buying new glider and dpf retrofit

New motors without retrofits are getting impressive fuel economy. Issues I hear of these days have less to do with EGR and more to do with all the other new stuff on motors. So adding an unproven technology onto a your motor is going to get you a lower fuel economy with much of the same issues being seen with these new trucks.

 

If speced properly and driven correctly a Columbia glider w/12.7L Detroit, direct drive trans, & 2.79 gears is very capable of 7.5-8mpg.
If you are willing go the extra mile and go single screw w/a tag axle and microblue treated wheel bearings & differential units I see no reason why 8.5-9mpg wouldn't be possible
And YES the 12.7 detroit will be more reliable.

Keep in mind the numbers I am giving are ideal operation of the vehicle at 55-58 mph. If you are going to operate at higher speeds reduce the mpg by .1mpg for every 1mph increased.

 

Why waste that money? All results have been from people replacing old bearings with new ones. You will see an improvement just from putting new bearings in. You need to use a microscope to see the friction causing imperfections. On old bearings you can see friction causing nicks with naked eye. Throw in a set a new bearings and test then do a set of blued and test.

But agree the 12.7 will be more reliable. It is the retro fit that is untested.

Plenty of fleets that are governed at 62 with Prostars are seeing 9's (when they are not in shop). And these are company drivers that could care less about MPG.

But as someone else mentioned, I would wait another year or so until all this new motor stuff is figured out and get a new one.

 

I'm not familiar with any fleet with any truck averaging 9's.
MVT has made some outstanding claims, however according to international of Springfield Mo. they have downloaded numerous MVT trucks, none of which had an average mpg of over 7.2

 

One thing that needs to be factored into this is that the 12.7, while definitely a good engine for fuel economy, also must breath properly to run properly and get those numbers. Once you choke up the exhaust system with a DPF, it is highly doubtful it will exhibit the same results. Most get the best performance out of a 12.7 when they eliminate any and all restrictions in the exhaust stream. It seems that if one just has to do California and meet their requirements, then it would be better to just pull the trigger on one of the new trucks and the engines. Those engines, unlike the 12.7, are designed with all the add ons in mind. And some get some pretty impressive numbers with them. Henry Albert, part of the "Slice of Life" Freightliner program, has almost 200,000 miles on a Cascadia, running around 65 mph most of the time, and his lifetime ECM fuel mileage is well into the 8's. I would like to know all the details on his specs, like tranny and final drive ratio and rear end ratio tied to that DD15. And of course, what loads he hauls, where he hauls them most of the time, etc.

I don't do California, and I have a glider with a 12.7 on order now. But instead of choking it up with a DPF, it will be opened up with high flow exhaust, ported and coated exhaust manifold, and a larger turbo. Tied to an 18 speed running in direct (16th) most of the time, with 2.79 rears in aluminum axles and wide based wheels, this should be a similar 8 mpg truck. Just for a lot less money, less headaches, and about 2000 lb lighter than a typical new truck. I went for the 18 instead of a direct 10 only because I have to pull some heavy loads in some hilly areas on two lanes more frequently than most do.

 

So you went with an 18spd due to the heavy loads you run, but aluminum axles???

 

You know the coated exhaust manifolds are a waste of money? The "jet coated" crap will be peeling off in short order.

 

"Jet coating" is a type of ceramic coating that is designed for high temp usage. I've been using ceramic coated headers on hot rods & race cars for years and have never had a "peeling" problem

 

Yes. The axles are Meritor RT-40-145A. A is for Aluminum. They are 11mm thickness housing. They have the DualTrac option, which is an intermediate width track axle that allows using wide based or duals. In between the standard track and a full wide track axle. The bearings are set differently than a regular axle to keep bearing wear minimal using either wheel. The weight savings for the axles is over 200 lb compared to ferrous cast housing, the weigh savings on the wide based take away another 380 lb. I got them them in 40K rating, but you can get aluminum axles up to 46K rating.

It isn't the axles shafts that are aluminum, just the axle housing. Aluminum axle housings have been used for years. The average truck doesn't have them, so most drivers do not know they exist and are just as functional and reliable as a ferrous cast housing. And they didn't cost any more than a traditional axle on my spec sheet. The 11mm housing thickness is greater than the traditional 9.5mm axle housing thickness, so flex is eliminated.