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Old 07-08-2012, 05:27 PM   #1
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i've been driving wrong: downshifting to slow is bad

it's been on here a few times
http://986forum.com/forums/general-discussions/12123-down-shift-brakes.html
http://986forum.com/forums/general-discussions/29822-how-much-do-you-use-engine-brakes.html

and i have started doing it myself, using the gears to slow the car rather than the brakes, until I'm at a slow speed

But experts say it's wrong:
The Straight Dope: To slow a stick-shift car, should you brake or downshift?

Quote:
Numerous mechanics, auto engineers, and auto buffs echo this view. They say downshifting may have made sense in the 60s and earlier, when many cars had manual drum brakes. These were much less effective than today's power disk brakes and you needed all the help you could get stopping the car. But not any more.
so there you have it, i'll... try and stop, even though it is fun

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Old 07-08-2012, 05:42 PM   #2
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Brakes are far cheaper than a clutch, even on lesser cars than the boxster.
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Old 07-08-2012, 09:54 PM   #3
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Down shifting is for old people, lol!
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Old 07-09-2012, 03:27 AM   #4
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But if you match the revs properly, the clutch wear should me minimal, and you'll always be in the right gear in case the light turns green or you need to "get out of the way"
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Old 07-09-2012, 03:33 AM   #5
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But if you match the revs properly, the clutch wear should me minimal, and you'll always be in the right gear in case the light turns green or you need to "get out of the way"
Matching revs save the synchros, not the clutch.

Your clutch wears when you slip it.
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Old 07-09-2012, 04:53 AM   #6
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If you push the clutch in, and rev the motor, the synchros (on the input shaft side) do not change speed. If you match the revs properly, the clutch slip is minimized. You would have to rev match with a double clutch action to match the synchro speeds. Double clutching takes too long and is generally only needed on LARGE trucks. Symchros wear from prematurely when you force the next gear before they have time to synchronize the input shaft speed to the output shaft speed. Ask anyone who drives an older Audi with an 012 or 016 based transmission.
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Old 07-09-2012, 07:13 AM   #7
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Agreed that match-rev downshifting is primarily to preserve the clutch and prevent torque spikes in your drive train.

*When to downshift for engine braking- To control your speed when running down a mountain road. Use minimum braking here.

*When to use brakes- To slow the car under normal driving conditions or at the track.
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Old 07-09-2012, 09:21 AM   #8
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^ What Topless said.
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Old 07-09-2012, 10:33 AM   #9
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Down shifting is for old people, lol!
OUCH !!!!!!! That HURT.
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Old 07-09-2012, 11:44 AM   #10
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The purpose of down shifting is not to save the brakes really, its about being in control of your car and to leave you in the right gear to take off quickly if something dangerous is headed your way, like drivers on their cell phones, tire treads flying off trucks and peoples junk flying out of pickup beds.

The car will be balanced, nimble and ready to respond instantly in the right gear.

Also if you apply your 4 oversized disk brakes hard in your Boxster S, what do you think the chances of the car behind you stopping before your rear is???!!!

Using downshifts moderates your braking so folks behind have more time to react as they hear your engine rev on the downshift and the car start to slow.

The only bad thing is that your brake lights don't come on so I always apply some light brake at the same time to light up the brake lights when in traffic.

And most of all its fun, when you get the shifts right its magic, the deceleration forces and the engine sound let you know that you are driving a real sports car and everyone else will envy your big ass smile while your doing it.
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Old 07-09-2012, 11:53 AM   #11
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Be nice...

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Down shifting is for old people, lol!
or all us old guys will have to take out the dentures and beat you with our canes & walkers.
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Old 07-09-2012, 01:08 PM   #12
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Just ribbing you old farts! I'm not too young, myself.
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Old 07-09-2012, 10:36 PM   #13
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Well I brake and downshift to slow down. It all depends on the situation. I don't know about you guys but when i am in second gear and i let go of the accelerator I get a decent amount of engine braking. So for city driving I let the engine slow me down and use the breaks toward the end if i need to come to a stop. Now if were talking about high way driving and using a downshift to slow down I never do that. I feel like your forcing the engine to much. If anything there has to be a balance, and I guess it comes from rev matching.

Thats just what I do.
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Old 07-10-2012, 03:10 AM   #14
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Brakes are for stopping, gears are for going. Downshifting only slows the rear wheels and if done improperly at the edge of adhesion can put you in a spin. Brakes on the other hand act on all four wheels and will not disturb the balance of the car as much as locking up the rear wheels would. ABS improves the efficiency of the brakes and traction control completes the trifecta of controlling the car at the limits.

Smile all you want but downshifting to slow is just bad technique.
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Old 07-10-2012, 03:47 AM   #15
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Originally Posted by 986_inquiry View Post

so there you have it, i'll... try and stop, even though it is fun
Do you're downshifts correctly rev matched with heel and toe and you'll find it 10x more fun than what you're doing at the moment. And you won't be wearing the clutch. Win-win.

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