Philosophies on Downshifting
12-10-2002, 09:37 AM
#1
Philosophies on Downshifting
First of all, I am referring to downshifting to aid in slowing the car down as you are coming to a stop under normal driving conditions as opposed to downshifting while performance driving where one downshifts and maintains or increases the current speed. Back in the day, when my Father was teaching me to drive a stick, I was taught that as you are coming to a stop, it's best to downshift and let the engine slow you down, thereby reducing brake wear. The lessons stuck, and I've always done it; if I'm driving leisurely and am approaching a stop sign or light, I will shift from 5th to 4th (current car), let the engine pull my speed down, then from 4th to 3rd and so on, using the brakes only near the end as I'm about to stop. By this time I have shifted down to 2nd gear and let the engine do most of the work. It occurs to me now that I'm about to buy one of my dream cars, that I've never really gotten anyone elses opinion of this practice and I start to wonder if my Dad's philosophy wasn't a little backwards. Would it not be better to use the brakes, with relatively cheap and easy to replace components rather than cause more wear on the clutch and engine? You don't do this with an automatic transmission, so I have to wonder. What is better for the car? Does it really hurt anything or promote more wear? What about doing it while during break-in? I'd like to know everyones thoughts on this.
12-10-2002, 10:18 AM
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Yup- you have a bad habit
Brakes are for stopping. All that extra shifting and clutch wear will eventually catch up to your tranny and clutch down the road. Every time you shift (especially downshifting) the clutch slips against the flywheel and wears. The less the clutch slips the longer it will last.
Use your brakes for stopping --- brake pads are cheap. Replacing a clutch is big dollars.
Use your brakes for stopping --- brake pads are cheap. Replacing a clutch is big dollars.
Do I need therapy? At least I have a couple months or so to change my driving habits before I get my Z. Thanks. Any other input?
12-10-2002, 10:34 AM
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When this thread has shown up before, i think the general opinion is that it is better for your car to use the brakes, because, like you said, the brakes are easy and relatively easy to replace, compared to the clutch (not to mention the extra wear and tear on your engine and drivetrain). But, of course, people still chosse to downshift (myself included, occasionally) because it is kind a fun, and sounds cool, it works, and also, because you could, in an emergency situation, accelerate faster if you were to need it.
12-12-2002, 05:08 AM
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Man this is a tough one because I like to downshift and have a habit of doing it. How long do you really think it takes to wear out a transmission? If its in the 6+ year range...I think its okay. Breaks are chep though. Aghhh 
12-12-2002, 05:11 PM
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There's actually a pretty simple solution to this. What you are doing is sometimes called "engine braking". You are letting the friction inside the engine do the same work the brakes normally do. Not a big deal. I do it all the time. But downshifting four times per stop is excessive and does put nominal wear on the drivetrain. The easiest way to get the benefits of both is to simply stay in whatever gear you were running, coast to slow, and depress the clutch whenever the tach indicates that the rev's are near to idle. The higher gears won't slow you as quickly as the lower gears, but the effect is similar.
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12-13-2002, 09:35 AM
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with the manual transmission, learning to heel and toe on the downshift is really the only way to set up and hit some turns at their fastest. Books like Ayrton Senna's Principles of Race car Driving, and, Vic Elford's Porsche High Performance Driving Handbook, are good sources for learning the principles and technique.
As for Engine Braking, a proper heel and toe won''t utilize the engine for resistance, but when all hell is about to break and you really have to slow the car down as fast as possible, when the brake pedal is pressed as far as it will go and you need more stopping power a properly selected low gear and manipulation of the clutch to get some engine braking is a perfectly acceptable technique.
Is engine braking hard on the drivetrain. yeah, but probably less so than maximum acceleration starts from a complete stop.
As for Engine Braking, a proper heel and toe won''t utilize the engine for resistance, but when all hell is about to break and you really have to slow the car down as fast as possible, when the brake pedal is pressed as far as it will go and you need more stopping power a properly selected low gear and manipulation of the clutch to get some engine braking is a perfectly acceptable technique.
Is engine braking hard on the drivetrain. yeah, but probably less so than maximum acceleration starts from a complete stop.
12-13-2002, 09:52 AM
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I have owned only MT vehicles for thirty years and driven some of those vehicles for up to 150000 miles, yet have never replaced or repaired a clutch or transmission while consistently downshifting under must circumstances. My conclusion then, is that although there is no doubt that this technique may cause some nominal wear and tear to some parts of the drive system, the fun, satisfaction, and control specially in spirited driving situations is more than worse the price, if you are doing it right.
Just my $.02.
Just my $.02.
12-13-2002, 10:25 AM
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continuing with transmission health...
When at a stop if you keep the clutch depressed while in neutarl or gear is this damaging to the transmission? I would think if fully depressed it would not cause any additional wear on clutch surfaces or bearing, the only problem being if you keep the car in gear and clutch fully depressed and someone hits you from behind and your foot slips off the clutch, you could launch yourself into trouble.
When coasting to a stop from different speeds is it harmful to throw the gear in neutral and just use the brake? in an automatic transmission I can see where it may be harmful, at higher engine speeds higher engine vacum has a direct effect on the transmission function? is this correct - I am not certain where the damage would occur, is it a lack of lubrication to the transmission or the design of the torque converter the way it is coupled to the engine.
With a manual transmission coasting to a stop while in neutral, are some gear clusters still moving? and would a manual transmission depend on the engine through vacum to lubricate the moving cluster? except for some possibilities with the traction control system I cannot see where coasting to a stop in neutral is harmful.
Aeration of transmission fluid or a transmission oil cooler, can these be negatively effected by coasting? my guess, as long as you are not freewheeling down mountain sides, coasting to a stop is harmless.
When at a stop if you keep the clutch depressed while in neutarl or gear is this damaging to the transmission? I would think if fully depressed it would not cause any additional wear on clutch surfaces or bearing, the only problem being if you keep the car in gear and clutch fully depressed and someone hits you from behind and your foot slips off the clutch, you could launch yourself into trouble.
When coasting to a stop from different speeds is it harmful to throw the gear in neutral and just use the brake? in an automatic transmission I can see where it may be harmful, at higher engine speeds higher engine vacum has a direct effect on the transmission function? is this correct - I am not certain where the damage would occur, is it a lack of lubrication to the transmission or the design of the torque converter the way it is coupled to the engine.
With a manual transmission coasting to a stop while in neutral, are some gear clusters still moving? and would a manual transmission depend on the engine through vacum to lubricate the moving cluster? except for some possibilities with the traction control system I cannot see where coasting to a stop in neutral is harmful.
Aeration of transmission fluid or a transmission oil cooler, can these be negatively effected by coasting? my guess, as long as you are not freewheeling down mountain sides, coasting to a stop is harmless.
12-14-2002, 06:53 AM
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I've been doing the downshift and engine braking thing for 140,000 miles on my other Nissan. My clutch pressure plate is finally going, but, the clutch plate itself is still good. I wouldn't change your habits based solely on the fear that it will screw up the car.
However, two things I do religiously to extend tranny life:
1) always let both the engine and tranny warm up before letting loose.
2) never keep my foot on the clutch while at stop lights etc.
However, when at the track, I always heel and toe. Using engine braking at the track WILL kill your clutch and/or tranny.
Fly
However, two things I do religiously to extend tranny life:
1) always let both the engine and tranny warm up before letting loose.
2) never keep my foot on the clutch while at stop lights etc.
However, when at the track, I always heel and toe. Using engine braking at the track WILL kill your clutch and/or tranny.
Fly
