What Is The "Best" RPM To Run A Diesel Engine At? Torque vs. Horsepower?

[@billmoran3812]

Josh, as an engineer, I have to commend you on your thorough knowledge of the engineering principles of engine design.

[@theperson185]

Bill, as a mechanic, i have to commend you for putting oil filters bolts and sensors in ass backwards spots

[@another183]

@@theperson185 ouch

[@MacMilly707]

@@theperson185 🤣

[@behroozkhaleghirad]

I'm a colleague of you from Iran, and man do I enjoy it when I see that someone speaks with knowledge. All you said was correct, and you earnt yourself a new subscriber. Basically: Best fuel economy: torque span Best accelration: max torque to max HP Very low RPM with heavy load: destruction of engine

[@larrytalley117]

For my 2004 Cat C7, in my 40' motorhome, I allow the Allison Automatic transmission to pick the best RPM and Gear, UNTIL, starting to climb a grade...then I watch the coolant temp very carefully and if the engine starts to drop below 1500 rpm, and the temp starts to climb, I manually select a lower gear which allows the rpm to go up to about 2000 to 2100 rpm, and let the speed drop. Usually the "sweet spot" is 3rd gear, 2000 rpm, and the speed will be about 35 rpm. This is what works for my motorhome, but the best rule of thumb is reduce the gear, until the vehicle can accelerate up the grade, then reduce the throttle until you get down to the sweet spot. At the "sweet spot" the engine is generating enough torque to climb, and most importantly the fan is spinning fast enough to push enough air through the radiator to keep the engine cool. Everyone wins! Josh, thanks for another great diesel video. BTW I love the special effects.

[@mikeobrien3744]

Good explanation. Always a sweet spot, you just have to find it.

[@roadtoad7704]

This is what I do with my N14 Cummins. Sure, I lose some upgrade speed but I'm rewarded with 1,500,000 miles of no problems, overhauls or bearing wear. We pulled them at 1.3 million and reinstalled 👍

[@janosvarga962]

University level explanation of a topic. Clear and understandable even for the masses. Another great diesel video.

[@guyconnell2250]

On a couple Harley forums I have joined, it comes up every once in a while, "what RPM is lugging?" Too many variables as you say. Uphill? Downhill? Part throttle? Full throttle? Road speed? Parking lot speed? Cruising speed? Headwind or crosswind? Tailwind? To me, at cruising, an engine speed at which increase in throttle position produces an appreciable unlabored increase in engine speed and road speed is not lugging. Best explanation of torque vs horsepower I have seen on KZbin to date by the way.

[@ethanb2554]

I agree I could never wrap my head around the fact that TQ went down while HP went until he mentioned the valves, then my head exploded 😃

[@michaeltaylors2456]

This was what I was taught in my oilfield driving job, if it cannot gain RPM with additional throttle it’s lugging and you’d best downshift now

[@holmes1956O]

Lugging is always in regard to loaded rpm even on a motorcycle. Your passenger has to be pretty heavy to lug your engine through a parking lot

[@martinbrousseau2560]

You just explained why Gale Banks of Banks Power wants to turn a 2,000 RPM Diesel to turn up to 7-8,000 RPM... Thank You.

[@acemobile9806]

EXCELLENT video Josh. I get asked the same question by boat owners all the time, outboards, cruisers with small or big blocks, some with yachts & 3208s, 3406s, etc. I have always deferred to looking up rated tq/hp specs at respective RPMs & tell them to split the difference. Those who have followed my advice seem to never have problems & report favorable fuel consumption numbers. Looks like my theory wasn't far off... Next 1 that asks, I'm gonna start this video & hand them the phone.

[@hugoboyce7241]

"They tried to clean it with a shovel, or a stick of dynamite" lol

[@electric7487]

Or a sledgehammer.

[@gpam03]

that was the best and easiest to understand explanation of torque and horsepower ive seen, and ive seen and read a lot, and ive been around a while. great work.

[@officialweldingfarmingarch2041]

DESTRUCTION OF THE WEEK IS BACK!! Ahhhhhhh yeah

[@robertstetson4077]

If you don't mind me asking what happened to your new you tube channel

[@johnnylightning1491]

Thank you for that explanation, it's the first time I've heard a good explanation of the relationship between torque an horsepower. Keep the good stuff coming.

