Caterpillar MPG anecdotes

Im wondering what kind of fuel economy to expect from a Cat and what other owners experience. Specifically in a flat nose pulling a van trailer but all input will be helpful

 

Buddy running a C16 600, flat top running flat out west mostly, little over 6.

Usually runs 68ish

 

Cat made a few different models over quite a few years. It would be helpful to know what specific engine you’re talking about

 

Yeah that's a vague question. It could be anywhere but I put my money on it being awfully low and not really the best choice for that application. CAT's are good, reliable engines but they suck fuel like crazy. What you really need, and current sarcastic advice here on the forum is lol, a Cascadia with a downsped drivetrain. Sarcastic or not it's right. Not the cool choice I know but your bank account will definitely be much fatter.

 

While not wrong i think cats are better on fuel then people give them credit for. A lot of the fuel sucking reputation comes from over horsed or 13 liter vs 15 liter engine comparisons where used in light loads. And i tend to see a lot of people romp the hell out of them ontop of that. Going to be a huge fuel consumption diffrence then a 500-550 horse stock cat c-15 vs one tuned up to 800HP and turned esentially into a C-18. You even see that with smaller C13 scale engines where people tend to wind them up high and have leadfootitus

In MY personal experince however, they (cats) are usually more sutible for applications where power is the go word of the day. An end dump for example with a C15 is going to get simular or better mileage on average then a little 13 liter working at max capacity most of the time with that truck at max 80k+ gross more then not and wont be a lot worse then a ISX or detriot 15 liter. However, in applications where your truck is usually in the 50-65K range such as van or refer loads a little 13 liter is going to stomp the crap out of a cat in terms of lower costs and will be better for line haul. And this line of argument even extends to the smaller engines.

A C13 in a medium duty application where your at max gross most of the time will out perform a smaller lighter engine in fuel and power, but will struggle against them when the loads are lighter on average as the lighter engines will just be better for that application. However, i have limited hands on experince with the C13 so take what i say with a grain of salt as a lot of it is second hand.

However, one argument against newer engines and even some pre emissions motors is def systems and down time could easily make up the diffrence in a years fuel bills. Cats and specificly the 6nz are legendary for relaibility for a reason with noteable exceptions (looking at you C9 and acert engines!)

So back on topic here. To the op in MY opinion if you can get a smaller 13ish liter pre emissions engine it will be vastly better then a 15 liter cat for line haul UNLESS you know you will always or near always be at 80K+. Even a modern emissions engine if correctly installed and maintained will be better for van applications. Id go with a DD13 myself as if you gear it right it will still outperform a cat in the mountains for the application your talking about in terms of fuel though less so in terms of reliability.

As for mileage, a long nose with a cat with an average of 80k was getting 5.5 when i drove a 389K and 6.7 when i uses a t660 vs the 6.5 my MX13 in a 579 gets to answer your specific question.

 

04 379 with a MBN which is the redheaded step child of all 3406- c15's flat top sleeper so make it even worse and it was a 15 speed initially so check another box for horrible fuel mileage I was around 5 flat on a good day pulling van, could touch around 6 with a flatbed and the right load. Now with 2.74 gearing an 18 speed I am around 5.5 with a van its also not stock anymore I have different injectors and a different turbo now and can get into the mid 6's nearing 7 with a good load of sheet steel on a flatbed. I also need a different tune then the 550 6nz file that is in there right now considering my injectors are to heavy for it right now I don't know how much of a difference that will make on mileage but she is a little smokey right now. I never expect it to get decent with a van trailer, not what I am building it for, its a hood with a flat top sleeper and will never compete with an aero truck for mileage but I wouldn't trade it straight up for a new aero truck because I don't like them and want to be able to enjoy myself when I am in the truck.

 

I was being intentionally vague because I dont have one myself only looking for what would be reasonable to expect. I have an X15 with high mileage and am considering the costs and benefits of doing an engine swap to something pre emission or rebuilding mine. So I guess I would only be interested in 6NZ C15s or older haha

 

Thats how I feel too, I dont want an aero truck id rather spend the money on fuel to enjoy what I drive. I have an x15 and its pretty good with 6 mpg on average with my van trailer. When im going against wind though it drops a lot. I thought maybe if I could get the same mpg from an old cat and then save on DEF and emission repairs and plus have a cooler sounding engine it might be worth it to swap rather than rebuild

 

Thank you for the detailed response. I haul fairly light usually only 20,000 lb loads except when I have to pick up peat moss im grossing 80k. I drive line haul mainly flat with some hills on the east coast of Canada. Im interested in Cats specifically the 6nz for the reliability people always praise them for.

 

If you want economy and reliability then look at a Series 60.