2050lbs of torque

Are you planning on running more than 80k gross? If not, it's entirely unnecessary. Unless you are doing heavy haul or B-trains in Canada (140,000 lbs gross or more) you won't NEED more than about 500 hp and 1850 lb ft.

I run a 2004 C-13 CAT set at 470/1750 and run up to and including 46,000 kg gross (101,400 lbs) and get 5-5.5 mpg reliably throughout Canada (not BC) on summer fuel. A couple weeks ago I was coming back on the 11 through Ontario at 6.5 mpg running 94,000 lbs gross. Down in the US, at 80k or under, I've been getting between 6 and 7 mpg reliably.

Running heavy usually means spec'ing a truck with a heavy duty drive-line to put up with the extra abuse over time (i.e. 46k rears, heavy drive shaft, 2050 clutch/18 speed, etc).

I'm really starting to learn that excessive power and torque don't mean much outside of bragging rights (unless you are doing heavy work). A typical truck in the US won't need to be a beast to handle daily work.

Just look at the Series 60 Detroit's, both the 14.0 and 12.7, 515hp/455hp respectively, and most guys running them get between 7 and 8 mpg on a regular basis... in flat nose conventionals no less.

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If I were buying a truck, I'd be looking in the N14 Cummins or 14.0 S60 Detroit direction for used. Cheaper to maintain than a CAT, and also lighter overall (I'd be looking at doing bulk work along with some flat).

New, if money was limited (and I couldn't just go to Peterbilt Steve) I'd probably go for a 389 with a 48" flattop with a X12 under the hood set at 500/1700 (it weighs 1000 lbs less than the X15 dry). Yeah, it'd be a waste of engine bay space, but the cut to the overall weight would be worth it.

 

Just because that torque is available, doesn't mean you have to use it.

 

HP Good Torque better.

 

True about 12.7 I’ve had 2 of them over 18 yrs. Running light with no real hills Great mpg. Hit hills heavy and forget it.Gotta wind it up good to 1700 and hope for best. MPG down the tube. I hear lots of different stories but talked to enough Operators over years with same experience. My main concern is not overworking ( Lugging) as I’m usually 76 k or more. The last 10% (4000 lb)

 

Lack of torque makes 76k vs 80 k very noticeable

 

Yeah the motor has a wide range it's rated for in trucks. In marine trim the D13 goes the whole way to 900hp from factory. pretty crazy considering the average load state is way higher than highway use.

The 1850 motor used to lose warranty coverage length on iShift also, allot.

If performance is the goal, go straight torque , not the Eco Torque. Eco Torque is Volvo's fancy name for Dual Tq motor.... It had two different tq curves that the computer chooses from when driving.

I'd go 2.64 or 2.85 rears with XE high Tq spec, it'll pull down better. With xe package you don't need higher than 2.85 rears, It's usually a waste. Running gross # in the West with my 2.64 rears XE was never an issue. A 3.08 rear would be Overkill with the Volvo Unless you run slower speeds... Depends on software package too.

55-63 with 3.08 or 2.85
63-68 with 2.85 or 2.64
68+ with 2.64
(With 22.5 LP tires.....)
If 11R , drop each speed range 3-5mph.

 

Biggest hangup is the very high rpm. It could cruise 70 very well if the rears were correct for the speed... I'm sure it eats fuel with high rpm at that speed.