Newbie guide for Manual Transmissions

[vr4gasmtt]

Originally Posted by Tastycakes

Proper "Double Clutch" Down shifting:

Go from 4th to neutral
Take you foot off the clutch
Blip the gas (push the gas pedal to the floor and back very fast)
Hit the clutch and go to 2nd





The hardest part is guessing how high to rev the engine but it's not hard once you do it after a while.

For the above just use simple math. If your going 45 MPH in 4th and you know 2nd redlines at 55 MPH its pretty safe to say you should be in the 6-6500 RPM range so just rev it up to 6200ish and go to 2nd. You dont have to be exact, just within a couple hundred rpms.

Hope that helps.

I was referring to a regular rev match, from what I read it sound like you have to let the clutch out and then rev match and then clutch in.. (doesnt make sense the way I wrote it out but I hope you know what I mean)

[phawx]

Originally Posted by vr4gasmtt

I was referring to a regular rev match, from what I read it sound like you have to let the clutch out and then rev match and then clutch in.. (doesnt make sense the way I wrote it out but I hope you know what I mean)

Maybe ur getting confused by clutch in and clutch out? I had that problem before when my friends were explaining rev match to me.
Clutch in refers to STEPPING on the clutch pedal and clutch out is letting off the clutch.

So step on clutch, blip throttle while shift to lower gear, and then let off clutch relatively quickly is the way for a regular rev match.

I have a question though - is double clutch rev matching absolutely needed? I've just been practicing regular rev matching so far, I'm still kinda slow. What's the difference between the two? Does regular rev match damage the synchros?

[bangmonsta]

from my understanding since modern cars have syncros you no longer need to double clutch, you can if you want, but it's definitely not "absolutely needed".

As for the actual difference I would ask a mechanic or google for the answer. I would guess that double clutch puts less stress on the syncros but the syncros are designed for it so why not put them to use?

I saw a nice video of the transmission on howstuffworks the other day, go look for it

[SilentBob420BMFJ]

Originally Posted by jokka

rev match downshift.


clutch in

simultaneously blip the throttle while lowering the gear

release clutch

enjoy the ever increasing engine sound as you go into lower gears

well ya, of course i do that when going from 6th to 3rd or something, but im talking about going from 3rd to 6th, and is it doing massive wear on my syncros? like is going from 3rd to 6th the same as shifting up 1 gear normally like 5x? dumb question i guess because nobody will know the answer

Originally Posted by vr4gasmtt

ok this doesnt make sense, so from what I'm reading you guys are saying that to rev match the clutch isnt supposed to be depressed?

for example, downshift from 4-2nd when you blip the throttle the clutch is going to be depressed so why is it that you guys posted that the clutch isnt suppsoed ot be depressed and it has to be in neutral?

this is double clutch downshifting, see my reply below

Originally Posted by phawx

I have a question though - is double clutch rev matching absolutely needed? I've just been practicing regular rev matching so far, I'm still kinda slow. What's the difference between the two? Does regular rev match damage the synchros?

i already went around the web and looked all this crap up after seeing a lot of people on here talking about how you should double clutch.. i found out that saying you should double clutch to save your syncros is basically like saying you should take corners slow to save your tires.. do you want to become a scientist at shifting and saving only $100s per like (wild guess here) ~30000 miles, or do you want to just drive your car and use the technology it has.. if i double clutched, i would do it because i hate the notchy feeling of the syncros working when i shifted, not to save the syncros.. i dont feel like looking it up now, but maybe somebody who knows could tell us how much syncros cost? if its like less than $200 per syncro, and there is 1 syncro per gear, then that is ridiculous that people would double clutch, unless of course you could wear out a syncro in like 6000 miles

[Tastycakes]

Well first off synchros are very expensive. I'd guarantee you'll never leave a shop w/ a bill less than a grand. I had 2 bad ones in my Trans Am and the bill was like $3500. Mind you that was a T-56 transmission and was built alot stronger than the ones in Civics so i doubt it'd be that much for a Civic.

And you are kinda correct tho in saying its like take turns slow to save on tires.

Its not about becoming a scientist at shifting its about driving stick right. Double clutching is sorta over kill yea, but if you know how to do it or can learn to and it takes seriously no effort to do, then why not do it?

