So, I figure it’s about time that I try come to grips with a few things that I’ve never understood:

1. How exactly should one drive in order to maximize the life of the clutch and transmission? I’ve think I’ve got this one down fairly well; don’t ride the clutch, don’t balance on the clutch and gas, shift smoothly and gently, avoid downshifting, etc. Anything else?

2. How long can I expect my new clutch to last (provided I don’t abuse it)?

3. I’ve always heard that you shouldn’t downshift to slow down, because it shortens the life of your (engine? clutch? transmission?), and it’s better to use your brakes, as brake pads are cheap and easy to replace. Makes sense to me. However, I’ve also talked to people who swear that downshifting to slow down is the correct way to do it. Is there any reason to downshift rather than brake (other than driving down long hills)?

4. Is it normal to smell burning clutch when you back up a steep hill?

5. My brother swears that it’s a good idea to put the car in neutral and coast when going down hill – to save gas; and that you should put it in neutral and take your foot off the clutch when stopped at a red light – to save the clutch. I think my brother’s an idiot, and that you should never do the first, and that the second has no effect on the life of the clutch. Who’s right?

6. What, exactly, happens inside my car when I do the following, and which part is being abused? (no, I don’t make a habit of these things, just want to know):
a) drive in too low a gear (e.g., 35mph in 2nd)
b) drive in too high a gear (e.g., 30mph in 4th)
c) start in 2nd gear

I hope that someone can explain at least a few of these mysteries.

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Originally posted by Senerie:
1. How exactly should one drive in order to maximize the life of the clutch and transmission? I’ve think I’ve got this one down fairly well; don’t ride the clutch, don’t balance on the clutch and gas, shift smoothly and gently, avoid downshifting, etc. Anything else?

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Seems good so far, though there are cases where the latter three are necessary.

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2. How long can I expect my new clutch to last (provided I don’t abuse it)?

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My last car, a 10 year old pickup truck (at the time) needed a clutch replacement every six months or so. I also had the drive shaft fall right out the bottom of the damn thing, which was actually less annoying and an easier fix. Let's just say I learned a lot of mechanics the hard way on that car.

Of course, since the thing was so old and the vehicle on which I learned to drive manual transmission, perhaps it's not fair to blame my Jeep pickup, which I aptly named the "Millenium Rustbucket."

My current car is a seven-year-old SUV that I drive but rarely (normally less than 200 miles a week, and much less since I moved closer to campus this semester) and the clutch has been there for a good four years now. I can feel the clutch getting a bit pissy at times, but I don't think I have to worry about replacing it for at least a year or two.

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3. I’ve always heard that you shouldn’t downshift to slow down, because it shortens the life of your (engine? clutch? transmission?), and it’s better to use your brakes, as brake pads are cheap and easy to replace. Makes sense to me. However, I’ve also talked to people who swear that downshifting to slow down is the correct way to do it. Is there any reason to downshift rather than brake (other than driving down long hills)?

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AFAIK, downshifting means (or at least implies) shifting to a lower gear for the purpose of slowing down a vehicle. Downshifting is important to know because it's exceedingly helpful in emergency situations (gotta stop fast but with control). So yeah, you should do it often enough that you know how. You're right about the brakes, though. Brakes are built to be worn and easily replaced. Clutch plates are not.

You should shift to a lower gear when you need to pass someone quickly or when the engine is lugging due to travelling up a hill or any other heavy load.

I downshift when I need to slow down and expect to maintain a speed within that gear setting, tapping my brakes at the same time to alert the guy behind me.

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4. Is it normal to smell burning clutch when you back up a steep hill?

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Nope. It's not good, either.

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5. My brother swears that it’s a good idea to put the car in neutral and coast when going down hill – to save gas; and that you should put it in neutral and take your foot off the clutch when stopped at a red light – to save the clutch. I think my brother’s an idiot, and that you should never do the first, and that the second has no effect on the life of the clutch. Who’s right?

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You're absolutely right on the first. If he's going down the hill and needs to stop quickly, the brakes aren't going to help much. It's also time consuming to figure out what gear you need to shift into when coasting - not a matter of more than a second or two, but enough to make the difference between a close call and an accident.

The second probably has minimal effect on the clutch, but giving my left foot a rest is worth the effort of shifting into neutral when at a long traffic light.

