Harmful to shift without clutch? - Page 2 - Toyota Yaris Forums

Loren · 02-09-2009, 10:59 AM

Rev matching is matching the speed of the engine to the speed of the transmission thereby making the synchros have to do less work. When you're clutchless shifting, especially downshifting, it's nearly impossible to do smoothly without doing some rev-matching.

Best example is the first gear downshift that a lot of people think is difficult. It's difficult if you try to do it from too high of a speed and too quickly, but if you slow down to an appropriate speed for first gear and give the synchros time to work, it will slip right in. OR, you can do it quickly and smoothly at a somewhat higher speed (still needs to be a mid-range first gear speed!) by adding a little blip of the throttle as you depress the clutch to zing the revs up, thereby increasing the transmission input shaft speed and allowing the gears to easily mesh.

Works even better if you learn to "double-clutch". That is, to let the clutch back out while you're in neutral so that when you rev the engine, you're REALLY spinning up the transmission input shaft. Then clutching again, slipping the stick into gear and declutching again.

It all takes practice. Lots of practice. Don't force it, just let things happen. When you have the input shaft speed right for the gear you're trying to go into, it will slip right in.

It's a Zen thing.

ztlonewolf · 02-09-2009, 01:22 PM

Quote:

Originally Posted by Tamago

that right there is the key, with or with out clutch.. we're talkin tiny lil gears here people. if you can't revmatch on an up AND DOWN shift, you shouldn't be driving a manual trans IMO

the only time you may need to do revmatching on an upshift is if you shifted too slow,anymore than a 1000rpm drop between gears,you would have to rev the engine to match the roadspeed,or not be lazy and use the clutch

twowheels · 02-09-2009, 09:32 PM

Quote:

Originally Posted by Loren

Works even better if you learn to "double-clutch". That is, to let the clutch back out while you're in neutral so that when you rev the engine, you're REALLY spinning up the transmission input shaft. Then clutching again, slipping the stick into gear and declutching again.

Darn... I was going to point out the double clutch, but you beat me to it! :-) I find that the Yaris really does prefer to be double clutched into first, even at slow speeds. Not sure why first is so picky compared to others cars I've driven.

RagnaCaT · 02-09-2009, 10:34 PM

Double Clutch? Hmmmmm?! This intresting very intresting I'm gonna try it. The first time I heard about it was in Fast and the Furios in the first race Vin Diesel said it " Not Double Clutching like you should" Lol I kinda liked that movie.

ddongbap · 02-10-2009, 12:38 AM

I do this all the time. Its sorta how a motorcycle tranny works. I mean the nonclutch part.

There are some sequential trannys that require a clutch for first gear, but every gear after that just requires the gear pull.

Tamago · 02-10-2009, 12:39 AM

Quote:

Originally Posted by RagnaCaT

Double Clutch? Hmmmmm?! This intresting very intresting I'm gonna try it. The first time I heard about it was in Fast and the Furios in the first race Vin Diesel said it " Not Double Clutching like you should" Lol I kinda liked that movie.

lol double clutching is for tractors and broken transmisssions

Tamago · 02-10-2009, 12:40 AM

Quote:

Originally Posted by ztlonewolf

the only time you may need to do revmatching on an upshift is if you shifted too slow,anymore than a 1000rpm drop between gears,you would have to rev the engine to match the roadspeed,or not be lazy and use the clutch

huh? i rev-match/heel-toe every downshift in my car.. it's a nice treat for your driveline to practice this.

ztlonewolf · 02-10-2009, 09:21 AM

Quote:

Originally Posted by Tamago

huh? i rev-match/heel-toe every downshift in my car.. it's a nice treat for your driveline to practice this.

revmatching is a must for downshifting,my post only refered to upshifting

SeaYa · 02-10-2009, 09:37 AM

OP: I agree 100% that you'll do little / no harm by shifting without the clutch if, like most of the above posts suggest, you rev match carefully. When I first read this, I thought it was rediculous, but then I thought about what was actually happening in the transmission, so, I held my breath and gave it a try from 3rd to 4th. AMAZING! Get the revs right, and the syncs almost guide your throw (more like a left-handed, underhand, one finger toss).

Hope you heal up well!

