Lugging your mom is different from lugging an engine.

The higher gear you are in the lower the available torque for manuvering. The lugging comes from any load on the engine causing it to hesitate, because you are in wrong gear.

http://www.motorera.com/dictionary/LU.HTM

For the barely literate:
http://hamptonroads.com/node/48181

For motorcycle jocks:
http://www.jpcycles.com/Tech/Articles/enginebreak.aspx

For Canadians:
http://www.canadiandriver.com/articles/jk/070815.htm

 

Daayyuumm!! I thought the shift points were at 40 MPH for 1-2, 62 MPH for 2-3, 93 MPH for 3-4, etc.

Of course I only average about 24 MPG.

 

Lugging the engine:
Letting the rpms fall below the engine's powerband

Power band:
The subjectively defined rpm range over which an engine delivers a substantial fraction of its peak power. The power band usually extends from slightly below the engine's torque peak to slightly above its power peak.

If you take that literally, the S2000's power band starts slightly below 6,800 rpm, so you are "lugging the engine" slightly below 6,800 rpm. That's a bit of a stretch. You're not getting optimum fuel mileage if you always rev higher than, say, 6,000 rpm.

This was a topic in Car Talk just a few weeks ago, by the way. Someone with a Geo Metro was complaining he had lost 4th gear and was thus in 5th when he used to be in 4th and inquired if the resultant improved fuel economy had any determinal side effects. No, Click and Clack said, then they mused on the cultural differences between European drivers and US drivers. In Europe, they claimed, drivers shift up much much earlier.

 

Wow, I hate the major bog on the engine below 3k RPM.
I dunno how you ppl do it. But props to you guys for saving gas

 

I didn't write this, but it is a much better definition of lugging.

"If the car isn't accelerating, and you are below 1250-1500 RPM and there is a deep low bwoooaaaaaaa, if you hear knocking, or if the car is vibrating harshly/bucking you are luggint the engine."

I'd modify it to say that whether the car is accelerating or not, and regardless of the engine speed, the engine will make a very unique and easily identifiable noise when it is lugged. That noise is a sure sign that you are lugging the engine, and if you don't hear it, you're not lugging the engine. Knocking may or may not be associated with lugging, but if you hear knocking with the S2000 it will only be momentary, because the car has a knock sensor and will retard the timing, but if you hear even a slight knock, it *could* mean that you're lugging the engine. If the car is vibrating or bucking, then you have a case of sever lugging.

What many people seem to fail to realize is that the F2xC isn't any different than a pre-VTEC Honda engine until VTEC engages. This engine pulls at low revs in exactly the same way it would if the redline were 6,000 RPM. That is in fact, the gift of VTEC, and the reason Honda put it on the car.

The "power band" theory doesn't even make sense in a car with two distinct power bands.

 

Hey Boofer.

Just so everyone else knows, you also sent me a PM asking this same question, and I have already responded. However, I think it's worth repeating a part of my response here in the public thread.

What you are describing sounds more like a "bog" than lugging. If you are cruising at a constant speed or slowing gradually, and suddenly snap the throttle open, the car can lean out momentarily, because it takes the MAP sensor and ECU a moment to respond to the change in manifold absolute pressure (or what we use to incorrectly call vacuum). The ECU sees the throttle opening through the TPS (throttle position sensor) and adds fuel to compensate as the throttle opens, but snapping the throttle open suddenly can still produce a momentary lean condition and a bog. I cannot be certain that this is what you are seeing, but try *squeezing* the throttle rather than snapping it open suddenly. If you squeeze the throttle more slowly, do you still get the hesitation?

 

I don't think I get 24 MPG when I use those shift points, but then when I'm shifting at those speeds I'm running WOT, and the fuel flows pretty freely.

Do you really get 24 MPG? I raraly get under 26.

 

Well, there are usually a couple of autocrosses a month that figure into that mileage. 5 miles on a Sunday afternoon in second gear does not help the fuel economy.

 

The first link is the best, because it is simple and doesn't go far enough to get anything wrong.

Lugging really is laboring the engine. Engines make a very specific sound when lugged (varies from engine to engine, but is consistent with a given engine) and it is NOT entirely due to detonation. It is simply the result of making the engine labor, and it's easy to identify by the way a laboring engine sounds. Bogging, hesitation, and detonation, are not the same as lugging, but all can be signs of lugging. Lugging will destroy an engine in short order, and it will sound like it is distroying the engine in the process, so if you're lugging your engine, you will know. It's not subtle. First the engine will sound labored. Lug harder and it will protest by bucking or bogging. At this point you are WAY over the top and if you can't stop accelerating so hard in the higher gears, you really need an automatic. Anyone who can lug an engine and ignore the sounds an engine makes when it is "laboring" simply isn't paying attention.

LOL, your first link was better than anything I managed to turn up when I was looking for links.

 

Torque for maneuvering? In commute-mode, I enter turns without slowing and exit without applying more throttle. No additional load on the engine.

"Lugging" is not what I'm doing when I am cruising at 40-45mph in 6th gear. On the rare occasion that I do have to pass someone, I drop down to 4th or 3rd, as required.

I agree with REDMX5 that the first link is a good-enough working definition:
"To cause the engine to labor by failing to shift to a lower gear when necessary. The British term is "labour.""

Only the last link addresses high bearing loads with reduced hydrodynamic wedge (which increases with rpm) to support them.

I agree that lugging the engine is bad. So I don't do it.