[Multiades]

Originally Posted by iraghava

Welcome to the forum Chris, that was quite a first post!! I believe now that you've given us some very good technical knowledge perhaps you won't mind posting an introduction of youself!

Thanks for the warm welcome. I'll get around to a formal introduction soon.

Originally Posted by iraghava

Ummmm... sorry but no bypasses here, spend sometime on the forum & get your post count to 50+ & the magic rule is waived off!!

I was half kidding, but I've never been on a forum before where posts need to be moderator-approved for an amount of time. Seems like a whole lot of hassle for everyone involved, but I guess it might help prevent spam.

[Shan2nu]

I double-clutch and heel-toe religiously for practice, and I've used the techniques on a racetrack as well (see sig pic).

Isn't it just an amazing feeling when you get it right? But tell me, why double clutch? Doesn't your car have a synchromesh gearbox? I've heard that double clutching on a synch-gearbox can actually be harmful for the synschronizers.

Shan2nu

[Multiades]

Originally Posted by Shan2nu

Isn't it just an amazing feeling when you get it right? But tell me, why double clutch? Doesn't your car have a synchromesh gearbox? I've heard that double clutching on a synch-gearbox can actually be harmful for the synschronizers.

If you're actually precise, it isn't harmful at all. The debate about double-clutching vs. simply rev-matching is a misguided one, IMO. With just a little bit of practice it is possible to double-clutch without wasting any more time over just rev-matching: eliminate the first clutching action by coming to neutral throttle and flicking the shifter out of gear -- it should come out with no resistance if you do it properly. Next, rev-match, pop the clutch in, flick shifter into gear, pop clutch out. Same amount of time but protects the syncros and will allow you to get into gear slightly faster.

Nobody is perfect all of the time, but with practice you will be more precise more of the time. It's all about improving your average skill level.

-Chris

[Shan2nu]

No, you got me wrong. I'm not asking how it's done. I'm asking.... why?

I can understand DC on old gearboxes that don't have synchronizers but the newer gearboxes can do without DC.

I've never faced any probs with single clutching. Even if you take the "Best Motoring" drivers, tiff needell or even the great Ayrton Senna....they all use single clutching when they race normal cars on track.


The only time i use DC is when i need to directly downshift from 5th to 2nd (which i rarely do).

But yeah, it's good to know everything there is to know about driving a M/T. You never know when you might need it.

Shan2nu

[Rtech]

Back to shifting to neutral...I don't agree with Chris's statements. Yes, in a perfect world, change to neutral and coasting along the road would cause no harm, BUT, the real world throws up unexpected instances where you would need to swerve/maneuver out of the way of a kid running across the street or something similar.

In cases like that, it is far far safer to have the car in gear and ready to take aversive action if/when needed.

[Multiades]

Originally Posted by Shan2nu

No, you got me wrong. I'm not asking how it's done. I'm asking.... why?

I can understand DC on old gearboxes that don't have synchronizers but the newer gearboxes can do without DC.

Good question. Either my synchronizers suck or I've never owned a car with syncros powerful enough to make me not worry about wear. The gearbox found in the RSX Type-S here is probably the best-synchronized gearbox I've ever used, and I still wasn't quite comfortable just stuffing it into gear.

Originally Posted by Shan2nu

I've never faced any probs with single clutching. Even if you take the "Best Motoring" drivers, tiff needell or even the great Ayrton Senna....they all use single clutching when they race normal cars on track.

Do they? I guess I've never seen the videos. All of them are vastly, vastly better drivers than I am, but I'm not sure how many have to work on the cars when they're done driving them.

Originally Posted by Shan2nu

The only time i use DC is when i need to directly downshift from 5th to 2nd (which i rarely do).

What you mean when you say that is shifting into second at high speed. What gear you were in before is mostly irrelevant unless you're upshifting or shifting very quickly (no-no for syncros). For example, I'll downshift to the top of second from third on corner entry very often. Anything that leaves you at redline in the destination gear is going to require a whole lot of syncro work if the gearbox will tolerate it. Personally, I'd rather not.

Originally Posted by Rtech

Back to shifting to neutral...I don't agree with Chris's statements. Yes, in a perfect world, change to neutral and coasting along the road would cause no harm, BUT, the real world throws up unexpected instances where you would need to swerve/maneuver out of the way of a kid running across the street or something similar.

In cases like that, it is far far safer to have the car in gear and ready to take aversive action if/when needed.

