Double clutching

[ekam]

How to drive a manual part II: Double clutching - YouTube

[san rensho]

Chick wiith a stick, can't beat that.

[Flavor 987S]

She needs to vacuum her floor mats. High heels would have been a nice touch, too.

[Kenny Boxster]

No need to double clutch unless you are driving a tractor or semi truck. Huge annoying misconception popularized by a Need for Speed Movie by clueless Hollywood directors... Modern day cars have synchronizers in their transmissions. You can double clutch, but it's counterproductive and somewhat obsolete.

As one person puts it:
"Double clutching is used by truck drivers because most semi-truck manual transmisisons don’t have synchronizers. They double clutch so that the pressure plate completely disengages to disconnect the engine from the trans in which lets them shift gears. "

[ekam]

She did drive in heels in her earlier videos... the carpet is indeed filthy. lol.

Girls and Sports Cars: pedal work! - YouTube

I double clutch if I need to downshift so I don't wear the synchros out.

[Mrmaddbrad]

Originally Posted by Kenny Boxster

No need to double clutch unless you are driving a tractor or semi truck. Huge annoying misconception popularized by a Need for Speed Movie by clueless Hollywood directors... Modern day cars have synchronizers in their transmissions. You can double clutch, but it's counterproductive and somewhat obsolete.

As one person puts it:
"Double clutching is used by truck drivers because most semi-truck manual transmisisons don’t have synchronizers. They double clutch so that the pressure plate completely disengages to disconnect the engine from the trans in which lets them shift gears. "

Dear Kenny,

You should start double clutching. Having to replace your clutch due to a worn out synchro is the worst feeling in the world. Every time you use your synchro, such as a hard downshift, it is wearing ever so slightly. Eventually they will wear out and you will be forced to shift either without using the clutch or at the very least double clutch.

If you have never felt the need to double clutch, you do not drive your car hard enough. If you've downshifted under braking, just in time to get back on the throttle, lets say going from 3rd to 2nd at ~60mph. (Assuming in an S model where 2nd will do ~72 at redline); You will go from about 4500rpms to 6000. The faster this is done the better, in racing applications at least. If you jump 1500 rpms by simply dropping the clutch it's extremely uncomfortable, especially for your passenger (if any).

All I'm really trying to say is two simple things:
1) Although not "necessary", double clutching slows down the wear on your syncrhos.
2) Double clutching makes for much smoother, faster shifts that are MUCH easier on your transmission.

If you don't believe me, as any of our fellow members that participate in regular track-days.

Happy Boxstering,
~Brad

[san rensho]

I have an alternate point of view. I am fairly proficient at double clutch downshifting, having owned several Italian cars that have synchros that seem to fail a couple of weeks after you drive the car out of the show room.

That being said, if you rev match properly, you really don't need to double clutch. If you make sure that you are blipping the throttle as you are shifting through neutral on the downshift, it has almost the same effect as double clutching. Even though you have your foot on the clutch, there is still some drag in the clutch which will transfer some of the engine power to the input shaft and spin it up so that it more closely matches the speed of the output shaft in the transmission. If you put it in the lower gear first, then blip the throttle, then of course there is no advantage and you are putting the most wear on the synchros.

But these cars have fairly robust synchro's, so usually its not an issue. I found out mine will downshift from 2nd at 6500 rpm very easily into first on the track when I missed an upshift to 3rd. Luckily I was was able to catch the "money shift" and get the clutch back in without even an over-rev in the first zone.

[ekam]

Originally Posted by san rensho

But these cars have fairly robust synchro's,

... you can exclude the 986 S 6-speed 2nd gear synchro out of that comment!

[san rensho]

Originally Posted by ekam

... you can exclude the 986 S 6-speed 2nd gear synchro out of that comment!

Not to criticise, but 2nd gear synchro problems tend to be caused by ham fisted drivers that slam the shifter into second, rather than gently guiding it in.

[ekam]

Originally Posted by san rensho

Not to criticise, but 2nd gear synchro problems tend to be caused by ham fisted drivers that slam the shifter into second, rather than gently guiding it in.

Ouch!

[Mrmaddbrad]

Originally Posted by san rensho

Not to criticise, but 2nd gear synchro problems tend to be caused by ham fisted drivers that slam the shifter into second, rather than gently guiding it in.

I would just like to say that you're wrong.

100% wrong. Although, different driving styles do cause varying level of wear on the transmission, why does it seem that every other synchro never fails? Oh yeah, i forgot, those ham fisted drivers MUST be slamming the shifter into second, and "gently guiding it" into every other gear. Because that makes sense.....

[Kenny Boxster]

Originally Posted by Mrmaddbrad

Dear Kenny,

You should start double clutching. Having to replace your clutch due to a worn out synchro is the worst feeling in the world. Every time you use your synchro, such as a hard downshift, it is wearing ever so slightly. Eventually they will wear out and you will be forced to shift either without using the clutch or at the very least double clutch.

If you have never felt the need to double clutch, you do not drive your car hard enough. If you've downshifted under braking, just in time to get back on the throttle, lets say going from 3rd to 2nd at ~60mph. (Assuming in an S model where 2nd will do ~72 at redline); You will go from about 4500rpms to 6000. The faster this is done the better, in racing applications at least. If you jump 1500 rpms by simply dropping the clutch it's extremely uncomfortable, especially for your passenger (if any).

All I'm really trying to say is two simple things:
1) Although not "necessary", double clutching slows down the wear on your syncrhos.
2) Double clutching makes for much smoother, faster shifts that are MUCH easier on your transmission.

If you don't believe me, as any of our fellow members that participate in regular track-days.

Happy Boxstering,
~Brad

Rev matching is fine for me downshifting on a daily basis, and suffices. As of now the car isn't tracked, but I'd love to attend a track day. I've heard of people say "double clutch" when cars are going down a drag strip UPSHIFTING, and it makes me slap my forehead.

[san rensho]

Originally Posted by Mrmaddbrad

I would just like to say that you're wrong.

100% wrong. Although, different driving styles do cause varying level of wear on the transmission, why does it seem that every other synchro never fails? Oh yeah, i forgot, those ham fisted drivers MUST be slamming the shifter into second, and "gently guiding it" into every other gear. Because that makes sense.....

Its really very simple, you shift into 2nd much more often than the other gears in most driving situations. More shifts means more wear wear, and when you are slamming the gear, well, that explains the 2nd synchro failure.