Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 28th December 2010, 21:49   #196
BHPian
 
Garipagol's Avatar
 
Join Date: Jul 2007
Location: Calcutta
Posts: 192
Thanked: 7 Times
Red face Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by DWind View Post
I do not agree! AFAIK you always use your handbrake. This is to avoid your clutch getting burnt. The key is coordination. The steps to be followed is

1. Put the hand brake.
2. Slot to first gear.
3. With your right leg on the accelerator (ready to accelerate), your hand on the hand brake, release your clutch till biting point
4. Release handbrake (immediately) and accelerate and releasing the clutch at the same time.

This ensures that
1. Your clutch does not get burnt out.
2. You do not roll back
3. You do not need to use more than necessary acceleration (more quiet and elegant)
3. and can be done on any car which you are not used to.

And never ever use your second gear, unless you have a torquey engine. And even then not always.
I fully agree that the advice of not using yor hand brake is not correct at all. However, do not apply your hand brake when the car is moving. You will be in for a jolt and / or your car may fishtail. Apply your hand brake when the car comes to a stop. I have always used the hand brake on a slope when in a manaul car.

I learnt my driving (27 seven years ago) in New Zealand (North Island) where the terrain undulates a lot. Roads going uphill at 20/30 deg incline are common and then a stop sign at the crossing at the top of the slope. The correct procedure is to go up in 2nd gear (or even in first if you need more torque) and stop at the sign and apply your hand brake so that you do not roll back. Once it is your turn to move forward go into first gear and apply gas slowly and slowly start releasing the clutch you will feel the biting point of the clutch (in your seat!!) i.e when it engages the gear. The car will try to move forward. Release the hand brake and increase the gas and move forward slowly. If your are the 5th guy at the stop sign you have to keep doing it till you reach the top of the slope. Practice.. pratice ...

At the driving test they will make you do this several times at different inclines. If your car rolls back even an inch or rabbit hops because you put in too much gas -- that will be the end of the test.

It is unfortunate that the goal of our trainers in India is to get us a licence quickly and not to make us good drivers. The bad driving habits they impart to us are very difficult to break later. The tests are also a farce. In india most of us learn to drive (survive the chaos) after we get our licence.

Do not get too close to the car in front when you are uphill (bridge/ flyover). The guy can roll back if he does not use his hand brake.

Rgds
Garipagol is offline   Reply With Quote
Old 30th December 2010, 10:00   #197
BHPian
 
agbenny's Avatar
 
Join Date: Sep 2006
Location: TN38
Posts: 956
Thanked: 95 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by gigy View Post
From my experience
If you are in slow <40 until you are experienced use clutch first and follow with brakes.
If you are experienced enough with the particular car then use both together till you can manage to keep engine running without stalling

If you are in good speed always apply brake first and as you have slowed down enough apply clutch.

In all cases prevent engine stall as successive braking power reduces if car is still in motion and in case you need maneuverability.

Finally the price of brake pads to clutch plates matters most on which to follow.

but in emergency brake first and then clutch as it reduces car speed the fastest.
Thanks for explaining this. I always had this question in my mind, whether I am doing correctly or not. I always do as you explained, and I am happy that I apply the brakes first (on low speeds) and clutch in a second or two later. On high speeds I apply brakes first, and apply clutch when needed to avoid engine stall.

I still have one question:

Assume I need to reduce speed from 100+ to 40 or 50, and if there is enough distance, should I apply brake continuously? I normally press brakes 2-3 times with a gap and do not apply continuously. Is that a good practice?

Finally, I remember when I was learning in a Amby about 15 years ago, the trainer said that I need to reclutch (press the clutch more than once), if the gear shift is not smooth in first gear while starting the car. I see sometimes I had to do this with my Scorpio even now, Is that still applicable to diesel cars?
agbenny is offline   Reply With Quote
Old 30th December 2010, 11:31   #198
Distinguished - BHPian
 
sgiitk's Avatar
 
Join Date: Dec 2007
Location: Kanpur
Posts: 7,160
Thanked: 3,755 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by agbenny View Post
1. Assume I need to reduce speed from 100+ to 40 or 50, and if there is enough distance, should I apply brake continuously? I normally press brakes 2-3 times with a gap and do not apply continuously. Is that a good practice?

