double-down shifting
10-21-2012, 02:09 PM
#31
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...The synchros wear when being "forced" to match the internal gear speeds. Everytime this is done, there will be some (perhaps infinitesimal) wear on the synchros. By double clutching properly, the gear lever will almost fall into the down gear with almost no pressure on the lever. No "force", no wear. Same thing on the upshifts, except there is no need to double clutch an upshift, unless you are REALLY slow on the lever. By pausing slightly before engaging the next higher gear, you are matching the gear speeds, and the lever just falls into place. Try upshifting quickly and see how much more force is required... force equals synchro wear....
And there it is, in a nutshell. You know when you're doing it right when the lever "falls" into gear, as if literaly sliding into that position almost by vaccuum. The ease in which the lever falls is my indication that I done it right
And if not, you feel the force (Luke, use the ...nevermind), and that tells you your synchros are working harder to compensate for what I didn't do.
BTW, I often skip gears. I love the sail to redline
...but don't relish the speeding ticket. So I often do a 1-2 (tach it out 
) to 4 shift, then loaf at the speed limit. Also, when exiting a fwy offramp, I may be in 5th or perhaps 4th, then will leave it there and drop into 2nd for the turn onto the street.Edward
01-08-2013, 03:27 PM
#32
Instructor
As a new 993 owner (but old driver of old cars) this has been a fascinating thread. When I first read the 993 manual I saw the shifting max/min points and I thought, WTH -- you can downshift to 1st at 34 mph??? That sounded crazy to me. Now I see things haven't changed so much since my days in older cars (and that is crazy unless you really need to do it for some reason, and then you'd better double it).
Especially loved Steve's tip about putting her in 5th or 6th at a light. Brilliant.
Thanks!
Especially loved Steve's tip about putting her in 5th or 6th at a light. Brilliant.
Thanks!
01-08-2013, 04:21 PM
#33
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As a new 993 owner (but old driver of old cars) this has been a fascinating thread. When I first read the 993 manual I saw the shifting max/min points and I thought, WTH -- you can downshift to 1st at 34 mph??? That sounded crazy to me. Now I see things haven't changed so much since my days in older cars (and that is crazy unless you really need to do it for some reason, and then you'd better double it).
Especially loved Steve's tip about putting her in 5th or 6th at a light. Brilliant.
Thanks!
Especially loved Steve's tip about putting her in 5th or 6th at a light. Brilliant.
Thanks!
What do you guys recommend? Also, isn't skipping gears kind of like lugging it unless you go wot?
01-08-2013, 05:21 PM
#34
Race Director
Regarding that, how many rpms would you have? I always hate it when I'm in traffic and all those slushbox cars are driving between 20 to 30mph. My 993 is at around 3500 to 4500 rpm at those speeds but if I shift to 2nd then I have the sensation that I'm lugging the engine at around 2k. I have an RS clutch if that makes a difference.
What do you guys recommend? Also, isn't skipping gears kind of like lugging it unless you go wot?
What do you guys recommend? Also, isn't skipping gears kind of like lugging it unless you go wot?
skipping gears isn't lugging if you are at high enough rpms.
I shift from 2nd to 4th and 4th to 6th all the time.
01-08-2013, 05:40 PM
#35
For those who rev match (whether doubleclutch) or not, how do you hit the desired rpm? I usually just blip, but it is hard to hit the exact rpm for the given speed/gear.
01-08-2013, 05:48 PM
#36
Rennlist Member
If you try to actually move your car from stopped in 5th or 6th gear you will either stall the engine or have to slip the clutch so badly that you will leave a smokey haze in your wake. No, just pop the lever into 5th or 6th gear to stop the input shaft BEFORE selecting 1st gear and moving off.
01-08-2013, 05:54 PM
#38
Nordschleife Master
I can't speak for any of the others, but for me, its all done by ear and experience. You have to have a feel for the gear spread and a sense of the appropriate RPM by sound. I never use the tach when double clutching or just rev matching. If you don't get it just right every time, it still helps with smoother shifting and (if double clutching) less synchro wear. But when you do it JUST RIGHT, and the gear lever just falls into the lower gear, you get to pat yourself on the back for a downshift well done. This is becoming a lost art.
01-09-2013, 12:05 AM
#39
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I can't speak for any of the others, but for me, its all done by ear and experience. You have to have a feel for the gear spread and a sense of the appropriate RPM by sound. I never use the tach when double clutching or just rev matching. If you don't get it just right every time, it still helps with smoother shifting and (if double clutching) less synchro wear. But when you do it JUST RIGHT, and the gear lever just falls into the lower gear, you get to pat yourself on the back for a downshift well done. This is becoming a lost art.
'tis why it befuddles me when folks say driving their 911 no longer does it for them
I hope 'that' never grows old, as I'm prevelidged to experience it as much as humaly possible
I'll say that throwing R's @ my 993 downshifts has been one of the trickier cars to 'time' and 'get right'... for a car not having a LWFW, I'm shocked how much 'too much rev' I can inadvertantly throw @ the attempt. The miscalculation is unfun. Makes you learn quicklike 8-).
Once timed right? Oh the reward!
Def a lost art. DPK / SMG / etc... more 'effective'... at what cost?
01-09-2013, 05:24 PM
#40
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Great thread...I always double clutched and matched RPM on the downshifts.
It is easier to do, for me anyways, when driving hard such as at the track or very spirited backroad driving. When putting around town it seemed harder for me to match the RPM accurately. It helps to have the exhaust modded when you have a helmet on so you get a little audio feedback.
ca993twin wrote: "This is becoming a lost art"
No doubt double clutching is...but outside of a small group of sports car enthusiasts simply operating a manual trans in the USA is becoming a lost art!
When we were getting a rental last May in Munich, I asked what kind of car we were getting. The woman at the Sixt counter said "BMW 3 series automatic." I said "Oh, no. I want a manual diesel." With a twinkle in her eye she said: "You are American, of course you want an automatic!". She gave us an almost new A6 TDI with a 6-speed. SWEET!
It is easier to do, for me anyways, when driving hard such as at the track or very spirited backroad driving. When putting around town it seemed harder for me to match the RPM accurately. It helps to have the exhaust modded when you have a helmet on so you get a little audio feedback.
ca993twin wrote: "This is becoming a lost art"
No doubt double clutching is...but outside of a small group of sports car enthusiasts simply operating a manual trans in the USA is becoming a lost art!
When we were getting a rental last May in Munich, I asked what kind of car we were getting. The woman at the Sixt counter said "BMW 3 series automatic." I said "Oh, no. I want a manual diesel." With a twinkle in her eye she said: "You are American, of course you want an automatic!". She gave us an almost new A6 TDI with a 6-speed. SWEET!
