NCTL05

iTrader: (9)

^^^If you're not decelerating then what I do is shift before the turn. No matter how fast you are at shifting once you stop putting power to the wheels, say by going into nuetral, you lose a little grip which can throw off the balance of the car in the turn. That's why I don't shift in a turn while accelerating. Try it out.You'll see what I mean.

The thing I love about a FWD car is the harder you accelerate through a turn the better grip you have.

GoldnKnight22

I don't know as much as I should about the mechanics of a manual transmission....

Let me get this straight:

Revving, paused in N, clutch disengaged: helps match up shaft speeds. (reduced synchro wear)

Revving, while lower gear selected, clutch engaged: helps match up engine speed (reduced clutch wear)


Southern Boy, can I get a confirmation on this? Thanks.

.......all this time I've been ignoring the double-clutch, thinking that rev matching with the clutch engaged was still doing the same thing.

I hate cars

Rev match does accomplish a lot. Your passengers will thank you, your clutch will thank you, and if you're on the track and at the limit it won't upset the balance of the car as much.

Double clutching is to save wear on the syncros, nothing else. It's a lot of extra work. This was done before transmissions had syncros and was necessary back then. Not it's only to lessen the load on the syncros.

You push the clutch in, shift to neutral, let it out, push it back in, and shift to the next gear. When you let it out in neutral it "syncronizes" everything inside of the transmission so it's all spinning at the correct speed so the syncros don't have to speed up or slow things down (like a mini clutch).

There's also the lazy way. When I was practically falling asleep on the commute, I would pull it out of gear without using the clutch and then push the clutch and shift. It's the lazy man's double clutch but it's harder on the trans.

SouthernBoy

See my post, #27, on the first page of this thread. That will give you a more detailed explanation of this procedure.

Rev matching reduces clutch component wear. Double clutching reduces clutch component wear and synchronizer wear. If you can only do one of these, rev matching is easier to learn and I would do that technique first. Double clutching carries this further but does take more effort to learn and do properly. But it's not hard. Hell, I've been doing it since I was a teenager.

403 UA6

Does downshifting the regular old fashioned way provide a greater amount of engine braking/deceleration than rev-matched downshifting?

I hate cars

Engine braking remains the same. You're eliminating the initial shock when you rev match. This shock (matching of speed between the engine and trans) is what wears things out and can cause you to break traction or upset the car in a corner.

SouthernBoy

Initially, yes it does and here is why. When you downshift like this;

o Remove foot from throttle.
o Depress clutch.
o Shift to selected lower gear.
o Slowly begin releasing the clutch.

the drive wheels are going to have to pull engine speed back up to and beyond where it was when the downshift started. They are working against engine vacuum magnified by gearing.

There are some who think this sounds cool but this is anything but that. What it is, is a sure way to reduce your clutch life.

skd2k1

iTrader: (1)

I disagree with you on the necessity of double clutching. When I was 18 I inherited a 5spd e34 bmw with 200k+ miles on the mt. I learned to drive stick on this car and owned until it had over 300k miles (still on original clutch!!). I learned to double clutch but rarely did that although I always rev match when downshifting. My next car was a 5spd e36 m3 and treated the trans the same way on this car although my technique did improve through experience. Sold the m3 with 150k+ miles on the odo. I know the owners of both of my previous cars and there has been no transmission trouble out of either of them to this day.

IMO, as long as a person doesn't just jam the stick in gear and gives the synchros ample time to do their job there won't be problems (be smooth!). Will there be wear on the synchros by using them? Sure, but you put wear on all the parts of the car by driving it. Synchros are in there to be used.

SouthernBoy

Disagree all you wish. However, the fact remains that double clutching when downshifting will reduce synchronizer wear. Rev matching is certainly better than just doing 'lift foot-clutch in-complete shift-release clutch', no doubt about it. But rev matching does not reduce synchronizer wear.

I am not here to sell a technique or argue any specific position on this or any other topic for the simple reason that what anyone else does with their cars is none of my business and therefore, none of my concern. I know what works and why it works and that's really all I care about. When I am posed a question, I try to give an honest answer with the knowledge and experience I have. When I am in error, I freely admit it. We all have opinions, but opinions are not always facts. Still, how someone chooses to operate their car is completely and utterly their own affair. I have never said that double clutching was a necessity (at least I don't recall having ever said that). It is a preferred method to use if one wishes to significantly reduce wear to one's synchronizers. And with the problems many TL manual owners have experienced with their transmissions, anything one can do to ward off trouble seems to me to only be common sense.