TheSilkySmooth · 02-10-2009, 11:01 AM

If your not good at it would will put some x-tra wear on the blockers, and they are usually a soft metal alloy. Purpose bilt pedal setups are great for heel and toe - but I find most passenger cars are not set up well for that. Maybe porsche/vw with the bottom pivot go pedal ...

marcus · 02-10-2009, 11:03 AM

wait rev matching requires pressing the clutch aint it....so how can you rev match without pressing the clutch..do you just shift on certain rpm??

TheSilkySmooth · 02-10-2009, 11:03 AM

Quote:

Originally Posted by Loren

It all takes practice. Lots of practice. Don't force it, just let things happen. When you have the input shaft speed right for the gear you're trying to go into, it will slip right in.

It's a Zen thing.

Ohh, Loren TOOO sexy. I'm HOT now!

-Sis

Loren · 02-10-2009, 11:08 AM

Quote:

Originally Posted by TheSilkySmooth

Ohh, Loren TOOO sexy. I'm HOT now!

Do I need to put a parental advisory on such discussions? :)

You should hear me talk about driving smoothly at the limit, using a gentle touch with finesse to stay right on the edge without going past it.

Aren't cars fun?

Loren · 02-10-2009, 11:13 AM

Quote:

Originally Posted by marcus

wait rev matching requires pressing the clutch aint it....so how can you rev match without pressing the clutch..do you just shift on certain rpm??

We've gotten a little off-topic talking about double-clutching.

The revs will pretty much take care of themselves on a clutchless upshift. Just takes patience and a gentle touch.

Where you've got to conciously "match revs" is on a clutchless downshift. You have to blip the throttle to get the revs up PAST where they need to be for the gear you're downshifting to, and then drop into the gear just as you would on an upshift.

marcus · 02-10-2009, 11:22 AM

cool although i have grinding gear phobia..i get spasm when i hear it..im not even joking.. just curious how it works...

IllusionX · 02-10-2009, 12:23 PM

i can't shift for shit with the yaris.

anyways, with a 93 civic, i was able to do exactly as loren suggests. I was able to upshift all the way to 5th and onto the highway, and downshift all the gears down to 2nd. (I didn't feel comfortable doing the 1st gear, but oh well!) not a single grinding gear.

There's a little timing to do for when you can pull out of gear without clutch. It has to be done without any pressure on the transmission. ie, not accelerating, nor decelerating.

marcus: it's pretty much impossible to grind gears when shifting without clutch. You cannot pull out of gear when there's pressure on the transmission. And when the rev do not match, the synchro would simply block you from shifting in anyways. When it's open, then the gears will slide in like warm butter.

twowheels · 02-10-2009, 07:17 PM

Quote:

Originally Posted by Loren

You have to blip the throttle ***** to get the revs up PAST where they need to be for the gear you're downshifting to, and then drop into the gear just as you would on an upshift.

***** while in neutral

TheSilkySmooth · 02-10-2009, 07:19 PM

A lot of people dont know that in a moderm synchromesh transmission, all gears are permanently engaged and you dont grind the gears at all. You are pushing a collar over a dog clutch that locks the idling gear to the mainshaft ; now the power goes down to the layshaft then back up to the final drive gear on the output shaft. Oh there must be a .GIF on the web somewhere ... Oh reverse is another story.

02-09-2009, 10:59 AM	#19
Loren What? Drives: 2007 Yaris LB Join Date: Nov 2008 Location: Safety Harbor, FL Posts: 1,006	Rev matching is matching the speed of the engine to the speed of the transmission thereby making the synchros have to do less work. When you're clutchless shifting, especially downshifting, it's nearly impossible to do smoothly without doing some rev-matching. Best example is the first gear downshift that a lot of people think is difficult. It's difficult if you try to do it from too high of a speed and too quickly, but if you slow down to an appropriate speed for first gear and give the synchros time to work, it will slip right in. OR, you can do it quickly and smoothly at a somewhat higher speed (still needs to be a mid-range first gear speed!) by adding a little blip of the throttle as you depress the clutch to zing the revs up, thereby increasing the transmission input shaft speed and allowing the gears to easily mesh. Works even better if you learn to "double-clutch". That is, to let the clutch back out while you're in neutral so that when you rev the engine, you're REALLY spinning up the transmission input shaft. Then clutching again, slipping the stick into gear and declutching again. It all takes practice. Lots of practice. Don't force it, just let things happen. When you have the input shaft speed right for the gear you're trying to go into, it will slip right in. It's a Zen thing. __________________ ----------------------- Loren@InvisibleSun.org -----------------------

