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#201531 - 30/01/2004 22:32 Beating a dead horse
ricin
veteran

Registered: 19/06/2000
Posts: 1495
Loc: US: CA
OK, this one has been beaten to death all over the place, but, I still think it will spark a more intelligent discussion here than what I've seen from anywhere else.

To slow a stick-shift car, should you brake or downshift?

/me hands out various blunt objects.

Disclaimer: No horses or animals of any kind were harmed in the creation of this post.
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#201532 - 30/01/2004 23:03 Re: Beating a dead horse [Re: ricin]
foxtrot_xray
addict

Registered: 03/03/2002
Posts: 687
Loc: Atlanta, Georgia
I'm going to completely throw this thread into a loop, and bring up the last point in the column:

OK, I'm not claiming I've got an airtight case. Tell you what: I won't hassle you about tapping the top of your Coke can to keep the fizz from exploding, and you don't hassle me about my idiosyncrasies with the clutch.

Uhm. I do that. The tapping thing. I don't know why. I started it, thinking it was actually doing something, then realized that doing that did absolutely NOTHING, but.. still do it.


(Oh, and as for that down-shifting thing.. I do it when I need to. Sometimes, I do BOTH at the same time to REALLY slow down. )

Me.
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#201533 - 30/01/2004 23:47 Re: Beating a dead horse [Re: ricin]
lastdan
enthusiast

Registered: 31/05/2002
Posts: 352
Loc: santa cruz,ca
if you brake without downshifting you'll be in too high of a gear when you come out of a curve, assuming you were in a curve to begine with.
on the other hand, brakes are much cheaper than other parts of the drive line.

note:I drive for sh*t, don't listen to me.

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#201534 - 30/01/2004 23:50 Re: Beating a dead horse [Re: ricin]
SE_Sport_Driver
carpal tunnel

Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
Yes, brakes are cheaper than engines. Brakes nowadays are damn good too.

Of course, WHILE or ahortly after you've braked, downshifting is a good idea if you want to get moving again.
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#201535 - 31/01/2004 01:43 Re: Beating a dead horse [Re: ricin]
drakino
carpal tunnel

Registered: 08/06/1999
Posts: 7868
So, what about on a motorcycle...

*runs off*

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#201536 - 31/01/2004 03:44 Re: Beating a dead horse [Re: drakino]
andy
carpal tunnel

Registered: 10/06/1999
Posts: 5916
Loc: Wivenhoe, Essex, UK
So, what about on a motorcycle...

What vintage ?
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#201537 - 31/01/2004 08:27 Re: Beating a dead horse [Re: ricin]
LittleBlueThing
addict

Registered: 11/01/2002
Posts: 612
Loc: Reading, UK
Depends why you are slowing down.

On a motorway when you need to lose a few mph you use engine braking - unless you want people behind to *know* you are braking (eg if you've seen stopped/slow traffic)

I've you're going hell for leather on the twisty stuff then you brake and drop a gear or so - but that's as much about keeping the engine at the right revs for whatever you're doing as anything else.

I'd say you never drop a gear *just* to slow down in normal driving (aparently this came about when clutches were cheaper than brakes) - and I can think of times I do it.

Of course if you are about to slow down and you're at a change-up point then don't change up and let the engine slow you.

If you think you can drive with a hard and fast set of rules though you ought to ask why computers don't drive cars yet

Easy.

LBT
(of course I drive a TVR Tuscan - better known as "the one in Swordfish" - so what do I know )
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#201538 - 31/01/2004 09:27 Re: Beating a dead horse [Re: ricin]
JeffS
carpal tunnel

Registered: 14/01/2002
Posts: 2858
Loc: Atlanta, GA
Interesting . . . my dad used to race cars (a long time ago) and when I first got my standard he SWORE to me that I had to downshift and not use the brakes. I really tried at first, but it just felt wrong to me. Finally I gave up and just started putting the car in neutral and breaking. This feels more natural to me and so it's what I do. I just don't tell him that.
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#201539 - 31/01/2004 10:09 Re: Beating a dead horse [Re: JeffS]
g_attrill
old hand

Registered: 14/04/2002
Posts: 1172
Loc: Hants, UK
Do what the taxis do in Russia - as soon as you are going down the slightest incline switch off the engine and coast to the bottom.

Gareth

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#201540 - 31/01/2004 11:29 Re: Beating a dead horse [Re: ricin]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
I'm with Click and Clack on this one. Brake jobs are cheap, clutch jobs are expensive.

Funny thing is, before I'd even heard of CarTalk, I was braking rather than downshifting simply because it was (a) easier, and (b) just felt right. And I was constantly chided by everyone telling me I should have been downshifting.

