Most Fuel Efficient Engine/trans?

[NotStock]

Im shopping around for a used rig to stretch and convert. I will be building a 40'-42' total length conversion with a large rear garage that is apart of a portion of the living quarters. I plan on towing a 8k lb boat regularly and want it to be fully capable to tow a legitamite weight since I cannot tell what the future holds and dont want to wish I had done ***blank***. I am leaning towards a T2000 as I really like the dash/body design prob in the 1998-2000 era as my budget is $15k. From doing alot of research I lean towards a cummins M11 in a 370 or 400 hp configuration. What do you all think is the most fuel efficient engine/trans? Is this combo available in the T2000? Thanks ya'll!!

[Radman]

I went through a similar thought process and was looking for a KW or a PB with the Cat C12. When all was said and done the smaller motors don’t appear to provide enough (if any in some cases) fuel mileage advantage to warrant seeking them out. Even 2,000 lbs one-way or the other doesn’t seem to affect the mileage that much. I think an even bigger influence is how many miles a year our really going to drive and what is the real payback. At fewer than 20K miles per year, we decided not to worry about the last 5 percent and go for the bigger more readily available motors.

We ended up building a 41ft 2001 model T2000 with the N14 - 460hp 10sp Autoshift. We weigh less than 40,000lbs with our garage loaded up full of motorcycles. We get almost 9mpg cruising at about 65mph in the Midwest, which is to say not in the mountains. We will know more about mountain performance this summer.

Rad

[geofkaye]

.....MY RIG gets 8.6 at 68 mph all the time now with the trailer and the generator running all nite in a Truck Stop....I'm have a Volvo with-n-14/ 500hp-[turned up from 475]-10 speed and 3:58's not singled with bed and 12k# trailer....bobtail-I get in the high 9's average and if I watch my driving and really concentrate on what I'm doing I can get 10 plus a little.....but less than 20k a year...so what?....I might have to get a few more gallons when I top off the tanks each day....one day I used 70 gallons total and was busting my butt getting to North Carolina and the next day I slacked off/day dreamed and needed 66 gallons....big deal!.....fuel mileage is not the thing I needed to be concerned about....my personal comfort and safety is.....and 4 gallons a day is a very small price for both IMHO..........geofkaye

[NotStock]

I compltely understand your point Geofkaye. But as I am shopping, there are hundreds of rigs for sale at great prices. The cheap part of the conversion is the truck itself (so to speak), its all the time and money that is gonna go into the conversion. I simply want to start with the best possible engine/tranny/chassis since right now, its easy for me to select which one to buy. In 6 months or a year when I have done half the conversion, it wont be so easy to switch, lol.

[happygolucky]

Hey ive had a cat c12 for 10 years and its been phonominal in fuel mileage. and as far as the big block motors go unless youre lookin for a 600 horse motor the extra 1000 lbs the bigger motor,trans ,and driveline weigh arent really doin any good. 580,000 miles on my c12 only thing ive done to it is a turbo.I pull 80,000 lb loads as an owner operator and the company trucks w/ the big cat c15 motors cant pass me up. my fuel mileage pulling a flatbed in Illinois has been avg 8.5.when i convert this to a motorhome (when i retire) i expect to get 10 1/2 to 12 mpg.9 or 10 spd trans would be ur most fuel efficient manual trans to run.