Heavy Haul - Fuel Economy and Engine Life

[KWT880]

All,

I have a;

2019 Kenworth T880 with a X15 565/2050,18sp, 4.11 gears, 24.5 tires
2450 hours and 60,000 miles/98,000km
8 axle set up - Tri drive truck with a quad wagon logging truck
Loaded - 140,000lbs/63,500kg Empty - 43,000lbs/19,500kg
Cruise speed - 55-60mph or less depending on the road
Fuel Economy - 3.7mpg avg

I run in extremely mountainous terrain, from 8% on the highway to over 15% off road
All this leaves me with terrible fuel economy but being an O/O I want to try and maximize the fuel economy as best while trying to minimize engine wear. I keep seeing "keep the boost under 15lbs" but with my application, weight and terrain that isn't a reality for me, I would go backwards down a snow covered bush road. I try to keep it as low as possible while maintaining enough speed to keep going forwards. I also try and drive as slow as I can while still making my multiple trips per day during the available mill scale hours and HOS. The truck is still new but what sensors should I be cleaning or checking? What EGTs should I try to stay around? What help, advice, tips can you guys offer me to help me keep more money in my pocket?
I've added some pictures for you guys to check out.

Thank you


            

[Rawze]

you want it to last longer? --- drop the torque to just about 1790 ft-lbs, set the power to 605HP, and re-gear it taller (maybe 4.63's or 4.88's thereabouts) so that it can stay in the 1600 - 1900 rpm ranges all the time. Maybe also put a 500 series VGT on it to go with that for better heat xfer out of the engine too.

(18-speed w/24.5's)...





HP does not wear out the isx... torque does, and that 2050 torque in that X15 is all below 1300rpm where it tortures it.

some related info: http://rawze.com/forums/showthread.php?t...3#pid17353

[the missing link]

(as someone who hauls exactly the kind of stuff like this and in those conditions) ...

What he said ^^^^ ...
In my opinion running offroad as much as you do .you could even go to 4.30 or with 24.5 go to 4.56 and be turning about 1650 at 95 km/ he. Keep in mind I never ran the numbers .
Just keep in mind that you would be making more power to the ground so you could back out more .
Now I highly dought you will regear the truck .so keep the truck at 1650 or higher as much as you can when running any boost at all .
Aside from a tune ,that's about it .
By the way I do know the country your in and what it's like to pull heavy .
To do your job ,you need to make power , but if you can drop a gear or even a half a gear on hills it all helps .


As far as sensors ,do a little reading on here .
I dont know those newer motors ,but your imap and backpresser .


Oh , depending where you at there is a guy up in your area ( starlight I believe) . He is a great guy . Somebody should have his info .

[KWT880]

With the truck being so new and still under warranty I don't want to risk paying for a motor. Is there anything I can do tuning wise to improve the HP but change back to stock if need be? I don't have Insite yet but it on my list of wanted items. As for sensors I've read IMAP and Delta P. The truck has been on a chassis dyno and gets peak HP at 1500 RPM

1400 RPM - 440 HP
1500 RPM - 476 HP
1600 RPM - 455 HP
1700 RPM - 443 HP
1800 RPM - 401 HP

Gearing wise, when under heavy load (loaded and pulling hills empty) I should try and keep it around 1600RPM? When empty and light engine loads try to stay around 1400? What would you say is a heavy engine load? Over 15lbs of boost?

[Rawze]

heavy engine load = anything more than about half way on the fuel pedal.

[Rawze]

(05-16-2020 )KWT880 Wrote:  ...
1400 RPM - 440 HP
1500 RPM - 476 HP
1600 RPM - 455 HP
1700 RPM - 443 HP
1800 RPM - 401 HP
...

Looks like you have that bulls$it 78% restricted torque fuel mapping in that thing.

- If you worried about warranty above longevity and productivity in your business, then your in the wrong line of business. Run the damn thing 30k miles to ensure its ok, then have it custom programmed (legally, I am not referring to delete programming),.. to be more lenient on the emissions bullsH#$it shutdowns, but still pass, have the power/torque set Like I mentioned above ... REMOVE THAT BULLS$IT 78% restrictive mapping they have set in that engine (also is seen on your dyno numbers there). - That is what I would do to it if I owned it ... as well as get rid of those rear ends that are too tall for what your doing.

====================

* Overhead valve adjustments should be done every 250k miles.

* Engine needs an bypass oil system on it (a cheaper amsoil bypass filter is sufficient ) to help keep the soot out of the oil from day one.

* Engine oil needs replacing according to miles instead of some bull#shi#t cummins statements about every X miles/hours ... This is because of the soot buildup (due to egr) in the engine. Here is the recommended oil change intervals to make it last as long as possible without wasting moneys...

Rawze Wrote:If your average fuel mileage, roughly every IFTA quarter is ...

less than 5 MG -- Change your oil every 8,000 miles ( or 180 hours) or so.

5 - 6 MPG -- Change your oil every 10,000 - 12,000 miles ( or 220 - 260 hours) or so.

6 - 7 MPG -- Change your oil every 12,000 - 15,000 miles ( or 260 - 328 hours) or so.

7 - 8 MPG -- Change your oil every 15,000 - 18,000 miles ( or 328 - 392 hours) or so.

8 - 9 MPG -- Change your oil every 18,000 - 22,000 miles ( or 392 - 478 hours) or so.

above 9 MPG -- Change your oil every 22,000 - 28,000 miles ( or 478 - 600 hours) or so.

These recommendations are based on more than just engine wear alone. They are based on getting the most engine life vs the cost of oil changes themselves, and the fact that soot and other deposits are going to keep building up in your engine more rapidly than you can flush them out. A bypass oil filter system can extend this, but not by the claims they are making. You would be good to get an extra 8,000 - 10,000 miles ( 150 hours ) on your oil before having to change it anyways. That is my experience on it, and is what I tell others that ask about these types of systems, etc.

* A gallon of GEAR OIL used in the engine at every oil change is very helpful towards longevity of the lubricated components. it will not only raise viscosity to help it, but also add back some of those well-established additives that have been stripped out of from these modern oils by the Epa.

* Regular tune-up work to prevent the engine from making excessive soot that includes replacing sensors, cleaning things out, etc. <- A person has to stay on top of these engines.

* EVERY 400k miles ( or 8,000 hours) -- Replacing the guts of those high pressure fuel pumps. This is an absolute MUST, or you risk loosing the whole engine without warning.

====================


Wise investments and wise decisions = way more long term profits and reliability than any warranty is ever going to cover. -- besides that,.. I would not let a certified OEM shop anywhere near my engine if it were to fail.. nothing but half-arsed repairs and waiting forever to get it back while all your good customers find someone else to haul their freight.

just my own thoughts on it any ways.

[KWT880]

Those are some great points and information Rawze. I will start taking steps towards changing/adding the things you have suggested. Thanks guys.

[rolling18]

do those things ALL apply to new 2021 X-15 Productivity series? (565 Hp)
and where does someone get these mods/ tune done? cost est.??
thanks

[Rawze]

(11-18-2020 )rolling18 Wrote:  do those things ALL apply to new 2021 X-15 Productivity series? (565 Hp)
and where does someone get these mods/ tune done? cost est.??
thanks

Any custom programming voids all engine and drive train warranties. if you not worried about the warranty then I would suggest you get with Mr. Hag, Mommaburt, or pull the program out of it yourself via C a l ^ t e r m software and e-mail it over to me for an opinion on what is in there, how it is set, and what can be done with it.

I PM'd you my number if u have any questions or need some advice.