Gear Swap vs. Fuel Economy

[txfiremn]

Guess I'll test the under 2k theory out. I have a 80 mile commute to work. I always fill up befor going, so fuel weight or amount shouldn't be a factor. I'll see what I come up with when I set my cc at 2k instead of 75 mph.

[NAVAG]

Originally Posted by txfiremn Guess I'll test the under 2k theory out. I have a 80 mile commute to work. I always fill up befor going, so fuel weight or amount shouldn't be a factor. I'll see what I come up with when I set my cc at 2k instead of 75 mph.

I have about the same commute. 65-70mph gets me the best MPG. Much below 60 and the engine has to work harder in 6th gear. I usually reset my MPG each time I leave the house to make the 60 mile drive to work and IF I don't stomp on it much I get around 27-28. I got 29 on one trip but I drove 65 and slower the whole way. It's really hard to do. lol.

Not sure how accurate the MPG gauge is in the Premium but since I started driving slow I can make 2 1/2 trips to work and back before I fill it up again. Still too many miles and I'm going to buy a beater for DD asap.

[txfiremn]

Originally Posted by NAVAG I have about the same commute. 65-70mph gets me the best MPG. Much below 60 and the engine has to work harder in 6th gear. I usually reset my MPG each time I leave the house to make the 60 mile drive to work and IF I don't stomp on it much I get around 27-28. I got 29 on one trip but I drove 65 and slower the whole way. It's really hard to do. lol. Not sure how accurate the MPG gauge is in the Premium but since I started driving slow I can make 2 1/2 trips to work and back before I fill it up again. Still too many miles and I'm going to buy a beater for DD asap.

I wasa driving a 4 door Jeep on 35" tires and getting close to 15 mpg. So, the 20 mpg I'm getting out of the Mustang has been great. I'll slow try to slow down next time, lol. My commute is only every third day. There one morning, back home the next.

[DirtyD]

Originally Posted by txfiremn I was just thinking about this today. I took the kids to the Fort Worth Zoo today from Waco, I never got above 20.8 mpg. I was traveling, on average, at 75-80 mph with an A6 an stock 5.0.

The auto has a shorter OD ratio in 6th gear than the manuals do. 75-80 MPH in an auto is like turning 2400 RPM.

Originally Posted by NAVAG Mine has 3:31 Gears or what Ford calls "Rear Axle Promo Pack" With Bama performance tune on the Highway I get 27-28 MPG...when I go the speed limit and I set Cruise Control. Above 2K RPM and the MPG drops like a ton of bricks.

I have gotten 25-25.5 multiple times on trips home, south of Houston, doing 80-85 on I45 almost the entire time. Surprisingly the over 2k theory isn't as bad on these cars as I've seen in the past. I've actually found that there is a second sweet spot around 80 MPH that if you set cruise at, you can still get good MPG for the speed and RPM you are turning.

Originally Posted by NAVAG I have about the same commute. 65-70mph gets me the best MPG. Much below 60 and the engine has to work harder in 6th gear. I usually reset my MPG each time I leave the house to make the 60 mile drive to work and IF I don't stomp on it much I get around 27-28. I got 29 on one trip but I drove 65 and slower the whole way. It's really hard to do. lol. Not sure how accurate the MPG gauge is in the Premium but since I started driving slow I can make 2 1/2 trips to work and back before I fill it up again. Still too many miles and I'm going to buy a beater for DD asap.

The in dash MPG calculator is really accurate. I've hardly ever been more than +/- 0.5 MPG off hand calculations with it, and over the life of the car it's been a running average of +/- 0.3 MPG difference