Just another thing to throw in there, the reason to double clutch on an upshift would be if you are shifting multiple gears at the same time (which is a big no no if you dont double clutch). it has been my observation that the lay-shaft (or whatever the part connecting the clutch to the tranny is called) slows down slower than the engine if left to spin on its own. Thus, if say, im getting on the freeway in third, and i want sixth. I put the clutch in, shift to neutral, clutch out, wait for revs to drop to around 3k, and clutch in, shift to sixth, clutch out.

 

Thanks gang ... I'm convinced now and will keep double-clutching on down-shifts and that makes me happy. It adds to the pleasure of driving, sharpens my driving skills and mechanical awareness, saves the syncromeshers, sounds cool and impresses the ladies. What could be better.

 

if you read this description, he mentions clutch in, neutral, clutch out; clutch in, throttle blip, downshift, clutch out......double clutch.

not the clutch in, neutral, blip, downshift, clutch out that you described.




he has the definition for double clutch right, he simply uses the term rev-matching in different context than most of s2ki.com.

 

You shouldn't be quoting Felix Wong. He may know what he's talking about (or maybe not), but for sure he has absolutely no clue as to how to put his thoughts in print. What he put in print is ambiguous and at times, conflicting and misleading. Most of us know what he means even though he didn't write it down that way. For those who blindly take for gospel what he put in print, you are being slightly misled.

You can rev-match without double clutching. You can double clutch without rev-matching and you can rev-match AND double clutch. Oh and this has NOTHING to do with "heel/toe". This is yet another variable which may or may not be combined with everything else that I've listed.

Rev-matching is just bringing the engine rpm up or down to match the speed of the rear wheels when the next gear (up or down) is selected.
Double clutching is moving the shifter to NEUTRAL, then letting the clutch out so that the engine can control the speed of the transmission. Whether you wish to spin the tranny up or down will depend upon what you intend to do with the car at the time. Putting the tranny into neutral and leaving the clutch on the floor accomplishes nothing. This basically isolates all 3 components of the drivetrain from each other -- the engine, the tranny and the rear wheels. The engine will turn based on how much gas you give it. This will be independent of the tranny, which will spin itself down from the fluid viscosity within. BOTH of these will be independent of the rear wheels, which will be governed by the road speed. ALL 3 will do their own thing as long as you have the clutch on the floor. (The engine is NOT connected to the tranny which is NOT connected to the rear wheels.)
"Heel/toe" is using one foot to operate both the brake and gas pedal at the same time so you can maximize braking AND shift at the same time. This is generally done when going into a corner HOT and there is need to scrub off speed, yet prepare the tranny (putting it into a lower gear) so you can power out of the corner.

First gear on most manuals is hard to engage when on a roll and decelerating. This is because of the "blocker ring" that is built into most manuals. Because 1st gear's ratio is so far from the rest of the gears, manufacturers want to make it difficult to engage first if the road speed is too fast. However, the blocker ring can be defeated by double clutching and rev-matching should you have the need or the desire to continue driving and accelerate from whatever you were slowing down for. For those of you who find it easy to downshift into 1st gear at a high speed without double clutching and rev-matching, I contend that you have used so much force to engage 1st that you have worn down the blocker ring. Not a big deal but just know that it was there originally for a reason.

So come guys, read "How Stuff Works" and stop confusing yourselves.

 

I downshift into 1st quite often, works like butter everytime.

 

I'm glad you're not driving my car. I don't care what anyone says, 1st gear was not meant to be downshifted into, in any standard shift tranny. 1st gear is to be shifted FROM, not into. I would never downshift into 1st. I always come to a COMPLETE stop before shifting my car into 1st.

 

xviper.. so say if im downshifting from 5th to 3rd. i push in the clutch move the shifter from 5th to 3rd. blip the throttle to match the rpm to the road speed and let out the clutch.
this uses the synchros because i didnt blip it in neutral with the clutch out right?
will that cause excessive where? to me it's just easier to do that.

 

Never say "never!"

There are obviously some roads you've never been on! Hwy 1 in California has some nice tight near 180 switch backs that have you slowing down on a healthy downhill, followed by a decreasing radius near 180 turn, and then a "very" healthy uphill section to accelerate out of the turn with. If you're not in 1st gear when you're ready to head back up that hill, you'll be in trouble. And if you come to a full stop "before" putting it in 1st gear, you'll have whoever's behind you totally pissed off!!

There is nothing wrong with downshifting into first gear as long as you're not traveling faster than the car can go while "in" first gear! It's easiest on the tranny if you do the double clutch as described by Xviper and it's not a big deal. FWIW, on "routine" downshifts, I've found that my car slips into first the easiest if I perform the shift while the car is still moving "a little," say, 5 mph or less.

 

First of all, "Woodwork" has advised against skip shifting, so I won't be saying it's OK to do it.
However, "if" I were to find the need to do what you ask I would have to assess the engine speed of the gear I'm leaving (and the road speed) and compare this to the engine speed of the gear I'm "skipping" to. If I didn't understand this concept and the importance of it, then I wouldn't be attempting a skip shift. Now, depending upon the rpm differential between the starting gear and the next (skipped) gear, I might elect to do a double clutch rev match to perform this task. It will make for less wear and tear on the syncros. That's all I'll say on this subject. You'll have to read between the lines to see what I'm getting at.


"exceltoexcel", You can always shift into 1st if your road speed is low enough. How low? Well, that depends on how much your blocker ring has been worn down. With a "fresh" car, you should be able to "easily" downshift into 1st on a roll from about 5 mph or less. If you can do it from much higher speeds (and I've witnessed S2000s that can), then I would guess that your blocker ring no longer does what it was there to do.


"Tommy-S2K", I think you have a bit of misconception here and Intrepid has addressed this quite nicely.

 

You seem to understand the gear/clutch relationship.

I missed it.