Maiden Voyage and how it went. Not doing something right here 😬 Peterbilt 579 MPGS? 

That's why I like this guy. He puts the emphasis on the important aspects of the trucking business. I know, by now, he has it figured out. He does a great job at articulating the info, in a way you can understand. This kind of effort is never unrewarded. Thanks,man.

IMO, Sammy, first you gotta have something to work with before you can even begin to worry about fuel efficiency 😂, the days of #150gal tanks and no watered down fuel and $1.09 a gallon fuel cost 💲, those days are long gone. Plus you have DEF Fuel, You’re a 1 trick Pony, worrying about fuel mileage only makes sense, Pardon the pun, if you are running a Fleet of trucks, otherwise your concern should be focused on running freight for No less than $4.70 a mile and definitely No less than $3.90 a mile!! INNOVATION AND CAPITALISM will eat you alive. Let the Foreigners have it.

I have 550 2016 Cummins 3.36 13 speed 18.50 torque 68 green lith rpm flatbed 6 and 8

Here’s my two cents… just because you asked. Aero truck X15(same spec) 13 speed Eaton cruising 62 not more than 63 mph. 1325 rpm (sweet spot for me) 60 day average 8.4mpg. Remember the physics, the faster you go the more drag you produce. I never measure speed by my road speed but by your moving average. The faster you drive the worse your moving average will be. Been doing this 39 years, money is made by consistency not speed.

I bought a truck with a Paccer engine last august and I'm still on my first tank of fuel .

You’re choosing the wrong gears for MPGs. So your choices are slow down and loose freight or buy more fuel. As for lugging a lot of modern engines are down sped and don’t like the higher RPMs

Call Pittsburgh power, emissions legal tune. Help you with speed to run for fuel economy. Switch to 3.08 would probably be a better gears too

I love it when you talk nice about paccar, say washing machine

I recently purchased the same truck from the same dealership only difference is the color and it’s automated with 2.64 gears. It’s a great truck but I feel your pain on finding the sweet spot. Cruising at 70 I’m running 1200rpm. It really sounds and feels like it’s lugging but I will say after Bob tailing 900mi, and pulling an empty box an additional 600mi I was averaging 8.9mpg.

I had 95 W900L with Aero 1 sleeper with 600 N14 straight 6"stacks 13"8 tall 3.25 rears, 18spd manual with 11r24.5 tall tires Pullin Reefer with 11r24.5 as well with 50k - 55k payload running 70-75 & average 7mpg with gvw between 84k- 90k running coast 2 coast for 8yrs

Geez ..lol..now i gotta go check out/research exactly what a pacccar engine is .i drive a kw with that engine...first time or one...(Last 4months)...well im glad forst trip out was awesome...got to see a little bit of the beautiful snow...the kind that sticks to everything but the pavement... happy Easter 🐰🐣✝️🤎yall

I have 2016 579 with cummins engine and a 10 speed. My ifta reports is 6.8 mpg consistently. I pull a flatbed with usually 46000 pounds on the deck. I run my cruise all day long at 66mph to 68 mph. The truck pulls and runs great at 71 mph but I will notice my fuel mileage start dropping. When I was going down south and running 75 mph all day long my fuel mileage would drop below 6 mpg average. I slowed down to save money. I also have an apu which keeps my idle time to a bare minimum. I would love to know how to increase mileage even more

These newer trucks are design to run lower rpm.love ya vids.my truck runs 1300 rpm at70mph that's my sweet spot.youll find that truck is gonna save u at the pump.luv ya vids be safe

2023 next gen t680. X15 13 speed 3:08 72mph. Best i get is 6.8- 7.2 running 3 trips a week va to mi and back with about 34k in the box

I have a 2016 579 glider with a 60 series and love it. 7.5-8 consistently with 40-46k. 9-10 empty. Its a 97 pre emissions engine. 3:42 gears, 13 speed. Been a great truck. Love the room it has.

Hey Sammy, I’m running my Cascadia DD 15 with a 13 speed 307 rear ends. I cruise along 1300 RPM 68 mph. If the average on fuel is around 8 1/2 close to 9 miles to the gallon I have 930,000 miles on my motor. Don’t be afraid to run at 1300.

IX 15, auto. 65mph at 1350. 7.7 mpg from 80k miles

That is a downsped engine. It’s built to operate at low rpm, 1100-1300 max. Feels better at higher rpm because you are dumping fuel and building the higher horsepower. I wouldn’t run it over about 1200rpm.

