[ZPrime]

Originally Posted by M2-007

Thank you for the write up. For some one with little experience on how to drive a MT properly like myself, I found this write up to be most easy to understand and apply. I am also very glad the M2 comes with auto rev match. It is a bit too complicated for a beginner like me to do the rev match properly, especially applying the brake with the left foot and pressing the throttle at the same time as shown in the video.

Rev matching properly (without the car doing it for you) doesn't require your left foot to brake.

Your left foot normally would only work the clutch, and you'd use the right to hit the gas while the clutch is in and rev up the engine to match where everything needs to be.

If you're trying to do it all while braking, that becomes "heel & toe" where you either press the brake with your heel and hit the gas with your toe, or the other way around (whatever is more comfortable for you / what your body can do). Personally I brake with my big toe / inside of my right foot, and then roll my foot / ankle over to hit the gas pedal at the same time... but I wear size 13-13.5 shoes, and it can be difficult if I'm not wearing something narrow enough. (I can often have problems driving at all in my current car with a big snow boot on, since the gas and brake are close enough that my shoe can get caught or hit both simultaneously when I don't want to.)

[doug_999]

Originally Posted by ZPrime

I'd love to know where you're getting that from. The second I come off throttle in my TT, it's pretty obvious. The car definitely slows down, especially in a lower gear.

Now, in a modern BMW, I can imagine that if you're in comfort/eco mode, it might pull some silliness to allow the car to roll/coast more easily, but the principles of physics have not changed with the advance of technology. Closing the throttle (or in a VANOS-type system, reducing the amount of time the intake valves are open) causes a manifold vacuum, which the pistons have to work against to reciprocate, and this slows you down.

There are actually fuel saving benefits to in-gear coasting too - when you come off throttle, almost any modern car cuts fuel & spark and simply allows everything to spin under the power from the momentum of the car through the wheels. By pressing the clutch and disconnecting the gearbox, the engine has to go back into a standard idle, which will use fuel.

I'm not following you - first you say there is lots of engine braking and then you say that the modern car cuts fuel and spark and allows everything to spin under power. Which is it?

Short story here, in my M2 stick, I don't remember too much engine braking - but I'll try it tomorrow and see if I notice.

Originally Posted by ZPrime

Ok, I'll give you the second point. On the third point, I literally just saw two different episodes of Wheeler Dealers where they replaced the throwout bearing, one because it was actually whining and starting to go (on a BMW Z1, no less), and the other just because they had the gearbox out for other work. So is it common? Maybe not... but neither is a manual transmission these days. I certainly don't want to need to go through $500+ of labor to remove a gearbox and replace a $30 throwout bearing.

Agreed - and in a modern car, they (the throwout bearing) just doesn't wear out much. I've never replaced one and I've driven stick (clutched in during turns) for a long time.

Originally Posted by LinkF1

The responses in this thread are ridiculous. So much good information and then followed with contradictory information.

I drove manual for my first 10 years of driving and had all sorts of bad habits when I started. I've since moved to the dark side (DCT) because I am an engineer and I love the technology.

I'm really not sure what you are saying here Did you move to the DCT cause you could not solve your bad habits? And wow, 10 years of driving stick!

(messing with you here - but honestly, you are not adding to the thread by throwing out valid discussion points).

Originally Posted by LinkF1

.....
5. Never take a turn when not in gear, you are not sure what obstacles you may encounter. If you are not in gear, the car will severely understeer and slow down the car significantly as the friction and rolling resistance of the tires overcome the forward motion.

Severely understeer and slow the car down significantly? Really? Now we have re-defined ridiculous comments

Originally Posted by LinkF1

I hope this helps the OP. To all who are offering conflicting advice, please do some research before posting, don't rely on the way you have been taught. There are real engineering-based reasons for all of the advice.

I don't think you helped much here.

[ZPrime]

Originally Posted by ZPrime

I'd love to know where you're getting that from. The second I come off throttle in my TT, it's pretty obvious. The car definitely slows down, especially in a lower gear.

Now, in a modern BMW, I can imagine that if you're in comfort/eco mode, it might pull some silliness to allow the car to roll/coast more easily, but the principles of physics have not changed with the advance of technology. Closing the throttle (or in a VANOS-type system, reducing the amount of time the intake valves are open) causes a manifold vacuum, which the pistons have to work against to reciprocate, and this slows you down.

There are actually fuel saving benefits to in-gear coasting too - when you come off throttle, almost any modern car cuts fuel & spark and simply allows everything to spin under the power from the momentum of the car through the wheels. By pressing the clutch and disconnecting the gearbox, the engine has to go back into a standard idle, which will use fuel.

Originally Posted by doug_999

I'm not following you - first you say there is lots of engine braking and then you say that the modern car cuts fuel and spark and allows everything to spin under power. Which is it?

Short story here, in my M2 stick, I don't remember too much engine braking - but I'll try it tomorrow and see if I notice.

I didn't say "spin under engine power." I said everything spins from momentum... which you are overriding by pushing in the clutch during your turn.

First, for sake of explanation, let's ignore any weirdness that BMW might be doing with Comfort mode to lessen engine braking. (I don't know whether this happens or not, since I don't have my M2 yet.) I'll revisit this in a few paragraphs.

As long as you don't push the clutch, the transmission (permanently attached to the wheels) remains connected to the engine. When you come off the gas pedal, a modern car generally will cut spark and fuel injection, if not instantly, within a few milliseconds. (This is for better MPG.) The pistons are still reciprocating "for free" - the wheels are spinning due to the forward momentum of the car, which spins the axles, which spins the transmission, which spins the crankshaft, thus the pistons move.

