09-26-2017, 06:11 PM | #89 | |
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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.)
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09-26-2017, 09:28 PM | #90 | ||||
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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. Quote:
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(messing with you here - but honestly, you are not adding to the thread by throwing out valid discussion points). Quote:
I don't think you helped much here.
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09-26-2017, 11:43 PM | #91 | |||
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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. Quote:
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2004 Matrix XRS 6MT => 2008 VW R32 DSG => 2012 Audi TTRS 6MT => 2018 BMW ///M2 6MT
I'm an IT guy by trade and tech nerd by choice. I like HPDEs, parts of US Hwy 129, NC 28, and the Cherohala Skyway. I'm also a fan of aural pleasure. Last edited by ZPrime; 09-27-2017 at 12:02 AM.. |
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09-27-2017, 06:20 AM | #92 | |
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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. |
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09-27-2017, 12:31 PM | #93 | |
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This thread is getting ludicrous! |
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09-30-2017, 06:52 PM | #99 | |
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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.
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09-30-2017, 07:24 PM | #100 |
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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. |
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09-30-2017, 08:07 PM | #101 |
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10-11-2017, 07:20 AM | #102 |
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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 !
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