I have an old Classic XL with a 12.7L and with lite loads I get about 6.5 mpg and I have a friend who has the same truck & engine who gets 7.5mpg or better. The difference is he has 279 rears and I have 373 rears, so that can definitely make a difference.

i have 2019 579 auto. going up hill it will not downshift till it gets down to 1000 rpm. Sweet spot depends on how many horses you need at the time. If you are bobtail 900 rpm will get best fuel milage

I run 3.25 rears 18913a 14l Detroit 650 hp 2050 tq run 1425 at 70 but I usually keep it in 12th up to 70 or hang back at 68 mph mine usually lugs under 1400 and fuel economy tanks

Newer trucks get their peak horsepower and fuel economy at lower rpm. 1200 rpm is ideal the ultralofts peak mpg is 63mpg at 1100 rpm have that 5th wheel tucked up close.

I'm going to say your "Sweet spot" is going to be 60-65 or 1100 R.P.M.

We had this conversation 2.5 years ago. lol

The cruise will make a big difference. Try it and see for yourself. 🤔 The truck knows what it likes.

The Ideal RPM for this is x15 is 1300, you can see this by hooking up a computer,, it get best mpg & it isn't logging, you were just light loaded, going up to 14,15 is over working it.

I don’t down shift till 11-12rpm. To me it doesn’t feel like it’s lugging until after it drops below 1100rmp

Remember the x-15 makes peak torque at 950 RPM, I got an 18-speed with 336 is I run exactly 1300 RPM grossing at 80,000 lbs in a 389 and my lifetime fuel mileage is 7.4mpg.

Super curious on where this goes....655/2350 tune in a 389....4 mpg on 4.10 rears and 24 talls....swapped to 3.54 rears same tires with no measurable change usually stays 3.8-4.0 pulling a pot.....have noticed that ambient air temps do influence efficency to a degree. Usually running in the 14-1600 rpm range but ive tried running down in the 12-1300 and it went up maybe .2 to .3....biggest factors are hills and wind

Fyi... my uncle has drove for frymiller for 8 years.. he drove one of those 579s the whole time.. always drove between 65 and 68( they were governed at 68).. he always got 7 to 8 loaded and 9 to 10 empty.. also these new motors are designed to run at a lower rpm.. 1300 is optimal... im still old school.. 03 379 with cat 6nz 550 tuned to 600.. Bought my first trk in 2001... Getting ready to go get a 2021 579 here soon.. Enjoy your videos

I’ve never used cruise control except very rare occasions. My sweet spot was 68-72 mph. And I averaged around 7-7.8 mpg. I also did my PMs every 15-20,000 miles

Keep those rpm below 1500 when cruising. Do you not have the green band on the rmp gauge? That’s where your cruising speed should be

Man you thinking to hard. Use your cruise much as you can. Run between 67-70 mph find your sweet spot. Stop comparing your old fuel burning w900 isx to that New x15 because they're not on the same level. Man just call Pdi for an Big Boy Intake keep it moving. If you bought that 579 for fuel efficiency just leave it the hell alone and DRIVE IT.

Gears final drives. Low rpm better fuel economy. Longevity. At 55 mph You could be getting 10 mpg at 25 k or under on level ground. I got 11 mpg from alabama to pa. Almost no weight very unique load. Probably never get another. But it is possible at 55 mph driving like a pendilum. No cruise. 2015 cascadia dd15 505 hp dt 12 autoshift ( love hate these transmissions ) 2.58 axel ratios. My next truck will have a manual. I know i can do a more efficent better mpg. I used to hyper mile. Allowing for all systems to be in spec. No air leaks etc. I would leave my truck in gear and would hold the clutch in on long downgrades with no possibility of traffic. Sometimes i would turn the truck off .( condutions permitting.) Restart on uphill approach. And let speed slow limit. Once over the hill slowly accelerate. Repeat As a company driver (3000 trucks) i was getting 1 mpg better that was said could be done at the time. Corporate thought i was adding fuel. I started driving the entire back then 10 hour shift continusly when possible . Satellite tracked showed and confirmed my non stop runs. They had me in 9 trucks in one year. Achieved stellar mpg in all. Corprate didnt believe my mpg. The lead shop believed me they issued and maintained the trucks. Corporate refused to pay my fuel bonus. Your truck has the capacity to excell into double digit fuel economy . Stupid lightweight load mostly flat terrain and temp around 80 f. Hyper miling helps tremendously. With todays fuel prices were having a six figure + conversation of savings for a career operator. The key is being aircraft level preventive maintenance especially when emmissions era equipment is lost its durability compared to pre emissions. Ps. Double digits are rare unless you have a dedicated super light loads. My average lifetime in 24 years is 8 mpg.