[@billnlori3149]

I have found that my Pyro temp stays lower when I work my 6NZ at a higher RPM. More air though the engine. Also, I have talked with transmission rebuilders and they say they are noticing more wear with the "gear fast, run slow" spec trucks. All that torque wears stuff out in the trans and diffs.

[@holmes1956O]

That low rpm is also what takes head gaskets out and causes liners to drop. Find the sweet spot that your engines runs well at and run there. A cat 3406 sweet spot is between 1400 and 1800 rpm. Run there and your engine will last at least 1 million miles with good maintenance

[@auseeker726]

@@holmes1956O I try not to go below 1500 rpm at all but we pulling 190 odd tonnes. Kenworth T909 super quads in Australia. They are fun to drive..these are driven on the road with other vehicles. We are limited to 90 kms/hr and they are 60 metres long.

[@crabmansteve6844]

@@auseeker726 Man those are amazing. I want to see a road train so bad but we don't have any in the US. Most we're legally allowed to pull iirc are doubles

[@ryanfisher6402]

Dude you have one of the smoothest voiceovers ever!

[@speed150mph]

As a locomotive mechanic, I love explaining this to people. One of hour engines makes 4500 hp at 950 rpm. Compare this to a top fuel dragster which makes 11,000 hp at 9500 rpm. We make almost 25,000 lb-ft of torque while a dragster only makes 6000. This means two things. Firstly, due to the rpm involved and the fact that they have 500 cubic inches compared to the 11,000 cubic inches of our engine means that their engine may have almost triple our power but wouldn't have even a quarter of our pulling power. Secondly, our engines are designed for a sustained output load. We can make 4500 hp for hours and hours. Technically barring mechanical failure and refuelling we could hold that power level nonstop. A top fuel dragster can hold that power output for a matter of seconds, and with the frequency in which they blow up on the track it's clear that's pushing the limit

[@PistonAvatarGuy]

Actually, the dragster engine would have more than double the pulling power. That's the whole purpose of the horsepower rating, to describe how much work can be done (like the work of pulling something) in a given timeframe. Alternatively, the dragster engine could pull the same load more than twice as fast as the locomotive engine.

[@electric7487]

"One of hour engines makes 4500 hp at 950 rpm" Is this an EMD 710?

[@speed150mph]

@@electric7487 can be either a 710 or a GEVO-T4. They both put out about 4500 hp at 950 rpm.

[@electric7487]

@@speed150mph While the 710 and GEVO are great engines, I wish they kept making the 7FDL (which you can find in the AC4400) as well in the US and Canada. But it would be used for things like marine propulsion and and power generation and would come with a DEF system (to avoid the use of EGR which is way inferior to DEF systems) to take care of NOx emissions. The FDL is interesting because it is one of the few V engines with master/slave con rods, and it has been in production for around 80 years. This is the longest production run for any Diesel engine I've ever heard of.

[@speed150mph]

@@electric7487 having worked on the FDL and the GEVO, I'd rather work on the GEVO. For one, the intake and exhaust and water piping is alot more reliable and easier to deal with when changing power assemblies. The master/slave Rod isn't that great. It makes it way harder to change the piston/rod assembly, especially when it's the master side that's gone. On top of that I'm not going to even consider how many failures I've seen where the bolts snapped off on the slave rod and knocked the rod through the cam and out the side. Also NOx is just one of the emissions that is dictated by tier 4 specs. In order to meet them in the tier 4 it was more than just adding EGR. The entire Gevo engine from the block up had to be completely reengineered. The fuel system needed to be upgraded, injection pressures boosted, manifold pressure increased, cooling system and oiling system revamped. The changes required to make a FDL tier 4 compliant, if even possible, would mean it wouldn't even resemble an FDL anymore

[@mikeobrien3744]

I drive myself crazy trying to explain torque and horsepower to people. You did a nice job. I run my cars and trucks at what I feel is the harmonic balance. Never had a car or truck that didn't have a speed where everything was harmonically "happy" at "x" speed. People think I am weird, but my stuff don't break.

