[raptorcavalry]

I've seen this phrase "lugging" mentioned before, which seems to indicate running the engine at low RPMs.

I was wondering what might the advantages and disadvantages of riding like this would be. Say I'm going 40mph in 6th, which has really low RPMs, how does that compare to going 40mph in 5th or 4th, where it takes more RPMs to achieve that speed?

I guess what I'm trying to understand more in-depth is how the RPMs affect the performance as well as fuel economy.

 

[MotoMike]

"Lugging" the engine is detrimental to the performance, and service life of the engine. There are no advantages whatsoever to operating any engine below the RPM range where it makes power.

 

[Deanohh]

Basically, when the engine is struggling to turn over under load (lugging), bearing pressures are the highest while at the same time because of low rpm, oil pressure is quite low (compared to normal running speed). Hence there is "mechanical pain" going on when you do this.

 

[raptorcavalry]

Thanks for the responses, this clears up a myth I have read in numerous online sources that states that using the highest gear and lowest RPMs possible is not only okay to drive with but also good for gas mileage.

 

[r100]

+1 on what MM and Deanohh said.
One must have empathy with the machine.

 

[PAJKRUBI]

Thanks for the responses, this clears up a myth I have read in numerous online sources that states that using the highest gear and lowest RPMs possible is not only okay to drive with but also good for gas mileage.

This probably goes for big V-twins and V8's in vehicles. These are lower rpm enignes and can be happy running 1,500 rpm even under load. Our engines are very small and make very little torque, especially in lower rpms and don't like to be below about 5,000rpms.

I know when I had my nissan titan with a big honking V8 under the hood I would try to keep it under 2,000rpm for best gas mileage.

 

[NorCal707]

Think about it like a bicycle... Are your legs happy when you are climbing a hill in a high gear? Similar situation with your bike

 

[Iamahood]

Look at the torque and horse power graph for the motor and keep it with in. On the
Low end but still with in where it generates it's numbers. That is true of any motor.
I've a diesel and it generates a flat torque band at 1375 rpm. It's meant to be run from there on. The lower the motor is run the better the mpg. It makes a huge difference. Do not go below or it will not lube propped. If you have a second rider or extra weight keep it in a lesser gear for longer before the shift.


Sent from my iPhone using MO Free

 

[jkv357]

Thanks for the responses, this clears up a myth I have read in numerous online sources that states that using the highest gear and lowest RPMs possible is not only okay to drive with but also good for gas mileage.

That's not necessarily a myth.

The difference is the amount of load. If you are "lugging" the engine you are opening the throttle and asking for power that isn't there. In that situation you need to downshift and bring the RPMs up to a point where the engine is producing enough power to overcome the load.

If you are cruising with minimal load, and want the best economy, lower RPMs is what you want. Your speed, size, weight, etc, all effect at what point the load is too high for a particular RPM and you are "lugging" the engine.


Jay

 

[sendler]

If you feel the engine bucking and chugging, then you need to shift to an easier gear. If it still running smoothly then there is no damage being done and you are getting the best fuel economy. An engine only burns fuel every time it goes pop. You will generally want to keep it above 4,000 rpm with the CBR250. My Ninja650 will pull happily at 2,500

 

[Iamahood]

Best example of what I could find. 4000 looks fine. 5000 looks a little better.


Sent from my iPhone using MO Free

 

[sendler]

If you need a full efficiency pulse then 90% load centered around 5- 5,500 rpm will be the most fuel efficient. I was using 4,000 to 5,200 rpm when I broke 100 mpgUS in the rain on the road at the Green Grand Prix but I may have actually done a better number to use 5th all the way to use a slightly more aggressive pulse at 5,000 to 6,000 rpm and then glide. I will be able to find the best efficiency when I get my MPGuino scan gauge installed. When just maintaining 35 mph through town, a fine hand on the throttle can keep it smooth down below 3,500 but you have to drop down 2 or 3 gears to accelerate or it will chug.

 

[TX_Dj]

Yes, the "chug-n-buck" is the sure sign of lugging, but lugging does start before that. If you're in a gear/speed/rpm combo that opening the throttle changes the exhaust note but there is little to no speed variation within a few seconds of doing so, you are technically in the lugging range.

