The Art Of Double-Clutching

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Amskeptic
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The Art Of Double-Clutching

Post by Amskeptic » Mon Mar 01, 2010 1:03 am

The updated version, five luxurious pages where the original was but one.

Please read through the whole thang and see if there is sufficient flow that you are "insightfulized" by the end. This is my first computer-generated font + Paint® drawing assistance. It takes three times longer than straight drawing, but with no paper to crumple up and throw away every time I mis-printed a word, the time savings is ENORMOUSLY . . . negligible.
Colin


Image

Image

Image

Image

Image
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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grandfatherjim
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Post by grandfatherjim » Mon Mar 01, 2010 7:13 am

Page 1 - no apostrophe in LET'S
Page 2 at the bottom - I don't get the colour coding where you show which gears arre locked to the shaft vs. spinning freely - the concentric circle colours don't match the gearsets.
Also, when at a stop light, where you say everything above coloured green - do you mean everything above withat least some green in it?
Page 3 - I start to get lost. I have rebuilt a couple of transmissions and so know how synchronizers work, but think I would have a hard time following this if I hadn't. My suggestion would be to explain the synchronizers themselves (page 4 content) before the typical downshift scenario (page 3 content). All through page 3 I am wondering...how can this be? are these synchros magic? - as I always wondered before tearing into a transmission.

I think also in the preface, it would be a nice addition to tell how our forebears all had to double-clutch, and how it's a nearly lost art that we can learn to our car's benefit as well as for our personal satisfaction. To put it another way, if you ever want to try driving your cousin'd Model A, you need to learn this technique.

All told I would say you have gone a long way toward demystifying a very difficult topic.
Finally, I might suggest spreading the last two pages into three. They are intimidatingly dense to my eye.
Jim

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glasseye
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Post by glasseye » Mon Mar 01, 2010 8:39 am

That's fine art, right there. Beautiful. Clear and concise.

Makes me wish that Frito had a six-speed manual like it does everywhere else on the planet.
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Paul Wolfowitz, speaking of Iraq.

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hambone
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Post by hambone » Mon Mar 01, 2010 12:59 pm

Is this how you're able to drive a car with a broken clutch cable by "finding the sweet spot"? Must be.
Makes sense, and I think I already do it intuitively. In a nutshell, only shift at the RPM/gear combo that is correct at that moment, or else it beats on your engine and trans.
http://greencascadia.blogspot.com
http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
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dhoch14
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Post by dhoch14 » Mon Mar 01, 2010 1:10 pm

Ok. Soooooooo consider me confused. If you were to double clutch, you would do the following?

3rd to 4th example:
Driving in 3rd, getting close to 4th
CLUTCH IN, SHIFT TO NEUTRAL, CLUTCH OUT,
CLUTCH IN, SHIFT TO 4TH, CLUTCH OUT.

Do you go a neutral position first?

-dave
93 VW T4 2.4D Cali

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hambone
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Post by hambone » Mon Mar 01, 2010 1:16 pm

Can't you leave the clutch in? It's still neutral.
http://greencascadia.blogspot.com
http://pdxvolksfolks.blogspot.com
it balances on your head just like a mattress balances on a bottle of wine
your brand new leopard skin pillbox hat

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Amskeptic
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Post by Amskeptic » Mon Mar 01, 2010 2:33 pm

hambone wrote:Can't you leave the clutch in? It's still neutral.
Your engine has to communicate with the input shaft. On a downshift, we have to speed up the input shaft to match the gear we want, and the engine is the only device in the vicinity that can do that for us, other than the synchronizer.

On an upshift, yes you can time a regular shift to allow the input shaft to slow down of its own accord to match the next gear up, but I am so double-clutch hard-wired now that I can't shift normally.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Amskeptic
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Post by Amskeptic » Mon Mar 01, 2010 2:39 pm

dhoch14 wrote:Ok.
-dave
WHEN you double clutch, you do the following:

3rd to 4th example:
Driving in 3rd, getting close to 4th
CLUTCH IN, SHIFT TO NEUTRAL,

CLUTCH OUT WHILE IN NEUTRAL,
( The Neutral Staging Area! Match the engine speed here)

