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Driving habits - good or bad for the car?

Discussion in 'Warranty questions' started by az3579, Feb 11, 2009.

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    az3579

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    First and foremost - I'm sorry, but I didn't know where exactly to put this thread!

    Now, there have been a number of things that have crossed my mind and have wondered what the answer was to these unasked questions.

    For vehicles with a manual transmission, what's healthier for the vehicle in general: slipping the clutch for a smooth shift while shifting up or down (mostly down that I'm wondering about) or just engaging the clutch fully and immediately? Most of the people I've been in a car with (with them driving) just let the clutch pedal out immediately, and naturally the car jerks because the clutch is suddenly engaged. I get particularly irked when someone's downshifting and they just let the pedal out without even trying to make it a smooth downshift. Which method is healthier for the transmission components: slipping the clutch or making sudden clutch movements?

    Second, there are those people who drive their cars hard and others who drive like grannies and never rev their engines. What is healthier for the engine: shifting in mid rev range or shifting down low? I ask this question because I noticed that if I'm in say 4th gear on the street doing about 30mph and I floor it, naturally the car has no go as it's not in the right gear and powerband, but as it accelerates it gets much better fuel economy than if I was to downshift to second and give it the beans. Is this "economy" acceleration hurting the engine? How stressful is it to the engine? Is it less stressful to rev it to redline and shift or to floor it in a high gear?
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    Satch SoSoCalifortified

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    Most people can't drive

    Maybe this is why only 15% of the American public can drive a stick: They don't know how to use the clutch. They eeeeeeease it out when downshifting without having brought the engine speed up to match the lower gear, using the clutch as a sort of brake. Yes, matching the revs will allow quicker clutch operation with less wear.
    • Member

    az3579

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    I understand that, but I'm talking about when you're not rev matching. I usually rev match, but my car is so loud (I'm really embarrassed) that most of the time I don't do it when driving around town. Perhaps I should pose another one of those unasked questions:

    Which is better; rev matching but not getting it perfect or just downshifting normally?

    drummerfc guest

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    Good point...

    I was also told when I learned how to drive a manual tranny years ago that downshifting can help to slow down the car, thereby saving your brakes. Of course it makes sense to do it (downshifting) "right", whatever that might be, if you're going to do it at all. I try to match the revs (if I'm not going too fast and have the time ;)!) whenever possible. Just makes for a smoother transition.
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    Jeff Gomon

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    We don't need no stinkin' brakes....

    For some reason, I use the brakes to slow down...:D That is what they were designed to do after-all.:p Besides, brakes are much easier and less expensive to replace than a worn clutch or transmission. MUCH happier to slap some new pads and rotors on in a few hours.

    For my M5, I slip it into neutral and release the clutch when rolling up to stop lights, off ramps etc. I can always match rev and get it re-engaged quickly and proceed if necessary. I do NOT hold the clutch down at stop lights for a long period of time either. On the track, this mentality is totally different. If you are not accelerating, you should be braking...there should be no coasting . Alas, we are speaking about street use here, so I digress.

    I do NOT condone just shifting and "dumping" the clutch....it is harder on internal components and you "shock" the drive line and engine internals as well accelerating wear. I strive to be as smooth as possible up or down shifting as I do not want to have to remove my trans again anytime soon for repairs. Again, "slipping it" into engagement, you only affect the clutch pad material, which is a wear item and can be replaced fairly easily.

    Not certain about the accelerating in 4th gear for mileage gains in town. Don't know how that gets better mileage as you are lugging the engine requiring more gas to do more mechanical work. Could be wrong on this. Gaining mechanical advantage thru proper gearing has got to be easier and put less stress on the transmission gear set as well. The diff gears don't care either way, just the trans. I would watch for detonation as well while doing this as internal engine damage will occur.

    I must agree with Satch, most people do not know how to operate a manual transmission clutch properly and are causing themselves their own problems.
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    granthr

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    This is a tough subject, because some of it is just person choice and the wear of an engine and driveline usually takes tens of thousands of miles to show up. So it is hard to pin point what causes what. But here is my take on it.

    It is not a good idea to aggressively use downshifting to slow a vehicle. It puts extra wear on the clutch and drive line. Brakes are designed to wear out and are easy and cheap to replace when comparing to a new clutch and flywheel or even transmission.

    Now letting off the gas at a distance to slow down does not really increase wear, particularly if you are in a higher gear, 4th for instance.

    As for shifting, I would say rev matching as best you can. Just easy around town driving you can easily upshift without clutch slip or jerk. Downshifts will take a little blip, but don't downshift too soon or often. I will often come to a stop in third or fourth gear. Why aggressively downshift, you are just wear stuff out.

    I guess I drive like a granny in heavy urban/suburban traffic. There is no point racing from light to light just to sit there. If I take it easy I will almost always catch up with the "racers" and never actually have to come to a full stop. Now that is where you save wear on the car.

    Botond I don't think accelerating in 4th will hurt your car if you are not going too slow to begin with. Just don't lug the engine. It also depends on what other kinds of loads are on the car, just you or full of people, uphill, flat, or downhill. You do have a motor with a lot of torque down low, so you do have an advantage in that sense.
    • Member

    az3579

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    The 4th gear statement was just an example. So, in essence, if the vehicle responds more to a particular input then it is most likely not so good for it? That does make sense, but I wanted to confirm what I'm doing is better for the engine than what I'm not doing.

