wokuku

Please don't flame me for this as I am still relatively new to driving manual. So this is what happened. I was crusing on the freeway..about 65@6th gear. As I approace a hard right turn I..

1) Let the car roll by itself until about 35mph
2) Clutch in, move the shifter to N, clutch out
3) Rev match to about 3800 RPM
4) Clutch in, shift to third gear, clutch out.

As I let the clutch out I felt the car was braking hard as if the wheel locked up or something (sorry I don't know how to describe it correctly) so I quickly clutch in. So my question is...did I rev match correctly?? I am thinking I need to rev it higher...and I am also wondering what was causing that lock up feeling when I let go of the clutch. Did I hurt anything? Thanks~

Tony Orlando

That feeling was the clutch and driveline slowing the car down. Perhaps slightly higher revs would have avoided it. You won't do any harm this way, unless you repeatedly engine brake. Plus, you got very close to the correct RPM, you would only damage the clutch if you severely miss match revs, (i.e; dropping it into 2nd at 55 and letting the clutch out without any throttle.) If your wheels had locked up, you wouldn't have felt the car slow, it would have skidded, and you definitely would hear it.

Practice makes perfect.

Mat

I concur When you feel the car "braking" after letting the clutch out, it's because the engine is not reving quickly enough to accomodate the change in gear ratios. Next time, try a few hundred rpms extra.

arattle

In addition to higher RPMs, as people have mentioned, be smoother with the clutch when downshifting. The slower you release it, the more time the clutch plate has to come to the right speed and the less jerky the car will be. Especially if you're not sure if your RPMs are right for the situation. Good luck, it's no big deal, I do what you just described all the time - not on purpose though.

-arattle

Modena4RE

Well in 3rd gear, if you were traveling at 35mph, you would be turning 3500rpms. So when downshifting you would need to match the revs to however fast the car is going. If you were downshifting into 3rd gear at say 60mph, you would have to let the clutch out at 6000rpms for it to match exactly. 3rd gear is an easy one to downshift into since tha rpms pretty much match the mph (1000rpms=10mph, 2000rpms=20mph, and so on) You need to rev it a little higher because as you put the clutch in the second time, the revs will drop some.

AF-RX8

Are you sure you didn't slip it into 1st gear by accident ... at 35mph I don't think you would get that large of a braking affect even if you didn't match the revs

Photic

This reminds me of what might be stupid questions that I have been meaning to look into,
how exactly does someone burn out their clutch?

Is it when you use the clutch and the gas at the same time, like from a stop?

I've been driving manuals for about 7 years now and have never had one burn out on me or been warned about it. So I was curious.

Also I was going down a hill and I held in the clutch while it was in gear to put it in a pseudo neutral, my girlfriend said I would burn out my clutch doing that, I told her I hadn't heard that before, and told her she might be right, so stopped doing it.
So I guess thats my other question, will having the clutch depressed while in gear burn it out?

wokuku

I am pretty sure I was in 3rd coz I did the double clutch very slowly...and my shifter was at center and I just pushed up. That should go into 3rd gear right? And I don't think I could go into 1st while I was traveling that fast. The thing I don't understand is that I felt a rather "violent" braking force. And it made a nasty sound too....like if you put the gear into 6th instead of reverse and let go of the clutch..that kind of sound.

nt5k

If you don't do it properly it alerts Mazda through the ECU. The next time you go in for service they will void your warranty..

MRX_Rotary

iTrader: (1)

No that doesn't burn out your clutch. Your clutch disc wears just like brake pads. You ruin your clutch by slipping it. Slippage when the clutch is engaged, but the flywheel and clutch are spinning at different speeds. When the clutch is fully engaged, the fkywheel and clutch disc are locked together and spinning at the same speeds. So basically you are ruining your clutch when you go from a stop, and when you shift without matching the revs of the flywheel and the clutch disc.

Go here to learn more about clutches (bookmark howstuffworks.com very good site)
http://auto.howstuffworks.com/clutch.htm

red_rx8_red_int

Yes third is definately the easiest gear to rev match. I also agree with the person that said let clutch out slowly. I believe you should always (unless racing) let clutch out slowly. In gears other than first it shouldn't be too slow, remember while the clutch is slightly engaged, its wearing. But it should be slow enough that if you had mis-shifted you can re-clutch with little or no harm.