CLUTCH IN, SHIFT TO 4TH,

CLUTCH OUT.
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Amskeptic
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Post by Amskeptic » Mon Mar 01, 2010 2:59 pm

grandfatherjim wrote: Page 1 - no apostrophe in LET'S
You are correct. I pasted that "Let's" (as in Let's learn about synchronizers!) in where the word "allowed" used to be before I ran out of room. and forgot to update its new context . . . Good eye!
grandfatherjim wrote: Page 2 at the bottom - I don't get the colour coding where you show which gears arre locked to the shaft vs. spinning freely - the concentric circle colours don't match the gearsets.
Also, when at a stop light, where you say everything above coloured green - do you mean everything above withat least some green in it?
Clumsy first fully computer-generated picture. Yes, so the big green and red circles were supposed to denote the gears being firmly attached to the shafts, as in:
1st and 2nd UPPER gears are attached to the INPUT shaft, while their lower gears spin around the output shaft on bearings.
3rd and 4th LOWER gears are attached to the OUTPUT shaft while their upper gears are spinning on bearings on the input shaft.
grandfatherjim wrote: Page 3 - I start to get lost. I have rebuilt a couple of transmissions and so know how synchronizers work, but think I would have a hard time following this if I hadn't. My suggestion would be to explain the synchronizers themselves (page 4 content) before the typical downshift scenario (page 3 content). All through page 3 I am wondering...how can this be? are these synchros magic? - as I always wondered before tearing into a transmission.
Page 3 did not want to get lost in the "how", just the what.
I wanted people to sit on the magic like I had to for thirty five years or so.
Yep, you were doing 1,760 rpm in 4th, you moved the gearshift and now the engine is going faster.

Then I started page 4 with "What happened when you shifted?"
grandfatherjim wrote: I think also in the preface, it would be a nice addition to tell how our forebears all had to double-clutch, and how it's a nearly lost art that we can learn to our car's benefit as well as for our personal satisfaction. To put it another way, if you ever want to try driving your cousin'd Model A, you need to learn this technique.
I only got so far as the "improved sense of participation" in the art of driving. I was having difficulty (oh was I) with my stupid fonts not being legible below 28 point and had to remove a lot of words in the name of size. Then I found an old previous font that was darker, but the alignment of :"';, were awful. Anyways . . .
grandfatherjim wrote: All told I would say you have gone a long way toward demystifying a very difficult topic.
Finally, I might suggest spreading the last two pages into three. They are intimidatingly dense to my eye.
Jim
I agree. Can you believe that the first one was all on one page?

Image
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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bretski
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Post by bretski » Mon Mar 01, 2010 3:11 pm

Amskeptic wrote:Can you believe that the first one was all on one page?

Image
My cluttered, ADD-ridden mind finds this picture soothing. How's about a bigger version for the afflicted??? :cyclopsani:





PS - After much practice, my 15mph 2nd-to-1st downshift has become frighteningly smooth...and it scares the crap outta my passengers. Tee-hee. :king:
1978 Deluxe Westfalia - "Klaus"

"transcripts are overrated. hardware store receipts: those are useful." --skin daddio

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Amskeptic
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Post by Amskeptic » Mon Mar 01, 2010 3:25 pm

bretski wrote:
Amskeptic wrote:Can you believe that the first one was all on one page?
My cluttered, ADD-ridden mind finds this picture soothing. How's about a bigger version for the afflicted??? :cyclopsani:

PS - After much practice, my 15mph 2nd-to-1st downshift has become frighteningly smooth...and it scares the crap outta my passengers. Tee-hee. :king:
Amazing. I recoil from that thing . . . but remember how fun it was to draw.
Colin
(click it and expand your browser window or download it and expand)
(if you download and expand the new page 1 and 5 you will see almost hidden things like the numbers on the speedometer, clock and fuel gauge)
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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bretski
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Post by bretski » Mon Mar 01, 2010 3:38 pm

Already downloaded...that's why I ask. :D

This one (on Photobucket) is lower-rez than the ones on TS's gallery (and gets blurry when magnified).
1978 Deluxe Westfalia - "Klaus"

"transcripts are overrated. hardware store receipts: those are useful." --skin daddio

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BellePlaine
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Post by BellePlaine » Tue Mar 02, 2010 7:51 am

Amskeptic wrote:
dhoch14 wrote:Ok.
-dave
WHEN you double clutch, you do the following:

3rd to 4th example:
Driving in 3rd, getting close to 4th
CLUTCH IN, SHIFT TO NEUTRAL,

CLUTCH OUT WHILE IN NEUTRAL,
( The Neutral Staging Area! Match the engine speed here)

CLUTCH IN, SHIFT TO 4TH,


CLUTCH OUT.
I have a question. You gas the engine to match the speed of the down shift; I understand this. But do you continue to gas as you put the clutch in and shift to 4th? I imagine that you do, but holding high rpm's to an engine under no load would be hard for me to get used to.
1975 Riviera we call "Spider-Man"

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grandfatherjim
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Post by grandfatherjim » Tue Mar 02, 2010 8:38 am

When going from third to fourth the engine speed will need to drop.
Jim

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BellePlaine
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Post by BellePlaine » Tue Mar 02, 2010 8:49 am

grandfatherjim wrote:When going from third to fourth the engine speed will need to drop.
Jim
I'm sorry, I misread. I was thinking of downshifting from 4th to 3rd. Do HOLD the RPMs while in N and clutching into 4th. I suppose that you do, huh? It's just that I'm accustomed to letting off the gas while clutching.
1975 Riviera we call "Spider-Man"

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