$$$frumnuttin'

I swear I am getting better gas mileage driving in 6th instead of 7th....anyone else notice this, or have data to support?

mdiiulio

Depends on how I'm driving really. Up hill, 6th... Down hill, 7th... Cruise control at 60mph, 6th... cruise set at 80, 7th... It all depends

jagamajajaran

There have been discussion on this topic and many have come to the conclusion that better fuel economy at highway speeds can be found in 6th instead of 7th. The engine seems to perform more efficiently at the higher RPM level in 6th than it does in 7th. My personal experience has been that the better fuel economy is indeed in 6th.

RocketGuy3

It's hard to imagine GM's engineers making such a terrible oversight. If this is true, 7th gear is pretty much entirely pointless.

jagamajajaran

I don't think that's the case at all. I just think that 7th gear most likely performs the most efficiently at speeds higher than what most US highway speed limits are. My personal experience is that the most efficient RPM for my C7 is right around 1500. If I'm running in 7th at 70 mph, I'm running at something around 1250 RPM.

LS6GXP

75-80mph 7th slower than that 6th. Thats been my experience

runutzzzzz

As others have mentioned it all depends on your driving style and what terrain you are one.

Flat highway and you're cruising along at 70-80 and very gentle on the throttle then 7th will always win. Lower RPM so the engine drinks less.

LIStingray

Roads on Long Island are as flat as anywhere.
If I am running steady at 70 mph (in V8 mode) in 6th I get and indicated 31-32 mpg, while in 7th it indicates 33-34. I haven't tried it in V4 mode.

birdflu

6th gear in touring mode gets me a steady 31MPG on the highway with the cruise set at 72MPH. 7th gear in echo mode at the same speed, I have never been over 28MPG. I never use 7th gear anymore.

TEXHAWK0

On my last highway trip to Abilene, I decided to leave it in 6th so I could use cruise control and not worry about lugging the engine going up hills and I got 32.9 MPG....and not in ECO mode.... Don't know how I could do much better than that...

aj98

For mine, in v8 mode, mpg in 6th is better than mpg 7th below 70-72mph. Above that, 7th is better.

87C4_4spd

I never really use 7th in my driving around town and my commute to work and back. Maybe if I take a long trip or am on the Autobahn someday...lol

jagamajajaran

It appears that 7th may perform better than 6th when it's not under too much load, like in your case on flat roads.

$$$frumnuttin'

ok, thanks guys....I guess I am not imagining things.

fsvoboda

Somewhat on a tangent, my wife's Jeep Cherokee (9 speed auto transmission) almost never gets above 8th gear. Reports are that you have to be traveling 80 or above to reach 9th, which may be the same principle at work that you mention.

wgood

That would only happen if you are driving on slightly hilly terrain and the car is lugging and 6th might be better than 7th otherwise less revs means better mileage in most cases !!!! Wayne