I'd personally consider anything below 4500 to be lugging this engine, but the amount of load you have (read: your fat arse) will tend to change this because you'll be working the engine harder.

Keep in mind also, for safety, if you're too far from your power band, the time it takes to downshift a couple-few clicks to get back to it could consume much precious time in the extremely rare situations where the correct response to a situation is to twist the grip and get away.

Edit: more info i forgot to add, one other symptom of lugging can be cracks developing in the cylinder wall and the other nasty things people have mentioned before. Pilots of fixed-pitch planes don't worry about lugging, pilots of constant-speed prop planes do (the variable prop angle sets the RPM, the throttle sets the power. Too much throttle, not enough RPM quickly means rebuilding an engine, which often costs over $20k on a plane.)

 

[bockscar]

Think about it like a bicycle... Are your legs happy when you are climbing a hill in a high gear? Similar situation with your bike

Well put. Think of that 'lugging' sound as your poor little engine screaming "OH MY GOD ITS TIME TO SHIFT ALREADY!"

 

[Soul Searcher]

Lugging the Engine?????

.
What is Lugging the Engine ?

Cause (Condition) and Effect (Symptoms).

An abnormal, operator induced engine condition that is described by the symptoms listed in this Thread.

A Subject that has been discussed in all of the Motorcycle/Automotive Fourms and some none automotive Forums that I have visited.

Still Searching, but so far, haven't found an answer to the Root Cause (Condition) that explains this abnormal engine operation.

I'm sure that a lot of Members and Visiting Guests would appreciate, if this question had an answer.
.

 

[Deanohh]

Lets all hit the bong one more time.

 

[NSU]

Still Searching, but so far, haven't found an answer to the Root Cause (Condition) that explains this abnormal engine operation.

You deliver an extra amount of air and fuel to an engine while the engine is cycling at a speed where it cannot generate enough power to efficiently overcome the load that it's under. It's more noticeable at low engine speeds because the pulses are lower frequency.

 

[TX_Dj]

It gets far more technical than what NSU said, I'll presume he could have gone more technical, but refrained from doing so.

It has quite a lot to do with the momentum of the rotating mass of the engine parts, the amount of power that can be delivered in a single power stroke, how many degrees of rotation are necessary before the next power stroke (i.e. many more degrees required w/ single cylinder vs, say, a V-12), how much flywheel is involved, etc.

Lots and lots of (to most folks) boring physics involved...

But suffice to say, the engine is being operated in an RPM range where it cannot sufficiently provide enough torque to make a complete cycle to the next power stroke without struggling under the presented load. Too far below the power band. Downshift and make the engine happy.

 

[Soul Searcher]

Information for New & First Time Riders.

.
Posting Valid Information for New and First Time Riders.

From the symptoms and descriptions listed in this Thread. Without knowing what is causing the condition, what is the potential damage to the cbr's engine? This is also listed in this Thread.

If the cbr is operated until you encounter one or more of the symptoms, and the cbr's engine is damaged. Who is going to pay for the Repair ?

When you ask a Question. You should receive one of three Answers.

1. I don't Know.
2. Information, that you can comprehend, understand and verify.
3. Something that makes no sense. An example in the Quote below.

Lets all hit the bong one more time.

Deanohh, was Thanked by two other Forum Members, for the Post.
.

 

[Soul Searcher]

Engine Operation.

You deliver an extra amount of air and fuel to an engine while the engine is cycling at a speed where it cannot generate enough power to efficiently overcome the load that it's under. It's more noticeable at low engine speeds because the pulses are lower frequency.

The cbr's engine is a normally aspirated, gasoline powered, internal combustion engine.

In the above Quote. Using "You deliver an extra amount of air".

For this statement to be correct. A turbo or super charger would have to installed on the cbr.

The amount of air that fills the combustion chamber is designed into the engine for each position of the throttle plate and for each rpm of the crankshaft.

In the above Quote. Using "You deliver an extra amount of fuel".

Fuel that is delivered to the cbr's injector is controlled by the ECM and the sensors that it monitors. The program(s) inside the ECM is calibrated for all different operating conditions that the engine will encounter.

If, for some reason, the ECM delivered more gas, that what the engine could handle. It would create the condition, known as Flooding the engine. The results would be that the engine's crankshaft would quit rotating(engine died).
.