BTW, I applaud you on getting such fabulous mileage out of your clutch.

Roger555

iTrader: (3)

Another question for you guys about downshifting.. Say im on the highway going 60-75 in 6th gear and I really need power to either pass someone or whatever. In the auto I of course floor it and let it downshift and i'm off. Whats the best way to do this in the TL? Downshift to 4 rev match and floor it? downshift to 3rd?

I hate cars

Rev match straight to 3rd.

I hate cars

I agree. Facts are:

Double clutching reduces syncro wear period.

Rev matching reduces clutch wear and shock but does nothing for syncro wear.

The gray are is whether or not it's worth it for you. Most manual transmissions will go 200,000 miles without double clutching. You can probably double the life of the syncros by double clutching but will you have the car past 200,000?That's personal preference. For some it's worth it. For others it's not.

I suppose double clutching would cure the 3rd gear issues common with the 6mt.

Ascendancy523

With all the discussion on proper downshifting technique, it's interesting to note that our car manual advises the operator to perform downshifting as described above. Just had a little chuckle after reading that.

SouthernBoy

Now that got my attention, so I just now went out to my garage to check my owner's manual for my '04 manual TL and it doesn't say anything like this. I must admit, I only looked at the pages referenced in the index for Manual Transmissions. I didn't look any other place.

If it says this, the reason is most likely to avoid confusion on the part of the buyer. You can bet if they put something in there for rev matching or double clutching, they could expect a host of calls.

SouthernBoy

Thanks. I hope that post I made that you referenced here did not give the wrong impression to folks. I really do feel that if someone doesn't wish to practice these techniques, for whatever reason, that is certainly their prerogative. I may not want to buy a car from someone like that but then again, that's why I buy new. I don't want other people's problems.

All of you folks should do what you believe best serves your purposes and your needs. An open discourse is a wonderful way to learn things and exchange ideas and such, but the final responsibility rests with the individual.

Ascendancy523

Not exactly word for word but it just suggests to downshift for extra braking. So assuming someone who has no idea on how to properly downshift, they could take piece of info and apply it everytime they need to downshift. At least that's what I took from that

fz409040422

go with A if u are racing driver or someone with that kind of ability; otherwise, use B; or C, simply dont down shift. XD

skd2k1

iTrader: (1)

Thanks! No doubt that double clutching is easier on the synchros but in my experience it is unnecessary. Every time I downshifted and rev matched I can feel the synchros doing their job and if you don't jam the stick in gear the synchros should be fine. That being said I've never owned a manual honda/acura.

Chessie724

Alright, I've been trying to do this in my car ever since the thread got the first few posts. I have experienced the enlightening smoothness of some good rev-matches while downshifting, but mostly out of luck and not skill. So I've been able to apply the theory into practice. Backing up a bit, I've had a manual for a daily driver for the last ten years and got 120k out of my Maxima's original clutch before getting the TL. I think I'm competent and have enough skill not to abuse the tranny. But it just doesn't feel like I'm progressing with these methods described.

I have a basic question/point that I don't think was really made clear anywhere in the thread... is this really practical/necessary in the most common scenario I'd downshift: while slowing the car down at a significant rate? I find that at the rate I usually have decelerate and go from 4th to 3rd, there's no time to do all this and brake at the same time. I know during the typical city-ish driving portion of my commute, it's more likely I'll rear-end someone if I add all this extra clutching and shifting. For those of you who do this regularly, do you do it for every downshift (even while braking with pace), or is it mostly/exclusively for a downshift with the intention of accelerating right after?

Not challenging anyone's ideas...it makes sense to me mechanically...just really trying to understand the application...

I hate cars

I understand what you're saying. With a few month's worth of practice you become very quick and it's second nature.

When you rev match, try and heel and toe using your right foot to brake and at the same time blip the throttle. So you're on the brakes while you're blipping the throttle for the rev match. I found it a little awkward on the one manual transmission TL I've driven with the gas pedal hinged from the floor. I never did master it because I only had a day. I hit the brake with my toe and the throttle with my heel. I hit the bottom of the gas pedal so it blipped to the floor very quickly. It seems so weird at first but you will feel like a pro once you master it. Heel and toeing wont take away from the braking time at all.

