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Are the 4.10's more fuel efficient than 3.73's?

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sanda

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Having both this is my first real road test empty. 2021 hemi 8 speed with 4.10's vs. 2014 hemi 6 speed with 3.73's. Total of 453 miles. 200 miles at 75 mph, 100 miles at 65 mph, and the balance pulling 4 high mountain passes with steep grades and slow curves.
The 4.10's allow the cylinder deactivation to engage often while with the 3.73's seldom engaged.
Evic reading read 18.7 while actual hand calculated was 18.26.
I think with the 4.10's running on 4 cylinders more than the 3.73's the improvement is understandable.
I also was running 85 octane as our regular gas.
Notice the range that can be expected with the 50 gallon tank.
This is real world test over many driving conditions
Hope it helps those trying to decide on what gear ration they want.
20221027_092957[20779].jpg
 
I run close to 100mi per day on 4.10s and 37's. Around town the EVIC really gives sucky numbers (I have seen 11 just putting around place to place downtown with lots of idling). When I just do my commute which is 1 lane country (35mph), 2 lane blacktop(60mph), 4 lane highway (65mph not interstate), and back down to inner city (25ish mph), I can get the EVIC back up to 14.5.

I think my 37's make the 4.10's more like 3.73's.
 
ClawSS said:
I run close to 100mi per day on 4.10s and 37's. Around town the EVIC really gives sucky numbers (I have seen 11 just putting around place to place downtown with lots of idling). When I just do my commute which is 1 lane country (35mph), 2 lane blacktop(60mph), 4 lane highway (65mph not interstate), and back down to inner city (25ish mph), I can get the EVIC back up to 14.5.

I think my 37's make the 4.10's more like 3.73's.
Click to expand...
And if you think your evic numbers are bad try hand calculating to get your real mileage. It might bring a tear to your eye. Cancel that. Don't want to ruin your day.
 
Its not the diff gears that make much of the difference its the 8speed, you usually only see 1-2mpg difference between the 3.73 and the 4.10s
 
That must be a lemon.

Or maybe it is just envy. I didn't even get through my first full tank before adding lift and moving up to 37s so no clue if I could have done that in mine, but I'm still happy with the consistent 13.5-14 and 600+ mile range when not towing.

But back to the comparison, I came from a 2016 with 3.73s with very nearly the same mods. In that I saw about 1mpg lower (12.5-13). Just as tchur1 and Helzsn1p3r mentioned, I attributed it to the 8 vs 6 speed.
 
I get pretty close to that with my 2020 on 35's. I have found that if I am doing mostly highway miles my evic and hand calculations are really close. If it is just day to day driving my evic is optimistic.
4BAF6586-0135-4182-BB1C-8E82A72AF445.pngB5E71088-B884-48E6-8BB0-23BEFCAF351E.jpegD2ADF8C5-D15E-48C0-9BBA-347798EA421B.jpeg7CAAEC7B-3FE3-4557-AAC0-0BC45BAB231E.jpeg
 
$4.50ish a gallon here in ID. I did pay $7.25 a gallon recently, but it was the only gas for many miles of dirt “road”.
 
H3LZSN1P3R said:
Its not the diff gears that make much of the difference its the 8speed, you usually only see 1-2mpg difference between the 3.73 and the 4.10s
Click to expand...
Best I ever got with my 2014 3.73's was 16.96 with speeds at 65. I'm sure the 8 speed helps with mileage but I also think with the 4.10's and running on 4 cylinders more often also helps.
Even at 2 mpg better mileage empty it adds up quick as I do a lot of traveling via TT. Old truck 9.3 longtime average, new truck 10.5 + longtime average.
 
sanda said:
Best I ever got with my 2014 3.73's was 16.96 with speeds at 65. I'm sure the 8 speed helps with mileage but I also think with the 4.10's and running on 4 cylinders more often also helps.
Even at 2 mpg better mileage empty it adds up quick as I do a lot of traveling via TT. Old truck 9.3 longtime average, new truck 10.5 + longtime average.
Click to expand...
It has less to do with the 4.10s than you think as the tire size difference from a stock 14 truck (31.7”) to the stock new truck (33”)negates the rear end difference…. Usually you get less millage on the highways with 4.10 your gains are all thanks to the 8speed.
 
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I can’t compare to anything else, but my 2020 Hemi w/ 4.10s gets great MPG performance the best has been 19 MPG. However, daily about 16.
 
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