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6. What, exactly, happens inside my car when I do the following, and which part is being abused? (no, I don’t make a habit of these things, just want to know):
a) drive in too low a gear (e.g., 35mph in 2nd)
b) drive in too high a gear (e.g., 30mph in 4th)
c) start in 2nd gear

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a) The engine has to turn faster than it was designed to maintain that speed. This causes wear on the engine parts. As long as you're well below the red line, you're not causing terrible damage, but you'll find your engine will last much longer and run better if you keep at the proper gear for your speed.

b) The engine is "lugging" - it's forced to operate at a speed slower than it was designed. Not quite as bad as the opposite case, but still not good. It also causes a lot of wear on the engine - the pistons are still doing their thing, but the wheels are (eventually) connected to them and keeping them from pushing as fast as they're trying to push.

c) You get a bloody nose.

Unless you mean starting in neutral and then shifting to second from a dead stop. You're fine if you're pointed down a hill - gravity will give you the little momentum you need to be at the right speed for second the moment you ease off the brake.

If you're on flat ground, then you're causing a lot of friction in the clutch as you start easing it out. This same thing happens in first gear except the gear ratio is such that much less friction is made. Less friction=less wear.

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I hope that someone can explain at least a few of these mysteries.

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And I hope I was helpful.

General rules on clutch use are good.

Your brother is an idiot. In fact it may be illegal to coast down a hill.

Clutch smell when backing up a hill is not good, but not abnormal since you are probably slipping the clutch a lot as you do that.

My clutches tend to last at least 80,000 miles except on the rally car where 1000 miles is good.

If your clutch is lasting less than 60,000 miles, check the linkage to be sure clutch is fully engaging. Not fully disengageing makes shifting difficult. Not fully engaging makes the clutch slip.

Putting the transmission in neutral at a light reduces the wear on the throwout bearing, not the clutch per se.

I especially appreciate

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Originally posted by RichardM:
Your brother is an idiot.

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Originally posted by Alchemy:
My last car, a 10 year old pickup truck (at the time) needed a clutch replacement every six months or so."

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RichardM: to reply with quotes, click the "Quote" icon above the post you want to reply to. Or you can click "Post Reply" in the regular way, and then insert quotes between [ quote ] and [ /quote ] (but with no spaces inside the brackets).

downshifting

Hence the reason the .357 Magnum was developed. (How's that for a UL?)
RichardM: to reply with quotes, click the "Quote" icon above the post you want to reply to. Or you can click "Post Reply" in the regular way, and then insert quotes between [ quote ] and [ /quote ] (but with no spaces inside the brackets).

Sen "getting in gear" erie[/QB][/QUOTE]

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Originally posted by RichardM:
[QB]If my car starts needing a new clutch every six months, I'm going to take it out and shoot it.

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I've had several cars go way over 100K miles on the original clutch. When I was learning to drive however, the clutch went out on Mom's wagon which I had to replace. A year or so later after my two sisters learned to drive it went out again.

If I know I'll be coming to a full stop, I slip it out of gear without using the clutch and sit idling in neutral until time to go. Sometimes if leisurely accelerating, I'll shift without the clutch, just matching engine speed to road speed and gear. Works on upshifts and downshifts if you are careful.

Once I saw a TV program on Formula One racing, a driver was asked why he downshifted approaching a turn. He said that was only to make sure he was in the right gear for accelerating out of the turn. He also mentioned the brakes pads are fairly easily replaced and clutches are not. FWD cars are even more difficult.

You should try to keep the engine in the range between 1200-3000 turns (???)/min.

You will use much less gas if you down-shift to slow down instead of using the brakes. If you take tour foot of the gas-pedal and down-shift your car will use no gasoline till 1200 turns/min.

I feel like I'm rambeling and making no sense... But I know that I drive cheaper since I started to follow the above. Of course I live in a country where gas is expensive. And also even if the cost is not the issue, there's the environmental effects to be considered.

/J

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Originally posted by v94jsi:
So if you want to drive economical you should turn off your car like at traincrossings and other times when you have to stand still.

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Depends on how long you are stopped. You may save gas, but you will add wear and tear to your engine. Driving economical is more than just saving gas. Less than 5 or 10 minutes, it's better for the majority of the cars parts to leave it running.

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You should try to keep the engine in the range between 1200-3000 turns (???)/min.

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It's revolutions per minute (RPM)

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If you take tour foot of the gas-pedal and down-shift your car will use no gasoline till 1200 turns/min.

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Since even the most inefficient cars use much less than a gallon of gasoline an hour at idle, I can't imagine that turning off the engine for a minute or two would have any reasonable effect on fuel efficiency.