Also yes you can kill a synchro in 6k miles. And 90% of the time your warranty company is gonna give you the middle finger cause blown synchros are a huge indication of abuse, weather it be driving stick wrong or racing its still abuse. This is why i "go out of my way" to make sure i dont put alot of wear on em.

[OhondaU]

Ok, provided the clutch is completely released and you are currently in 3rd gear...

There is no input from the engine, so the output shaft will be driven by the rolling wheels. At this point this is your only source of incoming force into the transmission. The output shaft will be driving the input shaft, which is spinning close to whatever RPM the engine was at when you released the clutch. At this point whenever you upshift, the synchros have the wonderful job of slowing all the rotating mass of the input shaft and all the gears riding on it to the speed dictated by the new gear ratio. So if you are at say 60 mph in 3rd and shift to 6th the input shaft will have to slow from ~6000rpm to ~2700rpm. Now if you were in 5th gear at 60mph and shifted into 6th the drop would only be from ~3600rpm to ~2700rpm, quite a bit less energy to dissipate. So the skip-shifting means more energy dissipation which is more heat generated which is more wear created. Seeing as the equation for rotational kinetic energy is: (1/2)*I*omega^2, where omega is your angular velocity (RPMs). It would seem going from the 5th-6th shift of 900rpm drop to a 3rd-6th shift with a drop of 3300rpms would result in having to dissipate 7 times the amount of energy as a normal shift! So instead of your 6th gear synchro lasting, oh say 210,000 miles, it would only last 30,000 miles!

Now that is entirely a theoretical discussion and real life is infinitely more complex than what is represented above, your shifting habits, the type of MTF your run, and even the speed at which you skip-shift among many others will all affect the mileage you get from your transmission.

The safest bet, double clutch your upshift if you are going to be skipping that many gears. And if you don't, as long as these aren't redline skip shifts under high load, you should be ok.

[bangmonsta]

Originally Posted by OhondaU

Ok, provided the clutch is completely released and you are currently in 3rd gear...

There is no input from the engine, so the output shaft will be driven by the rolling wheels. At this point this is your only source of incoming force into the transmission. The output shaft will be driving the input shaft, which is spinning close to whatever RPM the engine was at when you released the clutch. At this point whenever you upshift, the synchros have the wonderful job of slowing all the rotating mass of the input shaft and all the gears riding on it to the speed dictated by the new gear ratio. So if you are at say 60 mph in 3rd and shift to 6th the input shaft will have to slow from ~6000rpm to ~2700rpm. Now if you were in 5th gear at 60mph and shifted into 6th the drop would only be from ~3600rpm to ~2700rpm, quite a bit less energy to dissipate. So the skip-shifting means more energy dissipation which is more heat generated which is more wear created. Seeing as the equation for rotational kinetic energy is: (1/2)*I*omega^2, where omega is your angular velocity (RPMs). It would seem going from the 5th-6th shift of 900rpm drop to a 3rd-6th shift with a drop of 3300rpms would result in having to dissipate 7 times the amount of energy as a normal shift! So instead of your 6th gear synchro lasting, oh say 210,000 miles, it would only last 30,000 miles!

Now that is entirely a theoretical discussion and real life is infinitely more complex than what is represented above, your shifting habits, the type of MTF your run, and even the speed at which you skip-shift among many others will all affect the mileage you get from your transmission.

The safest bet, double clutch your upshift if you are going to be skipping that many gears. And if you don't, as long as these aren't redline skip shifts under high load, you should be ok.

Great explanations, you seem to understand this stuff. I'm still a bit confused though. Could you explain the synchros in more detail? I've never quiet understood what happens to them during shifting. I only know they help the dog teeth in the collar connect to the gears, but I dont see what exactly happens when you shift.

So far all I know about the engine is that it's connected to the transmission via the clutch. Transmission picks the gear by using selectors, then there is a differential connected to the transmission. To put it short, here's what I know on why/how a car moves.

Engine -> crankshaft -> flywheel -> clutch -> transmission -> differential -> ????? ->wheels. I have no clue where that differential go or what it does, howstuffworks.com. Got any good reading material? I'd like to complete my little arrow diagram and understand it all lol. I think the input shaft comes from the engine, and output shaft goes to the differential?