[@joesalazar770]

So true it is an individual engine thing and that's how it is. I've told many the same thing simple terms. Torque is the number generated according to a rotating mass. The heavier the mass the more torque you can generate oh and if u get into the laws of physics think about an airplane moving at 800 miles an hour engines maxed out. Hint. Ok a engine loaded max used apintof fuel at full load not changing full load running at 50 mph. U get 10 mpg increase your speed to 150 mph what will change only the amount of mph. Not your fuel economy. Think real hardon this it's been backwards for a long time. Load is load max fuel is max fuel it's gets very interesting. Could research this forever.

[@david1967able]

You have answered questions I’ve had for a long time. Thanks for the great content!

[@robpeters5204]

My uncle taught me to always match your rpm’s with your road speed. His equipment always looked like it came off the showroom floor. While most of the guys would be driving the piss out of their trucks during the day, he would be right there with them using less fuel, less wear and fatigue on his truck.

[@prabhathmbbs2012]

What do you mean by matching RPM with road speed?

[@sasquatchcrew]

@@prabhathmbbs2012 I wonder if its the needles.

[@jeffreysheldrake7943]

Running a working tractor ploughing it was up to the temperature. Free spinning and the correct gear selection is important.

[@johndavidwolf4239]

The owners manual of a a car I had years ago said "Drive in the highest gear that gives you the acceleration you want". Using the engine you showed data for, lets say that you were on a road that was perfectly level, and for legal reasons you had to go at exactly 50 MPH, and in those conditions the vehicle requires exactly 200 HP to counteract the air drag, it would be okay to be in a gear that caused the engine to spin at 1,050 rpm as the engine would only be producing 1000 LB-FT of torque, or 57% of what the engine is rated for, if the road started to have a slight uphill grade, the HP required would go up you would need to give it more "gas" to maintain the same speed until the pedal is about 7/8 down (as a general rule of thumb, when below running the 'max torque RPM' [in this case 1200], depress the pedal no more than the ratio of the RPM you are at to the Max torque RPM, [1050÷1200=.875=7/8]) , at which point you would downshift to bring the RPM up.

[@Greataviator1]

HP is the work and TQ is the force.

[@hoost3056]

Depends on many things, but Cats like 1400-1600 rpm most of the time ( big block Cats.....15L and up ). The Series 60 Detroit I drive likes to be between 1550-1650 rpms in the flatland and 1800-1900 pulling a grade. Gets best mpg between 1450-1650 in 1:1 direct

[@aaronmoody8043]

Yes, new vid. I’m learning all about Cats, since I’m about to buy a 94 Pete 379 with a 425 horse Cat

[@yesdeere1376]

I like horse cats

[@briantruck2284]

Good luck

[@lesliegibbons6917]

You turn your radio off and listen to your motor. It will talk to you. When you go into a hill as it starts pulling you dont stuff your foot in it. You slowly back out of it and listen when you find the sweet spot you will hear it and it will pull a hole in the wind. Try it it works.

[@VladGoro25]

I knew all of that stuff, but your explanation is one of the best over the internet! There is trucker on YT, doing heavy stuff and runnin it's 15L Cummins uphills at 13-1100 rpm....he doesn't know that he should do 14-1600. It will be better for the engine and even for fuel (cause slower speeds (i mean really slow) means lover gear and higher rolling resistanse)

[@jcjc2593]

My 3406E 1LW is currently at 475HP 1750Lbs torque I like to run it between 1200rpm and 1500rpm when shifting gears at flat roads and when I hit the hill I keep it at 1700rpm max depending on the load I'm carrying I try as you said just the necessary rpms no more no less and I never push the right pedal to the floor,never... I've been having this truck for 7 years by now and it has more than a 1 million miles on it,I don't know if it was rebuilt before it came to my country (Costa Rica) but it is the best truck I've ever had... I always thought that if you drive your truck at the lower rpms needed you'll get more durability because it isn't turning everything up and wasting torque and if lower rpm speed then longer the engine will last... As always very good video pretty informative and interesting facts... Keep them coming...