In a real emergency situation mashing the throttle (even at peak power) is going to do too little too slowly. The sheer difference in rate of deceleration vs. rate of acceleration (or cornering, for that matter) on just about any normal car you can name is huge.

In my experience a swerve is often more successful than braking also. What I learned years later in track instruction is that if you're braking to avoid hitting something ahead of you and realize you will never stop in time, try to dodge -- 80% of the time it works (or so they tell me).

And honestly, how often do you see a kid running across the street and feel the need to mash the throttle?

[Shan2nu]

Good question. Either my synchronizers suck or I've never owned a car with syncros powerful enough to make me not worry about wear. The gearbox found in the RSX Type-S here is probably the best-synchronized gearbox I've ever used, and I still wasn't quite comfortable just stuffing it into gear.

Not sure about your car, but an RSX should definately have no probs with single clutching.

Do they? I guess I've never seen the videos. All of them are vastly, vastly better drivers than I am, but I'm not sure how many have to work on the cars when they're done driving them.

Yes they do. Nothing happens to the car if it's done correctly. The synchronizers were developed for a reason....to eliminate double clutching.

What you mean when you say that is shifting into second at high speed. What gear you were in before is mostly irrelevant unless you're upshifting or shifting very quickly (no-no for syncros). For example, I'll downshift to the top of second from third on corner entry very often. Anything that leaves you at redline in the destination gear is going to require a whole lot of syncro work if the gearbox will tolerate it. Personally, I'd rather not.

Not at high speeds. Lets say i'm cruising at 60kmph (38mph) in 5th and a suddenly need the extra power/torque to overtake a bus in front, i double clutch while i shift from 5th to 2nd (at 60kmph).

When decelerating from high speeds, it's always safe to go down the gears in a sequence.

And honestly, how often do you see a kid running across the street and feel the need to mash the throttle?

In India, almost every day. And if it ain't a kid, it'l be a dog or a cow or something else.

Shan2nu

[Vid6639]

Multiades,

LOL!!! not mash the throttle towards the kid infront. but say a bus or an auto (3-wheeled contraption) comes out from no where just a few inches on your side and your coasting in neutral, your gonna have a big dent. You need to be ingear to take evasive action like go past him to maintain distance. If you slow down get rear ended or still get hit by the auto cause he wont bother and keep coming at 20-30kmph.

India is about defensive driving. you sometimes have to make sure you dont give way to a lunatic like a bus or a cab cause if you do they will push you off the road. It's better to accelerate in those situations than brake or dodge. We can't dodge much cause remember there are cars a few inches to our left as well as right.

It's not as bad as I have made it sound I am giving worst case scenarios. But people who come from US are literally scared to sit in the front seat. Those that do think its an adventure. I've had one customer of mine say that in US we do bungee jumping and track days to get some adventure in our lives and hone our driving skills but for you it's everyday.

[Multiades]

Originally Posted by Shan2nu

Yes they do. Nothing happens to the car if it's done correctly. The synchronizers were developed for a reason....to eliminate double clutching.

Are you sure? Happen to have any links to the videos? It's always nice to see a pro's footwork.

Originally Posted by Shan2nu

Not at high speeds. Lets say i'm cruising at 60kmph (38mph) in 5th and a suddenly need the extra power/torque to overtake a bus in front, i double clutch while i shift from 5th to 2nd (at 60kmph).

Right, but 38mph is a fairly high speed for second in most cars. What does the engine speed end up at when you get into second?

Originally Posted by Shan2nu

When decelerating from high speeds, it's always safe to go down the gears in a sequence.

Yes and no. Believe it or not, race drivers will often just skip to the last gear at the end of the braking zone rather than ride each gear down along the way -- when you're concentrating on maximum-effort braking it does not pay dividends to worry about making each downshift perfect (and they would need to be to prevent loss of traction at max braking). Notable exceptions include sequential gearboxes in which you must go down in order. There's a great video of Hans Stuck in an M3 GTR at Nurburgring in which he downshifts through each gear in sequence in the braking zones -- and that's on an H-pattern gearbox too!


Whew, I'm deviating off-topic a lot. Makes me forget what I wanted to say...

Originally Posted by vid6639

Multiades,

LOL!!! not mash the throttle towards the kid infront. but say a bus or an auto (3-wheeled contraption) comes out from no where just a few inches on your side and your coasting in neutral, your gonna have a big dent. You need to be ingear to take evasive action like go past him to maintain distance. If you slow down get rear ended or still get hit by the auto cause he wont bother and keep coming at 20-30kmph.

