 12:06 PM
Ok, bit of poking in the dark here. 
Seems most folks are re-gearing to keep RPM vs. Speed pretty much the same as stock. For me, that means a hair over 1500 RPM @ 60mph. Personally, I think that is a bit low. Of course, need to keep in mind, that I am unsure of what the powerband of our engines looks like. I think a better comparison might be mpg as compared to engine rpm at 60. (or freeway speed....) Gotta remember that dodge PURPOSELY geared these trucks for 'gas mileage' with the stock size tires. Which for most, I think is 245/70/16's? Their reasoning was probably "lower RPM at cruise speed means better fuel economy", which isn't necessarily the case.
I wonder if re-gearing to put your engine a bit further into the torque 'range' of operation wouldn't yield better fuel economy results? Or am I overthinking this?
Seems most folks are re-gearing to keep RPM vs. Speed pretty much the same as stock. For me, that means a hair over 1500 RPM @ 60mph. Personally, I think that is a bit low. Of course, need to keep in mind, that I am unsure of what the powerband of our engines looks like. I think a better comparison might be mpg as compared to engine rpm at 60. (or freeway speed....) Gotta remember that dodge PURPOSELY geared these trucks for 'gas mileage' with the stock size tires. Which for most, I think is 245/70/16's? Their reasoning was probably "lower RPM at cruise speed means better fuel economy", which isn't necessarily the case.
I wonder if re-gearing to put your engine a bit further into the torque 'range' of operation wouldn't yield better fuel economy results? Or am I overthinking this?
#25
08-05-2010, 12:35 PM
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Ok, bit of poking in the dark here.
Seems most folks are re-gearing to keep RPM vs. Speed pretty much the same as stock. For me, that means a hair over 1500 RPM @ 60mph. Personally, I think that is a bit low. Of course, need to keep in mind, that I am unsure of what the powerband of our engines looks like. I think a better comparison might be mpg as compared to engine rpm at 60. (or freeway speed....) Gotta remember that dodge PURPOSELY geared these trucks for 'gas mileage' with the stock size tires. Which for most, I think is 245/70/16's? Their reasoning was probably "lower RPM at cruise speed means better fuel economy", which isn't necessarily the case.
I wonder if re-gearing to put your engine a bit further into the torque 'range' of operation wouldn't yield better fuel economy results? Or am I overthinking this?
Seems most folks are re-gearing to keep RPM vs. Speed pretty much the same as stock. For me, that means a hair over 1500 RPM @ 60mph. Personally, I think that is a bit low. Of course, need to keep in mind, that I am unsure of what the powerband of our engines looks like. I think a better comparison might be mpg as compared to engine rpm at 60. (or freeway speed....) Gotta remember that dodge PURPOSELY geared these trucks for 'gas mileage' with the stock size tires. Which for most, I think is 245/70/16's? Their reasoning was probably "lower RPM at cruise speed means better fuel economy", which isn't necessarily the case.
I wonder if re-gearing to put your engine a bit further into the torque 'range' of operation wouldn't yield better fuel economy results? Or am I overthinking this?
The 4.56 gears would probably make the most sense for my set up, but I only plan on going as large as 33" tires so I don't want to overgear.
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08-05-2010, 03:44 PM
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#28
08-05-2010, 04:09 PM
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Easy way to find your "powerband."
Drive on highway and find the spot where your truck responds with relatively large amounts of speed for a very small amount of gas pedal. I kind of think of it as "floating" where you barely press the pedal and you really get going. Note the relative RPM's.
Taking you tire size into account, find a gear chart and tire size calculator to estimate the the RPMs at the speed that you want to travel (on highway or street) and plug that number into the calculator to find the gear size you want.
This may or may not be the most fuel efficient place to be, but it'll make it easier to pass people.
Modifications to your truck can affect this powerband as well. I know shorty headers, a round air cleaner, Fastman TB and cutting down the runners on my stock kegger helped passing efficiency, the air gap furthered that.
Drive on highway and find the spot where your truck responds with relatively large amounts of speed for a very small amount of gas pedal. I kind of think of it as "floating" where you barely press the pedal and you really get going. Note the relative RPM's.
Taking you tire size into account, find a gear chart and tire size calculator to estimate the the RPMs at the speed that you want to travel (on highway or street) and plug that number into the calculator to find the gear size you want.
This may or may not be the most fuel efficient place to be, but it'll make it easier to pass people.
Modifications to your truck can affect this powerband as well. I know shorty headers, a round air cleaner, Fastman TB and cutting down the runners on my stock kegger helped passing efficiency, the air gap furthered that.
#29
08-06-2010, 07:35 AM
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Easy way to find your "powerband."
Drive on highway and find the spot where your truck responds with relatively large amounts of speed for a very small amount of gas pedal. I kind of think of it as "floating" where you barely press the pedal and you really get going. Note the relative RPM's.
Taking you tire size into account, find a gear chart and tire size calculator to estimate the the RPMs at the speed that you want to travel (on highway or street) and plug that number into the calculator to find the gear size you want.
This may or may not be the most fuel efficient place to be, but it'll make it easier to pass people.
Modifications to your truck can affect this powerband as well. I know shorty headers, a round air cleaner, Fastman TB and cutting down the runners on my stock kegger helped passing efficiency, the air gap furthered that.
Drive on highway and find the spot where your truck responds with relatively large amounts of speed for a very small amount of gas pedal. I kind of think of it as "floating" where you barely press the pedal and you really get going. Note the relative RPM's.
Taking you tire size into account, find a gear chart and tire size calculator to estimate the the RPMs at the speed that you want to travel (on highway or street) and plug that number into the calculator to find the gear size you want.
This may or may not be the most fuel efficient place to be, but it'll make it easier to pass people.
Modifications to your truck can affect this powerband as well. I know shorty headers, a round air cleaner, Fastman TB and cutting down the runners on my stock kegger helped passing efficiency, the air gap furthered that.