2+MPG when using adaptive cruise and forcing 8th gear

[letapragas]

My morning commute is 41 highway miles and use adaptive cruise religiously. I can average between 50-85mph and I've recently noticed that I can control the gears when I'm using adaptive cruise. So as an experiment I forced my 2015 3.8 AWD Ultimate to stay in 8th gear for two weeks so when traffic occasionally slows me down to 50ish and clears.. instead of automatically shifting down to 6th or 7th to speed up it stays in 8th. I prefer this because it forces my car to accelerate slower thus break less when the car in front speeds up and breaks repeatedly. In 20 trips I've noticed a jump from 20.8mpg to about 22.5mpg.

Does anyone else use this trick and can someone verify if this could be dangerous to the transmission?

 

[dudmleh522]

My morning commute is 41 highway miles and use adaptive cruise religiously. I can average between 50-85mph and I've recently noticed that I can control the gears when I'm using adaptive cruise. So as an experiment I forced my 2015 3.8 AWD Ultimate to stay in 8th gear for two weeks so when traffic occasionally slows me down to 50ish and clears.. instead of automatically shifting down to 6th or 7th to speed up it stays in 8th. I prefer this because it forces my car to accelerate slower thus break less when the car in front speeds up and breaks repeatedly. In 20 trips I've noticed a jump from 20.8mpg to about 22.5mpg.

Does anyone else use this trick and can someone verify if this could be dangerous to the transmission?

I dont have adaptive cruise control but i manua shift mine every time i drive. I am just used to driving manual transmission my whole life before 2015 3.8 awd. I find brtter mpg when manual shifting vs having it in auto mode. By the way my commute is 120 miles everybday round trip pretty much all highway speeds between 55-75mph

 

[Mr. Incredible]

in my 2018 sport I can set the SCC to accel Slow, Normal, or Fast in the cluster settings. on slow the system does exactly what you are doing manually.
I average 22mpg using SCC on my commute 36 miles almost all highway. I just set it and let it do it's thing.

 

[Huey P. Freeman]

I really stopped using SCC after a few weeks because I found on my commute I got 2.5 mpg more (24.5 vs 22) not using it. It downshifts too aggressively when accelerating using SCC. A lot of times it doesn’t need to at all.

 

[EdP]

I really stopped using SCC after a few weeks because I found on my commute I got 2.5 mpg more (24.5 vs 22) not using it. It downshifts too aggressively when accelerating using SCC. A lot of times it doesn’t need to at all.

If you drive 10,000 miles, that is 46 gallons of fuel. Sometimes I don't think it accelerates fast enough. Depends on traffic.

 

[bigpapa0825]

My morning commute is 41 highway miles and use adaptive cruise religiously. I can average between 50-85mph and I've recently noticed that I can control the gears when I'm using adaptive cruise. So as an experiment I forced my 2015 3.8 AWD Ultimate to stay in 8th gear for two weeks so when traffic occasionally slows me down to 50ish and clears.. instead of automatically shifting down to 6th or 7th to speed up it stays in 8th. I prefer this because it forces my car to accelerate slower thus break less when the car in front speeds up and breaks repeatedly. In 20 trips I've noticed a jump from 20.8mpg to about 22.5mpg.

Does anyone else use this trick and can someone verify if this could be dangerous to the transmission?

How did you force it to stay in 8th?? I have no idea how to do that in my 2015 Ultimate.

 

[PMCErnie]

Lugging an engine is never a good idea.

What Is Engine Lugging - Why Lugging Your Engine Is Bad for Turbocharged Cars

 

[bigpapa0825]

Lugging an engine is never a good idea.

What Is Engine Lugging - Why Lugging Your Engine Is Bad for Turbocharged Cars

Thanx for that...

 

[Mr. Incredible]

Thing is if you set the car correctly it can do this on its own.

Initially I did complain here that it seemed to be too agressive with its braking and accel in SCC But once I tweaked the settings in SCC for slow accel and normal (not early) braking for collision avoidance. Then put the car in ECO mode and use 2 dots for distance when cruising and 3 dots when in stop and go traffic the SCCsystem works very well and very smooth for braking and acceleration.

I average 22mpg per tank and overall it has reduced my commute stress level significantly which is more important to me, I let the car do its thing and don’t get stressed over other drivers behaviors any longer.