[Joonsup]

Originally Posted by txusa03

negative, you can test this yourself at your own risk.

i guess it's for automatics only then. either that or i just don't know what the fawk i'm talking about and it's something completely different from what you guys are discussing. haha

[OC 335i]

Wow Nabil, useful thread.

(wth?)

[Couch]

Originally Posted by BMdblU

The best way to learn how to drive, is by driving. Not reading a thread online.

+1

To be more precise though, drive in traffic during your learning process. For me this increased the quickness of my learning curve.

Before trying to get the throttle to clutch ratio down, I suggest learning to launch the car using only the clutch. That way you know whereabout the egagement is related to release of the clutch pedal.

[!Xoible]

Originally Posted by txusa03

Ok, I will play along. Someone tell me what is so bad about this technique. Here is my version of rev matching going from 5th to 4th:

1) depress clutch
2) shift from 5th to 4th
3) blib gas and let gas off very slowly
4) let go of clutch

I skip the neutral part...

There are 3 speeds in your car.
1. Engine speed RPM
2. Wheel speed MPH
3. Flywheel and other internal tranny part speed

When you skip the neutral part you are synchronizing engine speed with wheel speed, but not the internals speed. your synchros will still have to work to get everything spinning up to speed.

what you are doing is the minimum that should be done. but still not enough

[achien]

You are fine, your ride comfort won't be punish from going from 6th to 5th, or from 5th to 4th, or even from 6th to 4th.

You will need to rev-match a bit more accurately (a.k.a. less forgiving) if you downshift to 3rd or 2nd. Otherwise, your ride comfort will suffer.

Originally Posted by txusa03

Ok, I will play along. Someone tell me what is so bad about this technique. Here is my version of rev matching going from 5th to 4th:

1) depress clutch
2) shift from 5th to 4th
3) blib gas and let gas off very slowly
4) let go of clutch

I skip the neutral part...

[!Xoible]

Originally Posted by joonsup

i thought on the new bimmers you don't have have to blip the gas b/c it rev matches for you, no?

nope. Manual transmissions have not changed much since the 30's. They have synchnronizers that do the rev-matching, but that means the synchros are wearing out.

Originally Posted by .:bHd:.

I got a question. When you park the car, do you shut it off in neutral or in gear? Sometimes when i park on hills i put it in first gear and pull the handbrake because i can feel the handbrake struggling to hold the car. Any opinions?

You should have it in 1st, 2nd, or R gear when you park. Handbrake should not be relied on to hold the car, especially on hills

Originally Posted by checuervo

+1 ... but it sounds like from that earlier post we're not doing it right.

Someone lay some knowledge on me!

not enough, i posted a reply

Originally Posted by nub340

- Don't ride the clutch! That means take your foot COMPLETELY off the clutch pedal when your not clutching. Good habit to keep your foot on the foot rest when not clutching.

- Don't use the clutch to keep the car from rolling backwards. Luckily the newer Bims have the Hill Start Assistant to help us out, but it doesn't kick in unless the grade is steep enough. If you're on a slight hill, our cars WILL slowly roll backwards. Use the brakes!

Which reminds me: for those who have trouble with hills you can use one of the following:

1. Pull e-brake, put in gear, and start releasing clutch while giving gas. Right before the gear engages, release your e-brake
2. if you are experienced enough just let it roll for a little bit and take off as usual giving more gas
3. bmw hill assist sucks IMO, coz i love the feeling of falling back might be a good thing to have though

Originally Posted by txusa03

Mantis would you ask your friend about the technique i used above and what he thinks about it.

LOL

[!Xoible]

to see different parts that spin:

[!Xoible]

Originally Posted by achien

You are fine, your ride comfort won't be punish from going from 6th to 5th, or from 5th to 4th, or even from 6th to 4th.

You will need to rev-match a bit more accurately (a.k.a. less forgiving) if you downshift to 3rd or 2nd. Otherwise, your ride comfort will suffer.

nope, it's not enough coz he's not synchronizing fly wheel with clutch disc:

The clutch only wears while the clutch disc and the flywheel are spinning at different speeds. When they are locked together, the friction material is held tightly against the flywheel, and they spin in sync. It's only when the clutch disc is slipping against the flywheel that wearing occurs. So, if you are the type of driver who slips the clutch a lot, you'll wear out your clutch a lot faster.

source: http://auto.howstuffworks.com/clutch2.htm

[Welshman]

0000000000

Originally Posted by mantis

Rev-Matching technique: Double Clutching

Correct me if I'm wrong, which probably am.