    My current driving style is as follows:
    * For upshifts: From one to two, I slip the clutch to make this transition as smooth as possible, and two to three also but not as much. Everything else is smooth regardless of how quickly I engage the clutch.
    * For downshifts, when the engine isn't revving above 2k rpm, I slip the clutch when downshifting to prevent sudden shock to the driveline and to make it as smooth as possible. When I'm on the highway at higher speeds, I always rev-match, but on the street on roads with about a 25mph speed limit, I always slip it. I find it nearly impossible to do a perfect rev-match while in the low rpm ranges, around 1.5k to 2k, as my throttle response (being an old car with older technology) lags a bit.
    * When doing an economy run (don't ask me why - I don't want to, I swear!), I usually shift as early as possible, usually around 1.5k two 2k as the car has plenty of torque to deal with minor acceleration. Depending on how quickly I need to accelerate if there is a need to, I either leave it in gear and give it a slight push (not flooring it) or I downshift while slipping the clutch for a smooth transition so that the engine has enough power to accelerate at a decent rate.
    • Member

    CRKrieger

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    OK, I will unequivocally say that slipping the clutch is BAD! It is bad no matter when or why you do it. The less slipping,the better.

    Secondary to that is smoothness. You need to do BOTH, and this is why Satch says almost no one knows how to drive a manual. Be smooth and don't slip the clutch. That means you need to learn how to rev match when shifting up or down and make your clutch engagements quickly. As well as making you smooth, this is your 'limp home' mode if your clutch system fails (or is failing).

    You don't need the clutch to shift if you rev match well enough. I have driven my car for weeks on end leading up to a throwout bearing replacement using the clutch for little more than to start out in first or reverse. There is nothing inherently wrong with engine braking as long as you don't mechanically over rev the engine. If you rev match the downshifts, there is no appreciable wear on the clutch. The more capable drivers will heel-and-toe downshift while braking. (I do, habitually.) The most capable will double clutch as well. (I don't. Too lazy.)

    The engine is designed to rev to redline without damage, but if there is anything at all going wrong with it, driving that way will hasten a failure. There is generally no reason to rev to redline. The best shift points are usually 1000 rpm below it. Lugging the engine can be harmful in that your oil pressure will be low while your engine loading will be high. You could have brief lapses in lubrication at critical bearings. The best acceleration will be in the gear where your engine is nearest its torque peak - usually near the middle of the rpm range.

    If you manage to develop your default driving habits around these guidelines, you will enjoy a comfortable, economical, and efficient driving style.

    missmelyssa guest

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    I drive like Jeff G

    Apparently I drive like Jeff G. I coast to the stop as well. I don't like to ride the clutch. And I do rev-match as much as possible, so I just go by the sound of the engine.

    When I was looking for an e30, I drove several of them. On test drives the owners would say, "You do that well." And I would ask what they were talking about. They were telling me that I drove the car well. So it must be true that many Americans do not know how to drive a stick correctly.

    missmelyssa guest

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    My husband can drive without a clutch. I haven't mastered it yet, but I don't try often.
    • Member

    granthr

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    Did you just buy the E30 in your picture? If I remember right you were looking to get one.
    • Member

    az3579

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    Rev-matching on the downshift isn't as hard as on the upshift, IMO. On the downshift, you get used to how much throttle to apply at what rpm and in what gear, but when upshifting, I don't see how you do it without constantly looking at the tach to estimate the correct rev range. Some cars it would be next to impossible in because with the stock exhaust system, some of them are really quiet. Mine's a bit loud, but I still can't hear the engine all that well when not applying any throttle... :confused:

    melyssa, you finally got an E30?? :)
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    MGarrison

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    Perhaps it's just practice & experience w/ the car Botond, the more you do it, the more you get the hang of it. I think rev-matching the upshifts is pretty straightforward - you don't have to take your foot off the gas pedal, just hold the revs so they don't fall down to idle speed and match as best you can. I think it's probably better if you don't look @ the tach, that will distract you & you want to make it automatic & instinctive.
    • Member

    az3579

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    Well I still am on the throttle a very little bit when upshifting to make the shift smooth and to prevent the revs from dropping too much, but occasionally still get a little shock when in gear and engaging the clutch.

    missmelyssa guest

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    yes, an e30

    Grant, Botond -

    Yes, I got it. It felt like I was looking for one forever. I'm glad I was patient and got what I wanted, convertible (just because I never had one) and a 5spd. I'm hoping to get my hands dirty this weekend!
    I'll update the other thread.

    To avoid straying away from the topic of this post....I'm going to try shifting without a clutch once I master rev-matching on one of my vehicles.
    • Member

    CRKrieger

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    That is exactly how I recommend you do it. After learning to rev match, though, the next best thing you can learn is how to do it while braking - heel-and-toe downshifting. This is actually a lot more valuable skill than being able to drive without the clutch. I only rarely shift without the clutch either because I must, because I'm bored and I want to practice, or because I'm showing off. However, I habitually heel-and-toe downshift.
    • Member

    az3579

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    Ditto. But I find heel-and-toe downshifting sooooo much easier... after trying all day today, not once have I been able to rev-match while upshifting.
    Downshifting isn't hard, just the upshift...
    • Member

    MGarrison

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    Practice, practice, practice!!

    And don't forget to smile while you take your castor oil, it doesn't taste that bad! :p
    • Member

    az3579

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    Actually, I realized I was looking at it all wrong...
    The reason I was doing so badly yesterday at rev-matching while upshifting is because I was trying. I noticed today that I wasn't trying at all yet almost on every upshift, specifically on the "harsher" lower gears, I could easily let out the clutch immediately and it would already be rev matched. I guess it's just the feel I have for my car that makes me so used to it that I know to shift at a certain pace (not too quickly or slowly). I would say 7/10 times I would shift while rev-matching and not even noticing!


    But quite honestly, I think I'm putting less wear on the car at the track than in the street; on the track, I have no problems at all heel-and-toe'ing. :D

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