[RichieRich]

So on my first day from picking up my car I took the car on a drive for about 150 miles. On that trip the computer showed 29.7 Average speed about 70mph. My trip from home to work and vise versa the highway max speed is 55mph but i usually go around 60-65. I noticed my computer has dropped alot all the way to 22.4 mpg but I do mostly highway which confused me a bit. So yesterday I decided to play with manual mode and noticed that the ascent wont use the 8th simulated gear and stays in 7th unless you go past like 75mph. So i decided to leave my car in manual mode when highway cruising and just put into 8th gear, now my mpg has gone up to 23.1 and noticed that the meter is usually in green even when trying to pick up speed a little. Now I do realize the car is at a lower rpm like 1700rpm opposed to like 2100rpm and that can bog the engine but its not like im going Wide Open Throttle im just cruising. Maybe someone can give it a try and see if there is a difference.

 

[Engelwood]

This is an awesome tip. Tried this today and anecdotally saw much better mileage than keeping it in D.

Wondering if the lower RPMs are keeping the turbo from kicking in and lowering mileage?

Realize it's only one trip so it's hard to say one way or another, but I'll be testing going forward.

 

[zulater]

Does manual mode take away adaptive cruise control?

 

[RichieRich]

Does manual mode take away adaptive cruise control?

I dont think it does but you can set the adaptive cruise control to eco mode and it does a great job of saving gas. It has the same effect. I can confirm that using manual mode when cruising on the highway helps in a big way. I just cruise in 8th gear and when i need to pick up any speed i just down shift to 7 and once im at a steady speed I got back to 8. This is my second tank and ive done more city driving and spirited driving and im still getting 22.5/23 mpg by using this method when im just cruising

 

[zulater]

Adaptive cruise control works in manual mode.
I'm thinking confirmation bias but I seemed to get better mileage doing this as well. Seems odd that the engineers wouldn't lock "8th gear" in cruise for better mileage but we'll see.

I'm wondering if it's really true or if I just paid more attention to making sure it was better. I'm not 100% convinced yet but it does appear to help.

 

[Rustkolector]

Manual mode MPG improvement

I to have found definite on highway fuel consumption improvements using the Manual mode but with a caveat. The simulated 8th speed is a bit too high for anything but very flat highways since the current turbo torque curve isn't helping in the 1500-1600 RPM range. Kia 2.0T and others bring on the turbo starting at 1400 RPM which if done with the 2.4T would allow use of the 8th speed on most all Interstate highway grades without downshifting in Manual, and probably very significant on highway MPG improvement.

 

[bverant]

I to have found definite on highway fuel consumption improvements using the Manual mode but with a caveat. The simulated 8th speed is a bit too high for anything but very flat highways since the current turbo torque curve isn't helping in the 1500-1600 RPM range. Kia 2.0T and others bring on the turbo starting at 1400 RPM which if done with the 2.4T would allow use of the 8th speed on most all Interstate highway grades without downshifting in Manual, and probably very significant on highway MPG improvement.

The more I am experimenting with it, it seems that the Ascent didn't need that 8th gear entirely. It's wasted at highway speeds in Drive mode because of the frequent downshifts to 7th and then the upshift back to 8th, causing that stutter/shudder that some people, myself included, have been complaining about.

 

[pilot1226]

Cool trick. I've found in certain situations on flat highway even my 2011's CVT will get improved MPG when in manual "6" vs D. I think the standard setting on the CVT likes to keep some power at the ready in the event you need to get power and pass someone... I've run non-adaptive "Standard" Cruise Control in Manual Mode on my Outback, and it will not shift for you - you'll need to downshift to 5th or 4th to start getting some acceleration.

But, it is a good technique you've found, especially if you know you're going to be on a flat highway for a while.

Do you run your "cruise" parameters in "Eco" mode right now?

 

[BoxerRules]

Does the Adaptive Cruise Control work in manual transmission mode? That would be interesting to try out.

 

[other.guy]

So on my first day from picking up my car I took the car on a drive for about 150 miles. On that trip the computer showed 29.7 Average speed about 70mph. My trip from home to work and vise versa the highway max speed is 55mph but i usually go around 60-65. I noticed my computer has dropped alot all the way to 22.4 mpg but I do mostly highway which confused me a bit. So yesterday I decided to play with manual mode and noticed that the ascent wont use the 8th simulated gear and stays in 7th unless you go past like 75mph. So i decided to leave my car in manual mode when highway cruising and just put into 8th gear, now my mpg has gone up to 23.1 and noticed that the meter is usually in green even when trying to pick up speed a little. Now I do realize the car is at a lower rpm like 1700rpm opposed to like 2100rpm and that can bog the engine but its not like im going Wide Open Throttle im just cruising. Maybe someone can give it a try and see if there is a difference.

Thanks for the tip. Will try this definitely!

 

[GaryInMI]

Yesterday, I tried switching from "D" to "M" on a flat stretch of interstate highway, the ACC was set for 70 MPH and everything was warmed up from the previous 150 miles of the trip. The tach immediately jumped up about 200 rpms when I slid the shifter over into "M". When I manually upshifted into "8th" the rpms dropped right back to where they were in "D". So I was definitely cruising in 8th. My indicated average gas mileage for this 176 mile trip was 26.8. Except for 4 miles of surface streets it was all interstate using the ACC with the default acceleration setting.

 

[denissh]

... for speeds 60MPH+ "D" and "M8" i get same RPM's