It's nice to be proved right sometimes...
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#201541 - 31/01/2004 11:52 Re: Beating a dead horse [Re: JeffS]
andy
carpal tunnel

Registered: 10/06/1999
Posts: 5916
Loc: Wivenhoe, Essex, UK
Finally I gave up and just started putting the car in neutral and breaking. This feels more natural to me and so it's what I do.

I'm sorry, but that it is a very silly idea. You shouldn't take the car out of gear when you are braking.

If you do this and something goes wrong you won't have proper control over the car immediately. You are going down a hill, you need to brake so you brake and take the car out of gear. Now imagine your foot slips off the brake pedal, or your brakes fail. You will now be left with a car that is accelerating down hill, until you reapply the brakes or get the car into gear again.

Also, think about what would happen if you are braking and then the situation changes and you need to accelerate again quickly to avoid a collision. Again you won't be able to do it until get the car into gear.

Finally, imagine you are braking and then someone steps out in front of you, or a car pulls out. You need to change direction to avoid them because you know you can't stop in time. To do this safely you are going to have to release the brake (unless you have good ABS maybe), again you will end up accelerating (or at best not slowing at all) towards the obstacle.

Taking the car out of gear (except to change gear obviously) while you are driving is not a good plan.

I personally use a combination of engine braking and brakes. On my MX5/Miata the front brake pads and disks lasted about 80,000 miles, the clutch made it to 90,000 (it wasn't the friction surfaces that went) and the rear brake pads and disks are still going strong at 130,000 so this can't be too bad a combination...
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#201542 - 31/01/2004 12:09 Re: Beating a dead horse [Re: andy]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5683
Loc: London, UK
Taking the car out of gear (except to change gear obviously) while you are driving is not a good plan.

This is called "coasting", and if you do it during a driving test in the UK, it will count as a fault (IIRC). This includes both putting the car into neutral or travelling with the clutch pushed in, unless actually changing gear.

A book I have here, "The Driving Manual" (published by HMSO) lists all the reasons that Andy gives as to why coasting is a bad idea.

I also use a combination of engine braking and brakes. I use less engine braking on my new car, because it just doesn't seem as effective (relatively high-revving petrol vs diesel).

I never change into neutral unless I've stopped the car and am getting out, or unless I'm stopped at lights for a long time, in which case I'll put the handbrake on as well. Normally I just push the clutch in as I come to a stop, and put the car in first, ready to go again.
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#201543 - 31/01/2004 12:32 Re: Beating a dead horse [Re: ricin]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
It's also important to point out that you shouldn't coast downhill a long way, as down a mountain, keeping your speed using the brakes. You should definitely use the engine for that, as glazing your brakes becomes an issue and could be dangerous.

Otherwise, why would you use your engine to slow down? The brakes are going to do a better job in almost all cases. It takes a significant amount of time to change gears, especially if you match revs to avoid damaging your drivetrain components. Of course, you should also put your car in the correct gear for the speed you're going once you've slowed down, and preferably as you slow down, too.

I'm too lazy to read the whole thing. What was the argument for using your engine?
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#201544 - 31/01/2004 14:55 Re: Beating a dead horse [Re: wfaulk]
drakino
carpal tunnel

Registered: 08/06/1999
Posts: 7868
It's a requirement going down Pikes Peak to use your engine in the lowest gear, along with breaks as needed. About midway down, someone checks your break temperatures, and will require you to stop if needed.

My Saturn, lacking a way to keep the automatic transmission in anything lower then second gear, led to a 30 minute stop.

For some odd reason, I'll shift down my Saturn all the time on big hills around here. Not sure who I picked the habit up from, but I started doing it more after learning how to ride my motorcycle.

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#201545 - 31/01/2004 17:48 Re: Beating a dead horse [Re: JeffS]
AndrewT
old hand

Registered: 16/02/2002
Posts: 867
Loc: Oxford, UK
Finally I gave up and just started putting the car in neutral and breaking.

Bad idea. Your braking force relies upon the engine's vacuum, without that you have virtually no braking - try it sometime when you're alone somewhere, you will be alarmed at how little braking you have without it. So, the rhetorical question is; what if you're engine cuts out while coast-braking?


Edited by Rue (31/01/2004 17:49)

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#201546 - 01/02/2004 12:00 Re: Beating a dead horse [Re: tfabris]
boxer
pooh-bah

Registered: 16/04/2002
Posts: 2011
Loc: Yorkshire UK
Brake jobs are cheap, clutch jobs are expensive

I tend to change down, it's the way I was taught, but 40 years ago, when I was learning, brakes weren't so good, so it was necessary.
You're basically right, but it's the crankshaft you're knacking by engine braking and that's really expensive: This was the advice given to me by the Daily Telegraph motoring correspondent.
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#201547 - 02/02/2004 10:36 Re: Beating a dead horse [Re: ricin]
TigerJimmy
old hand

Registered: 15/02/2002
Posts: 1049
Jackie Stewart, in his book Principles of Performance Driving, says that you should use the brakes to slow down. You should downshift *while* you are braking so that you are in the correct gear and ready to go immediately after releasing the brakes -- which you should do *gently*. Tony mentioned the reason: you can break your clutch or gearbox by over-zealous engine braking and the brakes are designed to slow the car down -- not the clutch/gearbox.

