Hazade

iTrader: (8)

you will get some smells in a new car like that. if it hasnt been run hard much yet it could still be the cat heating up. they can give off some interesting smells. I bought my Z used so I cant speak for this car but i've noticed it with other cars

eazy

Learn to rev-match!!! Problem solved!!

shopdog

If you *rev match* you won't need to slip the clutch when changing gears, *and* you'll cause much less wear of the synchros too.

Except when starting off from a stop, you shouldn't need to touch the clutch *at all*. IF you rev match properly, the tranny will just drop into gear without the need to clutch. Of course if you don't know how to rev match, you'll grind the gears something fierce.

hurahn

How in THE hell do you learn how rev match and not use the clutch? I thought that was only for race cars.

g35cfan

I have a question about rev matching and down shifting. Say you are in 6th and want to downshift to 5th. Step in clutch ... now, do you wait until your are in 5th than blip the throttle to rev match, or is it ok to blip the throttle while in the process of shifting it into 5th, so that you're ready to blast off as soon as you are in gear. I know the engine is disconnected from the drivetrain when the clutch is engaged, so this should be ok, but for some odd reason, I just feel that blipping the throttle before I'm completely in gear is doing harm to my baby.

sausage5000

if you "blip" while moving the shifter into gear, that is called "double clutching" ...something that is not really needed ever since syncros were invented.

if you give it gas to "rev match" as you are letting out the clutch, that's a good thing.

g35cfan

Believe me, I'm not trying to double clutch. Takes me way too long to try to double clutch. I'm just blipping the throttle so the needle goes by the desired rpm, sliding the shifter into gear, and then letting out the clutch. So, by the time I'm releasing the clutch, the rpms should have dropped slightly and into the desired rpms. What I'm asking is ... should I wait until the shifter is in gear then blip the throttle, or is it ok to blip the throttle while moving the shifter at the same time (all while clutch is engaged)?

sausage5000

okay i see. not double clutching, but not just rev matching either.

my opinion is that what you are describing is totally okay.

however, i find that it is not needed if i give it a very slight tap or sustain of the gas coming out of the gear, and then move the shifter and engage quickly. as i put the clutch in while in gear, it will rev an almost imperceptable amount right before i let off the accelerator and start to move the stick, then it slides in the next gear like butta, every time. of course this is mostly up-shifting.

if i just let off the accel and then put the clutch in, then move the stick... it will feel notchy going in, every time. ...so i can see where your method would work. maybe i should check it cause i grind sliding my stick into a lower gear sometimes.

mp3car

just to clear some things....

double clutching is, as I understand, can be done either upshifting or down shifting.....

downshifting... let's say you're in 4th.... you put in the clutch, take it out of gear into neutral... then you bring the rpms up to where the need to be for that speed in 3rd, or 2nd, then once the rpms are at that spot, put the clutch back in while holding the gas there, then put it into 3rd (or whatever), and now when you let the clutch out, your engine should remain at the same rpms....

upshifting, same idea, but when going from 3rd to 4th for example, you put in the clutch and tke it out of 3rd and let off the gas, let off the clutch, let the RPMs fall to where they need to be for 4th, then get on the clutch and put it into fourth and let off the clutch and get on the gas.... the idea of double-clutching.... using the clutch twice.... i think mostly used before syncros....

but... unless your trying to shift super fast during normal driving, the amount of time it takes to put in the clutch let off the gas and put it into the next gear, the rpms have probably fallen right about where they need to be for that next gear....

when downshifting, what I do is when i put in the clutch, i "blip" the throttle the right amount to get the RPMs up where they need to be fore that speed in the lower gear, this way there is no "jerk" or egine breaking when downshifting.... so I just quickly raise the rpms while having the clutch in between going from 4th to 3rd instead of haveing the clutch out and it in neutral while revving.....

also... something some cars have in common.... I have only driven a Z a few times and don't remember on it... but... on some other cars, 4th is not directly below 3rd! even though, of course the little "diagram" shows it that way.... in a few cars I have driven, 4th is SLIGHTLY to the right and down.... and I do mean slightly! In my integra GSR, if you tried to bring it straight down, it would get "stuck" on the "notch" in between 4th and 2nd... and if you acidently dropped it to 2nd instead of 3rd.... VROOM!! 10k RPMs!! I did it once, pegged the tach at 9500... boy was I scared! It engine braked so hard that it barked the tires!

eazy

I can't get away with just that one-liner!

Here is a simple/extreme example of rev-matching.

You're going 60mph on the freeway and joe blow pulls up next to you wanting to do a 60mph roll on 3.

You're in 6th gear! To accelerate as hard as possible from 60mph you need to be in 3rd gear before the race even begins.

Take it out of 6th and quickly match rpms to about 4400 rpm(actual rpm can vary from Z to Z). Put it in gear as soon as it will slide in easily and release the clutch when the rpms are right. If you release the clutch at the right time, it will grab quickly and smoothly with no engine brake, no surge forward, no slipping of the clutch, and no damage to the drivetrain. God forbids any "bucking", "jerking", "slipping", ever! Ugh. hehe.

Well, I take that back. You can slip the clutch when you launch. It is normal and acceptable, just don't slip it hard, or slip it for a long time; keep it to a minimum. Also, don't slip the clutch after you're rolling, it's definately bad practice. It's a beginners easy solution to rough shifting. If you are doing this you definately should learn to shift properly.

