12 replies to this topic

[countourkid98]

this may be a stupid question to some but what is double clutching?....ive heard a few ppl mention it and im curious....and sry for the quadruple post, idk if its my computer or the site but it keeps entering before im done typing

Edited by countourkid98, 23 December 2009 - 04:29 PM.

[Gar]

You already know that the gear box lets you re-use the same engine speeds to go faster each shift... So it follows that as you down shift, the engine must be spinning faster than it was prior to shifting... I say engine, but what's really the issue is the tranny input shaft speed so that the "about to mesh" gears are spinning the same speed. Syncros do this by dragging the slower input shaft up to the spinning output gear's speed. Double clutching is a shuffle of the throttle, clutch, and gear shift lever that manually attempts to match the gears rates. Before syncros, THIS is the way everyone shifted.
As engine speed gets lower and you leave the power range of the engine, your clutch and select neutral allowing the clutch to return to its rest position. You pop the throtle with the clutch engaged to speed up the input shaft and gear in the trans. Then you clutch again, and select the lower gear.... this time letting the clutch out more slowly while applying throttle.
After you get the hang of the hand/foot ballet, plus the degree of throttle you need to spin up the input shaft, you'll become smooth (and sound cool), plus you'll be saving the syncros for the other drivers that use your car. It can be done pretty quick... about the time it takes syncros to spin up the input shaft so you don't lose time in a "coast" condition.... most double clutchers feel it's faster (me included), and is the absolute quickest way into first gear as you roll up to the signal light about to turn green..... or getting out of the most wicked tight hairpin the quickest. Can also be used to initiate a drift... but you have to practice that.

Gar.... 50 years double clutcher :)

[countourkid98]

Gar, on 23 December 2009 - 07:33 PM, said:

You already know that the gear box lets you re-use the same engine speeds to go faster each shift... So it follows that as you down shift, the engine must be spinning faster than it was prior to shifting... I say engine, but what's really the issue is the tranny input shaft speed so that the "about to mesh" gears are spinning the same speed. Syncros do this by dragging the slower input shaft up to the spinning output gear's speed. Double clutching is a shuffle of the throttle, clutch, and gear shift lever that manually attempts to match the gears rates. Before syncros, THIS is the way everyone shifted.
As engine speed gets lower and you leave the power range of the engine, your clutch and select neutral allowing the clutch to return to its rest position. You pop the throtle with the clutch engaged to speed up the input shaft and gear in the trans. Then you clutch again, and select the lower gear.... this time letting the clutch out more slowly while applying throttle.
After you get the hang of the hand/foot ballet, plus the degree of throttle you need to spin up the input shaft, you'll become smooth (and sound cool), plus you'll be saving the syncros for the other drivers that use your car. It can be done pretty quick... about the time it takes syncros to spin up the input shaft so you don't lose time in a "coast" condition.... most double clutchers feel it's faster (me included), and is the absolute quickest way into first gear as you roll up to the signal light about to turn green..... or getting out of the most wicked tight hairpin the quickest. Can also be used to initiate a drift... but you have to practice that.

Gar.... 50 years double clutcher :)

so "double clutching" is actually not using the clutch at all?

[jeffmknight]

countourkid98, on 23 December 2009 - 08:55 PM, said:

so "double clutching" is actually not using the clutch at all?

No, it's the opposite. You'll use the clutch twice instead of once. Press the clutch pedal to exit the current gear and enter neutral. Release the clutch pedal while in neutral and adjust the the throttle to spin-up or spin-down the gearset, depending on whether you're upshifting or downshifting. Then clutch again to enter the next desired gear. This helps the synchros last much longer, as you're essentially doing their job for them.