[@bizim_eller]

That is how you drive, I was even more cautious going up to 1700 rpm but occasionally I did it🙂✌️

[@kiwidiesel]

I used to drive a Kenworth K100E with a 3406B that had a nice little increase in fuel pressure prior to me getting it. On an extended climb that thing would pull down to 1000rpm an have egt at 560 which was well in the yellow but regardless of how much steeper that climb got, that beautiful cat engine wouldn't lose a single rpm more. The exhaust stream out the top was like a jet exhaust pipe roaring due to gas velocity and always had a nice black haze to it where it was running slightly rich of peak. Needed that heat tho when she was cold wouldn't quite pull a planet like when it was on the boil at that 98 deg C water temp. Would recover from that 1000rpm with a vengeance at the top too. Aint nothing like a caterpillar engine!

[@roadtoad7704]

EGTs at 560*? 😳 That sounds really really low for those conditions. Every Cat I've driven would be over 900* if I did that.

[@kiwidiesel]

@@roadtoad7704 sorry I had referenced it in celsius which my egt was callibrated to, thTs 1060 deg f.

[@roadtoad7704]

@@kiwidiesel That's fine. Actually, it's on me. "Kiwi" in your screen name should have told me "Oh, OK. Maybe he meant Celsius."

[@jameslast7555]

Couldn't afford a Cummins Aye!!

[@dnailit385]

wish I could give you billion views on this on here.... Also wish I could sit in a class taught by you

[@renacimientoargentino7515]

It also depends a lot on the compression ratio, in the Cat c18 with 14:1 compression ratio the sweet spot where there's the lowest fuel consumption is between 1400 and 1600 RPM, similar with the C15 and 3406 with 16:1 compression. For the Road use ones which are the C18s with 16.5 :1 and C15 with 18.5:1 compression is between 1200 and 1400RPM, with higher compression the torque curve moves down, but there's also higher pressure and temperature, at 1800 RPM which is normal in marine engines the cylinder head would overheat and crack, while the low compression C15 can go rather well in the 2000RPM before head overheating problems

[@ShainAndrews]

Thought the answer was always another question. Who owns the machine? Company machine? On the mat as often as possible, it has a rev limiter.

[@aussiebloke609]

Same as how all rental cars are offroad-capable, while simultaneously being the fastest cars in the world. :-D

[@outdoor044]

@@aussiebloke609 Rentals are also good for pulling stumps out.

[@giggiddy]

@@outdoor044 lolololol 🤣

[@wyatttipton9957]

Facts, working for spectrum that little nissan four cylibder was at 6200 all day

[@AdeptApe]

That poor engine.

[@cranerigging3604]

1800 RPM on trucks ,farm tractors and bull dozers is the sweet spot on our equipment .

[@jaydunbar7538]

"Sweet spot" can mean so many things, best fyel economy and best power will be very different rpms and both could be described as the sweet spot.

[@johnhull6363]

If it's a Detroit. On the floorboard. But cat on a long pull I'd say at peak hp, but other conditions...peak torque

[@elijahrobinson2362]

That s ONLY for the old V engines. The inline (Series 60 and newer) are not 2 stroke engines. Totally different design. For any engine on a long pull, peak torque. That’s what keeps you rolling. HP is more for the acceleration.

[@MrTheHillfolk]

@@elijahrobinson2362 once a year I get to hear that sweet song of a 2 stroke Detroit. I hardly believe my ears at first. My town highway dept has a leaf pickup truck that still runs one.

[@mitchless1589]

A high torque load at low rpm is hard on everything from rod and main bearings to transmission and rearends.

[@iamthemoss]

Always enjoy your videos, I own my first diesel and have always loved diesels for some reason.

[@antonpandoursky9790]

Very informative video like always, Josh🙂The only thing I'm thinking is when you said that running at higher rpm won't make a significant difference in fuel mileage, but running at lower speed will give a better mpg.Yes,and lower speed means lower rpm 😁

[@falcon8553]

I truly enjoy your videos. Your able to put this information to simple 1 + 1 = 2.

[@dakotajohnson8782]

I wish I knew half the stuff he knows about engines I've learned alot just watching his videos

[@AdeptApe]

Hey thank you.