I used to rally race and do some SCCA autocross. I have had some (not enough!) training in performance motorcycle riding.

Gearing down while breaking is hard to do correctly. By "correctly" I mean that you change the engine speed to the correct speed for the next gear down while the clutch is "in". In a car, that means all three pedals need to do something -- brakes on, clutch in, accellerator to match revs -- all in the time you are gearing down. They call it "heel and toe" because you end up using your right foot for both brake and accellerator, but as it was taught to me you use the right side of the right foot for the accellerator, not really the heel.

It is slightly easier on a bike, but still difficult to do smoothly because you need to work the front brake and the throttle with the same hand.

On the other hand, this is all for performance driving, but I think the principles are applicable to any kind of driving.

Racers also spare the brakes and brake as little as possible. A race driver would not use the brakes to slow down 5 mph in traffic because he/she would anticipate the traffic and just let off the gas a bit. In that sense, I suppose, they are engine braking.

I think it was Maseratti who said that, "you can always tell a good driver in the city because they rarely use the brakes." That's not because they are going crazy with downshifting, but because they *anticipate* the traffic, lights, etc. and don't ever need to make sudden adjustments to the car.

On a bike, slowing by downshifting can be dangerous because of the sudden torque change to the rear wheel. Its like using only the rear brake. If you do it too aggressively, you can easily crash. Same goes for a car, but it is less sensitive. Not good to do in a curve, though...

On long hills, using engine compression is necessary so the brakes don't fade. Its especially important for heavy trucks. Modern cars have really good brakes, so fade is much less of an issue than it was 20 years ago. I remember the first time I experienced fade -- I pushed the pedal as hard as I could and there was nothing there! Definitely something to avoid in the mountains!

Jim

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#201548 - 02/02/2004 10:39 Re: Beating a dead horse [Re: TigerJimmy]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I've been told that the term ``heel and toe'' was coined by Ferrari driver way back when they actually used their heel and toe because of the different placement of the pedals (that is, it wasn't clutch-brake-gas, but some other order).
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#201549 - 02/02/2004 13:25 Re: Beating a dead horse [Re: wfaulk]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5683
Loc: London, UK
actually used their heel and toe

I've seen film of an (amateur?) race driver on a track day. He has his foot turned so that it sits across both pedals, and appears to actually be using his heel and toe to accelerate and brake at the same time.
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#201550 - 02/02/2004 14:12 Re: Beating a dead horse [Re: Roger]
TigerJimmy
old hand

Registered: 15/02/2002
Posts: 1049
Cool. I think a lot of it has to do with where the pedals are in relation to one another and what works best for the particular driver, etc.

Some of the newer race cars have a computer controlled throttle that does all of this for the driver. The new BMW M3 has this feature. The gearbox is an electronically operated sequential box. You can hold the gas to the floor and just hit the "up" button. The computer operates the clutch, throttle and gear selection. Downshifting works the same way, with the computer adjusting engine RPM to match the lower gear. I'd love to get my hands on one of those...

Jim

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#201551 - 02/02/2004 14:29 Re: Beating a dead horse [Re: TigerJimmy]
ricin
veteran

Registered: 19/06/2000
Posts: 1495
Loc: US: CA
You should downshift *while* you are braking so that you are in the correct gear and ready to go immediately after releasing the brakes -- which you should do *gently*.


Agreed. That is how I drive.


I think it was Maseratti who said that, "you can always tell a good driver in the city because they rarely use the brakes." That's not because they are going crazy with downshifting, but because they *anticipate* the traffic, lights, etc. and don't ever need to make sudden adjustments to the car.


I do that all the time without even thinking about it. If I need to just slow down slightly I just let off the gas. If I need to slow down a lot over a period of time/distance, I double-clutch, and, depending on just how fast I need to decelerate, I brake (sometimes heal/toe) as well. If I need to come to a stop or slow down in a short distance, I use the brakes and downshift under braking. Just the way I learned. Hard to break habits.
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#201552 - 02/02/2004 14:45 Re: Beating a dead horse [Re: ricin]
davec
old hand

Registered: 18/08/2000
Posts: 992
Loc: Georgetown, TX USA
I would use the Jake Brake...
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#201553 - 06/02/2004 07:38 Re: Beating a dead horse [Re: ricin]
thinfourth2
Pooh-Bah

Registered: 13/04/2001
Posts: 1742
Loc: The land of the pale blue peop...
If all else fails aim for something soft and cheap
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