2. Finally, I remember when I was learning in a Amby about 15 years ago, the trainer said that I need to reclutch (press the clutch more than once), if the gear shift is not smooth in first gear while starting the car. I see sometimes I had to do this with my Scorpio even now, Is that still applicable to diesel cars?
1. Brake continuously, but do not loack the brakes (assuming you do not have ABS).
2. Double de-clutching is required in cars with no synchromesh (aka crash box). The old Amby (and FIAT) did not have synchromesh on 1st. This has nothing to do with diesel or petrol. This is the reason of many of us to go into first when moving, and use it only as a starting gear.

In the old crash-box cars double de-clutching was required for all gears!
sgiitk is offline   Reply With Quote
Old 30th December 2010, 11:55   #199
BHPian
 
DWind's Avatar
 
Join Date: Apr 2007
Location: Singara Chennai
Posts: 775
Thanked: 168 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by agbenny View Post
Assume I need to reduce speed from 100+ to 40 or 50, and if there is enough distance, should I apply brake continuously? I normally press brakes 2-3 times with a gap and do not apply continuously. Is that a good practice?
I would advice you to brake continuosly. It is always a good practice because
1. decelerating gently (and accelerating gently as well) increases your mileage.
2. braking continuously gives ample time for the vehicle behind you to reduce their speed and slow down looking at your tail light.

Bear in mind that over doing it can contribute to brake fade as well , for example when you are driving down hill. The right advice here is to drive at speeds where you are always in control of your car (slow down!!)
DWind is offline   Reply With Quote
Old 30th December 2010, 16:14   #200
Distinguished - BHPian
 
sgiitk's Avatar
 
Join Date: Dec 2007
Location: Kanpur
Posts: 7,160
Thanked: 3,755 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

@DWind: The correct gear for a descent is the same as for the ascent. Also, with an AT shift to Low or S in order to get engine braking.
sgiitk is offline   Reply With Quote
Old 30th December 2010, 16:28   #201
Team-BHP Support
 
bblost's Avatar
 
Join Date: Jul 2007
Location: Hyderabad
Posts: 9,650
Thanked: 6,662 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by sgiitk View Post
@DWind: The correct gear for a descent is the same as for the ascent. Also, with an AT shift to Low or S in order to get engine braking.
+1 to both the points.

I use the Clutch when changing gears. Period. The clutch is not meant for deceleration. Maybe for a timed heavy acceleration. But in day to day driving, its has no role in slowing down.

No matter what speed or which gear, I use the brake. A steady downward push. After the car slows enough that the engine rpm and tire rpm are not matched, I downshift. Maybe skip a gear, i.e. got from 5 to 3. But only using the clutch when the gear is being changed.

If I am driving a manual car downhill, I play with the gears to reduce speed.
If its an automatic, then chances are I am in the US and the car is a rental. In which case I keep running between D and 2.

Doing that gear jumping is what allowed me a auto-newbie to drive at the speed limits posted on California-1



Without gear jumps, it was very difficult to go fast enough to be at or just about the speedlimit.


But since I don't own an auto nor does anyone in my circle have one, have not bothered to finetune myself
bblost is offline   Reply With Quote
Old 30th December 2010, 16:30   #202
Senior - BHPian
 
anilisanil's Avatar
 
Join Date: Jun 2010
Location: Pune
Posts: 1,435
Thanked: 288 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by agbenny View Post
Assume I need to reduce speed from 100+ to 40 or 50, and if there is enough distance, should I apply brake continuously? I normally press brakes 2-3 times with a gap and do not apply continuously. Is that a good practice?
The best way to brake is by combination of braking and down shifting.

While you are braking from hundred assuming you have a 5 s gear box, you will be in fifth gear; down shift gradually while braking. so braking intermittently and down shifting as you do that is the correct way, though it depends on how soon you have to stop.

Cheers!!

Last edited by anilisanil : 30th December 2010 at 16:32.
anilisanil is offline   Reply With Quote
Old 30th December 2010, 16:54   #203
Senior - BHPian
 
longhorn's Avatar
 
Join Date: Nov 2009
Location: Chennai
Posts: 1,154
Thanked: 290 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by anilisanil View Post
While you are braking from hundred assuming you have a 5 s gear box, you will be in fifth gear; down shift gradually while braking. so braking intermittently and down shifting as you do that is the correct way, though it depends on how soon you have to stop.