I know rev matching helps keep the clutch healthy by matching the flywheel's speed to the speed the clutch should be spinning at and reducing friction wear, but I've always thought that rev matching would also save the synchros

Also, when you say clutch is "released", as mentioned on top. Are you saying that clutch pedal is down, meaning we're free to shift? Or gear is engaged?

[OhondaU]

Ok, here's a short article on transmission on howstuffworks.com

Howstuffworks "How Manual Transmissions Work"

You will probably be most interested in part 4.

Getting more in depth and answering your other questions probably deserves a thread on its own, especially the part on differentials (a subject that is misunderstood by most).

And when I said the clutch is "released" I meant the pedal is all the way down and the clutch is disconnected from the flywheel.

[06Honda06SI]

really good information...plus rep

[SilentBob420BMFJ]

Originally Posted by OhondaU

Ok, provided the clutch is completely released and you are currently in 3rd gear...

There is no input from the engine, so the output shaft will be driven by the rolling wheels. At this point this is your only source of incoming force into the transmission. The output shaft will be driving the input shaft, which is spinning close to whatever RPM the engine was at when you released the clutch. At this point whenever you upshift, the synchros have the wonderful job of slowing all the rotating mass of the input shaft and all the gears riding on it to the speed dictated by the new gear ratio. So if you are at say 60 mph in 3rd and shift to 6th the input shaft will have to slow from ~6000rpm to ~2700rpm. Now if you were in 5th gear at 60mph and shifted into 6th the drop would only be from ~3600rpm to ~2700rpm, quite a bit less energy to dissipate. So the skip-shifting means more energy dissipation which is more heat generated which is more wear created. Seeing as the equation for rotational kinetic energy is: (1/2)*I*omega^2, where omega is your angular velocity (RPMs). It would seem going from the 5th-6th shift of 900rpm drop to a 3rd-6th shift with a drop of 3300rpms would result in having to dissipate 7 times the amount of energy as a normal shift! So instead of your 6th gear synchro lasting, oh say 210,000 miles, it would only last 30,000 miles!

Now that is entirely a theoretical discussion and real life is infinitely more complex than what is represented above, your shifting habits, the type of MTF your run, and even the speed at which you skip-shift among many others will all affect the mileage you get from your transmission.

The safest bet, double clutch your upshift if you are going to be skipping that many gears. And if you don't, as long as these aren't redline skip shifts under high load, you should be ok.

with double clutch upshifting, alls you have to do is release the clutch in neutral for a second right? so this would be much easier than double clutch downshifting.. i can easily do this since im coasting anyways and ready to put it into 6th.. so clutch in > neutral > clutch out for 1 second > clutch in > 6th > clutch out.. basically your are engine braking the transmission, but since its in neutral.. right?

Originally Posted by bangmonsta

Great explanations, you seem to understand this stuff. I'm still a bit confused though. Could you explain the synchros in more detail? I've never quiet understood what happens to them during shifting. I only know they help the dog teeth in the collar connect to the gears, but I dont see what exactly happens when you shift.

So far all I know about the engine is that it's connected to the transmission via the clutch. Transmission picks the gear by using selectors, then there is a differential connected to the transmission. To put it short, here's what I know on why/how a car moves.

Engine -> crankshaft -> flywheel -> clutch -> transmission -> differential -> ????? ->wheels. I have no clue where that differential go or what it does, howstuffworks.com. Got any good reading material? I'd like to complete my little arrow diagram and understand it all lol. I think the input shaft comes from the engine, and output shaft goes to the differential?

I know rev matching helps keep the clutch healthy by matching the flywheel's speed to the speed the clutch should be spinning at and reducing friction wear, but I've always thought that rev matching would also save the synchros

Also, when you say clutch is "released", as mentioned on top. Are you saying that clutch pedal is down, meaning we're free to shift? Or gear is engaged?

99% of the time "clutch released" means your foot is off the pedal, this guy just used that 1% to confuse everybody

Originally Posted by OhondaU

Ok, here's a short article on transmission on howstuffworks.com

Howstuffworks "How Manual Transmissions Work"

You will probably be most interested in part 4.

Getting more in depth and answering your other questions probably deserves a thread on its own, especially the part on differentials (a subject that is misunderstood by most).