02-09-2009, 10:34 PM	#22
RagnaCaT HacKers WanTed! View User's Garage Drives: Yaris S HB & Yaris S SD Join Date: Aug 2007 Location: Villalba, Puerto Rico Posts: 435	Double Clutch? Hmmmmm?! This intresting very intresting I'm gonna try it. The first time I heard about it was in Fast and the Furios in the first race Vin Diesel said it " Not Double Clutching like you should" Lol I kinda liked that movie. __________________ *R-CaT* Project Yar 2ZR

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02-10-2009, 12:38 AM	#23
ddongbap Banned Drives: yw calls me douche and racist. Join Date: Aug 2007 Location: hay Posts: 2,183	I do this all the time. Its sorta how a motorcycle tranny works. I mean the nonclutch part. There are some sequential trannys that require a clutch for first gear, but every gear after that just requires the gear pull.

02-10-2009, 09:37 AM	#27
SeaYa Is about to 'SeaYa' later View User's Garage Drives: 08 MT Sedan Join Date: Jan 2009 Location: MI, USA Posts: 226	OP: I agree 100% that you'll do little / no harm by shifting without the clutch if, like most of the above posts suggest, you rev match carefully. When I first read this, I thought it was rediculous, but then I thought about what was actually happening in the transmission, so, I held my breath and gave it a try from 3rd to 4th. AMAZING! Get the revs right, and the syncs almost guide your throw (more like a left-handed, underhand, one finger toss). Hope you heal up well!

02-10-2009, 11:01 AM	#28
TheSilkySmooth Drives: 08 3DR 5M Bayou Blue; 09 Fos Join Date: Oct 2008 Location: New Hampshire Posts: 622	If your not good at it would will put some x-tra wear on the blockers, and they are usually a soft metal alloy. Purpose bilt pedal setups are great for heel and toe - but I find most passenger cars are not set up well for that. Maybe porsche/vw with the bottom pivot go pedal ...

02-10-2009, 11:03 AM	#29
marcus toyota View User's Garage Drives: 2007 Yaris RS Blazed Join Date: Oct 2006 Location: toronto, canada Posts: 3,637	wait rev matching requires pressing the clutch aint it....so how can you rev match without pressing the clutch..do you just shift on certain rpm??

02-10-2009, 11:22 AM	#33
marcus toyota View User's Garage Drives: 2007 Yaris RS Blazed Join Date: Oct 2006 Location: toronto, canada Posts: 3,637	cool although i have grinding gear phobia..i get spasm when i hear it..im not even joking.. just curious how it works...

02-10-2009, 12:23 PM	#34
IllusionX It's the illusion you see View User's Garage Drives: 07 Yaris Sedan Aero Join Date: Oct 2006 Location: Brossard, QC Posts: 3,888	i can't shift for shit with the yaris. anyways, with a 93 civic, i was able to do exactly as loren suggests. I was able to upshift all the way to 5th and onto the highway, and downshift all the gears down to 2nd. (I didn't feel comfortable doing the 1st gear, but oh well!) not a single grinding gear. There's a little timing to do for when you can pull out of gear without clutch. It has to be done without any pressure on the transmission. ie, not accelerating, nor decelerating. marcus: it's pretty much impossible to grind gears when shifting without clutch. You cannot pull out of gear when there's pressure on the transmission. And when the rev do not match, the synchro would simply block you from shifting in anyways. When it's open, then the gears will slide in like warm butter.

02-10-2009, 07:19 PM	#36
TheSilkySmooth Drives: 08 3DR 5M Bayou Blue; 09 Fos Join Date: Oct 2008 Location: New Hampshire Posts: 622	A lot of people dont know that in a moderm synchromesh transmission, all gears are permanently engaged and you dont grind the gears at all. You are pushing a collar over a dog clutch that locks the idling gear to the mainshaft ; now the power goes down to the layshaft then back up to the final drive gear on the output shaft. Oh there must be a .GIF on the web somewhere ... Oh reverse is another story.