What is lugging?

[B-Ark]

Greetings Gents,

Does anyone have a good definition of "lugging"?. I know that pulling a battleship up Vail Pass at 30 mph in top gear is lugging, but is there a more technical explanation? Also, why is lugging bad - what is likely to be damaged?

 

[Bob Wagner]

ok

lugging is running the engine at too low a rpm for a given speed



The cummins loves to run in the 2000-2200 RPM Range "its the sweet spot"



Hope this helps

 

[Archive]

Bob is correct... the cummins power boosters newsletter states that the 24 valve gets its best mileage between 1800-2000rpm and its best power between 2000 -2200 rpm... drive it there and check it out!

 

[WyoJim]

Put your truck in second and try maintaing 15 or 20 miles per hour. No Problem? Put it in 6th and maintain 15 or 20 mph. Thats Lugging.

 

[Max340]

Cummins official definition states that lugging is any situation where pressing harder on the accelerator does NOT increase engine speed.

 

[Texas Diesel]

Well said Max340!! That IS the basic definition. This type of operation will cause overheating and accelerated wear. I dont have a PhD in "phi-sics" so I cant explain the relationship between load vs time, but put simply: (max)load (full throttle) and time (basically low RPM = high heat load and stress) will shorten an engines life. When in doubt, DOWNSHIFT!!! But dont run at or near redline for more then necessary.

 

[DHatfield]

Okay now I am really getting confused which isn't to hard to do. I always thought that lugging is defined as what Max340 stated in which you can't gain engine speed when pressing the accelerator assuming you are not already against the govenor. So does that mean since last summer I pulled my 6,000 lbs trailer up the west side of Vail Pass in CO at 1600 RPM in 6th gear that I lugged my engine the whole way , I did have power to go faster as I was not on the floor yet I was trying to keep my EGT's under 1150 degrees. Next time I guess I need to rap it up somemore by driving faster .

 

[Champane Flight]

Well said 340,To go even further. Lugging: if the engine cannot accelerate at ANY RPM,you are lugging your engine. Except of course if you are against the governer.....

 

[BCFAST]

... and from an internal engine stand point, lugging (especially when loaded) will hammer the heck out of the bottom end! As I have been told, it loads the rod bolts etc. to rediculous levels.

 

[yogibear]

Doug, if you would have went to 5th, you would have been running about 2K rpm with lower egt's and better fuel mileage.

Larry

 

[Missouri Mule]

My thoughts exactly yogibear, down shift into a lower gear, keeps egts lower and more power at same speed.

 

[HC]

... the cummins power boosters newsletter states that the 24 valve gets its best mileage between 1800-2000rpm and its best power between 2000 -2200 rpm... drive it there and check it out!

I can state without a doubt, for my truck, running light loads, this is not the best mpg rpm! I get much better mileage running 1500 rpm than at 1900 rpm, and better still at 1400 rpm.



I suspect that if I was pulling a load and working my engine closer to it's true capability, then the data in the newsletter might be true, and with a load I'd have to get the rpm up there to prevent lugging. I also agree that efficiency is dramatically better at 1900 rpm than at 2100 rpm. But with light loads, the slower I go, the higher my mpg, even down to 1250 rpm. (but I don't stay there, because it is too easy to lug the engine on even a minor hill, plus, who can stand to drive that slow long enough to get an accurate mpg reading?)

 

[Diesel Freak]

lugging is actually relative to engine load and RPM. It is just as easy to lug an engine at 2600 rpm as it at 1500 rpm. If you have gages this is very easy to monitor.

-If you place your hand on the gearshift and feel sharp defined power pulses from the engine you are most likely lugging.

-If you are at 1600 rpm and EGT is climbing fast, but you are not speeding up, you are lugging.

-If you hear excessive gear lash from the transmission you are lugging.

It takes a little experience to tell if you are lugging the engine. There is no exact way to tell if you are lugging it just takes fammiliarity with the vehicle, how it performs and the load you place on the engine.

-Cliff

 

[WestTN]

Lugging

Lugging is running below the engines torque peak at heavy throttle. If you compare this to the Cummins statement, you will see they essentially mean the same thing. If you are below the torque peak and at full throttle, you will not gain speed unless the grade or load reduces or you downshift.

A property called torque rise is much desired in heavy truck engines. This is simply the amount the torque rises as the load pulls the engine down from the horsepower peak to the torque peak without lifting off the throttle. The more torque rise the better. It is expressed in percent of torque available at the horsepower peak. The useable power range is the range that starts at the torque peak and ends at the horsepower peak.

 

[Ladders]

Boost pressure?

To add to this (confusing or clearing), when I feel the "lugging" I notice no boost pressure also. Is like the eng is trying to go faster and the boost falls off to zero. Is this another indicator? Usually happens to me when in that "panic" situation and need to get out of the rear enders way after a quick slo down. After downshift, notice that boost is there very quickly - so - I am assuming, (OOOOPPPPSSS) that when lugging you have no boost or speed increase and EGTS CLIMB fast as fuel is not being burned in the chambers but in the exhaust/intake also.



SOTSU!!

\\BF//