[@dakotajohnson8782]

@@AdeptApe your welcome bud you seem like a pretty cool Guy I like your videos and thank you for commenting back

[@TheMarcosgoulart97]

In my truck peak torque comes at 1800 rpm and peak hp at 3500rpm....I just cruise at 2000 rpm....no stress for it and plenty of power

[@briantruck2284]

1500

[@dieselgeezer18]

cruising does not put much stress on the engine. You can safely run it at much lower RPM. I usually cruise at 1200RPM. redline is 4500RPM, peak torque 2000RPM. When i give it throttle at 1200RPM it accelerates which means i am not lugging the engine while cruising

[@MarkSmith-zt2zl]

Along with piston speed based on stroke, you would have to consider piston acceleration, dwell at TDC and BDC. Short stroke motors have shorter duration dwell and high acceleration rates that generate high G loads that don't favor high mass components.

[@scruffy6151]

Very information and explained well. Let's not forget the boom lol nice touch.

[@moondogdieselworks3883]

You never bore me you are a wealth of information, I watch every on of your videos to the end. How about a 3306 fuel injection pump episode, specifically the one that came in the mep007b military generator

[@JeffMTX]

when you tighten a bolt, (torque x angle through which you turn) is energy. you put energy in, where'd it go? A little to heat, but most of it is stored in the tension that you leave on the bolt. youre stretching it like a spring. (now here's the good part:) energy is in joules. power is in joules per second, ie watts. plot how many joules you've put into that bolt, over the time you turned it- that'll be a line that goes up with each second, cuz you keep on turning and keep on adding stored energy to the bolt. then the slope of that curve is how much power you were applying (how many joules per second) at every instant. HP is also power. 1 hp is exactly the same as 746 Watts.

[@michaeldunagan8268]

Cummins recommends 1450 RPM for efficiency where the truckn will spend most of its time: 65 or 70 MPH; 1500 for performance on the N14 ans ISX15. Personally, my 2000 Cummins N14 engine likes to spin to breathe as evidenced by the instant fuel meter. It will do 1,300 bobtail or empty w/o head wind but 1,500 is much better sounding and better instant fuel mileage when haing heavy. 1,500-1,600 uses the turbo less than 1,300. Lugs and bog when heavy at low RPM, but chops them hills down with the edge of its hand at moderately high RPM. Mounteagle I slay at 1,800 RPM. EATON 13-Speed allows the fine tuning in cities or other slower roads. It is a deal- breaker for me to own a truck-tractor that comes with less than 13 speeds or an automatic. Exceptions.: 22' dumps/short city day cabs wiring in the city or vocational.

[@powerdiesel8639]

Olá , sou aqui do Brasil , eu vejo teus vídeos sempre ,, eles são ótimos ,vc explica bem , tank you.

[@1958johndeere620]

I miss my 3406B. It was low power,,,,,310 but man it would pull hard at 1150 and keep going. I had a pilled up 3406b in another truck, but would fall off the turbo lower then 1300.

[@daciefusjones8128]

for class 8 trucks it's all about the torque.

[@tonyford9883]

great video👍🏾 i run cattle and we tend to run our B model up around 1750 1800 ish loaded and then unloaded i like to run 14-1500ish but seems to me the ole B likes to run up a little high i've seen her take 1850-1900 pulling heavy and have PLENTY of power on top end

[@shermanleung5839]

I have a Mack. If I idled at 650rpm, the engine would consume more fuel than idling at 1000rpm. I don't know why but that is the way it is. At 650, the engine load is at 8%, at 1000 the load goes down to 5% or 4% sometimes.

[@linuxman0]

I've always understood that the besh fuel economy came from running the engine at the speed of its lowest break specific fuel consumption point which is, as I understand it, the same speed as the peak torque.

[@nobenznofun9139]

Excellent vid on the pros and cons of each scenario love that channel

[@nagyandras8857]

13:19, that animation is actualy verry correctly showing what yer conrod will do if you are toooooo rev happy

[@giggiddy]

Love these topics. Nice length video and really enjoy your deep explanations.

[@Mmmmmppppppp]

I really appreciate your sharing your knowledge of diesels and explaining it so even I understand! 👍🇺🇸👍

[@josephmichuda6447]

First, thanks for the Destruction Of The Week.