Need to keep her down at 1200. She will run fine and is made to do that. I started in 98 and it was keep revs up to keep down the EGT’s. With the emissions systems now the goal is to keep heat in the combustion chamber to get a complete burn to cut down on soot. Your DEF usage will come down as you cut back on the revs. Just look at the trucks flying by with DEF fluid stains on the stack from running the engine way past it’s sweet spot. I drive a W9 with an 18 and an X15 at 605. 3:90 rears at 65 I’m at 1500 and average 4.4mpg. Cut back to 1300 and I go to 4.8. This is a day cab pulling a log trailer grossing 110K. Had a DD15 before this and she purred at 1150rpm at 64 with 2:47’s and no issues getting out of the hole. I feel Cummins is a bit behind with the down speeding as they were heading in a different direction with hydrogen and hybrid systems. Put a Fleet Air washable filter on your truck and let her breath at lower rpm and you’ll see your mpg’s climb. Skip shift when your lighter or empty and don’t worry about lugging these newer engines.

I'll be following you just lost my N-14 due to a faulty turbo .. So I'm in the market for a newer truck but I have no idea which truck or engine to get 🤔

At 54 9.7 mpg on last ifta that on all loads I haul up to 47k on the box

Cummins isx15 or x15? Try 1200 rpm on high gear. I'm getting 8.5 to 9.0 all the time!!!!

I drive a 680 with a paccar and it doesn't get good fuel I've tried it at 70 and 60 it doesn't matter when I had the Cummins it did a lot better

Find where the power band, keep play around with it you'll get it....rember it's not your kw naw😂

Go to California I 5 or the 99 to the grapevine

First from NC 👊🏻💪🏻

Stop looking at the gauges. Pay attention to the fuel, battery, oil and temp. Rest are useless. Listen with your ears, the engine will tell you everything you are talking about. I don’t even stud with speed or rpm. Once you learn the truck’s harmonics you will know exactly what you need to do to get what you are wanting. If I can (I said can not that I do it all the time, rather let it eat) get 7 from a unneutured N-14 pulling 9400 gallons of aviation fuel from Knoxville to Asheville twice a day just from listening to the engine and not some headset then you can get 8.5 easy in the lib influenced version of trucks.

I've found 68 mph is my sweet spot

PACCAR 💪🏾💪🏾💪🏾

I don't remember if said you had the performance or efficiency x15, I know there is a difference where they like to run.

Run in direct

Cummins engineer here.... any semi engine built in the last 10 years is going to be most fuel efficient at 1100-1300 RPM and over 50% throttle. Maybe engines older than 20+ years ago were designed for peak fuel economy at 1400-1600 RPM, but definitely not any more. Also you're not going to hurt the engine on the stock tune. They are designed to handle 600 hp for a million miles. On a 450 hp / 1750 ft*lb tune, the parts inside aren't even breaking a sweat. There are many fleets out there running 2.xx rear end ratios in the quest to get better fuel economy. Once you stop running 1500+ RPM, then it comes down to reducing idle time and aero drag (most easily controlled by speed). It's a common misconception that engines are more fuel efficient under light load. Generally gasoline and diesels are most efficient at low-medium speeds and medium to high load. High RPM's and light load is the lowest efficiency operating point outside of idling where you're doing no positive work. People get better fuel economy when being light on the pedal because they drive slower and end up with less aero drag and less energy wasted in braking, not because the engine is more efficient.

My old truck has 2.90's with a direct trans. Got unreal MPG, but most would have though they were killing it. That truck you have now. Is nothing like what your used to running. Keep the trans in Direct and run 62-65 and enjoy the savings. But keep those RPMS down. Its built to run lower then that W9.

My next gen T680 rattles like a Freightliner.... Does get awesome fuel mileage 10mpg on I- 95 PA to NC though but I've broken down 4 times in 100,000 miles probably lost about 8k in revenue so far....

i meann...a 579 and t680 os jus kw and petes version of a cascadia. it aint none to write home about.😂

My wife driving a 2021 ultra loft. Sweet spot seems to be about 1400rpm. Cruises at 70 and averages 7.5 to 8 mpg

I got a 14 t660, Cummins 13 speed with 325 gears that our friend GA worked on. I try to keep it around 67mph at 1350-ish RPM. I’ve played with the horsepower from 400 to 600 it’s always been a honest 6.6-6.8 MPG truck. So why not let it eat.

@MakeCents you may need to turn on power take off if it feels slow from a stop. I have 2.68 rears in mine. Not winning any races. I would have to be going over 80 to break 1500 rpm... I usually run under 65mph and get between 8.5-9.5 mpg at those speeds. If i am going 75-80, it drops to 6.8-7.5 mpg. It just feels a lot better running 1000 miles and only needing to put in 100 gallons

I’m running 2016 Cascadia with 1.3million miles (almost all were mine) automatic, DD15 averaging 7.8 miles per gallon. So, take that you 579 with the X15s!! 😂

I love the bull shit about hit rid trucks.

