How do you slow down?

[PsiFox]

Barrell into the corner in fourth, stamp on the middle pedal, catch the car as it slews sideways, dip clutch, stamp on the accelerator, short-shift to second gear then go around the corner in a perfect drift, smoke pouring off both rear tyres due to the welded diff, elbow out of the window and the supermodel in the passenger seat giving you oral gratification.

Have witnessed this in real life, well the oral gratification bit anyway.

Regretfully the important word is "witnessed" (from a vehicle with a rather higher seating position than the Sports car next to me in the queue on the M1)

 

[Entai]

No the way the police would do it and apparently the "other way" (wrong way) is:
Brake brake brake brake (desired speed) change gear, steer on a trailing throttle, corner, apply throttle.

Where as the right way to drive is:

constant braking while coming down through the box to wipe the speed off in a controlled fashion while being in the correct gear at all times through the braking manouver hit desired speed at entrace to corner cease braking, steer, corner on a trailing throttle to keep the wheels driving hit apex, accelerate away.

Admittedly the right way is the hardest way, its also the way you do it on a bike as it avoids all harsh braking and accelerating manouvers and stops you low siding in corners because you have to much Throttle on and high siding because you've been on the brakes all the way in on a shut throttle stamped down through the box released the clutch and locked the rear wheel.

Sorry but you have got the police (and IAM and ROSPA as they are all the same way) very wrong.

They are taught (and I know this for a fact as I am an IAM instructor, and have been personally taught to police Class A standard) to slow as approaching the corner in one continuous braking application, lift off the brake, change to correct gear for corner (direct from approaching gear to gear you need for corner and afterwards, not down through the gears) then apply throttle to balance the car (not accelerating and not slowing just keep constant speed, certainly not a trailing throttle as this will unbalance the car slightly) steer into and through the beginning of the corner, once you are at or just slightly past the corner's apex apply accelerator progressively to power out of the corner and up through the gears untill you approach the next corner or hazard, then repeat the procedure.

To clarify a few descriptions, a trailing throttle is NOT applying power it is slightly behind the pedal point needed to keep the speed up at a constant level, in fact with a trailing throttle you will be slowing down slightly.
A balanced throttle will keep you at a constant speed when in a straight line on a level road. However when cornering the term balanced throttle will mean that you are applying very slightly more throttle than needed to keep constant speed when in a straight line, because when cornering the scrub effect on the front tyres will be slowing you slightly so you need abit of applied throttle to balance the scrub effect and actualy give you a balanced throttle position.
Obviously a fully applied throttle will accelerate you.

 

[atpbx]

Sorry but you have got the police (and IAM and ROSPA as they are all the same way) very wrong.

They are taught (and I know this for a fact as I am an IAM instructor, and have been personally taught to police Class A standard) to slow as approaching the corner in one continuous braking application, lift off the brake, change to correct gear for corner (direct from approaching gear to gear you need for corner and afterwards, not down through the gears) then apply throttle to balance the car (not accelerating and not slowing just keep constant speed, certainly not a trailing throttle as this will unbalance the car slightly) steer into and through the beginning of the corner, once you are at or just slightly past the corner's apex apply accelerator progressively to power out of the corner and up through the gears untill you approach the next corner or hazard, then repeat the procedure.

To clarify a few descriptions, a trailing throttle is NOT applying power it is slightly behind the pedal point needed to keep the speed up at a constant level, in fact with a trailing throttle you will be slowing down slightly.
A balanced throttle will keep you at a constant speed when in a straight line on a level road. However when cornering the term balanced throttle will mean that you are applying very slightly more throttle than needed to keep constant speed when in a straight line, because when cornering the scrub effect on the front tyres will be slowing you slightly so you need abit of applied throttle to balance the scrub effect and actualy give you a balanced throttle position.
Obviously a fully applied throttle will accelerate you.

????????
I know what a trailing throttle is and the fact that you are a IAM instructer just means you are wrong as you were taught and teach the wrong way to go round corners.

 

[FireBIade]

I was thinking about this the other day, not sure why..

My driving instructor (who also taught the police) told me to change down through the gears while breaking to slow.
However, I did a 'driver improvement course' a few years later (oops!) and he told me "use breaks to slow, gears to go". i.e. break until you don't need to any more, and then change gear to the one you need.

So which is best and why?

Depends what your driving.

In an emergency you hit the brake pedal just before the clutch to prevent coasting and momentary speed increase, obvious really.

If you know your commming to a complete stop i.e. lights or junction there's no need to engine break.