When you downshift to gain more power your engine will be spinning at a higher speed (higher RPM). Synchronizers will be spinning harder to to synch the speeds. It is a good practice rev-match.

Rev-matching is manually bringing up the RPM before engaging the lower gear you are shifting into. So when you ditch your clutch, your synchros will not have much to do, and they wont wear out.

This is how it is executed: (let's say you are going on 5th gear cruising at 50 mph, and you want to pass someone, so you want to go to 3rd gear)
1. Depress clutch
2. put gear in neutral
3. Undepress the clutch
4. blip your gas to bump it up 1500-2500 RPM's more (Do not take the #'s literally here, i dont know im just guessing, but you'll get that down by practice/experience)
5. Depress clutch again
6. put shifter in 3rd gear
7. Undepress the clutch

The beauty of this technique is it has to be done in less than 1 second (sure with experience and practice)

This is an exercise to get your foot used to the concept if you have never done it. This is basically a short version of it for practice, to get you to the real double-clutching

1. Depress clutch
2. put gear in neutral
3. blip gas
4. engage 3rd gear
5. undepress the clutch

(note: the 5 steps i just listed are not enough, they do not synchronize tranny's internal parts spinning speed - you need to blip gas while clutch is undepressed to synch the speed of flywheel *i think*)

practice that ^^ a few times when in open road, and when safe. Then double clutching will be real easy.

First let me express my initial amazement at this thread.

I'd seen another thread where someone mentioned someone who put the car in neutral when going round bends and I postulated that this individual was in the running for a Darwin award.

Then I thought about it a bit and reckoned that the lack of knowledge on how to use a manual transmission might be due to what I understand to be the case that on your side of the pond automatic transmissions are the norm so many of you learn to drive using an auto box. So I'm not here to heap abuse and or ridicule on anyone.

So, the first method of downshifting you describe where the gearbox is moved into neutral and the clutch is reengaged, is what is known as double declutching - you attribute this to the second method.

You do not need to double declutch with a full synchromesh gearbox at all. This technique was used before synchro gearboxes were invented and I see no benefit in practicing it unless you need to drive a Heavy Goods Vehicle.

If you want to downshift use the second method i.e.

1 Clutch down i.e. disengaging the engine from the gearbox

2. Shift gear using a blip of the throttle to match the revs required for the same speed in a lower gear. You do not need to put the gear in neutral - just move it straight through neutral into the desired gear

3. Clutch up i.e. reengaging the engine and the gearbox.

Blipping the throttle is not necessary with a synchro gearbox but is good practice since as you have noted it means that when you reengage the clutch the engine is spinning at the same or a similar speed to the gearbox. This means that as the clutch is reengaged you don't have put a sudden load on either component, thus saving unnecessary wear on both the engine and gearbox. The basic idea is be smooth.

Other points.

Never leave the car in neutral when on the move. Always have the car in gear. Make sure that it is the appropriate gear for your speed and the road conditions. Neither hold a gear to the redline every time before changing up, nor hold the car in too high a gear as you slow down. The car needs to be able to respond at all times to deal with the unexpected.

When you come to a halt at say some stop lights and you can see that they won't change in less than a few seconds, engage the handbrake and put the car in neutral. Keeping the clutch depressed wears out the thrust bearing unnecessarily.

You should note that with a synchro box it is possible (but not recommended) to change gear without using the clutch at all. It is quite simple with upshifts, not so simple with downshifts, but the principle is true either way that if the engine revs are matched to the speed at which the gearbox is spinning the gears will engage without the use of the clutch.

Hear endeth the lesson.

May your manual gearboxes give you as much pleasure as mine does!....

[jdink]

Originally Posted by mantis

Bad Practice

Leaving car in neutral
I am guilty of this. I am going to quote a friend of mine. I sent him an email (when you guys grilled me before)



My friend's Answer:



Riding the Clutch
http://en.wikipedia.org/wiki/Riding_the_clutch

Correct me if i'm wrong....
a) Riding the clutch = bad
b) Dropping the clutch (such as on a quick launch = bad

Questions (assuming the above statements are true)
a) So is feathering the clutch bad also? Or is that the "ideal" way to go? I find that the only way to shift smoothly is to feather just about every shift in gears a lot (except maybe the higher gears)
b) Dropping the clutch is bad on the ____________.
c) Riding the cluch is bad on the ____________.