Engine braking happens because those pistons are working against a vacuum in the intake manifold, because your throttle is closed. The effect is amplified by the gearing of the car - if you're in a high gear, you get less braking, in a low gear you get more.

When you press the clutch pedal, the crankshaft isn't connected to the transmission input anymore. The transmission will keep spinning at an RPM corresponding to ground speed, but the crankshaft would eventually come to a stop... but instead the ECU steps in, opens up the throttle to an idle, injects fuel, and lights spark, and your engine drops to whatever idle speed the manufacturer sets. This is a waste of fuel, and a waste of perfectly useful engine braking potential as well.

As you're coming up to a slower speed turn, the "right" thing to do is downshift to a lower gear (fully, including releasing the clutch) before you need to start applying the brake. You then get to take advantage of engine braking, and depending on the gear you pick and how early you grab it, you may not even need to use the friction brakes at all. As you make the turn, you can then start to apply throttle gradually as you go through it, feeding more as you unwind the wheel, and then upshift as you go.

Now, I've heard some people mention on this board that BMW does weird stuff in Comfort mode to lessen engine braking. If they wanted to reduce the feeling / strength of it, they could have the computer adjust the throttle opening (technically, the intake valve duration, but the physics are identical) to lessen vacuum which would definitely make for less-effective engine braking. I don't know whether this is actually something they do or not, but I've seen at least one person say that engine braking is stronger in Sport & Sport+, which implies that Comfort mode is playing tricks. Even if they are messing with how much engine braking you get, you're still wasting (admittedly, tiny amounts of) gas by needlessly standing on the clutch through a turn - you're forcing the ECU to go back to an idle state instead of allowing the ground to spin the crankshaft for you.

About the only time I'd clutch into a turn is if this is a super slow turn where you're going to need first to get through it, since it is difficult to downshift to first in most cars.

Agreed - and in a modern car, they (the throwout bearing) just doesn't wear out much. I've never replaced one and I've driven stick (clutched in during turns) for a long time.

How many miles / how long are you keeping the cars though? I've seen plenty of people driving 2007-2010 VWs complaining about throwout bearing whine on forums (where I used to haunt before now). Possible they could just be flawed batches, but also possible that it's from people holding the clutch pedal more than they should be.

[LinkF1]

Originally Posted by doug_999

Severely understeer and slow the car down significantly? Really? Now we have re-defined ridiculous comments.

Try it and tell me what you feel. Take a turn at 10-15 MPH into a parking lot, do not put the car in gear and try to make the car react to a "sudden obstacle".

It will severely understeer and your speed will drop quickly. You will not have the control you expect until you put it back in gear.

[geogerf]

Originally Posted by LinkF1

Try it and tell me what you feel. Take a turn at 10-15 MPH into a parking lot, do not put the car in gear and try to make the car react to a "sudden obstacle".

It will severely understeer and your speed will drop quickly. You will not have the control you expect until you put it back in gear.

At 10-15 mph you have a better chance of not hitting the object by slamming on the brakes. It is more dangerous to swerve outside the normal lane than it is I brake.

This thread is getting ludicrous!

[M2Nebula]

Originally Posted by geogerf

This thread is getting ludicrous!

But we haven't gone to plaid yet!

[geogerf]

Originally Posted by M2Nebula

But we haven't gone to plaid yet!

I’m surrounded by a$$holes!

[M2Nebula]

Uncalled for....please keep it to yourself next time.

[geogerf]

Originally Posted by M2Nebula

Uncalled for....please keep it to yourself next time.

Lol I’m quoting Spaceballs - your vid..!?

[M2Nebula]

Originally Posted by geogerf

Lol I’m quoting Spaceballs - your vid..!?

Sorry man, too funny, glad I didn't go off on you then!

I can be an asshole, but only allow my wife to call me one!

[doug_999]

Originally Posted by ZPrime

How many miles / how long are you keeping the cars though? I've seen plenty of people driving 2007-2010 VWs complaining about throwout bearing whine on forums (where I used to haunt before now). Possible they could just be flawed batches, but also possible that it's from people holding the clutch pedal more than they should be.

Fair enough Have not had a manual transmission car past say 60,000 miles. Wait, maybe my 1995 Celica GTS - but that was a Toyota, so it does not count!

Originally Posted by geogerf

I’m surrounded by a$$holes!

Originally Posted by M2Nebula

Uncalled for....please keep it to yourself next time.

hehehehe - he got you. I love that line in the movie. In fact, I love that movie! Except when my 13 year old quotes it.

[M2Nebula]

He sure did, I was laughing about it for a while afterwards. There are so many good lines in that flick. I feel like I'm 13 when I watch it, that's the beauty of Mel Brooks' movies.

I owned an early SR5 Celica hatchback. Great car in it's day. BMW's are such good driver's cars, but early Toyotas were hard to beat for overall day to day needs without much hassle. Really enjoyed my two Supras as well, they offered a pretty good overall experience. As I mentioned once before, homogenization has taken over and everything is starting to blend together, including my memory.

[geogerf]

Originally Posted by M2Nebula

Sorry man, too funny, glad I didn't go off on you then!

I can be an asshole, but only allow my wife to call me one!

All good man - I should have included the clip but I was posting from my phone!

[Corinne]

Just to add my 2 cents here: I often push the clutch in on a very sharp downhill hairpin bend while in 2nd gear just as I'm slowed right down. The reason being that I'm not going to downshift into first, and if I leave the clutch out the car is going too slowly and will judder and risk stalling. Once I'm past it it's easy to accelerate away in second. Otherwise I fully agree - never take a turn with the clutch in. It's madness. I've been driving stick since 1973 !