I've looked all over the site, and a whole lot on the internet, and I can't find a good explanation of how to tell if I'm lugging my engine or not. Does anybody have a good way to tell when you're lugging your engine and when you're okay?
How can I tell when I'm lugging my engine?
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Interesting question. Presumably you have a manual tranny as this should never happen with an automatic. I normally don't worry about lugging as I tend to keep the rpms up from idle. Depending on the vehicle and power band, when your engine speed is too slow you don't want too much throttle or load lest it lug. A bad lug should sound like a pounding sound. I can (but normally don't) accelerate from 35 mph in overdrive (around 1000 rpm) but very gingerly lest it lug. I guess the safest thing is to avoid needing to tell if it is lugging because at that point you are beyond where you want to be. Lugging is hard on the bearings and a lot of it will really scuff up the rod bearings on the rod side. (BTW, lugging is where I would rather have the HT/HS of a 15w40 than a 5w20
) Might help if folks know what engine you have. So, I didn't answer your question, but hopefully got you thinking more and I also am interested in the coming responses from the members of BITOG.
Simply put it is when you are in too high a gear. The RPM's are low and you get on the gas and it just sits there and maybe knocks. Down shift, Down shift!!! Most women do this but I have seen a lot do it. V-8 can tolerate it much better than a small 4 since they have some torque. Rev it up some poeple...it won't break!
I think it is harder to tell with modern computer controlled engines, knock sensors, and FI. The older engines were quick to knock or jump around. Today's engines will quietly and smoothly pull, but any acceleration will be molasses like.
Low RPM at low throttle settings won't hurt anything. If you are wanting to accelerate or climb a hill, when in doubt, down shift. Just keep the tach needle out of the red and yellow. Your owners' manual may give more specific information, but I wouldn't count on it.
Low RPM at low throttle settings won't hurt anything. If you are wanting to accelerate or climb a hill, when in doubt, down shift. Just keep the tach needle out of the red and yellow. Your owners' manual may give more specific information, but I wouldn't count on it.
Imagine you are cruiseing along at 55 in 5th or 6th gear. Then you see a car accident and slowly decelerate with out down shifting to to 25MPH. You are so busy stareing at the accident you do not even realise that you are still in overdrive. Once you pass the accident and are done rubber necking you notice that the vechile is starteing to gently jerk and lunge. So you step on the gas and it gets worse and you get either no acceleration or very little compared to how much throtle you are useing. THis is luging.
In my Camry if I let it drop to 900-1000 RPM's im just starting to enter the luging area in 5th gear. If I let it drop to 800RPM or lower in 5th I will get the vibrateing, noise makeing lugging symptoms. If I keep it at 1100-1200 RPM's and in 5th I can accelerate fairly normaly just with more throtle and no down shift.
Hope this makes sense.
In my Camry if I let it drop to 900-1000 RPM's im just starting to enter the luging area in 5th gear. If I let it drop to 800RPM or lower in 5th I will get the vibrateing, noise makeing lugging symptoms. If I keep it at 1100-1200 RPM's and in 5th I can accelerate fairly normaly just with more throtle and no down shift.
Hope this makes sense.
My father does this too. His endless quest for gas mileage. He routinely shifts into 5th at 30mph on his tacoma. I used to rationalize it by thinking that he's used to shifting his Macks which have a redline of about 2500 RPM, but now I realize that he's just cheap!
So when I'm at low rpms and apply gas and I start hearing knocking or feel vibration from the engine, that's lugging? I've always tried to keep that from happening, even without knowing that that's lugging it. Thanks!
