[supremeBaleno]

Originally Posted by suman

in my Safari Dicor, I can leave it in 4th gear with my foot OFF the accelerator pedal & it chugs along happily & smoothly.

What would be the speed and rpm in this situation ? Since you mention that it can go on this way endlessly, it means the speed is maintained same. How does the engine automatically maintain the last speed even with foot off the accelerator in a high gear ?

Is this only a Safari thing or all diesels are like this ? I find this amazing because if I am cruising in 4th in my car @ 40kmph and if I take my foot off the A-pedal, I guess it would slow down gradually and if not downshifted or put to neutral, engine would go off. This would work in my car upto 2nd gear - foot off all pedals, car goes on and on. Never tried this in 3rd or higher gears though. Plan to check this soon.

Regarding whether you are lugging or not, till the time you putter along, I dont see any lugging because you say that engine is smooth & unstrained. But the moment you try to accelerate quickly, you are lugging.

Originally Posted by Shan2nu

When an engine is comfortable and not being overloaded, it doesn't matter what rpm or gear you're in, you're not lugging.

This was how I saw it and this is how I plan to go about it. Perfectly sums up the whole thing, Shan2nu.

[travelwriter]

Sometimes I hear a loud humming when I press the accelerator or even if I am cruising without pressing the pedal. Is that also lugging and harmful to the engine?

Also, in case of bumper to bumper traffic, which is the best way to avoid lugging?

Originally Posted by Shan2nu

If your engine is running smoothly without throttle, its not lugging.

Shan2nu

[suman]

It would be between 750 & 900 rpm; it is a Safari Dicor 3 litre trait, I don't know about all diesels, can only speak for myself. Be nice to Hrishi & Mahendra and try it out for yourself

Doesn't happen in Petrol vehicles.........

[supremeBaleno]

And what is the speed then ? Plus, what is idling rpm of the Dicor-3 ?

Well, Mahendra seems to have given up the wife (Safari) for the mistress (Esteem), in whose company he is mostly seen.

[suman]

Originally Posted by supremeBaleno

And what is the speed then ? Plus, what is idling rpm of the Dicor-3 ?

I've mentioned the speed - 40 kmph; it drops marginally, then the rpm goes up marginally & viola - back to 40. Mind you, all this is happening without any inputs from my end, hand or foot!

Idle is around 750-800 rpm. Try it & see - you'll never get it or believe it otherwise

EDIT: Forgot to mention that if the vehicle starts jerking or stalling at 40 kmph in 4th gear instead of coasting along, you have a problem with the clutch

[supremeBaleno]

Originally Posted by travelwriter

Also, in case of bumper to bumper traffic, which is the best way to avoid lugging?

By downshifting to the gear best suited for that speed. This varies from car to car - find the best one for yours.

Originally Posted by suman

I've mentioned the speed - 40 kmph; Try it & see - you'll never get it or believe it otherwise

Sorry, I missed the speed that yo had mentioned in the first post itself. OK, next time I get a chance to be in a Safari, need to try this. Will also try this in G3 and G4 of my car - I know that this works in first 2 gears, but never tried on higher gears.

Originally Posted by suman

if the vehicle starts jerking or stalling at 40 kmph in 4th gear instead of coasting along, you have a problem with the clutch

I guess you mean this only for the Safari.

Had a chance to see lugging in action last Saturday. My Dad had come to pick me up from the station and on our way home, at times he was driving the Swift in 5th with speed below 40. I could make out the straining engine, but he kept at it, by manipulating the clutch. I don't think he did it for FE. Either he is too lazy to change gears or just did not notice or does not think it is a big deal.

Anyway, I kept silent because no man likes being told that he is not driving correctly. And it becomes a more delicate situation when the criticism/advice/suggestion comes from someone whom you taught driving.

[suman]

Originally Posted by supremeBaleno

I guess you mean this only for the Safari.

Absolutely.

Originally Posted by supremeBaleno

Anyway, I kept silent because no man likes being told that he is not driving correctly. And it becomes a more delicate situation when the criticism/advice/suggestion comes from someone whom you taught driving.

Very sensitive situation

[zaks]

I can take my palio multijet to a low enough speed on the 4th or 3rd depending on the road, traffic and no of passengers.
Quite often in signals I just ease off the pedal in second gear and the car slows down slightly and then starts pulling gently at a constant speed even with two people. I use this whenever there is a stop and go kind of traffic.

[marlinspike]

After going through all the 9 pages on this thread, I now feel I know a few things more about lugging, but may be a summary could help and this can be part of the advice section after how to run in your car. Like a best practices guide.

A periodic summary by a moderator every 10,25,50 pages would improve the readability and usability of all long threads. this could work out as a better deal for people who browse the threads may a year later and still find useful info on it.

Bhp and torque graphs for most cars added to the test drive section could be useful as well.

[pLeaSe Dont]

Imo universal speeds to respective gear shifts should be as follows
0-5 kph -1st gear
5-20 kph-2nd gear
20-30 kph-3rd gear
30-40 kph-4th gear
40 kph- 5th gear

[supremeBaleno]

Originally Posted by zaks

Quite often in signals I just ease off the pedal in second gear and the car slows down slightly and then starts pulling gently at a constant speed even with two people.

I think most petrol cars would do this in 1st and 2nd gears - atleast mine does. But I doubt if petrol-cars can do this in 4th gear like a diesel Safari does.

Originally Posted by pLeaSe Dont

Imo universal speeds to respective gear shifts should be as follows : 40 kph- 5th gear

I don't think there is any universal speed which fits all cars. To give a small example, try running the Swift in 5th gear at 40kmph and you will know what I am saying. But slot a Baleno in 5th @ 40kmph and it will chug along happily.

P.S. : BTW, the speed per gear details you quoted seem straight from a Maruti car manual - aiming for maximum FE.

[adheesh]

Engines not only require more fuel to run faster (at high rpms) but also need a lot more fuel to generate more torque. When an engine is being run in a higher gear than it is supposed to, it needs to generate a lot of torque. Since the driver feels that the engine is running at a lower rpm and would give him more fuel economy. Also not to forget, when an engine is lugged, the clutch useage also increases significantly inorder to prevent the car from stalling.The trick is to mantain a correct balance of rpm and torque developed by the engine. The easiest way is to stay in the the correct gear.

Regards,
Adheesh Parelkar

[teknophobia]

With all due respect, there should be separate threads for petrol and diesel cars, the two are now way comparable in low speed torque figures.

[anupmathur]

Originally Posted by teknophobia

With all due respect, there should be separate threads for petrol and diesel cars, the two are now way comparable in low speed torque figures.

Tekno, once the underlying principles are grasped, there is no difference in driving a petrol or diesel vehicle. This is not a game of absolute numbers but of trying to listen to what the engine is saying! Engines talk, yes!

[SS-Traveller]

I think I found the perfect answer on another forum: TDIClub Forums - View Single Post - What is Engine Lugging?, which I have tried to re-word for better comprehension:
A good way to look at lugging is to remember riding your bike (bicycle)... Going uphill and in high gear you feel the load on your legs. To (keep) running smoothly (in a lower gear) and not pedaling too fast (is like driving smoothly), but (lugging is) working so hard (in a higher gear) that (your legs)...ache.