475 ISX or 475 Twin Turbo Cat

TMC- Des Moines is running several hundred Cat 475's and is reporting many drivers getting over 6 mpg in their flatbed operation. 13 speeds with 3.36 ratio's I believe.

 

Expecting high mpg numbers out of a rolling windblock like the 379 or W900L is a longshot in itself.

 

The Cat costs more to buy but gives better MPG because the cumming has the EGR set up.

 

I have an 2005 Kenworth T800 with 475 CAT, meritor 12 speed autoshift, michelin X ones, 3:36 gears and 180,000 miles. According to the trucks computer I have averaged 7.26 mpg for lift of truck. Have 9 % idle.

If you want to post your truck and details maybe I can help you figure it out. Just how fast do you normally run?

 

I have a 2007 Peterbilt 379 with a 475 Cat C-15 Acert twin turbo. The truck has about 64,000 miles on it and the trucks computer shows an average of 5.8 mpg for the life of the truck. I'll admit, I was skeptical going to the twin turbo from the pre-emission Cat, but I am very pleased. The truck pulls hard and gets great fuel mileage I think. The set up I am running is 18 speed Eaton with 3:36 rears.

 

Folks, don't listen to the computer, it only works from preset variables, and not real world. Fill the tanks, run normally, refill tanks, calculate gallons versus miles driven. Get the actual, not the estimated.

I drove an 06 T600 with a twin turbo C15 Accert, and when it wasn't in the shop, I was lucky to get 5 mpg out of it. The computer said 6.4, I only idled on warm up and cool down, for better than 100k miles. Lost both of those pricey turbos at under 100k miles, lost all of the valve actuators in those three fancy heads, and had the computer crap out on me. Now you couldn't give me a CAT.

I currently drive an N14 Cummins, with 650k miles on it. I average 5.8 mpg actual, and I haul oversize loads. I don't idle much, but I do have a webasto fuel fired heater, so that eats a gallon or two a night...

I will stick with Cummins, but it's all a matter of what you need, what you prefer, and what kind of loads you are going to haul.

If you are concerned with fuel economy, go detroit.
If you want power and grunt, go Cat.
If you want a nice mix of the two, Go Cummins.
Then take that Cummins to pittsburg power and take that CAT's doors off. lol.

 

Cummins dabbled with twin compound turbos with the NTC-475. I believe they found them to be rather unreliable in regular service. I guess history repeats itself.