Engine/Transmission (1998.5 - 2002) what is considering lugging for standard

[jkidd]

I know that lower RPMs and lower speeds will give you better mpg.



At what point is there a load on the engine versus lugging. I will sometimes cruise around 1300-1400rpm unloaded, if I need throttle, I will down shift or ease into it until I am at higher rpm before putting much fuel in.



Comments, suggestions... What do you guys do



(2001, 6spd, 4. 10, edge juice)

 

[Mundgyver]

I see you are running 410's so I know your RPM will be higher than mine. At 55 mph I am turning 1500 RPM. I run this way unloaded cruising with the cruise control on. Pulling a load or loaded bed I will run at 1700 rpm which puts me between 60 and 65 and sets me right in my peak TQ band.



If I have to go to the store which is about 2 miles though town, I will not even touch the throttle. I just idle up through the gears. 5th gear idling set me at 21 mph and 6th gear idling will run at 31 mph. We have a long school zone with a permanent speed limit of 20, so 5th gear idling works well for me.

 

[NoSeeUm]

I believe excessive lugging for a Cummins is determined if you push on the throttle and speed does not increase. In my case, unloaded I just about can't lug the engine, but I can sure make the drive train groan. Loaded is another story all together.



Read through this if you are more interested.



Jim

 

[Forrest Nearing]

when you hear the transmission rattle and groan, you're lugging it...



this is one of those questions that baffles me... you just "know" these kinds of things

 

[Doubleclutch]

Something to remind you 5 gear grinders... Mundgyver has a 6 speed. Our 5 speeds tend to spit fifth gear off with low rpm. Probably a good idea to avoid even after the Blumenthal mainshaft fix, IMO.

Greg

 

[WestTN]

Lugging was defined as running at or below the torque peak when the truck would not accelerate. This was back when all injection pumps were mechanical. Under these conditions you could get almost full fuel flow even though the engine was overfueled at that rpm. It created excessive pressure on the rod and main bearings and would beat them out or even break pistons from the excessive pressures in the combustion chamber. Our electronically controlled engines run according to a fueling map in the ECM. As long as the engine remains stock it will be torque limited by this and will not be lugged at any rpm. Injectors, tuners change that limitation, so if you have power enhancements, you need to watch for lugging. Running above 1600 rpms or so will pretty much protect you as that would be the natural torque peak if the computer didn't shave a lot of it off at low rpms.

 

[jkidd]

thanks, I am new to diesels, and my ears are not yet keen to the small difference between slight lugging and normal acceleration at lower RPM.