[@37903abc]

13 speed c15 acert old werner tuck 03 ...67/70 mph at 14 to 1500 Loaded 75000+ truck runs great . 4.5 to 5 mpg.

[@rickjohnson1632]

I’ve driven CDL trucks for over 25 years . I also have known a few professional diesel mechanics. I was always told diesels love rpm. They told me lugging the motor will hurt them. I have always kept my trucks in the higher rpm range . Truth be told, I’ve always had a heavy foot and driving semis I never paid for my fuel so it was pedal to the medal ( with in reason) . As far as idling a truck basically , when I started it in the morning for work ,for the most part I never shut the truck off ( more or less)

[@ciroflores5871]

Is the timing adjustable on díesel engine

[@Second.Nature.Lawn.Michigan]

Paccar specs a fuel saving truck with a 12 speed auto and a crazy axle ratio like 2:64. My last fleet truck had this an ran under 1200 rpm at 70. It did get about 5 percent better fuel economy than the other spec trucks but it was a disaster to drive. Absolutely would not downshift until 900 rpm. The entire truck would shake and rattle and oil pressure about 20 psi at full pull.

[@ruxoneto6560]

On inline 6 cylinder 4 cycle diesel engine at around 1000 1200 rpm is a critical rpm where torsional vibration comes out & that is what destroys everything.!!

[@elijahrobinson2362]

The first example of torquing a bolt ignores that work was done TO produce the torque. Energy was put INTO the lever and then the bolt. HP is (according to some engineers/physicists I’ve heard) a mathematical function OF torque. Good vid, nice destruction (glad they are back). I’d love to see a discussion of what each (HP and torque) does, as it applies to driving a heavy truck. When is higher HP desirable? Under which conditions? When is higher torque more desirable/why? Which is needed to accelerate, which to maintain speed on a grade? That sort of talk.

[@fastinradfordable]

Hp and torque aren’t two different things. Just different terms, to describe a single force.

[@elijahrobinson2362]

@@fastinradfordable, not according to engineers. “Torque is simply a force acting on something from a distance (i.e. a piston pushing down on a crankshaft, using that leverage to rotate it), while horsepower is torque multiplied by RPM, or a measurement of how quickly an engine can accomplish a certain amount of work.” As I said, HP is a FUNCTION of torque. kzbin.info/www/bejne/q16weWepm5qrobs

[@szymoozz]

Wow incredibly informative. I understood how intercoolers and turbos affected an engines power but I didn't understand some of these seamingly simple points.

[@donnatalielucasheimbigner7598]

Farm & construction equipment typically gain better fuel economy than most trucks due to the incredible load.

[@damirvasiljkovic5767]

Just wanna say thank you for sharing your knowledge and and in doing so helping people. I made a little donation for you at PayPal. God bless you.

[@AdeptApe]

I saw that, thank you very much. I didn't see an email from you, but I'm glad you left a comment.

[@bryanwilliams9589]

Great video today Josh!

[@colonelmann]

I was just wondering this very thing today, as the auto transmission on my Cummins was running around 2500

[@merlinmonson2133]

Very well explained. Thank you

[@georgehofgren6123]

I would say simply knowing what rpms create peak hp and rpms is most important. (for gas Or diesel). Then just drive so that you choose a gear that gives you whichever you need for the given conditions (like passing or coasting). Then figure out at what speed the engine lugs and stay above that at all times. Unless you are running a fixed speed unit (like a generator or pump) really gearing is the key and applying the specs or torque and HP ~

[@georgehofgren6123]

A big difference actually probably occurs more based on the density of the air... so a hot day at sea level is going to create a lot more power at lower rpms than thin mountain air in the winter, where you probably need to bring up the rpms to make up for the lack of compression ~

[@MarcoAAOrtiz]

Power is Force (Torque) versus Displacement (RPM). Without displacement, may have static torque but no power is consumed or produced.

[@borisj4054]

Work = Force x Distance. Unit is joules. Rate of doing work is joules per second. Unit is Watts, kiloWatts or your old Horsepower 748Watts. Thus the rate of doing work is the force x the rate of distance change. Feet per second (old school) or meters per second. So kW = Force (torque) x distance/ time (rpm).