See what the lower rev floor is for a model of your vehicle with an automatic, and keep your revs at or above that. In general you'll need to rev higher before shifting when pulling a load or going uphill, in order to catch the next shift at the lower rev limit, and can get by with shifting at lower revs if rolling downhill or doing a rolling stop.
my dad lugs the **** out of his automobiles. his subaru he shifts at such a low rpm that when doing this the engine bucks and shakes like a diesel and even sounds like a diesel.
his dodge diesel he also lugs badly, shifting at 1500rpm, you can feel it shaking and sounding like a diesel even more than it should.
his bmw motorcycle is the same way, he dont understand that its destroying his rod bearings.
i cant convence him that he is wrecking his engines. he says he doesnt like to rev engines up because he thinks that shifting at 3000 or so will wear them out quicker.
so what i do to **** him off, when we are in MY car, i rutinely shift at redline (7800 rpm) and i awalys keep thew rpm's over 5000 even when sitting at a stoplight in neutral. it annoys the **** out of him to see me doing this to my engine hahahaha.
his dodge diesel he also lugs badly, shifting at 1500rpm, you can feel it shaking and sounding like a diesel even more than it should.
his bmw motorcycle is the same way, he dont understand that its destroying his rod bearings.
i cant convence him that he is wrecking his engines. he says he doesnt like to rev engines up because he thinks that shifting at 3000 or so will wear them out quicker.
so what i do to **** him off, when we are in MY car, i rutinely shift at redline (7800 rpm) and i awalys keep thew rpm's over 5000 even when sitting at a stoplight in neutral. it annoys the **** out of him to see me doing this to my engine hahahaha.
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Lugging occurs when you present a load to the engine that it can't cope with by using increased throttle ...and, in some cases, can't maintain at any throttle.
You can USE lugging for max fuel economy. This may be out the window with EFI ..but the carbed models worked well with just keeping the throttle just ahead of the engine and short shifting. It's a little harder to do in the rolling hills of PA ..but flat landers can really have a good time frustrating people behind them taking their time accellerating
I believe the the manufactures do their own form of this by allowing mild knocking and not retarding the ignition until severe knock occurs.
You can USE lugging for max fuel economy. This may be out the window with EFI ..but the carbed models worked well with just keeping the throttle just ahead of the engine and short shifting. It's a little harder to do in the rolling hills of PA ..but flat landers can really have a good time frustrating people behind them taking their time accellerating
I believe the the manufactures do their own form of this by allowing mild knocking and not retarding the ignition until severe knock occurs.
for 5th gear keep rpm higher then 2000
for 4th gear keep rpm higher then 1500
for 3rd gear keep rpm higher then 1000
2nd is fine in any range
for 4th gear keep rpm higher then 1500
for 3rd gear keep rpm higher then 1000
2nd is fine in any range
Then I couldn't use 5th gear for anything less than 80MPH in my Mustang 5.0 -- quite clearly NOT what Ford intended.
My Corvette owners manual says don't drive at under 900 rpm in 6th. I think that's about 40.
My 2.5L Ford Contour is around 35MPH at 1500RPM in 5th. That's about the slowest I'll drive in 5th.
That should be fine as far as lugging the engine goes, as the 2.5L makes 75% of it's peak torque at 1500RPM. (I think that's one reason this car is so tolerable in rush-hour traffic, despite being a stickshift...)
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Whenever you should be using a lower gear for better torque, instead of the gear you are using, you are lugging the engine.
That means, while you may well cruise in 4th gear at 40 mph without any ill effect, as soon as you intend to accelerate efficiently, or if you have to go uphill, you should shift down for more torque. An automatic will do this of course via the kick-down switch when you depress the accelerator all the way.
Three things affect whether you are lugging the engine:
1. Gear
2. RPM
3 Load on the engine (uphill, downhill, level, coasting, accelerating, decelerating)
Signs of lugging are of course poor acceleration and a stuttering engine. What RPM is best in what gear and under what load depends on your engine and tranny's gearing. Under load, a 1 L engine needs to be driven with higher RPM than a 3 L engine. For example, my 2.8 L Audi can easily get going in 2nd gear, while a Fiat 500 would stall. A big-"triple asterisks" Benz might be able to get moving in 3rd gear.
[ July 16, 2004, 03:48 AM: Message edited by: moribundman ]
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