27.4 MPG on the interstate!
On my stock tune I have been getting 26-27 on the highway @ 65mph. I can average 23 town and highway combined if I keep my foot out of it. Much better than before the factory reflash.
Well MPG is a big deal to me as I want my cake and I want to eat it too.
As far as why some cars do better on cruise then others, a lot of that depends on what kind of terrain you are driving on, and how much power your car has. In my 06 2500HD Duramax/Allison I can get 21-22 MPG on flat hwy running 35" tires. My original 245/75-16's would do much better. Now if I get into the East Texas hilly area's and leave it on cruise then MPG's go to hell as every time it goes down a dip the throttle gets pulled and is still pulled when it hits the bottom and starts going back uphill. At that point it really throws the fuel to it to try and get back up to speed and it invariably overshoots and pulls throttle again.
Now on level pavement I cannot be as precise as the cruise, but in hilly areas I can see ahead and anticipate adding throttle before I get to the incline, or pulling throttle as I start going downhill before the cruise would know to.
If your car has more power then it is not as big of a deal going up/down as it is easier to keep up without overshooting. My truck is running 450+ crank hp and 900 ft/lbs tq so even though it weighs 7000lbs it does alright until I throw 10,000-20,000 lbs behind it and then the cruise is all over the place going up and down hill.
As far as why some cars do better on cruise then others, a lot of that depends on what kind of terrain you are driving on, and how much power your car has. In my 06 2500HD Duramax/Allison I can get 21-22 MPG on flat hwy running 35" tires. My original 245/75-16's would do much better. Now if I get into the East Texas hilly area's and leave it on cruise then MPG's go to hell as every time it goes down a dip the throttle gets pulled and is still pulled when it hits the bottom and starts going back uphill. At that point it really throws the fuel to it to try and get back up to speed and it invariably overshoots and pulls throttle again.
Now on level pavement I cannot be as precise as the cruise, but in hilly areas I can see ahead and anticipate adding throttle before I get to the incline, or pulling throttle as I start going downhill before the cruise would know to.
If your car has more power then it is not as big of a deal going up/down as it is easier to keep up without overshooting. My truck is running 450+ crank hp and 900 ft/lbs tq so even though it weighs 7000lbs it does alright until I throw 10,000-20,000 lbs behind it and then the cruise is all over the place going up and down hill.
330 per tank is all highway at under 70mph...and that is the grandpa mode..in the mixed driving best mpg record is 300 a tank and it was REALLY close to walking to the gas station..it was stumbling when I got to the pump!!!!
Hehe, well that's what you call cutting it close 
300 miles is still pretty impressive.
I average about just over 400 km's a tank (~250 miles) with mixed city/hwy/rush-hour driving, which actually isn't too bad. I haven't taken the car on extended highway trips but from the shorter trips I've done on the highway, I see the tank average hit approximately around 24mpg (compared to ~18.5mpg in the city).. so 27 on the highway definitely seems doable.
Hopefully a new intake/drop-in filter will help lean the system out.
300 miles is still pretty impressive.I average about just over 400 km's a tank (~250 miles) with mixed city/hwy/rush-hour driving, which actually isn't too bad. I haven't taken the car on extended highway trips but from the shorter trips I've done on the highway, I see the tank average hit approximately around 24mpg (compared to ~18.5mpg in the city).. so 27 on the highway definitely seems doable.
Hopefully a new intake/drop-in filter will help lean the system out.