I used to have a W9 with 3.55s, 11R22s, 18 speed, 600hp ISX and would average 4.2mpg pulling double pneumatics at 132k gross. Now I'm running an identical set up W9 with a 3406E around 600hp averaging 4.8mpg I run wth some peterbilt 567 company trucks that have 500hp efficiency series ISX, 18 speed, 3.58 rears, tall 22.5s and governed at 65mph that are pulling a little less weight in lower profile trailer configurations. They rarely make more than 4mpg. Lots of mountains and a few hours every day running pto/blower

I drive a 2023 579 with an X15 economy model, 18spd, and 2.93 rears. Its sweet spot is between 1250-1300rpm. The X15’s are a low rpm motor, and their power band is between 1000-1400 rpm.

So are you selling the KW or are you going to be growing the fleet ?

579 x15 i run truck 70 to 72 1500 rpm 18 speed 500 hp im getting 6.7 to 7.0 depending where i am how bad wind is with tail wind i get 9.0 mpg with 79k load

I would run between 62 and 67 to get my best mpg's.... May I ask own much your "new" to your truck was? I'm looking for a new to me truck as well. Many thanks and all the best to you.

I try to tell them about that cummins

Look up the spec of your motor. Find out where peak torque is. That is the sweet spot for your engine. On x15 platform I believe that might be as low as 1050 rpm

No elog you would make the extra money and then some should of got a glider with a n14 or a 60 series and no emission’s and the easy process to workon them yourself its a win win! But thats me! I would never buy a plastic truck! Good luck!

When you coming through Ohio

You have to let it pull down. 1100-1300 rpm is the sweet spot.. And yes it's a huge adjustment in driving.

Been driving a 2020 579 sleeper that the small company I work for now bought from Werner @ around 360-400k miles. (6 of them) First time being in Petes since my oilfield days when I drove day cab Petes. HATE them! Have to constantly down shift manfully, or you burn too much fuel, because it stays at 1000 RPMS too long if you don't. Also LOTS of rattles and buzzing from stuff loose. Reminds me of Kenworths.

My old 2017 international Cummins ISX 15 is good on fuel efficiency of course I blocked the EGR 😂but pulling heavy through the Mountains I can see the difference in other trucks I had pulling heavy No cruise control 70miles to 75mph it run’s better because you’re right lugging at 60 mph or 65 drags that engine and makes it work harder 😅so you run a old school engine you know exactly how to run her🫡🍻🚛🚛💨💨

💪👍

I started off trucking working for a guy who had over thirtty years owner operator expirience. We had a cummins engine in our trucks and he told us the best cruise speed was at 13.6 rpm. and to progressivly shift the truck and use the manifold pressure gauge to guide you to the best Mpg. I have the truck specs saved in my email. pulling doubles running a team triangle from Northern Kentucky- sacramento Ca-Rialto Ca-Woodbridge NJ and back to Northern Kentucky we would get between 7.3-7.6 mpg. That was nearly fiftteen years ago. Try running at 1300 rpms. I was also told to downshift at 1000 rpm and have always done that since. I run in a large fleet now and honesty engine problems are prretty rare to see and the maintanence is no where near as good as what most owner operators would have done to their trucks and I see guys who are rough on trucks, they seem to be built well and the lower Rpm will not hurt them in fact the Rpm i menttioned are the Rpms i notice the fleetts automatic transmissions shift at.

Last year I bought a 2018 T680 with an MX13, 13speed transmission and 3.25 rears. I am usually pulling heavy produce 78-79.5k lbs reefer or flatbed and average only around 6-6.5mpg. Coming from a built C model mechanical cat in a 379, it is a gutless pig on any hill but the comp brakes sure do hold well on the downhills, it rides like a cadillac and it cruises nicely at 65-75 on the flats. It takes some getting used to, but I am not overly impressed with the fuel economy of the mx13 and the smaller 12.9L displacement.

These newer engines are designed to run lower rpm. For the older engines is not good even if truckers will tell you otherwise. I guess 1300 rpm at top gear on flat road. I wouldn't climb at that rpm tough.