To find the exact rpm for the above rev-match example, just accelerate to 60mph in third gear and take note of the rpm. That's the rpm to match when you're driving 60mph and you want to downshift into third. You can also reapply this scenario for 2nd and 3rd gear for a more tame experience and practice going back and forth. Once you get good you should be able to do any necessary rev-match, and shift smoothly whenever you like. When you get really good you can rev-match even while braking, AKA heel-toeing.

During casual driving, don't take the rpms past 3k, there is no need. Shift often and early. Get to a high gear asap and chilll. Upshifting at lower rpms is easier and more forgiving if you don't know how to catch the next gear when upshifting.

Also, never lug the engine. Lugging the engine is like driving 30mph in 6th gear. Always use the appropriate gear.

Double clutching is depressing the clutch, taking it out of gear, releasing the clutch, depressing the clutch again, selecting a new gear, and releasing the clutch. There are certain situations when a double clutch should be used. Like when shifting into 1st gear or reverse, you should always double clutch, and it also helps to be stopped.

I hope that might help!

Peace!

shopdog

How do you learn? Practice.

I learned to drive on the farm, with an old truck that didn't *have* synchros. If you didn't rev match, it wouldn't shift. It would just grind and grind until you stopped and started all over again. This forced you to get it right if you wanted to drive.

The clutch was really only used to get rolling. All other gear changes were done without bothering to depress the clutch. Just ease off the gas a bit and slip it out of gear, let the revs fall until they're right for the next gear and let it drop into gear, then back on the gas. To downshift, slip out of gear as before, but this time razz the throttle until the revs come up just past match, then slip it into the lower gear just as the revs fall to match. Do it right, and there's no grind at all.

With a transmission that has synchros, it is a whole lot easier. Your timing doesn't have to be perfect, just apply light shifting pressure as the revs are falling to match, and it'll just drop into gear when you hit match. This does put some wear on the synchros, but if you're close to match before you apply pressure, it won't be much, certainly less than trying to force the shift without rev matching.

Of course you *can* use the clutch, but if you are shifting right, it'll never need to be slipped. Using the clutch is really just a crutch to avoid doing damage if you try to force the shift before match is achieved. If your throttle control is good, and your shifting is right, it isn't needed.

shopdog

It is essential to blip it while the transmission is in neutral if you're shifting while leaving the clutch engaged.

If you are depressing the clutch when shifting, then you can blip it before or after you put it in the lower gear, but before you engage the clutch. Doesn't make any difference in that case.

But if you want to avoid synchro wear when downshifting, the clutch needs to be engaged while you blip it, ie double clutch. That gets the input shaft of the transmission up to speed so the synchro teeth just slip together with no synchro clutch action taking place at all.

Note that all modern transmissions have constant mesh gears. You aren't engaging and disengaging actual gears when shifting. The gears just freewheel on the shaft until the synchro teeth engage. What you're doing when shifting is engaging and disengaging synchro teeth.

The synchros have a cone part (clutch) and teeth. When you shift normally, the cone clutches touch before the teeth and force the input and output shaft speeds to match before the teeth engage. When the teeth engage, power is transferred to that particular set of already meshed gears. If you try to force a shift, you can override the cone clutches, and you'll get the familiar grinding sound. This isn't gears grinding, it is synchro teeth grinding.

Synchros used to be brass, modern transmissions may use other materials. But they will all wear, like any slipped clutch, if you don't rev match when shifting. If they wear a lot, then you'll lose synchromesh action, and then the *only* way to avoid grinding is to double clutch and shift by rev matching.

Globox

1,000k to 2,000k (1,000,000 to 2,000,000) RPM is way too much, your engine and clutch won't make very long this way.

defex

This is due in part to torque. When I drove a mustang I could ease off the clutch and the car would roll forward without even pressing the gas, whereas if I drive a friend's civic it just stalls if I try the same thing.

DeZigner

The "Car Talk" guys were talking about this just a few weeks ago. They recomended that from a stop, as you let the clutch out, wait until the last possible second before hitting the gas. Plain and simple.

ares

iTrader: (2)

the part in question is the throwout bearing, Ive heard the same thing. however Ive NEVER heard anyone ACTUALLY wear it out to the point of failure... seems more like an imaginary problem. I beleive its a 2$ part anyway that they will change with the clutch, and the clutch should always wear out sooner than the bearing. also the arguement is easy to make that waiting in 1st gear lets you gas it to get out of a bad situation like a car coming up fast from behind with no clear intention of stopping.

genieman17

guys go here: http://auto.howstuffworks.com/transmission1.htm read up. Before reading this i didn't understand at all what was going on in the tranny. And if someone sat down with me to explain it for 5 hours it wouldn't have made a difference because its so hard to imagine. This link has illustrations and various explanations of synchros, shifting, double-clutching...everything...

350ZTN

So is engine braking bad when down shifting? Say 5th to 4th and letting the clutch out and the engine slowing you down?

shopdog

No, it isn't bad, unless you don't rev match before letting out the clutch. That little blip of the throttle minimizes clutch wear. Then letting off the throttle slows the car, saving the brakes.

dkny_boi

iTrader: (2)

I was able to do this in my old car too. I didn't make a habit out of it, but when i was really lazy and driving home late i would do it. I've never tried it on the Z though... it's still a bit new to me, i don't know the exact timing for it yet... plus i just don't want to grind lol.

But i have to admit, it was pretty funny to show my friends, who also had been driving standard for quite some time. None of them would believe that you can shift without using the clutch