[@codyleonardo8324]

Hey Awesome video. I love watching your videos I’m always learning something. You make awesome videos. You should do a tool box tour next. Love to see the set up you have being the kind of mechanic you are.

[@Mikheno]

Max torque on my '02 Dodge/Cummins HO is at 1600rpm. For what it's worth the engine seems to just purr at around 1750rpm or so. Also, if you hit a hill etc and rpm wants to drop...it drops right back into peak torque and easily pulls itself back to 1750. I will force a downshift if I see a steep hill coming up (moderate load with full time camper and gear) but generally the engine seems to hold it's own in CC with little effort. Fuel mileage alone might tell you your best rpm.

[@glennshumaker2019]

The best RPM to run a diesel is what is recommended by the manufacture turning it too hard will not be good for it, especially if your want the engine to last, well over 1,000,000 miles with good maintenance

[@theautomotivegarage]

Thanks for Great Informative and Educational Video. Time to Learn new Information : )

[@Inspironator]

Great short answer!

[@bighorn9119]

This is why I love diesel engines more torque over horsepower

[@davidwalle5025]

good video on torque and horsepower.

[@j.daniels7429]

Regardless of rpm in whatever gear, it takes the same # of revolutions to go a same distance. Running at a lower rpm does not save revolutions for the said distance.

[@jaquigreenlees]

Wet exhaust marine diesels are better. No DPF or DEF. Why would you need either when they are sucking water from outside the boat, running it through the heat exchanger then dumping it into the exhaust system. This both cools the exhaust and captures any particles in it. a dry stack is no different than a diesel on a truck DPF/DEF required. Josh, I know the old 2 stroke Detroits had a TT option on many of them, TT being tuned turbo which was to make the engines sip fuel at 1800 rpm. Is there any way to set a Cat engine like this?

[@vinlemarechal8296]

best fuel effiency is basically at max torgue its where it engine breathes best,for fuel economy raise the rpm slightyly example max torque 2500rpm keep your rpm in range 2500 to 3000 ie can run in higher gear for longer hills etc intelligent cvt systems despite drawbacks do this well

[@openroadamerica]

excellent video!!! Very helpful

[@brianrinehart4231]

Now that you are not with Cat. Congratulations on going out on your own! Do you have any opinion on PDI, or IPD after market rebuild kits? I'm going to build my own engine, and have been getting specs and torque values from watching you and KT3406E. I still have a couple specialty tools to acquire, but I have a good mechanical knowledge to help me along. Thanks for all the videos. Hope to see more.

[@jondrew55]

10:59 picasso animates the combustion cycle

[@AdeptApe]

Lol, more like someone with no art skills animates the combustion process.

[@darrenrich3492]

But at the end if the day- it all depends on what truck It is in/ gears/ and tires- Yiu can have the same truck with a couple changes Amd have 2 very different rpm that max mpg is achieved.. also WhT come into play big time with a lower rev engine..

[@RDC_Autosports]

from my dyno cats make the most torque at 1500 but your workin it.... 1600-1800 seems to be the optimal for a cat

[@Cartelito3]

ISX15 runs a high volume oil pump, not a high pressure oil pump so it helps with low rpms while idling or driving.

[@rodneyward8357]

Mxs 6plus MPG with broke compression Ring's on 2 3 And 4

[@truckingjamaicans5045]

Nice vid Josh

[@n.l.7308]

Good info 👍. When empty run lower rpm but with wind resistant go higher. My 6nz close to 2,000,000miles I'm happy might not be as feul effience as 12.7detroit. I baby sit my engine is not the strongest but is weak. I do rpm with speed gear is in. Check exhaust temp. Wind resistance and weight also. My super10 don't give me lots of choices for rpm so I drive at certain speeds most of the time. I wanted another transmission but with over 10years trouble free I don't think is worth it. I've seen in other truck real good feul economy but they break more. My c15 is been good to me thanks for all the info its been very helpful 😊 👍👍👍👍👍

[@DumbCarGuy]

I once ran my diesel at 4,225 RPM's. Like I said, once.