Turbonut

iTrader: (1)

IMHO, don't downshift to slow the car down. There are a few exceptions such as coming down a long grade at a low speed, just keep the trans in a lower gear to help keep the car at the proper speed, but in the normal day to day activities, don't downshift to slow down. Slowing and coming to a stop, slow down using the brake and as the rpms drop to a point you'll hear that is about the minimum thresehold for that gear, just push in the clutch, slow and stop the car. if at a light, leave it in neutral, if at an intersection where you will be going quickly, shift into first after stopping. Slowing for a sharp turn, same idea, although as you're navigating the turn, put it in the gear selection you'll want, keeping the clutch disengaged, when exiting the turn just blip the throttle to match the RPM's, let out the clutch and off you go.

SouthernBoy

Yes, I do it every time I downshift which is most often a double clutched downshift but I admit to the infrequent rev matched downshift but only at the lower RPM's and slow road speeds. If I find myself coming up on somebody quicky (someone changes lanes, gets in front of me, then brakes kinda hard), I don't downshift at all.. I get on the brakes.

SouthernBoy

Good luck to people new to all of this tryhing to learn to heel-and-toe. You think learning how to double clutch a downshift in the normal fashion is a strain? Try this one.

Sorry, I had to throw that out. And it's just because I have never mastered this technique. And the reason is not because I can't, it's because I don't make the attempt. My hat's off to those who have mastered this and do it on a regular basis, though. Good for you folks.

6spdtl-s

iTrader: (1)

so if the 'correct' way to downshift is to double clutch, the 'correct' way to upshift should be to double clutch as well. I dont think anyone does this...

justnspace

iTrader: (1)

^no. upshift normally.
clucth in, shift to higher gear, clutch out.

6spdtl-s

iTrader: (1)

but this will wear out the synchos

justnspace

iTrader: (1)

Did you understand?

I couldnt tell with your sarcastic answer

6spdtl-s

iTrader: (1)

ha sorry. I know what you said.

Just dont get the logic that you must double cluth on down shifts so that you do not wear the synchos, but on upshifts you do not need to do so. am i missing something technical here?

justnspace

iTrader: (1)

its all about engine speeds.
re-read this whole thread.

especially the part, where waltah asks about upshifting.
basically, when you upshift, the engine is already at the correct speed to engage your next gear. it make sense...you're increasing speed, which raises the RPM for the next shift.

Don't know if I got all the terminology correct. Please correct me if I'm wrong.

Turbonut

iTrader: (1)

Are you stating that every time you slow down, if you have the time, you double clutch to a lower gear to aid the slowing?

SouthernBoy

No, not at all. Hope I didn't convey that message. I downshift when the need is there for me to do this. Granted, I will do this more often than not when approaching a light or stop sign, but not every time by any means.

Incidentally, I rev matched a few downshifts today for the reason I gave in a previous post. My speed was low enough that double clutching would not have gained me anything.

Turbonut

iTrader: (1)

Sorry, but that is what brakes are for as they are a great deal less expensive than a trans. Just think about the situation, normally slow down, then push in the clutch and roll to a stop, but no, you start to slow, double clutch to a lower gear then possibly double clutch to another lower gear??? It doesn't make sense as you say you want the trans to live long, then do extra shifting when not needed. I'll go back to my original statement, in that the syncros are well used when accelerating, and double clutching to a lower gear sure isn't going to be the saving grace as hitting the RPM's perfectly so as not to use the syncros at all is an impossibility, and also doing the shifting more than normal, or at least more than someone that doesn't downshift when stopping.
Maybe it's just me!

SouthernBoy

I rarely downshift more than two gears when approaching a light or stop sign... it almost completely depends upon which gear I'm in. For example, if I am in 4th and doing 38 MPH, I may downshift to 3rd, but almost never then do a downshift into 2nd. The only time I would likely do that is if the light changed and I was going to slow for 3rd gear to begin accelerating.

As for everything else I have written on this thread, I stand by what I have stated and the reasons I gave.

6spdtl-s

iTrader: (1)

nope, not just you. I'm 100% with you on that!

Cyberdemon

Lol this thread is fun.

I personally like to triple clutch and only use my odd gears (1-3-5) on odd days of the month and 2-4-6 on even days. This way I reduce gear wear by 50%!

Seriously though any modern car the synchros will be fine going with method A IF you are going down 1 or 2 gears. The only time I'll double clutch is when going down multiple gears (IE 5->2).

One thing is crystal clear regardless of which camp you're in - Rev matching is your friend. It still pains me when I drive with someone who will dump it into the lower gear and just let up the clutch slowly when downshifting. Yikes!

skd2k1

iTrader: (1)

Agreed, your trans and clutch will thank you for this. Downshifting is for more power and setting up for a corner. Learn to change your own pads and make a brake job totally affordable.

Waltah

iTrader: (3)

i downshift just before entering the turn then accelerate out of it.