lugging the engine

[fatmike]

Originally Posted by pierre shags

OK, we're not supposed to lug the engine.
Why, how does it hurt the engine?
And what constitutes lugging? Revs too low for the gear, but how low?

Sorry to be so ignorant.

You'll know it when you do it. The car will buck like a bronco and make some awful lurches and noises. Press the clutch, downshift and try again.

Can't say this has happened recently, and I've never once looked at the tach -- but I'd guess in the 1200/1400 RPM range.

[Topless]

The concept is pretty simple if you think about it. Shortly after startup all of our M96 moving parts are ideally floating on a thin coat of oil. Minimal metal to metal contact, minimal wear. When you put a heavy load on an engine at low rpm such as hard acceleration or climbing a hill you risk exceeding the ability of the oil to continue floating the parts and you get metal contact and excessive wear. Because the oil pump is tied to RPM, the lower the RPM the slower the oil replenish. When the engine load exceeds available oil replenish damage is done.

The severely lugged engine (bucking bronco) has gone far beyond overloading available lubrication, bearing surfaces are all on metal, and the motor will not turn over well enough to enable complete combustion causing detonation and further engine damage.

The simple solution is downshift to increase your oil replenish rate, float the internal moving parts and support the increased load. Our motors seem to be more sensitive to low RPM loading than most so unless I am at idle, coasting downhill, or approaching a stop with no engine load I rarely run my RPM below 2000.

[Brucelee]

In general, smaller motors are easier to lug, ie not much torque down low in the RPM range.

It much harder to lug a Corvette for example, as they make lots of torque way down low in the range.

Either way, it is a bad thing, as your car will tell you pretty quickly.

[dennis]

when my car is cold especially, I shift below 2k rpms and never hear an irregular engine sound.....i dont watch rpm too much unless its at the max side, i just listen for the engine

[jacabean]

why would someone drive their car like that ?

[landrovered]

Other than starting off in first gear, my engine does not see anything below 3000 rpms if I can help it.

[Quickurt]

Originally Posted by landrovered

Other than starting off in first gear, my engine does not see anything below 3000 rpms if I can help it.

Here, here, Landrovered! The S 6-speed and the perfect pedal set-up in the 987 make rpm matching downshifts soooooooo pleasurable, I look for excuses to shift!
Now that my Schnell short shifter is completely broken in, it makes it that much more enjoyable.
We did a 1700 mile vacation last weekend (four days) and I found myself in the way in traffic (going too slow) on the homeward bound trip because I didn't want it to end!
The roads around Harper's Ferry, WV were great!