I have an '06 39s Discovery which has about 14,000 miles on it. Currently I get about 7.1 miles per gallon towing. I just recently noticed that I have an economy mode setting for my Allison transmission.

Does anyone have any experience as to whether the economy mode increases miles per gallon?

Also, I'd be interested as to what to expect for mpg once my engine is broken in.

Thanks for any assistance.

Mike R

I doubt if you'll see much mpg improvement from the economy mode. Basically what economy does is change the shift points slighty. I generally run in econo, but its basic help is in geting away from the anoying down/up shifting on rolling terrain.

Your mileage will depend on many factors...total weight, the way you drive, speed you cruise at, engine.

My 03 Advantage, currently about 34000 lbs and towing a 3000lb Saturn is running 9mpg. This is with a 350 ISC Cummins, cruising at 60mph and using the cruise control. I don't race to stoplights and try to accelerate smoothly. I currently have 76000 miles on the coach, but I've been running about 9mpg since around 40000 miles.

Robb & Sue Steinheider
Duncan the Dalmation
03 Ultimate Advantage
02 Saturn L100 Toad

quote:

Originally posted by Mike R:
I have an '06 39s Discovery which has about 14,000 miles on it. Currently I get about 7.1 miles per gallon towing. I just recently noticed that I have an economy mode setting for my Allison transmission.

Does anyone have any experience as to whether the economy mode increases miles per gallon?

Also, I'd be interested as to what to expect for mpg once my engine is broken in.

Thanks for any assistance.

Mike R

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You will need 40,000-50000 miles on both the engine and tires before you hit the peak performance. What engine is in your 06? If CAT which I believe is all they used in that year then you may not see much beyond high 7's based upon earlier CAT D's performance. That said, speed will be major determinate since aerodynamic loss increases at the cube of speed which really kicks in above 50 MPH.

Leo,

Thanks for the info. You're correct, I have a C-7 330 Cat engine in my '06 Discovery.

Based on what you are saying, my mpg will stay in the 7's.

Thanks for the info.

Mike R.

Can you give us a link to that total load versus required power graph? Very interesting.

I don't agree. I have a 2006 Discovery 39J and tow an 07 Wrangler or a 16' enclosed trailer full of off road vehicles. Either way, I get high 8's and if I keep it at 55 mph, up to 9 mpg. I have a similar amount of miles on mine.

I always run in the Econ mode. Our trip west for the winter we averaged 8.6 and this trip to Nashville was 10.3 (no wind and only 62 mph.) We have a 370 hp Cummings and it is just getting broken in.