Jump to content

Do The 6 Speed Gas Really Get Better Mpg Then The 4


Recommended Posts

what kind of rpms do the 6 speed run on the highway vs the 4 and

 

My 6.2 6-speed with 3.73 gears gets the same mileage as my previous 6.0 Vmax 4-speed with 4.10 gears. But it does turn a few less RPM's on the highway so I'm sure that helps offset the larger motor some.

 

I'm sure apples to apples, You'd pick up 1-3 mpg better.

Link to comment
Share on other sites

well Im thinking of getting a 2500 since I have a plow, I don't really want to kill my 1500, I have to be mindful of plow operation right now, and I tow a 6200lb trailer in the summer with a big block boat. This would be much easier on a 2500 6.0 or even a duramax $$.

just wondered what the 6.0 with the 6spd and a tune could get on the highway. If its near my 1500 with a 4spd and 3.73 I turn 2000rpm on the highway

Link to comment
Share on other sites

I'd say highway you'd get easily 18mpg with the 6.0 6-speed and 3.73 gears. My previous Vmax got 13-19mpg average with the 4-speed and 4.10's. Given the extra weight and all, plus the 6-speed, you'd most likely be about the same for an average.

Link to comment
Share on other sites

The 6 speeds are supposed to get better mileage in city driving and mixed as well because the ECM has 6 gears to choose from and the engine isn't winding out as much.

 

DEWFPO

Link to comment
Share on other sites

I tend to be a little liberal with the speed limit here in MD, averaging 70-75 mph on a 45 mile hwy commute and I average about 15 in the summer and 14 now that it's winter......I have a 6.0 6 speed with 3.73's....I imagine I would increase my MPG's if I left a little earlier and slowed down but........

 

Dave

Link to comment
Share on other sites

GM states that the 6-spd adds "up to 4% increase in efficiency" over the 4-spd auto. If you take AFM into account, it's probably closer to "none" in daily driving. Actual EPA city/hwy mpg rating on the 5.3/4-spd is 15/20. Same rating for the 5.3/6-spd is 15/21. I'd guess the non-AFM 6.0HD motor would benefit to the full "4%" improvement.

Link to comment
Share on other sites

Right now im getting 14.9-15mpg in the city only driving, with my 2011 2500, I have yet to get on the highway for more than a mile or two. When im doing about 70mph on that short stretch i think im at 1450-1500rpm?? but will double check.

MPGS149.jpg

Link to comment
Share on other sites

My buds 07 gmt-900 4x4 1/2 ton 4 speed 5.3 3:73s gets 20+

 

I seriously doubt that. And even if, this would be in a very narrow speed range, with the AFM activated, and A/C off, crusing around 65 MPH. The moment you go over 70 MPH with A/C on, the highway mileage drops to 18 at best.

Link to comment
Share on other sites

I seriously doubt that. And even if, this would be in a very narrow speed range, with the AFM activated, and A/C off, crusing around 65 MPH. The moment you go over 70 MPH with A/C on, the highway mileage drops to 18 at best.

 

Not true. I've measured mine by hand and checked the DIC many times. I've yet to average less than ~19.5 on long trips running the speed limit +5 (2wd mode). Usually, that's 65 to 75 mph. The DIC has registered over 20 on most trips, but actual is usually a few tenths less. FWIW, mine goes to 4-cyl mode a lot, where some folks on here report that it doesn't. I'm currently "stock". Also, ambient temps effect mpg. I notice a drop on very cold days with the same gas.

 

If I could get the same (or similar) mpg as my 5.3... it would be my next truck. That would mean that I could pull the camper more comfortably with minimal impact on daily driving. I don't see it being close, based on all input I've gotten (both online and from friends).

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.