[@brianhurt3801]

Great video

[@michaeldunagan7838]

Cummins Publications for the N14 and X15 is to choose an axle ratio that will allow the engine to run at 1,440 RPMs at 65 MPH on flat ground in top gear for maximum ecomonmy and 1,500 ROM fir maximum performance. Clearly, Cummins wants their engines spinning well above 1,200. I guess the DDs can run at 1,200, but their half-life is about half that if a Cummins N14. CATs were strong pulling, at least the ones I drove, but very very thirsty. I never drive a Detroit with any power and not are they loud. Volvo and Mack....need I say more... ? Hence, I went with a Cummins N14 tractor: No EGR, no DEF, no ELDs. ,,😇.

[@Cliff_P]

Also wondering about wear vs rpm. Or piston speed. More of constant rpm situation.

[@albi2k88]

What power is good explains torque on wheels chart for every gear. It shows that torque on wheels on 3rd gear is bigger on max power RPM than o 4th on max torque RPM at the same vehicle speed.

[@HUMINT1]

Hello Mr. Ape. I’m digging the channel as I think it’s extremely informative. Especially for a guy like myself who knows very little about Diesel engines and how they work. With that said do you or have you done any videos of say non-commercial use Diesels , or do I dare say Ram 6.7 diesels in particular? Reasons I ask is because I noticed you had videos of a used Chevy truck, an electric bike, normal bicycle & because you guessed it I own a Ram 3500 DRW Diesel. Anyways there are very few channels out there that explain things and go into depth the way you do all while speaking in a way so a Knuckle dragging Neanderthal like myself can understand. Thanks for the videos! ✌🏽

[@grouprocox]

Well done! Engineering Explained did a similar video going in depth on HP vs TQ and acceleration using similar and derivative equations

[@somborn]

Thanks for the explanation 👍

[@flaviosorrentino772]

I overheard a driver say to a mechanic one time that he was disappointed in his engine’s torque and horsepower when climbing hills. The mechanic asked if the driver took a “run” at climbing the hills. The driver said not really. The mechanic answered, “your not running out of torque and horsepower, your running out of speed!”

[@fastinradfordable]

I have gotten 10-20% better fuel speeding up before hill and slowing down up hill. And re-accelerate while going down the other side.

[@jkearney5001]

Approach fast, climb fast, coast down. 👍

[@kenstogner2427]

I used to operate a Government vehicle with a 3208 sometimes it would zing up to 3,000

[@Porty1119]

How does this work with a hydrostatic transmission? Is there an optimal RPM or should it just be run flat-out for maximum flow?

[@daltonbrink9924]

For a hydrostatic transmission, you want to run it full throttle.

[@Porty1119]

@@daltonbrink9924 That's what I figured and what I have been doing, just wanted to make sure there wasn't a better way to do it.

[@adamfpv8294]

Headframe Hunters do you have a tractor with a Cat in it?

[@Porty1119]

@@adamfpv8294 I have two EIMCO 911 underground mine loaders with air-cooled Deutz diesels.

[@Rx7man]

good vid, but hasn't gotten into Volumetric efficiency, which is the root of why peak torque occurs where it does for a particular engine, and why it falls off Volumetric efficiency (VE) is how much (as a percentage) the cylinder gets filled on each stroke... around peak torque is where everything works together and you get maximum cylinder fill between intake and exhaust harmonics, and minimal pumping losses.. If you fall below peak torque RPM, usually you'll get intake reversion since the intake valve doesn't completely close until the piston is somewhere on its way back up for the compression stroke.. On the other hand, if you go much above peak torque RPM, the air can't flow through the valves fast enough to fill the cylinder, and exhaust restrictions (turbo, muffler, etc) start to choke it... you can still make more power for some time after that since you're still taking in more air, but it'll cost you since you're doing a lot of work to do so... At some point, it takes so much work to move the air you can't make any more power with more RPM

[@vandipradiktya2839]

great explanation

[@Brian-nt1hh]

Understood, thank you

[@johnbarham7718]

What an excellnt film. I've never really understood the relation ship between HP and Torque. (where does the 5252 come from? ( I don't doubt it, I just wondered where it comes from.)

[@mwhitelaw8569]

Some damn sweet dpf's man Wholly hell