Cheers!!
I diasgree. Braking intermittently is a bad idea. Once you start braking, you should not release the brakes and then start braking again. If you have released the brakes,there should be sufficient distance between your car and the vehicle in front of you, for you to come to a halt without touching your brakes again (this is called coasting and requires a few years of good driving experience). Else you should not stop applying the brake till your vehicle has come to a complete halt. It should be a continuous process till the vehicle has come to a halt irrespective of whether you use engine braking or not.

Last edited by longhorn : 30th December 2010 at 16:59.
longhorn is offline   Reply With Quote
Old 30th December 2010, 17:08   #204
Senior - BHPian
 
anilisanil's Avatar
 
Join Date: Jun 2010
Location: Pune
Posts: 1,435
Thanked: 288 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by longhorn View Post
I diasgree. Braking intermittently is a bad idea. Once you start braking, you should not release the brakes and then start braking again. If you have released the brakes,there should be sufficient distance between your car and the vehicle in front of you, for you to come to a halt without touching your brakes again (this is called coasting and requires a few years of good driving experience). Else you should not stop applying the brake till your vehicle has come to a complete halt. It should be a continuous process till the vehicle has come to a halt irrespective of whether you use engine braking or not.
I do not mean braking intermittantly in the sense you took it, my bad comprehension. All I want to mean is to alternate between down shifting and braking, and I did mention it depends on the distance on wants to stop. And this guy wants to decelerate from 100-50 but not to stand still. If it is stand still, I completely agree it is braking continuosly!!

Thanks for clarifying me though!!
anilisanil is offline   (1) Thanks Reply With Quote
Old 31st December 2010, 12:27   #205
Newbie
 
Join Date: Dec 2010
Location: Pune
Posts: 19
Thanked: 0 Times
Question Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Hi,
I found this thread similar to a doubt I had in mind, so posting it here.

1. No matter which gear you are driving on, the engine is at an RPM > 1500 usually. However, if I move to Neutral and cruise away at low speeds, my engine stays at 800-900 RPM. Does that mean I use lesser fuel while cruising on the Neutral gear than at any other? It does lead to loss of control over the vehicle and the engine, but what happens to the fuel consumption?

2. Does the engine consume more fuel at the instants when the clutch is pressed?
Ikonik is offline   Reply With Quote
Old 31st December 2010, 12:45   #206
Senior - BHPian
 
longhorn's Avatar
 
Join Date: Nov 2009
Location: Chennai
Posts: 1,154
Thanked: 290 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by Ikonik View Post
Hi,
I found this thread similar to a doubt I had in mind, so posting it here.

1. No matter which gear you are driving on, the engine is at an RPM > 1500 usually. However, if I move to Neutral and cruise away at low speeds, my engine stays at 800-900 RPM. Does that mean I use lesser fuel while cruising on the Neutral gear than at any other? It does lead to loss of control over the vehicle and the engine, but what happens to the fuel consumption?

2. Does the engine consume more fuel at the instants when the clutch is pressed?
1. 900 RPM is what most cars will be doing at idle(neutral). So this is basically your starting point. As you press the accelerator the rpms starts rising from here. In neutral the engine is disconnected from the gearbox hence the rpm goes down to the idle rpm (assuming your foot is off the accelerator). Of course your rpm will rise if you press the accelerator even though you are in neutral. If your vehicle is on the move and you engage a gear from neutral, the rpms rise because the engine is now connected to the gearbox and is powering the movement of your vehicle (which is not the case if in neutral). You will consume lesser fuel while moving in neutral than in any gear because lower the rpm, lesser will be the fuel consumption. However, this is a bad practice and is not advisable, as you will be in much better control of your vehicle while in gear than in neutral.2. The engine consumes more fuel not when the clutch is pressed, but rather when a gear is engaged, i.e. when you shift to a gear from neutral and release the clutch. This is due to the sudden rise in rpm as opposed to a grdual one if accelerating while in gear.

Last edited by longhorn : 31st December 2010 at 12:49.
longhorn is offline   Reply With Quote
Old 31st December 2010, 15:17   #207
BHPian
 
di1in's Avatar
 
Join Date: Jan 2009
Location: Bnglr&Thrissur
Posts: 384
Thanked: 66 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

@longhorn Simply engaging a gear while the car is coasting should not induce rapid fuel consumption because even if the rpms climb rapidly for a second or two the actual process taking place is engine braking.

Once the gear is engaged pressing the accelerator would only result in normal fuel consumption related to that acceleration. To make coming out of coasting smoother you could also slightly tap the accelerator while engaging gear.