When you turn off your car for a minute or two at a train crossing and restart it, you cause wear on the starter motor and create a large amount of pollution - a cold catalytic converter is completely useless; it doesn't cause a reduction in NOx pollutants until it reaches operating temperature about 30 seconds after the engine starts.

Why do all that for a savings of a few tablespoons of gasoline?

As for engine speed, you should realize that there is more than one type of automobile engine and they tend to have different operating speeds.

I doubt that if downshifting saves gas - in fact, I'm inclined to say it uses more gas than depressing the clutch and braking. If you car had some way to know you were downshifting and had a throttle cutoff, I imagine that the few drops of gas you save would not be worth the extra clutch wear.

I worry about people whose every action on the road is in the interest of pinching pennies out of every bit of gasoline.

While driving, my primary concern is the safety of myself, my passengers, and those around me. Far in second is concern about damaging my vehicle.

Fuel efficiency is a very distant third.

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Originally posted by v94jsi:
The reason to drive in a high gear is to save gas. Basically. The car uses more gas in neutral than it does driving in low speed.

Probably not true except that when the car is sitting still it is indeed getting zero miles per gallon.

So if you want to drive economical you should turn off your car like at traincrossings and other times when you have to stand still.

This methodology was used by VW a while back for a high mileage model diesel.

You should try to keep the engine in the range between 1200-3000 turns (???)/min.

This is the correct range for my 4 cylinder turbo Saab, V8 DOHC Mustang, V8 Mustang and V6 twin turbo Audi. Too high of rpm range though for my V8 diesel truck.

You will use much less gas if you down-shift to slow down instead of using the brakes. If you take tour foot of the gas-pedal and down-shift your car will use no gasoline till 1200 turns/min.

Eseentially true except that some fuel is taken in if the engine is carburated. However almost evry car today is fuel injected. But brakes are cheaper and easier to replace than clutches.

/J

(I will probably go back to edit...)

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Best advice to save fuel is drive gentle.

Of course you should take into account if you need to change brakes or clutch more often driving this way than that way. But honestly, how often do one normally need to change the clutch in a car? And does it matter at all how many times you change gears? (Apart from when you learn to drive and the car keeps 'jumping' every time you shift gears... )

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Originally posted by v94jsi:
The car uses more gas in neutral than it does driving in low speed.

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Driving at low speed is usually above idle speed, which I assume you would be at in neutral. For instance, Old Blue idles at 800 RPM, and my minimum low speed (first gear) RPM is 1200. More RPM=More fuel consumed.

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You will use much less gas if you down-shift to slow down instead of using the brakes. If you take tour foot of the gas-pedal and down-shift your car will use no gasoline till 1200 turns/min.

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If you let up the gas at the same time you clutch in, you should be at idle speed, which is the minimum usage of gasoline in any car. It was stated by another poster, and by me in an earlier thread on this subject, that the price of clutch repair vs. brake repair does not warrant downshifting as a more economical means of driving. You might save a tiny bit of gas, but your cost for that gas increases with more frequent clutch replacement. I had clutch replaced recently for $650 US, did front brakes including replacing the disc rotors for $75 US.

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And also even if the cost is not the issue, there's the environmental effects to be considered.

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By using better driving habits, you can save gas; no jackrabbit starts, etc.

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By using better driving habits, you can save gas; no jackrabbit starts, etc.

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OO! jackrabbit starts...

::imitates her old civic backing out of the driveway:: RRRRRRRRR? *chugga chugga pbbbbbbt! chunk* ::engine revs:: VRRRRRRRRRRR! *screek!* URRRRRRRRR! MRRRRRRRR! ::stops... thinks... starts making motorboat noises just for the hell of it::

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The reason to drive in a high gear is to save gas. Basically.

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Yes and no...if you switch into a higher gear too early, you will waste fuel... you also risk lugging your engine. Ow.
Some cars have shift indicators that can be helpful...though they don't work real well for mountian country (always advocating a higher gear when you're going up a hill...d'oh!).

Contrary to what your economical driving school (!) may have told you, I second (third? fourth?) the above comment that engine wear and tear will cost you more in the long run than the money you save on gas (and a car that is burning oil is much more environmentally ugly than one that burns fuel normally).
Choosing a car that is already fuel efficient might be a good choice... contrast a vehicle that costs .06 a mile to drive normally with the standard maintenance vs. one that costs .15-.20 cents a mile when you average out the cost of small repairs. I think my civic ran at about .08 cents a mile. And yes, I had a father anal enough to calculate exactly what my car cost to run from tires to antennea (which he yanked off one day...oops).

