X-15 Cummins thread

Friend of mine is running a brand new 389 with the X15 Efficiency 505/1850. Has about 20,000 miles on it now. Jakes hold him at 96,000 lbs gross in 6-over on 4-5% grades. He can out-pace a nearly-freshly rebuilt 550 hp C-15 CAT up a hill at equivalent weights. Gets between 7-9 mpg on flat ground at 80,000 lbs or less.

While it's the wrong colour for me, it seems like it's a very solid motor that should help keep the hoods around for quite some time.

 

I speced my truck with lots of help from Steve. The dude is super helpful.
I changed my bunk size to 48" from 36" and went to 275WB from my previous specs I posted. Steve was $150,550 out the door. My local Pete dealers witch are all owned by Fitzgerald was over $12,000 higher on same truck but not quite as nice and Steve even included a Texas bumper and 30" hogebuilt fenders.

 

Updates.

Friend's truck has been back to the dealer 5 times since it started rolling in January. He's currently sitting in southern Ontario with a 25% derate waiting for the dealer to open Monday. It seems like it might be the dud of the three the company bought.

He's getting between 8-9 mpg running 75,000-80,000 gross in the US, fantastic economy but it doesn't come without headaches. Every single issue so far has been emissions-related.

I don't think I'll give up my C-13 any time soon. I like getting home each week without having to worry about a computer cutting my power (more than 10%) to keep the motor from destroying itself.

 

What are the truck spec's for him? Im wondering if he has all the emissions problems because he is babying a high horse engine to get 8+ mpg's.

 

I spent a month in a 2017 W900 of a friend of mines a while back. 565 2050 torque, 18 speed, 3.36 rears 24.5 low pro rubber. Pulling a hopper and cattle pot.

I couldn't get it to pull under 1500 period. 4.8 mpg is about its best. No check engine lights or codes Kenworth says its fine. 35mph by the time we topped needles at 80k gross. It really seemed to like being revved up better than down low. I'm sure I was doing something wrong

 

That had to be an ISX. This thread is about the new X15.

 

389 flat top, 265" WB, 13-speed Eaton, pulling flats.

He's doing the exact opposite actually. He's been driving it like he stole it for over 25,000 miles. Always running with it pulling (dropping it off a few mph, then giving it throttle to bring it back up to speed, and running big hills constantly through Ontario, no cruise for the first 15,000). I'm amazed by the economy, given the fact it's a flat nose Pete, but these emissions issues are really frustrating.

Owner doesn't want to "modify" it because it'll void the warranty, but all the warranty work done so far has been because of emissions systems. Everything else is working perfectly.

 

Must be burning those big gallons....

He should be over 10 after break in and it is driven like a sane person drives. That is, unless, it is another one of these wonder engines like @BigHossCummins had, get 8-9 mpg for the first 80,000 km....and then the engine blows and it is towed to the dealer....

 

Your right it is an ISX15 my bad

 

I'm thinking it's a dud that needs the choker taken away to let it breathe properly.