[amitwiz1]

I'm not sre I fully understand. I'm on a highway, in 5th gear at 120+, and I need to bring the car to a complete halt. Do I :

Shift to nuetral and then brake ? or
Brake gradually at the same time downshifting one by one ? or ??

[hyper123]

The latter is correct. Down-shift by one gear at a time, blip the throttle while doing it, and brake simultaneously.

Shifting to neutral and then using only the brakes will cause brake wear at a faster rate.

[Rehaan]

As hyper123 said, the second option "downshift one by one" is the better way to do it.

There is an entire thread on this topic here : http://www.team-bhp.com/forum/techni...ral-right.html

cya
R

[DirtyDan]

Some vehicles have robust clutches and trannys. German cars are an example. These are made for downshifting, using the drive train as a brake and sports car handling. If you do the same maneuvers, heavy downshifting, with another car you risk premature wear of expensive drive train components. Heavy downshifting can cause excessive wear on the clutch pilot bearing, for example. If this wears out it often takes the tranny input shaft with it making for a very expensive repair. Lesson? Know your vehicle and drive according to its capabilities, your capabilities and your bank account's capabilities.

[amitwiz1]

Thanks hyper and Rehaan

[BaCkSeAtDrIVeR]

Originally Posted by amitwiz1

Shift to nuetral and then brake ? or

Brake gradually at the same time downshifting one by one?

First is no-no.

Second if you have time to anticipate the stop. (like when you spot a toll booth far away.)

In case of un anticipated stops which do not give you time to downshift, brake till vehicle stops / engine complains and then depress clutch only to avoid stalling.

[teknophobia]

Originally Posted by Rehaan

Hey Neel,

Rtech has pretty much covered it, let me just add>

If you brake while in gear, without leaving the clutch, you will get much better braking and put a lot less strain on your brakes, keeping them cooler and making them last longer. However, better than staying in gear while braking is downshifting before braking. Say you are at 50km/h in 5th gear and u need to break, you can brake and downshift to 3rd gear at that speed with ease. Just make sure that you dont downshift to too low a gear that will cause the engine to revv too high which can be bad. Instead you can keep downshifting while braking, (as our friend SG says, he goes from 6th to 5th to 4th to 3th to 2nd to 1st then nuttral (inside joke ..sorry) )

Also, as rtech says Always finish you gear changes and braking before the corner, and keep a constant throttle through the corner., that is one way of doing it, but personally i finish the braking before the corner in normal driving, but then i still keep my foot on the brakes through the corner without actually applying any pressure, because in traffic it is quite common to come to a sudden stop in the middle of a corner, or to stop for pedestrians who could not see you approaching from around the corner..etc etc... so this reduces reaction time.

Engine braking (using the gearbox and engine for breaking) is not considered bad at all... sure maybe it reduces the life of your gearbox by a couple of k-kms, and maybe you have to replace your clutch at 67k-km instead of 70k-km, but it extends the life of your brakepads by 6k-kms and decreases your stopping distance which is priceless as an extra 2meters of braking distance can make the difference between life or death. (all the above "km & m" figures being very rough estimates)

cya
Rehaan

^QFT

I had a bad accident (worse for the other guy :P) once because I didn't use the engine for braking. Rear ended a scorpio with my conty, and the entire thing was my fault :(. If I had braked without the clutch I would have stopped in time.

[teknophobia]

If it's an emergency, you hit the brake, steer away from the trouble, stall out your engine and pray you don't roll over. Under relatively normal circumstances you'd hit the clutch just before the engine stalls.

[GTO]

Originally Posted by DirtyDan

If you do the same maneuvers, heavy downshifting, with another car you risk premature wear of expensive drive train components. Heavy downshifting can cause excessive wear on the clutch pilot bearing, for example. If this wears out it often takes the tranny input shaft with it making for a very expensive repair.

Not to mention mechanical over-revving which can ruin your engine. Never downshift too low a gear at too high a speed.

[praveen_v]

Originally Posted by rahuldeodhar

Here how I would do it
#) take foot off accelerator
#) start braking
#) as speed eases- engage clutch
#) keep downshifting - to match gear and speed- but dont engage
#) Come to stop

This is different from 1 as I dont use engine force to stop the car - trying to reduce stress on engine

But this is also different from 3 as I always keep the option of using engine stop available - as a safety precaution - keeping car in neutral will remove this option

In case of urgent stop I can simply engage and reduce (similar to what you mentioned in option 1

Oh ok. so you mix and match 1&3. But you say you keep downshifting to match the engine speed without engaging the gear. As long as you dont release the clutch it does not matter which gear(or neutral) the vehicle is in right??

Originally Posted by hyper123

The latter is correct. Down-shift by one gear at a time, blip the throttle while doing it, and brake simultaneously.

Shifting to neutral and then using only the brakes will cause brake wear at a faster rate.

Originally Posted by Rehaan

As hyper123 said, the second option "downshift one by one" is the better way to do it.

I can do that when I anticipate a stop well ahead. How can I use engine braking in extreme cases?? Brake hard without pressing the clutch and let the engine stall??

Also what effect will the engine braking will on my FE?? and can I use engine braking when the engine is new and not fully run-in??

[nitrous]

Originally Posted by praveen

As long as you dont release the clutch it does not matter which gear(or neutral) the vehicle is in right??

No

How can I use engine braking in extreme cases??Brake hard without pressing the clutch and let the engine stall??

This practice of clutching and braking is from indian bike riding which is carried onto cars.Bad practice in cars!
Just brake,don't clutch.I've done this a million times and although it lugs once the speed goes real low,i cant remember once when its stalled.

[BaCkSeAtDrIVeR]

Slightly OT.

How many of you keep your heel on the floor while using the clutch? My instructor used to insist that I keep heel on the floor and operate the clutch with base of the thumb (of the foot, that is), but as I take feet off the clutch, the heel comes up. Result - aching left foot in stop and go traffic!!!

[hyper123]

Originally Posted by praveen_v

I can do that when I anticipate a stop well ahead. How can I use engine braking in extreme cases?? Brake hard without pressing the clutch and let the engine stall??

In very extreme cases, keep braking as hard as possible without locking up your wheels and simultaneously shift-down one gear at a time but do not blip the throttle (do not rev-match) when you engage the clutch after downshifting, but take care not to over-rev while doing so.
Most important - practice this before hand.

If your are not comfortable doing this, then its best to do what nitrous has suggested.

[rahuldeodhar]

Hi Praveen,

#) You are right - technically not engaging is similar to keeping car in neutral.

#) Engine braking is drain on FE (higher revs meanings more times fuel in cylinder - for reducing distance covered - hits FE- obviously!)

#) Brake and Clutch pads are designed to wear out - they are friction enhancers - your choice is essentially between clutch or brake - my choice is brake

#) Engine braking puts stress on quite a few components in the drive train - hence should not be done with a new engine.

RD

[praveen_v]

Originally Posted by nitrous

No

I didnt understand. You said no for which one??

Originally Posted by rahuldeodhar

#) Engine braking is drain on FE (higher revs meanings more times fuel in cylinder - for reducing distance covered - hits FE- obviously!)

#) Brake and Clutch pads are designed to wear out - they are friction enhancers - your choice is essentially between clutch or brake - my choice is brake

#) Engine braking puts stress on quite a few components in the drive train - hence should not be done with a new engine.

So i guess the best way would be to brake in whatever gear you are without the clutch pressed and then press the clutch when engine shows signs of struggling.

I have tried coming downhill twice with the car on 2nd gear, but felt that the rpm was getting high. What should I do in such cases??