2013 and beyond-Part 2: Downspeeding

It is going to be much bigger than that. There are some new designs that are going to hit the market that are really gone to change the way you think about a truck transmission.

 

I agree. My maxxforce peaks on torque at 1,000rpm. I can climb hills losing speed but it usually hangs at 1100-1000 rpm.

Ethan

 

EGT's have to be interesting running down speeding under full power. But then, to passive regen you need high exhaust temps. Guess it is a wash. But it will be interesting to see the longevity of exhaust manifolds and turbos running higher exhaust temps all the time. And with those higher exhaust temps, a cooler really has to strain to drop temps from exhaust going thru the EGR. And that crankshaft damper has to be taking a real beating. Will be interesting to see how engine longevity plays out and the overall cost to operate. And see how much the mpg's are better and if it actually proves to make things more cost effective overall. I know the government is wanting better fuel mileage, but if one has to sink more money into repairs and downtime, it really is not going to be that great from a business standpoint.

 

I went from brookville, PA to De Pere, WI.
687 miles.
Used 162 gallons of fuel.
2013 prostar+

Ever since I crossed 65k miles my MPG has steadily been declining.

Ethan

 

Ouch! And here I was complaining late last week with a heavy load and high winds that I got 6.7 mpg when I fueled up. My last three fills had me at 7.4 - 7.5 mpg. And that is on winter fuel. And I was still complaining. But then, it was getting some serious 8+ mpg's during the warm months. All out of a DDEC IV Series 60 500 hp with not an emission device in sight. The readout of the ECM mpg on my qualcomm gets reset each Friday night, and since last Friday, the ECM is showing dead on 8.0 mpg for the week so far on 2081 miles (261 gallons). So those fuelings, hand calculated at around 7.5 mpg are about right. ECM's are always off a little on most trucks. Not bad considering there was a couple of days playing around Chicago in and out of customers. Have to be honest here.... I wasn't running grossed out all the time. Most loads were an average of 30K, only one heavy. Will have a 45K load tomorrow and running some serious two lane hill pulls on that run (Hwy 20 out of Sioux City on thru Hwy 20 from Iowa to Rockford, IL). Sure it will knock the mpg's down a little. Especially on the Illinois side.

 

Exactly. My point is the EPA or whoever is demanding high MPG but is choking down these engines.

I used to get 7, but for the past 3 fill ups 4-5 is the best I can get.

Ethan

 

It is possible to speed down the engines, however I think, the skepticism is not baseless. Especially, if we are talking about engines which are not designed to handle the high torque at low RPM. Also, interestingly Cummins keeps the maximum torque from 1200 RPM on their engines over 450hp.