If you drive a Honda with a VTEC lump you get to learn to engine break & brake pedal as this puts you in the gear you need to accelerate away. If you engine break a bit it saves your brakes from fading and other over heating issue's which under certain circumstances can be useful

 

[Sp00n]

I change down a gear as i slow down because if i need to make a move, i'm allready in the right gear.

 

[Phate]

I use the engine to slow me down, and then brake if necessary

Coming up to a corner in 4th, - neutral - rev - into 3rd - will slow the car down - or 2nd if need be, also where you are in a lower gear gives better accleration out of the corner.

My mates once thought that my brake lights didn't work, but its where i use the engine properly to slow the car down and hardly ever the brakes

 

[Entai]

????????
I know what a trailing throttle is and the fact that you are a IAM instructer just means you are wrong as you were taught and teach the wrong way to go round corners.

So why, if you know what trailing throttle is, do you say that the police steer on a trailing throttle, when they don't, and never would because it unsettles the car. To keep the car in a settled balanced position, you should have the car in a slightly applied throttle position, which is not trailing throttle.

In your opinion I am wrong, in my opinion you are wrong, in that, when you are braking and going down the gears you are doing two three or maybe four completely unnecessary gear changes, thus adding to the wear and tear to your clutch and drivetrain.

Another point is that every time you dip the clutch to change gear you have the car in an uncontrolled situation, whereas if I am braking and then do one down change, I am limiting the time the car is un-powered and un-controlled situation, and I am also limiting the possibility that something will fail and cause the clutch to be inoperative.

Just my opinion though

 

[Phate]

Another point is that every time you dip the clutch to change gear you have the car in an uncontrolled situation, whereas if I am braking and then do one down change, I am limiting the time the car is un-powered and un-controlled situation, and I am also limiting the possibility that something will fail and cause the clutch to be inoperative.

Just my opinion though

Yes but if you are braking and change down then you run a higher rish of locking the wheels up as the engine is not engaged with the wheels to drive them

 

[chrislusty]

I brake the way Entai has descibed as i have recently passed the IAM test.

atpbx who taught you the way to brake then if you think/know your way is better? just curious and not having a go thats all

 

[volospian]

Yes but if you are braking and change down then you run a higher rish of locking the wheels up as the engine is not engaged with the wheels to drive them

Que?

Do you mean that as there is no power coming from the engine there is more chance of you locking the wheels under braking?

 

[Phate]

Que?

Do you mean that as there is no power coming from the engine there is more chance of you locking the wheels under braking?

No - The impression i got he was saying that WHILST braking he changes down, ok think about it, when the clutch is down the engine isnt engaging the wheels, therefore not turning them, and the car is merely moving from enertia (sp?).

Whilst braking if you put the clutch down your are more likely to lock the wheels up as the engine is not pushing the car along.

 

[Entai]

Yes but if you are braking and change down then you run a higher rish of locking the wheels up as the engine is not engaged with the wheels to drive them

But that is the whole point I do not do that nor do I teach that.
First you brake THEN you stop braking and change gear so at no time is the car likely to lock up anything.

 

[Phate]

But that is the whole point I do not do that nor do I teach that.
First you brake THEN you stop braking and change gear so at no time is the car likely to lock up anything.

Alright mate. chill yeh? i got the impression that you taught to change down whilst braking. And plus i disagree with that post aswell, i say change down then brake, but i rev when changing down so its as smooth as silk. and then brake, plus changing down help slow the car down anyway....

 

[volospian]

No - The impression i got he was saying that WHILST braking he changes down, ok think about it, when the clutch is down the engine isnt engaging the wheels, therefore not turning them, and the car is merely moving from enertia (sp?).

Whilst braking if you put the clutch down your are more likely to lock the wheels up as the engine is not pushing the car along.

Sorry, I don't get it. Do you say that you brake whilst still providing power to the engine?

The drag from an engaged engine that is starved of fuel is not really that great, otherwise cars wouldn't need brakes to stop them at all.

You engine brake by forcing the revs to increase by changing down through the gears, this increases the drag on the transmission as the engine is then revving much higher than the transmission, this creates a drag on the engine as there is no combustion forcing the pistons to move that fast.

The amount of drag created by just taking your foot off the loud pedal is highly unlikely to affect the efficiency of the braking system to such a degree that without it the brakes will lock as the engine will be spinning down in time with the decrease in wheel rotation. It will have some effect, but not much. Try just taking your foot off the throttle at 70mph on the motorway and see just how fast you stop.