And if i'm completely off here, someone feel free to me.

[nmulax]

The following is not me; but these are great videos if you're new to a manual trans. or just want to improve your driving.



Intro



Seating Position



Gentle Launch



Moderate Launch



Aggressive Launch



Heel and Toe Theory



Heel and Toe



Upshifting Theory



Upshifting



Single Clutch Downshift



Double Clutch Downshift



Putting it Together Part 1



Putting it Together Part 2

[jdink]

Originally Posted by Welshman

0000000000

You should note that with a synchro box it is possible (but not recommended) to change gear without using the clutch at all. It is quite simple with upshifts, not so simple with downshifts, but the principle is true either way that if the engine revs are matched to the speed at which the gearbox is spinning the gears will engage without the use of the clutch.

Hear endeth the lesson.

May your manual gearboxes give you as much pleasure as mine does!....

+1 That explains a lot I used to be able to switch gears on my parents old Miata without using the clutch sometimes and never knew why... Have yet to try it on my e90 as i'm afraid of making that heart breaking grinding noise (even those a previous link in the thread explained it and made me feel a little better about it!)

[asif163]

Maybe one of you guys can help with this. When I take off in 1st gear from a stop my car usually hesitates a bit before "engaging"- the hesitation is very slight...I don't know if I'm being clear or not- what do you folks think this is attributed too? I don't think I'm riding the clutch- maybe I'm letting it out too slow- or too fast?! I usually rev the engine just a little bit when in neutral and then I shift to 1st gear.

[!Xoible]

Originally Posted by jdink

Correct me if i'm wrong....
a) Riding the clutch = bad
b) Dropping the clutch (such as on a quick launch = bad

Questions (assuming the above statements are true)
a) So is feathering the clutch bad also? Or is that the "ideal" way to go? I find that the only way to shift smoothly is to feather just about every shift in gears a lot (except maybe the higher gears)
b) Dropping the clutch is bad on the ____________.
c) Riding the cluch is bad on the ____________.

And if i'm completely off here, someone feel free to me.

first 2 comments are correct. Dumping the clutch is not "wrong" but obviously you're driving your car hard, so wear and tear and other stuff is attached. but it's not like an incorrect practice.

we're not here to slap anyway
a) So is feathering the clutch bad also? Or is that the "ideal" way to go? I find that the only way to shift smoothly is to feather just about every shift in gears a lot (except maybe the higher gears) -- Im not sure feathering is bad at all...
b) Dropping the clutch is bad on the *clutch plate*... i think anyway
c) Riding the cluch is bad on the *clutch plate*

[Welshman]

Originally Posted by .:bHd:.

I got a question. When you park the car, do you shut it off in neutral or in gear? Sometimes when i park on hills i put it in first gear and pull the handbrake because i can feel the handbrake struggling to hold the car. Any opinions?

If it's that steep use the handbrake and put it in 1st gear. Also have the front wheels pointed so if the car does roll back it will roll into and not away from the kerb.

[!Xoible]

Originally Posted by Welshman

0000000000

First let me express my initial amazement at this thread.



May your manual gearboxes give you as much pleasure as mine does!....

great post! thanks for input

Originally Posted by nmulax

The following is not me; but these are great videos if you're new to a manual trans. or just want to improve your driving.

thanks man! that's one hell of a great post!!!!!!!!

Originally Posted by asif163

So when I take off in 1st gear from a stop my car usually hesitates a bit before "engaging"- the hesitation is very slight...I don't know if I'm being clear or not- what do you folks think this is attributed too? I don't think I'm riding the clutch- maybe I'm letting it out too slow- or too fast?! I usually rev the engine just a little bit when in neutral and then I shift to 1st gear.

hesitation or a bit of vibration is normal. the clutch is working to move those wheels from still. so yah, when you take off in first you need to spend a second or a second+ to smooth out your take off. that's normal wear to the clutch and not riding the clutch.

riding the clutch is when you're driving on freeway for example, and just rest your foot on the pedal. you think you're not depressing at all and barely touching, but in reality it's killing ur clutch

[jdink]

Originally Posted by asif163

Maybe when of you guys can help with this. When I take off in 1st gear from a stop my car usually hesitates a bit before "engaging"- the hesitation is very slight...I don't know if I'm being clear or not- what do you folks think this is attributed too? I don't think I'm riding the clutch- maybe I'm letting it out too slow- or too fast?! I usually rev the engine just a little bit when in neutral and then I shift to 1st gear.