This one is a 2023 x15 with a 12 speed auto company truck governed at 68 does 15mpg or more empty with a load average around 8 to 9

maybe a special tune with FULL TILT out of Jackson, Mn. or Pittsburg power would be the good investment. Maybe different cams, manifold, turbo, injectors

The more fuel efficient the truck the lower the rate paid by brokers 😂😂😂😂

At 1500rpm in mine I’m doing 90+. 1200rpm or less. It’s a down sped engine, Atkinson cycle, it’ll do it all day long. I know rawze will tell you it’s beating the liners out of them but it’s not. Mine cruises at 1100rpm at 70 and does its best. Run it at low rpm, and slow down. After I rebuilt it and put it on the dyno peak power was 1344rpm and torque all the way down to 950rpm was peak. At 68-70mph 1090-1150rpm 7.7-8.4mog average dry van.

My x15 manual says do not operate below 1200.

Sammy, you’ll get it figured out. That’s a whole different truck than the W9. I would throw the question at Cumings and ask them what is the best optimal operational speed ratio RPM for the best fuel mileage surely they can tell you. I think these new motors have meant to be luglugged

Sammy i run a 2020 t680 3.25 rears 18sp manual x15 565@1850 torque. I pull refer from nd to west coast or idaho falls area loaded to gross both ways i run 68 mph run as hard as it will up hills my average is only 6.7 mph. Now when i run south to omaha no mtns im at 7.4

I have a 2015 with a 10spd @ 67mph it average 8-9 mpg with pre cast concrete on the rear.

We currently have 8 - 579's between the years of 2016 to 2020. One has the Paccar and 7 have the Cummins, all with 18 speeds. On our IFTA reports we are consistently running 5.7 mpg to 5.9 mpg every month on every truck. Then there is the one 2007 Pete 379 with a 3046e that gets 6.3 - 6.5 on our IFTA every month.

Don't forget Rawze's EGR Tune up. What rear's? Get over to Rawze's for an Insight read out and check up.

Heartland is owned by Freymiller. The shop at Heartland is a great shop

That’s what those 2 green lines are for on the tach. Did it come with a manual?

I think those x15 are made for running at low rpms especially if you have the efficiency model. I ran those when i was at fedex freight so i didn't pay attention to mpgs and they were automatics governed at 65

my 12.7 is set at 550/1850 last quarter avg 7.9 in a int 9400 2.64 rears run 65-70

If you got manual, you got to use both foot & cruise to save on fuel, it's tiring not like these autos

I have a 22 579 with an X15 efficiency at 450hp. I do have 2.93 rears though, not 3.25s. I run between 63-66, right about 1280-1320rpm. I can easily pull 8.5-9mpg out of it with 40k in the box in that speed range. If I run up to 70/72 then I drop to mid 7s easy. I run cruise control everywhere I go unless I’m in a bigger city. Don’t be afraid to let it run down to 1000-1100rpm, my truck keeps peak torque until about 1050rpm then I’ll downshift if I need to. On the 579 in your tachometer you’ll see some green lines, that indicates where your drivetrain is most efficient, keep it in the green and you’re going to pay for the truck easy. Best of luck!

Sometimes more hp is better than the fuel economy setting or lower hp

Go to Cummins and get the revs set along with tuning a little and you will get better with the MPG cause that is what's going to when the race

Hey brother, I have a 2014 T680. 3.25 rears. She is a slug when heavy for sure, but about to hit 978k next week with Cummins, 13 speed. Average mpg is 8.51 from 3-1-23 to 3-1-24, on 74k. Sweet spot is at 65 at 1350rpm. Prepared for the inframe or new create. Not sure which way to go on that one yet, but so far she is still strong

2019 579 X 15 with 2.93:1 rears and have gotten up to 10mpg I do run light loads and I understand that makes a big difference if you have the regular gauges in that truck you will get the best fuel mileage when the tach needle is between the two green marks/ lights at around 1350 so if you have 3.25:1 gears that should be 67-68 on the cruise and it’s going to feel slow as hell

I get 4 mpg

Hey dude I call that truck sales place in Oklahoma ,and do you think I should get that 400,000 added warranty for an extra $12,000.00

'18 t680 x15eff 13spd man 3.22 rears. Dry Van. I tried to stay under 40k in the box. That motor is designed for lower ram, max efficiency. Hence the little green line on tach. I consistently ran 65-68mph with weight, and got low to mid 8mpg. Running heavy and slower, 7+mpg. Under 15k in the box, under 70mpg....9+mpg. Hope that helps.

579 x-15 efficiency series with 285 rears getting 8.8 mpg with 75,000 pounds. It turns 1250 rpm at 65 mph. 12 speed direct automatic.

Drive safe brotha!! Best of luck.

All yeah i run 70-75 most of the time it not 80 sometimes 😉

Hey Sammy. Good luck with your new truck. WHat did you do with the W-9? Stay safe.

Change out the headlights with LED’s