Silver Ecstasy
Member
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- 11 MS3 Sport
They should make a clutch that never wears, and a battery that never dies. One day..
Debate: downshifting vs. braking
- Thread starter shaitsta
- Start date
And an engine that never blows
Silver Ecstasy
Member
- :
- 11 MS3 Sport
You can typically contribute to the engine not blowing up (proper maintenance). Engines typically wouldn't blow up if it were maintained and used properly.
Batteries and clutches will wear no matter how often you recharge/replace them. There is no way to prolong them. Plus, an engine is meant to run and run it shall. Without proper air, fuel and oil circulation, then it fails. There arn't any perfect scenarios involved where a battery or clutch will be prolonged.
Batteries and clutches will wear no matter how often you recharge/replace them. There is no way to prolong them. Plus, an engine is meant to run and run it shall. Without proper air, fuel and oil circulation, then it fails. There arn't any perfect scenarios involved where a battery or clutch will be prolonged.
well, if anyone remembers, basic drivers ed teaches most people to avoid downshifting until the engine reaches around 1500rpm or so. IMO, for daily driving, there is no need to play racecar and rev-match/heel-toe downshift for anything above 1500rpm really. It does save slightly more gas to leave it in gear and have the injectors cut off, but when you can roll further in neutral without the engine-braking then its really moot. I honestly used to do this in my civic at almost every stop. Rev-match, downshift through each gear...and my buddy still does this. honestly though, he looks like a giant tool doing it in day-to day traffic. This is my .02, flame or not. Just a thought. And anyway you slice it, it still means more rpm on your engine, more clutch use, and more work... so I tend to coast to a stop and rev match only if the light changes or I need to move again before coming to a complete stop. If you are racing, driving "spirited" or feel like playing wannabe takumi, you can basically throw all that out the window and plan on rev-matching and braking.
My uncles toyota celica has 220K miles. Only thing replaced was a fuel pump and the A/C unit. A normal clutch should last a while.
dandydaniel
Member
- :
- 2008.5 Mazdaspeed 3
there is way too much to read to try and chime in relevance to the topic. so i'll just answer the question at hand with my own opinion.
i'm not sure about the rest of you but the majority of my friends who drive standard shift don't know what the hell they are doing. they learned how to get the car going in 1st and they also learned that the clutch goes in and out letting you change gears. thats about all they learned. I hate sitting in my friend's cars when they are just downshifting and either dumping the clutch, or slowing it back out (reduces the amount of jerking when you don't rev-match) and then have them tell me that what they are doing isn't damaging their clutch. the fact that the engine speed is significantly greater @ 40mph in 3rd than it is in 2nd gear should be enough for people to realize that their clutch is the thing that is making up for that difference and slowing you down.
In most if not all regular driving scenarios, there is no need to downshift if you are coming to a complete stop aka a red light. coast in your current gear until your rev's drop to about 1.5 - 2k rpm and pop it into neutral (all of this while putting light pressure on your breaks). By the time your revs have dropped to 1.5 - 2k, you shouldn't have ever had to slam on the breaks at all. this is the way I was taught and it is the only way that REALLY makes sense. I would only downshift to slow down if I knew I'd be getting back into motion rather soon per say going 40mph and having to slow down to 20mph and then get going again. just my .02
i'm not sure about the rest of you but the majority of my friends who drive standard shift don't know what the hell they are doing. they learned how to get the car going in 1st and they also learned that the clutch goes in and out letting you change gears. thats about all they learned. I hate sitting in my friend's cars when they are just downshifting and either dumping the clutch, or slowing it back out (reduces the amount of jerking when you don't rev-match) and then have them tell me that what they are doing isn't damaging their clutch. the fact that the engine speed is significantly greater @ 40mph in 3rd than it is in 2nd gear should be enough for people to realize that their clutch is the thing that is making up for that difference and slowing you down.
In most if not all regular driving scenarios, there is no need to downshift if you are coming to a complete stop aka a red light. coast in your current gear until your rev's drop to about 1.5 - 2k rpm and pop it into neutral (all of this while putting light pressure on your breaks). By the time your revs have dropped to 1.5 - 2k, you shouldn't have ever had to slam on the breaks at all. this is the way I was taught and it is the only way that REALLY makes sense. I would only downshift to slow down if I knew I'd be getting back into motion rather soon per say going 40mph and having to slow down to 20mph and then get going again. just my .02
dandydaniel
Member
- :
- 2008.5 Mazdaspeed 3
same. my friend's dad has an older prelude with 209,xxx on the clock. still running on the stock clutch and it barely slips.
happy and angry
Member
I understand that using components of a vehicle wears them, but the engine and transmission are designed to upshift and downshift and engine brake. That's what they are there for. We do more damage to our drivetrain by accelerating hard and slipping the clutch in first to get a good launch than you could ever do with 100,000 extra rev-matched downshifts.