It may be the Clutch Delav Valve (CDV) that is giving you the hesitation.

Also, I was concerned that the "hicups" I was feeling sometimes when i shifted from 1-2 or 2-3 were from either the CDV or just my bad manual driving abilities but my friend was saying when he drove my car that it may be the turbos kicking in. I know this isn't a "Turbo" thread, but it may be beneficial if someone could explain this so people would know what aspects of their driving (smoothness of shifts) is due to their manual driving abilities, and what can be attributed to other factors.

[Welshman]

Originally Posted by mantis

first 2 comments are correct. Dumping the clutch is not "wrong" but obviously you're driving your car hard, so wear and tear and other stuff is attached. but it's not like an incorrect practice.

we're not here to slap anyway
a) So is feathering the clutch bad also? Or is that the "ideal" way to go? I find that the only way to shift smoothly is to feather just about every shift in gears a lot (except maybe the higher gears) -- Im not sure feathering is bad at all...
b) Dropping the clutch is bad on the *clutch plate*... i think anyway
c) Riding the cluch is bad on the *clutch plate*

I'm not sure quite what the difference is between feathering the clutch and riding it.

Don't ride the clutch if you can avoid it - sometimes in heavy stop start traffic it's difficult to avoid.

If you're not changing gear your foot should never be on the clutch pedal - BMW provide you with a foot rest for your left foot so put it there.

As for dumping the clutch I see no point in it nor any need unless you are trying to post a 0 to 60 time when the revs will be high to start with and you want to get the power through to the rear wheels asap. Even then you won't truly dump the clutch. You will still need to feed the clutch in to take up the engine's power - you will just be doing it a lot quicker than normal. By the same token when you depress the clutch it shouldn't be a violent stamp on the clutch pedal.

The key is smoothness on both upshifts and downshifts. One thing I find helps is to hold the gear stick firmly - not with a death grip but not loosely either.

[Raja Ventureshield]

Originally Posted by BMdblU

The best way to learn how to drive, is by driving. Not reading a thread online.

funny as hell.

[asif163]

Originally Posted by mantis

great post! thanks for input


thanks man! that's one hell of a great post!!!!!!!!


hesitation or a bit of vibration is normal. the clutch is working to move those wheels from still. so yah, when you take off in first you need to spend a second or a second+ to smooth out your take off. that's normal wear to the clutch and not riding the clutch.

riding the clutch is when you're driving on freeway for example, and just rest your foot on the pedal. you think you're not depressing at all and barely touching, but in reality it's killing ur clutch

Ok so I'm not doing anything wrong when I take off in 1st gear- now what about when I want to launch the car? Just rev the engine in neutral to XYZ RPM and let the clutch out as I usually do? Noob question but, I just want to make sure I'm doing it right.

[!Xoible]

Ok good so I'm not doing anything wrong- now what about if I want to launch the car? Rev the engine to XYZ RPM and let out the clutch as I normally do? Wow- that's such a noob question but, hey, I'm just trying to make sure I'm doing it right

i think that's what's called dumping the clutch. it will wear your clutch, u'll have slippage soon. you're basically driving your car hard.

I have no idea which RPM's are bad for the 335, i'd imagine 2k and above are a lot of torque! I havent gotten my 6MT yet

someone else can chime in here.

[checuervo]

Originally Posted by Welshman

0000000000

You do not need to double declutch with a full synchromesh gearbox at all. This technique was used before synchro gearboxes were invented and I see no benefit in practicing it unless you need to drive a Heavy Goods Vehicle.

What if it's a pretty significant rev jump: from 6th to 4th or even to 3rd maybe? Will the internal synchro's still be fine?

From that M5 training vid, the guy seemed to agree with you that you really don't NEED to double-clutch in normal down shifting, but he did seem to imply that there was some minor benefit.