If you frequently start and stop your car vs. letting it idle, you'll find yourself with a vehicle that "nickel and dime"s you to death. On a different scale, this is why people value "highway miles" over "city" - in the city it is stop and go traffic - stop & go is hard on the engine... even worse are the little 1 mile grocery store trips where the engine never gets fully warmed up. Let the engine idle and focus on another way to conserve gas. I suggest a hybrid gas/electric car. The Honda Insight (? the new CRX) gets about 70 mpg... doesn't matter how many "tricks" you learn, you can't beat that! And hey, you'll have more energy to focus on the road.

You can also talk to a mechanic, if you're not mechanically inclined, about other ways to conserve fuel if it's that much of an issue for you. There are chips, airfilter kits, etc. that can be added to the car that will help with gas mileage. The chip, IIRC, for a truck runs about 400$... so you would have to drive a *lot* to justify the cost. Having good tires and the correct air pressure in them can also save you money in fuel... there are all kinds of things that you can do that will not involve leaping through hoops or making such a production out of every day driving. There are, IIRC, also things you can do to help your car burn fuel cleaner, if that's an issue.

Ditto on the clutch lasting forever... my civic's burnt out quickly because I was a lunatic teenage driver doing idiotic things to my vehicle. My CRX was sold at 170k and had never had a new clutch... if you take care of your car and don't drive like a nut, your clutch should last a heck of a long time.

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Originally posted by v94jsi:
You should try to keep the engine in the range between 1200-3000 turns (???)/min.

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That really depends on the car, my Honda Prelude will turn 3000rpm in high [5th] gear while only going 60 mph. It also bogs down at anything under 2000 rpm. The four bangers are generally built to rev higher than 6 or 8 cylinders.

Concerning gas consumption and fuel cutoff.

I've heard from what I consider to be a reliable source that your fuel is cutoff completely if you are:

1) in gear,
2) turning a certain rpm [not sure what the magic number is, and it probably varies by car] and
3) throttle is closed [i.e. your foot is off from the gas pedal].

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Originally posted by dcmoore:
I've heard from what I consider to be a reliable source that your fuel is cutoff completely if you are:

1) in gear,
2) turning a certain rpm [not sure what the magic number is, and it probably varies by car] and
3) throttle is closed [i.e. your foot is off from the gas pedal].

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Originally posted by dcmoore:
I've heard from what I consider to be a reliable source that your fuel is cutoff completely if you are:
1) in gear,
2) turning a certain rpm [not sure what the magic number is, and it probably varies by car] and
3) throttle is closed [i.e. your foot is off from the gas pedal].

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Thank you! That was exactly what I was trying to say! (With most modern cars the 'magic number' is above 2300 rpm when you take your foot off the gaspedal and it doesn't reopen till you go below 1200 rpm) And when you have the clutch down (or your foot on the gas pedal) the car is consuming fuel!

The VW Lupo turns off the engin at red lights and there's nothing you can do about it. (3 l / 100 km according to ads)

I think the fuel consumption is a bigger issue in Europe compared to the US. Where I live we pay like a buck a liter.

1) in gear,
2) turning a certain rpm [not sure what the magic number is, and it probably varies by car] and
3) throttle is closed [i.e. your foot is off from the gas pedal].

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Originally posted by dilbert:
I would seriously doubt that. Why would they go to the trouble or programming all that in for minimal fuel savings? Also, it would differentiate engine function of the same model from an automatic.

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OK, my fault, I should have known better than to post on this board with a FOAF-type reference. I've researched a bit, and it is true for most modern cars. I do not think it discriminates between manual or automatic transmission. The part that accomplishes this magic even has a name:

OVERRUN CUTOFF VALVE

A) This component curtails fuel delivery during coasting/deceleration conditions. B) The overrun cutoff valve will direct excess air into the intake manifold to stop fuel delivery when conditions of closed throttle, warm engine, and engine speed over a preset rpm are met (either coasting or decelerating). AKA) Decel Valve, Coasting Cutoff Valve.

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Originally posted by dcmoore:
OVERRUN CUTOFF VALVE

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Well, looking like I was wrong (I don't admit that very oftem). That actually explains the behavior of my truck. This looks like it is a relatively new development though (or possibly limited to certain vehicles/engines) because my 97 Cavalier did not exhibit the same behavior as my truck. Either that, or it was more transparent in my car than in my truck.. dunno. Wonder what the advantage is? Sure enough, now that I think about it, it changes behavior at 2000 RPM when I have my foot off the gas.

Although, it doesn't look like it completely shuts off fuel in all cases, but a specific set of cases.