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Old 10th November 2011, 19:04   #1
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Question Maintaining a constant speed on the highway

Hello All!

I have a doubt regarding maintenance of constant speeds on highway drives.
i.e. Since I have a daily travel of 70kms out of which 50kms is on the highway. Is it ok if I maintain a constant speed or should it keep varying?

Any harm to the transmission or engine internals if constant speed is maintained?
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Old 10th November 2011, 20:35   #2
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Default re: Maintaining a constant speed on the highway

Maintaining a constand speed (as long it's not on the 1st gear!) is actually beneficial; it helps improve FE as you don't have gear changes.

But of course, if you aim to ensure constant speed on diff. driving conditions (intermittent traffic, straight roads and then ghats etc), then it wouldn't be so effective. Also, maintaining a speed but at high rpms wouldn't help either.

All said and done, if you get to drive at a constand speed for long, you're lucky. You don't have to go thru' the trouble of constant gear-shifts. And it's only good for the engine and FE.
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Old 10th November 2011, 20:54   #3
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Default re: Maintaining a constant speed on the highway

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Originally Posted by a4anurag View Post
Any harm to the transmission or engine internals if constant speed is maintained?
Hi,
During the bad old days, it was recommended that during running in, both speed and load be varied. That advice still carries on to the current day. But IMHO, after the first tankful, not relevant in modern engines.

Regards
Sutripta
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Old 10th November 2011, 21:48   #4
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Default re: Maintaining a constant speed on the highway

Quote:
Originally Posted by a4anurag View Post
I have a doubt regarding maintenance of constant speeds on highway drives.
i.e. Since I have a daily travel of 70kms out of which 50kms is on the highway. Is it ok if I maintain a constant speed or should it keep varying?
Nothing to worry mate. Slot it in the top gear and enjoy the effortless drive to office.

There is nothing wrong in maintaining a constant speed. In fact it considerably reduces the wear and tear/km of the engine an transmission.

Unless.. as Sutripta sir rightly pointed out, you are running in your engine, where engine speed should be varied, and the engine should not be overreved or under-revved. (But I guess this matter is still in debate).
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Old 10th November 2011, 21:52   #5
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Default re: Maintaining a constant speed on the highway

Quote:
Originally Posted by a4anurag View Post
Hello All!

I have a doubt regarding maintenance of constant speeds on highway drives.
i.e. Since I have a daily travel of 70kms out of which 50kms is on the highway. Is it ok if I maintain a constant speed or should it keep varying?

Any harm to the transmission or engine internals if constant speed is maintained?
http://www.team-bhp.com/forum/techni...-gear-rpm.html (Is Fuel efficiency strictly a function of RPM or is it speed+gear+RPM?)

http://www.team-bhp.com/forum/techni...save-fuel.html (Does coasting save fuel?)

Check above threads.. some economical driving techniques are detailed there
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Old 11th November 2011, 01:14   #6
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Default re: Maintaining a constant speed on the highway

Thanks for the prompt replies.

I'm currently driving a Ritz VDi which is 1 year old and has covered 37000 kms. So the running in period is over long back.

Some of my friends had told that maintaining a constant speed for a long time will result in un-even wear of the pistons. Is this true?
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Old 11th November 2011, 08:56   #7
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Default re: Maintaining a constant speed on the highway

I do not think the running at a constant speed will cause any problem other saving your fuel and saving you the pain of continuously changing your gears. Wearing of the piston is due to its movement which will happen even if your speed is varying. But if u are over revving the car and maintaining your speed then it is not good at all. So just shift into top gear and have fun... but drive safely

If maintaining a constant speed was a bad thing for the engines, the manufacturers would not have created/implemented Cruz control (Though it was created for an entirely different purpose but still maintain a constant speed of the car) in the cars.
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Old 11th November 2011, 13:11   #8
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Default re: Maintaining a constant speed on the highway

As your car is in midlifecrises there is absolutely no need to worry about keeping a constant speed

On the contrary, constant speeds will help you achieve better FE, greater life of clutch plates, brake pads, tyres and not to mention the most important aspect, peace of mind.
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Old 11th November 2011, 16:02   #9
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Default Re: Maintaining a constant speed on the highway

Maintaining a constant speed is always preferred. Reasons:

- Lesser wear & tear on your car. Maintaining the same speed means lesser gear changes, lesser use of the brakes, clutch pedal etc.

- Easier on your passengers. Comfort levels are greatly enhanced for co-occupants when you cruise at the same speed.

It's just a smoother driving style & leads to way lesser driver stress. The only time that you should NOT maintain a constant speed is when running-in the engine.

Last edited by GTO : 11th November 2011 at 16:10.
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Old 11th November 2011, 16:38   #10
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Default Re: Maintaining a constant speed on the highway

All the above replies are correct only if our traffic conditions and driving habits are correct (read civic). Even if you get a 30 km clean stretch, maintaining constant speed is not possible most of the time.
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Old 11th November 2011, 17:15   #11
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Default Re: Maintaining a constant speed on the highway

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Originally Posted by GTO View Post
It's just a smoother driving style & leads to way lesser driver stress. The only time that you should NOT maintain a constant speed is when running-in the engine.
Does this still hold true? Any reasons why?
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Old 11th November 2011, 17:21   #12
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Default Re: Maintaining a constant speed on the highway

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Originally Posted by ghostrider View Post
Does this still hold true? Any reasons why?
OT, but pretty informative. Check this: http://www.team-bhp.com/forum/owning...r-new-car.html (ARTICLE: How to Run-In your new car)
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Old 12th November 2011, 11:10   #13
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Default Re: Maintaining a constant speed on the highway

I think people who told you that driving at a constant speed is harmful to the engine was trying to say that Driving constantly at high speed is not good for the engine. Since you have a Diesel Ritz. So I guess, if you were to drive constantly at 110km/hr (or less) on the highway then there should be no damage to the engine as opposed to driving at higher speeds constantly for hours.

Last edited by amrisharm : 12th November 2011 at 11:20.
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Old 12th November 2011, 11:12   #14
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Default Re: Maintaining a constant speed on the highway

The only reason I can think of not driving at constant speed, it that you may doze off due to boredom! That apart it is in no way damaging to your car. If it was so then all non automotive machinery - DG sets, marine propulsion etc would be ruined quite fast.

The FE is also best at constant speed.

Last edited by Aroy : 12th November 2011 at 11:24.
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Old 12th November 2011, 17:07   #15
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Default Re: Maintaining a constant speed on the highway

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Originally Posted by Aroy View Post
The only reason I can think of not driving at constant speed, it that you may doze off due to boredom!


I wouldn't sleep when behind the wheel!
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