[countourkid98]

jeffmknight, on 23 December 2009 - 09:27 PM, said:

No, it's the opposite. You'll use the clutch twice instead of once. Press the clutch pedal to exit the current gear and enter neutral. Release the clutch pedal while in neutral and adjust the the throttle to spin-up or spin-down the gearset, depending on whether you're upshifting or downshifting. Then clutch again to enter the next desired gear. This helps the synchros last much longer, as you're essentially doing their job for them.

ok so im pretty sure i understand for downshifting because it sounds like its the same way you shift without the clutch, at proper rpm your able to pull the car out of gear rather easily because both the engine and trans are spinning at the same speed, you then give the throttle a tap and bring the rpms up to where their matched with what the top of your lower gear wants to be and it should slip right in, i may be wrong with how i described that but i tried, im not an expert at all....but anyway i still dont understand the rev for upshifting....sry if im being stupid but im just tryin to learn

[Terry Haines]

..some call it 'rev matching'..Works well on down shifts to keep the engine in the power band so you can slow down by a lower gear, say in a bend, but hop back on the gas to 'power thru' without the drop off in power. I find myself doing this as normal part of driving and have to force myself not to do it! No syncros in the cars I started driving in!!
For 'serious' driving it will get you thru bends etc quicker than those who can't do it..In the past i have driven my customers in there cars after mods etc, round the twisties on our local roads, two inner wheels up on tight bends etc, rev matching and making the Contour 'sing' the high notes..I love it, the car was built for it, the customers ...look a bit scared at times with an 'ol British racer throwing their baby around like a rag doll!!

[countourkid98]

Terry Haines, on 24 December 2009 - 07:27 AM, said:

..some call it 'rev matching'..Works well on down shifts to keep the engine in the power band so you can slow down by a lower gear, say in a bend, but hop back on the gas to 'power thru' without the drop off in power. I find myself doing this as normal part of driving and have to force myself not to do it! No syncros in the cars I started driving in!!
For 'serious' driving it will get you thru bends etc quicker than those who can't do it..In the past i have driven my customers in there cars after mods etc, round the twisties on our local roads, two inner wheels up on tight bends etc, rev matching and making the Contour 'sing' the high notes..I love it, the car was built for it, the customers ...look a bit scared at times with an 'ol British racer throwing their baby around like a rag doll!!

ok so i was correct, ive been double clutching for a few yrs now and i didnt even kno thats what it was called....thanks for everyones help...much appreciated, and terry....i wish you could hear the way my contour sounds with how my exhaust is.....one of a kind

[SVTDEMON]

Someone pin this because it is always asked about every 3 months.

[jeffmknight]

I've noticed in any manual I've driven that the rev's are easy to match on downshifting, if driving on a level surface. It's like the gear ratios are spaced perfectly to allow "automatic matching" for downshifting. For instance, if I'm driving at a steady speed in, say, fifth gear and I want to drop to fourth, I can keep the gas exactly where it is, press the clutch, and the revs jump (because of the torque release) to the perfect rate to slip it into fourth. This seems true for any gear, and it works just the same in my old '73 Beetle as it does in my '98 CSVT. Doing it on a hill is a little more complicated, but this can be achieved over time as you get a feel for the rpm and torque characteristics of your vehicle.


Just my two cents.

BTW, I still have not been able to "get the hang of the hand/foot ballet.." (as our friend Gar put it) for double-clutching. This seems to take quite a bit of practice, coordination, and timing, not to mention a little humiliation and teeth clinching. I'll keep trying though, as practice makes perfect. Have fun people.

[Terry Haines]

...find an old car with a non syncro trans...a large parking lot...Practice, that was how I was taught my by old man when I was 11...You never loose the skill once you have it...and a '3 on the tree' is even more fun!!!

[Gar]

Might be tough to find one that old. I learned on a Crosley... no syncro into any gear. Back in 1959.

Gar

[jeffmknight]

Gar, on 15 January 2010 - 07:47 AM, said:

Might be tough to find one that old. I learned on a Crosley... no syncro into any gear. Back in 1959.

Gar

Would the old '73 Super Beetle have had any synchros? Never had any trouble shifting that thing. Fun car, easy maintenance. I kind of wish I still had it!

I did also drive an old Biscayne once. Man, the tree was a pain in the ass! That's the only reason I didn't buy the car. She sure was a beauty though.

[Gar]

Had lots of VW. Fairly sure you have to go back before 67 to find a non syncro VW, and even they had syncro into everything but first and reverse. Samba says before 60, and other references say VW exported syncro models as far back as the 50s. So if you go back to the days on totally non syncro VW, you're getting into the expensive ones these days. I think Mom's 60 Falcon was also non syncro into first, 3 on the tree.... the auotomatic version had just two speeds... imagine that.

It doesn't hurt one bit to use double clutching on new cars, so you don't really have to have something old.

Now if you get a race transmission, you're probably going to be non-syncro.

Gar