What the best APU

I know TK charged me $100 an hour for service work on my Tri-Pac

 

Buy your filters for a TriPac from ThermoKing, that way you can go the full 1000 hours between services, but get your service done someplace else and save a ton of money.

 

I dont run otr just local was reading here and your statement cought my eye. I have a Volvo with a ISX and it tells you how much fuel its burning. I know it might not be very accurate but it says .5 gals per hour at slightly higher than low idle (enough to move the op guage) only twice what the apu burns. Running it 10 hours a day 5 days a week 52 weeks a year thats only a savings of about 2700 bucks with fuel # 4.19 a gal. How could anyone ever justify the purchase with the exception of the stupid idle laws. Guess maybe thats why they made them The guys that make apu's need to eat too.
Not trying to bash anyone just never thought much about it. If I run otr I would have one for the comfort and not havine to worrie about the idle police.

 

If I take the head off your motor I can tell if you idle the main motor a lot, the cylinder will have a brown haze to it, there will be polished streaks up the wall, from carbon building up on the side of the piston, and when you drive off the piston grows to its proper shape it polishes the liner.
The rings on the piston will not be stuck but not free like they should be.
The oil rings wear a lot more on an engine that is idled a lot because the carbon gets on the liner and wears the rings.
The exhaust manifold and turbo get a carbon build up on then, like a wavy ripple that is very restrictive.
Fast idle does not help a great deal, and if you call Cummins they will tell you the engine at above idle burns more than 1.5 gallons an hour.
Fuel gets into the crank case and because it condenses on the cylinder, from incomplete combustion and acidifies the oil.
There is nothing positive about idling any engine.
And most bigger companies figure the payback of the APU at less than 2 years. It also cuts way back on the truck batteries going bad from heavy charge cycling.

 

Not sure how you are coming up with your numbers. My APU burns less than a gallon every 10 hours. And that is about average. The best, non-government study of fuel idel consumption is .8 gal/hour. But even using what your truck is telling you that is still a .4 g/hr savings. Or $1.66/hr. That is $4300 by your idel numbers.

Real world is more like 2000 idel hours a year with a savings of .9 gallons an hour at $4 per gallon that is $7200.

 

Just from what my Volvo was saying on the dash display and the numbers that were posted for a apu. Which is only .25 and hour differance. Like I was saying I dont run otr so never looked very deep at the numbers.

 

Almost all trucks idle between 1.0-1.3 gallons per hour. APUs can idle anywhere from .1gph (low RPM 1-cylinder APU) - .25gph (high RPM 3-cylinder). The average for an APU is general .18-.22.

 

I bumped into a video on Youtube that shows Forest Lucas of Lucas Oil making strong recommendation for Dynasys APU's based on testing of several other units. I guess his recommendation is about as good as anybody elses, depending on your perspective. Still haven't been able to justify a purchase yet, but there are number of factors that are swaying me toward the Dynasys unit. Mainly the unit design and less frame rail space compared to Tripac, Carrier, and similar units. That is an issue with my truck. And since a very reputable dealer is about 40 miles from my house (I have used that shop for several truck repairs in the past) and OOIDA has a deal going with them for $300 off the price, I am being pushed in that direction.

 

It might be guys like me you hear about. When I bought my truck it had 750,000 miles and a proheat with 7,000 hours on it. The idle time in the ecm was low that was a big plus for me. I've got almost 1 million miles now and still no oil consumption. But the generator played out at around 800,000 miles. I still don't idle no matter how hot or cold. I'm thinking about replacing my genset though it sure was nice when it worked and didnt burn a ton of fuel.. I do plan on keeping the truck for another million miles so it should be worth it..