GeorgeH

iTrader: (2)

I know I've tried to do the 6-3 downshift a few times, and I've found that if I don't intentionally run throught the gates (6-5-4-3) and instead, just slip it out of 6th, and then try to find third, invariably the transmission finds first instead. So, I'm wondering if you did get 1st.

The few times I have done this, the synchros talked to me and kept me from making the mistake - I've never actally put it in first doing this - I can tell by the resistance and feel of the shift lever that I'm about to get first, so I back off and look for third. But if you are new to manuals you might miss these clues.

My advice is to use the gates and run it back through the gears, even if you never let the clutch out until you are in third. You are much more likely to get the right gear that way.

George

Mazdax605

Driving with the clutch depressed.Your psuedo nuetral will not burn up the clutch but it puts stress and strain on the throw out bearing,clutch fork,and the hydraulics.It is even recommended to sit in nuetral at lights and such with the clutch pedal un depressed so you don't put any extra strain on these componenets.Now I have also heard people saying(mostly bikers)that you should be in 1st gear,and have the clutch depressed in case some one behind you can't stop as fast as you.That way you can get out of the way before they hit you.

Nemesis8

iTrader: (3)

Is there a way to clear this B4 you take it in for service?

Fat-RabbiT bP

how can they void your warrenty for not downshifting that well?
there are a lot of new manual drivers, so how could they expect all of them to know how to do it perfectly and if not void their warrenty?

Ajax

Lol. I don't believe that for a second. The ECU has no way to know what gear the car is in. There's no electrical information being supplied from the drive train to the computer other than wheel slippage and spin rates.

GeorgeH

iTrader: (2)

But if you over-rev due to an incorrect down shift, it will surely record that event (at least the what, but probably not the why). I don't think that will be the case for the originator of this thread, as he downshifted at 35, but I could see it happening.

beachdog

Some of us old timers learned manual on cars and trucks that only had synchro on first gear (sometimes not even first).

What you're describing is retracing the gears and it's how I have been downshifting for years. Except for rolling up to a red light in neutral where I expect to come to a full stop, I always retrace the gears, even if it is just the shifter without lifting off the clutch. When rolling up to a light, if it turns green while I am still rolling a bit, I will pull it into second before shifting to first. Always goes in with no effort at all that way.

Other_Dave

First, you don't have to double clutch. Second, did you hold the revs until the clutch was all the way out?
I think you did one of two things.
1. had it in 1st instead of 3rd
2. let the revs drop before letting the clutch out.

3800rpm in third @ 35mph will not cause engine breaking. When downshifting I let the clutch out smoothly, and push it back in if the engine doesn't do what I expect. You won't damage your car with only a few mistakes.
--Dave.

red_rx8_red_int

If what I'm reading re canzoomer is correct, there are different maps for different rpms for diffeent gears. So the ECU must know what gear you're in.

bcrothers

It is very possible to downshift into first while going 35mph. I've done it on purpose while autocrossing. Of course, you need to rev to about 8,500 first.

But I rarely downshift to 1st on the street. to 2nd and 3rd all the time.

Sure sounds to me like you grabbed 1st instead of 3rd.

Also, you dont really need to "match" your RPM to speed...close is good enough. You will develop a feel for it. I "blip" it if doing a mellow down shift and give more throtle as I get more aggressive.

JMHO,
Bob in Indy

Mat

I highly doubt it was in 1st. I'm having a hard time engaging 1st at 15mph, I would imagine it is near imposible to do at 35mph.

However, if he let the clutch out so slowly that by the time it reached engage point the revs were down to like 2000rpm (from the original 3800rpm), then he would experience "engine braking"

wokuku

Thanks for the response everyone. I think what happened was probably what Mat said.....are those double clutching and rev matching motions are still alien to me so I tend to do everything slowly...and thus letting the revs drop and stuff. I will definitelly be sure I am not int he wrong gear before I let go of the clutch though.

HeelnToe

No need to double clutch, IMHO. Some people say it saves the synchros, but my old CRX went for nearly 200,000 miles (many track days and autox included) without any tranny problems (never double clutching) - although I'll admit the clutch was finally starting to slip a bit when I traded it in

In any case, it might be easier to learn the rev matching first WITHOUT double-clutching. Then move on to it, if you still want to...

ProtoConVert

I would say that it takes an enormous amount of skill to be able to rev match a downshift from 6 to 3 and expect it to happen in a snap... i think you pretty much did it right, but let out the clutch slower, especially near the top, near the engagement point. It's tough exactly matching revs