However, changing down from, say 5th to 2nd in one movement from a high speed will almost certainly cause a loss of traction as the wheels will suddenly want to rotate much slower than the vehicle is travelling

 

[Entai]

No - The impression i got he was saying that WHILST braking he changes down, ok think about it, when the clutch is down the engine isnt engaging the wheels, therefore not turning them, and the car is merely moving from enertia (sp?).

Whilst braking if you put the clutch down your are more likely to lock the wheels up as the engine is not pushing the car along.

Inertia

Anyway the engine would not be pushing the car along, because you have not got your foot on the accelerator the engine would only be idling.

 

[volospian]

Inertia

Anyway the engine would not be pushing the car along, because you have not got your foot on the accelerator the engine would only be idling.

lol, such elegance compared to my answer

 

[Entai]

Alright mate. chill yeh? i got the impression that you taught to change down whilst braking. And plus i disagree with that post aswell, i say change down then brake, but i rev when changing down so its as smooth as silk. and then brake, plus changing down help slow the car down anyway....

Sorry did not mean that to sound nasty or anything.

To your other point if you change down then brake you can often find you are over revving the gear you are in and would not then have a ny room for manouver so to speak.

Reving whle changing down is fine but only after braking slightly so that you are not over revving a particular gear.

In my opinion using the engine to brake is not a mechanically sound idea, as you are putting streess and strain on parts that are not really designed for that sort of thing.

 

[Entai]

Sorry, I don't get it. Do you say that you brake whilst still providing power to the engine?

The drag from an engaged engine that is starved of fuel is not really that great, otherwise cars wouldn't need brakes to stop them at all.

You engine brake by forcing the revs to increase by changing down through the gears, this increases the drag on the transmission as the engine is then revving much higher than the transmission, this creates a drag on the engine as there is no combustion forcing the pistons to move that fast.

The amount of drag created by just taking your foot off the loud pedal is highly unlikely to affect the efficiency of the braking system to such a degree that without it the brakes will lock as the engine will be spinning down in time with the decrease in wheel rotation. It will have some effect, but not much. Try just taking your foot off the throttle at 70mph on the motorway and see just how fast you stop.

However, changing down from, say 5th to 2nd in one movement from a high speed will almost certainly cause a loss of traction as the wheels will suddenly want to rotate much slower than the vehicle is travelling

And yours is a great discription of why engine braking is mechanically unsound. Drag on the engine is not mechanically a good idea they are not designed for that.

Also the last part is wrong because you have no more chance of locking up changing from 5th to 2nd than from 5th to 4th it just means your blip during the downchange needs to be larger to match the revs.

 

[Phate]

Ok lets break this down

Sorry, I don't get it. Do you say that you brake whilst still providing power to the engine?

No. I change down from say 4th to 3rd, whilst revving it slightly when its in neutral, so the car doesn't jolt all over the place, where the engine is in a lower gear, it will slow down and if you know what you are doing you can do it properly so it slows down enough for most corners. and THEN i use the brake IF necessary. (Obviously i don't wait till the last minute )

The drag from an engaged engine that is starved of fuel is not really that great, otherwise cars wouldn't need brakes to stop them at all.

Yes i know, but with effective and correct gear changing (and not damaging the gear box) you can usually slow the car down enough to go around a corner (obviously not the really tight ones or the ones that need brakes to go around it)

The amount of drag created by just taking your foot off the loud pedal is highly unlikely to affect the efficiency of the braking system to such a degree that without it the brakes will lock as the engine will be spinning down in time with the decrease in wheel rotation. It will have some effect, but not much.

I didnt say just take your foot off the throttle and the wheels will lock up did i? i said if the clutch was down whilst applying the brake you will run a higher risk of locking up the wheels

However, changing down from, say 5th to 2nd in one movement from a high speed will almost certainly cause a loss of traction as the wheels will suddenly want to rotate much slower than the vehicle is travelling

Yeh but c'mon who changes from 5th to 2nd? i change from 5th to 3rd sometimes. but not 5th to 2nd.

 

[volospian]

And yours is a great discription of why engine braking is mechanically unsound.

Providing you are not redlining the engine, I would suggest that a transmission capable of putting the power down would be capable of putting up with the forces of "normal" engine braking. The clutch would probably suffer to some degree, but as I said earlier, I'm not that fussed, it's less than £100 to change it and while on an empty road my brakes are adequate, in busy traffic they often need all the help they can get.

A modern vehicle with ABS, with even the most basicly skilled driver behind the wheel, has a better braking efficiency than my 32 year old system. In busy traffic, in situations where the vehicle in front may have to stop suddenly, you need to be able to assist the brakes however you can.