Avoiding one of the design features of a standard combustion engine under the guise of "saving the clutch" is just kind of strange. We're talking about a design feature which smart automatics are starting to do more and more because of the fuel economy and safety benefits (it is always better to be in the right gear). If it was a serious wear and tear concern, engineers would not be putting time and effort into designing electronics that will do it for us.
I leave in gear and brake to slow down until 1k rpm, and then go to neutral and brake the rest of the way. I can't see it making a really huge difference on the brakes, and even if it does it's a simple matter of replacing the pads a little bit sooner.
I understand your point but in this quote what do you mean? You referring to automatics because you still have to rev match in a manual unless you want to slip a disc in your neck.
Also how does downshifting save gas? You have to blip the throttle to rev match which would use gas . . .
Automatics do not have clutches, syncros, or gears in the conventional fashion. When throttle is lifted in an automatic, the hydromechenical force applied to the torque converter is relieved and the engine is effectively offloaded. Under no load, and depending on how much 'looseness' is designed into the torque converter, the car coasts and does not downshift until it reaches much slower speeds or throttle is applied. The idle hydro mechanical force is what causes the car to crawl when the brakes are lifted.
Automatics also have a series of sequential locking ring gears (oddly named after planets) that are not conventional locking teeth selector-engaged gears as found in manual or DSG/sequential transmissions, but a different system of gears that close together through hydraulic force. See this article for more information. http://auto.howstuffworks.com/automatic-transmission3.htm
Also, the common increase in mileage on a manual is almost entirely because of weight decrease and less energy required to turn the ring gear assembly of an automatic, and also the loss in the torque converter. There are EPA estimates of improved economy on automatics that have locking torque converters with taller cruising final drive ratios.
Also, 'normal operating wear' on a transmission is never wrecking it, but over the course of 150,000 miles a car that has been downshifted to stop at every red light is going to show significantly more syncro and clutch wear than a car that was not downshifted every time. I still use engine braking, I just don't find it necessary to downshift. The injector cut in the cruising gear I was using seems perfectly adequate to slow the car down, then the gentle use of minor braking after idle would be, in my opinion, the ideal technique to stop the car with the least amount of use of any component on the car. The majority in this thread seem to prefer this technique aswell.
The very nature of this thread is arguing symantecs! Technically you're "supposed" to double clutch an unrevematched downshift. However I spent 288,000 kms on my 94 Civic never doing it once, just pulling the lever into 2nd before every corner. The transmission shows no signs of caring. The lesson is that automotive stuff is made pretty good.
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As far as heel toe goes for this car. I can't do it. Somebody suggested the side of the foot, i'll give this a try, but the pedals just aren't set up for it. Sad really, cause when I climbed into the RX8 r3 the other day, they were defintately set up for it.
Gmac
Gmac
Silver Ecstasy
Member
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- 11 MS3 Sport
Technically double clutching is rev-matching in a way? Clutch In, neutral, clutch out, rev, clutch in, downshift, clutch out?
happy and angry
Member
When you clutch in and blip the throttle, you burn a very small amount of fuel. It takes almost no gas to increase the revs of the motor when it is not in gear because the pistons and other moving internals of a motor by themselves weigh almost nothing and it takes very little energy to get them moving faster. Where as when you are clutched in and coasting in gear the injectors are shut off completely. For several seconds, in most cases.
If it makes much of a difference, I generally don't downshift beyond 3rd when coming to a stop and only go to 2nd when I'm going to be making a corner. Going from a 6th gear highway to a stop at a light at the end of an onramp, there's too much gear to really engine brake down much before stalling. Most of my downshifting is between 6th to 3rd. Also, the major point I am trying to make here is that no, engine braking isn't bad (the ops question) because a lot of people seem to think it is, and also to implore (beg) people to not ride the clutch out on downshifts to slow down but to rev match properly instead.
This is the least stress on the car of all the methods, guaranteed.
dandydaniel
Member
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- 2008.5 Mazdaspeed 3
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