And when I said the clutch is "released" I meant the pedal is all the way down and the clutch is disconnected from the flywheel.

like i said above, 99% of the time your talking about the clutch, you are referring to the pedal; its probably best not to refer to the clutch itself, as this gets confusing.. clutch in / clutch depressed / clutch down = pedal to the floor; clutch out / clutch released / clutch up = foot off pedal.. when we talk about steering, we refer to the steering wheel, when we talk about gas, we refer to the gas pedal, etc

[OhondaU]

^hmmmm....smart ass much?

[bangmonsta]

lol that IS a pretty smart way to look at double clutch upshift..! =]

and w00t for me being the 99% hahaha. Why are u trying to confuse me OhondaYOUUU! -_-

[Yodums]

Originally Posted by SilentBob420BMFJ

with double clutch upshifting, alls you have to do is release the clutch in neutral for a second right? so this would be much easier than double clutch downshifting.. i can easily do this since im coasting anyways and ready to put it into 6th.. so clutch in > neutral > clutch out for 1 second > clutch in > 6th > clutch out.. basically your are engine braking the transmission, but since its in neutral.. right?

Not sure what you're really saying here. The original message that you quoted is suggesting you only double clutch on an upshift if you're skipping more than one gear i.e. 2 to 4, 3 to 5, etc. This will in time put less wear on the synchros. Also, if you have any transmission-related issues and the dealership finds out you've been skipping gears on a daily basis, then they can ultimately blame you for the damage. There is no intent in engine braking on an upshift. That's on a downshift.

99% of the time "clutch released" means your foot is off the pedal, this guy just used that 1% to confuse everybody



like i said above, 99% of the time your talking about the clutch, you are referring to the pedal; its probably best not to refer to the clutch itself, as this gets confusing.. clutch in / clutch depressed / clutch down = pedal to the floor; clutch out / clutch released / clutch up = foot off pedal.. when we talk about steering, we refer to the steering wheel, when we talk about gas, we refer to the gas pedal, etc

Based on context, I completely understood what he meant by clutch released -> disengaged.

[SilentBob420BMFJ]

Originally Posted by OhondaU

^hmmmm....smart ass much?

there is a difference between being a smart ass just to try to fight with somebody, and correcting them so others who read the thread get the right information.. if i were to claim the si has 250 hp, i would hope somebody would correct me, regardless of how it sounds

Originally Posted by Yodums

Not sure what you're really saying here. The original message that you quoted is suggesting you only double clutch on an upshift if you're skipping more than one gear i.e. 2 to 4, 3 to 5, etc. This will in time put less wear on the synchros. Also, if you have any transmission-related issues and the dealership finds out you've been skipping gears on a daily basis, then they can ultimately blame you for the damage. There is no intent in engine braking on an upshift. That's on a downshift.

i know it was confusing, and i wasnt actually talking about engine braking, so nvm about that.. basically, how do you double clutch upshift? i know how to do it with downshifting, but how does it differ with upshifting?

[dorkiedoode]

i have a rev matching question. so when cruising at 5th and i want to go down to 2nd. First i clutch in, throw it down to 2nd, rev match the rpm, and let the clutch out. Is this bad or good? but when i do that i get into gear very smoothly.

[vr4gasmtt]

Originally Posted by dorkiedoode

i have a rev matching question. so when cruising at 5th and i want to go down to 2nd. First i clutch in, throw it down to 2nd, rev match the rpm, and let the clutch out. Is this bad or good? but when i do that i get into gear very smoothly.

You want to try rev matching while the gear is in neutral, takes awhile to learn but just keep trying it. Someone correct me if I'm wrong ^^

[dorkiedoode]

That what everyone been saying. Im just wondering if my first step is really bad for the tranny?

[OhondaU]

Originally Posted by SilentBob420BMFJ

there is a difference between being a smart ass just to try to fight with somebody, and correcting them so others who read the thread get the right information.. if i were to claim the si has 250 hp, i would hope somebody would correct me, regardless of how it sounds



i know it was confusing, and i wasnt actually talking about engine braking, so nvm about that.. basically, how do you double clutch upshift? i know how to do it with downshifting, but how does it differ with upshifting?

There is nothing to correct. In the manner in which I used "released" it was correct terminology. If that doesn't fit with your provincial vernacular then I'm sorry. Part of communication is being able to ascertain the meaning of a word or phrase by the surrounding context. Yodums didn't seem to have a problem doing that. Stop being so lazy.