This method is fuel efficient but dangerous as the sudden engine braking and corresponding decceleration of the car is not accompanied by a lit brake light. So traffic behind you might not be aware that you are braking.

Last edited by di1in : 31st December 2010 at 15:21.
di1in is offline   Reply With Quote
Old 31st December 2010, 15:50   #208
Senior - BHPian
 
longhorn's Avatar
 
Join Date: Nov 2009
Location: Chennai
Posts: 1,154
Thanked: 290 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

Quote:
Originally Posted by di1in View Post
@longhorn Simply engaging a gear while the car is coasting should not induce rapid fuel consumption because even if the rpms climb rapidly for a second or two the actual process taking place is engine braking.
Sudden acceleration/deceleration leads to excessive fuel consumption not to mention the increased wear and tear on your vehicle. No two ways about it. Ever wondered why you always get better FE on the highway than in the city. That's because we are able to maintain a constant speed for a longer period of time on the highway, which is just not possible in city traffic.
Quote:
Originally Posted by di1in View Post
Once the gear is engaged pressing the accelerator would only result in normal fuel consumption related to that acceleration.
+1 to that provided you are in the correct gear w.r.t your vehicle's speed.
Quote:
Originally Posted by di1in View Post
This method is fuel efficient but dangerous as the sudden engine braking and corresponding decceleration of the car is not accompanied by a lit brake light. So traffic behind you might not be aware that you are braking.
+1 to that too, which is why I have mentioned in my post that this practice is not advisable.

Last edited by longhorn : 31st December 2010 at 15:58.
longhorn is offline   Reply With Quote
Old 31st December 2010, 16:26   #209
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 47,714
Thanked: 89,175 Times
Default Re: Shifting to Neutral or Pressing the Clutch when Braking - Is this right?

I reiterate, only an IDIOT will shift into neutral when coasting. Here's an older post:

According to Toyota, shifting to neutral doesn't save any fuel. Most modern cars come with a fuel-cutoff system. Thus, stay in gear so you save fuel & get free engine braking.

Quote:
"We went in search of an expert opinion on this one. According to Paul Williamsen, the product education manager at Toyota, ďAll contemporary Toyota and Lexus vehicles (and every other car built since the 1990s that Iíve looked at) can detect the condition when engine revs are higher than idle with a fully closed throttle: Under these conditions, all current to the fuel injectors is stopped, and no fuel is injected.Ē That means if your foot is off the gas while the carís in gear, youíre not using any fuel.
C&D linky

And here's another confirmation:

Quote:
Originally Posted by the_maassk View Post
I can confirm this is true. I have an Aveo U-VA with a ScanGauge II installed. If I take my foot off the A pedal, the fuel to the engine is cut-off (ScanGauge shows 0.0 LHK (liters per hundred kilometers) and the Fuel Loop is open.
GTO is offline   (1) Thanks Reply With Quote
Old 15th September 2011, 22:51   #210
Senior - BHPian
 
VeluM's Avatar
 
Join Date: Jul 2008
Location: Bangalore
Posts: 1,297
Thanked: 663 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by deetjohn View Post
But then after down shifting, one would need to let go off the clutch for engine braking to occur and then press the clutch pedal again when the speed reduces and the engine is about to knock. However, I am not seeing that in this video.
Engine braking is Only to be used in regular driving situations, and not emergencies.

During an emergency, one's priority and focus will be on braking and avoiding the "obstacle", and trying to figure out when to clutch and de-clutch will do no good.

Also engine braking is only effective when the engine is turning at higher rpms. As the vehicle slows down, the engine will begin to provide motive force, detracting from the overall braking force being applied, which defeats the purpose.

In short, in emergencies - if the car has ABS, stand on both the clutch and brake pedals and concentrate on steering with gentle input to avoid the obstacle.
VeluM is offline   (1) Thanks Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Palio 1.2 nv - Pressing the clutch pedal while starting the car kapilsharma80 Technical Stuff 24 18th February 2013 22:12
Xing: High rev when pressing the clutch during gear change raghu Technical Stuff 11 11th October 2009 07:06
cheen-cheen-cheen noise when pressing accelerator vebmetal Technical Stuff 15 27th August 2008 13:33
Which is the right Sequence Clutch-Brake Or Brake-Clutch ankura12 Technical Stuff 2 9th July 2007 10:02


All times are GMT +5.5. The time now is 10:53.

Copyright ©2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks