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Old 11th February 2005, 16:19   #31
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My question is whether engine braking is detrimental to your gear-box and the engine valves?? Of-course, i'd rather change my brake-pads every 20K kms rather than change the transmission and the engine valves.
As long as you match the revvs, you won't have any problems with the engine or your gear box. But like you've mentioned, shifting into 2nd at 70-80kmph and comming off the clutch all of a sudden (without blipping the throttle) will definately affect the drivetrain and clutch.

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Old 11th February 2005, 16:22   #32
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Quote:
Originally Posted by Shan2nu
As long as you match the revvs, you won't have any problems with the engine or your gear box.
There you see, one more use of the Tacho !! Heh Heh !!
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Old 11th February 2005, 16:32   #33
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Quote:
Originally Posted by Shan2nu
Well technically, engine braking is not a "must". It's just a way, most people preffer to brake. There's nothing wrong in not doing it, provided you're ok with the brake wear and don't mind replacing them once every 20-25K kms.
Shan2nu
I would say, it is rather important when brakes fade a bit. Engine breaking is something most of us use, even without realising it (whether it's bike or car). Even auto manuals recommend using it. I can't imagine using only brakes and no engine braking, while descending a steep slope.
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Old 11th February 2005, 16:37   #34
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On a similar note, while it may not be exactly true, I see engine braking as one kind of ABS. You reduce the speed without locking the wheels.
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Old 11th February 2005, 18:07   #35
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On a similar note, while it may not be exactly true, I see engine braking as one kind of ABS. You reduce the speed without locking the wheels.
That's called threshold braking and it can be done without any help from the engine.

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Old 11th February 2005, 18:11   #36
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So much has been discussed about engine braking and plain braking.. i know for sure that engine braking is achieved by applying brake followed by changing to a lesser gear and releasing the clutch..that allows the vehicle to come to the speed based on the rpm reading ( shan2nu's speed formula..)

I feel this is effective in bikes as the brakes are not that efficient and sudden use of brakes to stop from 80-0 KMPH may cause the bike to skid..The cars dont need this as their brakes are pretty good i feel.

Another reason engine braking may be effective is that it gives a better grip on the road than when applying brakes only (am i wrong?)

Is there any difference in the braking distance b/w engine braking and just plain braking?
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Old 11th February 2005, 18:21   #37
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I feel this is effective in bikes as the brakes are not that efficient and sudden use of brakes to stop from 80-0 KMPH may cause the bike to skid..
If a bike skids while hard braking, then how can the brakes be weak?

Quote:
Another reason engine braking may be effective is that it gives a better grip on the road than when applying brakes only (am i wrong?)
Traction has everything to do with your tyres. Your braking can only decide whether a tyre keep rolling or locks up. I don't see any difference in the way a car stops whether it's engine braking or plain braking.

ABS is nothing but smart and optimum braking. You can literally stand on the brakes and yet, get away without wheel lockup. There is no engine braking involved here.

Shan2nu

Last edited by Shan2nu : 11th February 2005 at 18:25.
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Old 11th February 2005, 18:41   #38
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Quote:
Originally Posted by Shan2nu
That's called threshold braking and it can be done without any help from the engine.
Yeap, but I was not talking about it. Threshold braking will require lot more skill on driver's part as compared to engine braking.
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Old 11th February 2005, 18:43   #39
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Quote:
Originally Posted by Shan2nu
If a bike skids while hard braking, then how can the brakes be weak?
I was referring to drum brakes and 2 wheels of a motorbike not being stable..u brake a bike hard and it skids..maybe the weight is acting in an angle to cause a skid or the condition of the tyres..or the small contact area of the tyres

Quote:
Originally Posted by Shan2nu

Traction has everything to do with your tyres. Your braking can only decide whether a tyre keep rolling or locks up. I don't see any difference in the way a car stops whether it's engine braking or plain braking.

I donno why but i have a strong feeling one of them i.e, engine braking or plain braking may have a better braking distance...am curious about the braking distance not the locking up..

Last edited by muni : 11th February 2005 at 18:44.
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Old 11th February 2005, 19:02   #40
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A good article on braking, worth reading. It even talks about often discussed "pumping" of brakes

http://www.safespeed.org.uk/braking.html
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Old 11th February 2005, 19:20   #41
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I donno why but i have a strong feeling one of them i.e, engine braking or plain braking may have a better braking distance...am curious about the braking distance not the locking up..
Braking distances change when the surface beneath the car changes. One can't say that this sort of braking reduces stopping distance.

Many believe that ABS actually reduces stopping distance, but that's not the real reason for having ABS on a car.

The best braking maneuver is the one that provides the best braking power (without wheel lockup) and at the same time, gives the driver the freedom to steer the car away from an oncoming vehicle or object.

Diff people have diff ways of achieving this.

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Old 11th February 2005, 20:00   #42
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Question have not got the answer to my point..

my question was "which one may have a better braking distance..engine braking or plain braking without locking. Either one has to be better and both cannot be equal is what i feel"

Quote:
Originally Posted by Shan2nu
Braking distances change when the surface beneath the car changes. One can't say that this sort of braking reduces stopping distance.

Many believe that ABS actually reduces stopping distance, but that's not the real reason for having ABS on a car.

The best braking maneuver is the one that provides the best braking power (without wheel lockup) and at the same time, gives the driver the freedom to steer the car away from an oncoming vehicle or object.

Diff people have diff ways of achieving this.

Shan2nu

Quote:
Originally Posted by Shan2nu
The best braking maneuver is the one that provides the best braking power (without wheel lockup) and at the same time, gives the driver the freedom to steer the car away from an oncoming vehicle or object.

I agree to ur point abt the best braking power without locking the wheels...but manouering while braking can be tricky

Example:
I try to steer the vehicle left and right while braking to avoid collision , the body would be tending to move forward straight and the left/right steering plus braking would cause the tyres to skid..
am sure the physics would cause to behave like that..

Last edited by muni : 11th February 2005 at 20:03.
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Old 11th February 2005, 21:04   #43
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my question was "which one may have a better braking distance..engine braking or plain braking without locking. Either one has to be better and both cannot be equal is what i feel"
Why can't they be equal? As long as braking is performed correctly, how you do it doesn't matter. Both these techniques have the ability to perform equally well.

Quote:
but manouering while braking can be tricky
That is why people preffer ABS. So that they won't have to worry about locking up the wheels and can concentrate more on steering the car.

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Old 11th February 2005, 22:54   #44
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Originally Posted by man23ish
Yes, Warwick, near T.F.Green Airport RI USA. I used to work for GTECH. But returned back to India to settle down here man. I had a lot of fun with my Camry on the I-95..

What are you doing there??
Hey man, thats awesome!

Theres a new GTech building comming up right here near the Providence Place mall. What exactly did you do at Gtech??
I go to RISD, studying Industial Design.

Lol, for a minute i thought you said camaro instead of camry

I just have been having fun drifting in the parking lots filled with snow lately... even got stopped by rent-a-cops ! lol Too bad the indian metros dont have huge open spaces like this!

Muni,
To answer your question,
Lets assume in both cases we are breaking from 100km/h

(i)No engine breaking - Staying in 5th gear, only applying the brakes, not shifting gears.

(ii)Engine breaking - Staying in 3rd gear, only applying the brake, not shifting to lower gears.

I can pretty much guarantee you that you will have more confident and consistent breaking in eg.ii with engine braking.
Keep in mind that even though you are not downshifting in that case, you are still using a higher degree of engine braking.

cya
R

ps - Remember that no engine braking is better than engine breaking (over revving), but engine braking prevents engine breaking (from a collision) ...lol...if u get what im saying (braking vs breaking)


Actually, heres a simpler way to explain it.
Even if you stay in 5th you are still using *some* engine breaking. No matter which gear you are in, you are using it. (unless you get to near idle RPM).

The best way to actually notice engine braking vs non engine braking is to press the clutch as soon as you start braking (instead of when the car is almost at a stop). Then you will see how much of a positive difference engine braking makes. However, only do this to see the difference! Pressing the clutch right away is not the correct way to brake!

Then, think of choosing the gear as choosing the rate of engine braking (lower the gear = higher the rate of braking).

cya
R
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Old 11th February 2005, 23:24   #45
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(lower the gear = higher the rate of braking).
Man, don't say that. People will start shifting into 1st at 100kmph. LOL

More like higher the engine rpm, higher the rate of braking. And don't forget to keep the revvs below the red line.

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