I've been partially playing devil's advocate when I insist that it's not necessary to be in-gear all of the time. I'll continue to say that it isn't dangerous, but that doesn't mean that it isn't useful. No doubt most people in the USA aren't sticking to each other's bumpers in quite the same way, but at least if someone else rear-ends us it's considered their fault (at least in my state it is). Half the fun is driving a car that you can get hit in and not care.

Originally Posted by vid6639

It's not as bad as I have made it sound I am giving worst case scenarios. But people who come from US are literally scared to sit in the front seat. Those that do think its an adventure. I've had one customer of mine say that in US we do bungee jumping and track days to get some adventure in our lives and hone our driving skills but for you it's everyday.

If you ever happen to visit these parts I'll take you for a drive sometime. In the snow.

[v1p3r]

Originally Posted by Multiades

Right, but 38mph is a fairly high speed for second in most cars. What does the engine speed end up at when you get into second?

About 4500 rpm. To give you an idea, 1st tops out at about 55 kmph, or about 35 mph. 2nd would be between 60 and 70 mph, depending on which car. These are normally 1.5-1.6 litre engines with 100 bhp or so.

[sreenivass]

Originally Posted by Multiades

That said, for very extended distances downhill, engine braking may be useful to prevent brake overheating, but most people aren't driving down mountain roads very often, and brake heat buildup is rarely a problem in normal vehicle use.


The other reason cited often is that it saves gas to engine brake. While I see the logic applied to this, I think that answer misses the point. ANY friction applied to the car to convert kinetic energy into heat is essentially reducing your gas mileage. Braking of any kind is by definition taking useful energy (forward momentum) and wasting it. On the one hand we have the engine using no fuel (above a certain RPM only) with the throttle closed while the engine friction decelerates the vehicle, or the engine using a very small quantity of fuel to stay idling while the vehicle gradually coasts down from speed. Since the coasting vehicle will travel further, the comparison isn't really a fair one.


Again, I would say that it is not particularly inefficient, and definitely not unsafe to coast in neutral at speed.

-Chris


P.S. How's that for a first post?

What do I have to do to get a moderator to waive the 50-posts rule?

I am in agreement with most of the points said here. The reason one should use brakes is "they are meant/ designed for braking" where as transmission is not necessarily. If one uses some thing that might not have been designed for, it can cause problems, may work without problems. But I'd not do that.

However in my own experience driving downhill in lower gears (may be 3rd or 4th depending on visibility and ramp gave me a sense of better control.

[clipto333]

Originally Posted by netarchie

Hi,
I tried searching the other threads before posting this query, but could not find what i was looking for.
here's my query..
While driving at a certian speed say above 60 - 70 Kms/ hour, when i need to slow down my car , if suppose i am approaching a red light/Speed breaker, i usually shift my gears to the neutral , directly from the 5th or 4th geat and break genlty before i come to a comple halt or the speed at which i need to take off once again? This way i dont have to use the clutch much, just once to shift to the neutral.
in short, i shift to the neutral from a higher seed/higher gear and let the car come to a speed at which i can engage 2nd or 3rd gear.
just to give an e.g. if iam driving in the expressway at say 100 km/hr and when i see the sign - Toll 1000 meters ahead - i simply shift to the neutral and break gently till I approach the Toll booth , rather than shifting to 4th,3rd ect.
I do this while driving downhill also.(shifting to the neutral) but i do not keep my foot over the brakes.

by doing this i feel i am saving fuel.
Please correct me if i am wrong in the follwoing the above said method.

hi,

IMO. the best thing to do is read the owners manual that comes with the car. and make sure you read every warning in the manual. it will answer all your questions. i would never drive in neutral, i always use engine braking.

thanks

[Shan2nu]

Are you sure? Happen to have any links to the videos? It's always nice to see a pro's footwork.

Yeah i'm sure. I'l see if i can find something on youtube.com

Right, but 38mph is a fairly high speed for second in most cars. What does the engine speed end up at when you get into second?

Not on my car. 38mph comes to around 4200rpm in 2nd. My car redlines at 7100rpm. Infact 1st gear redlines at 36mph. So it's pretty safe to do so.

Yes and no. Believe it or not, race drivers will often just skip to the last gear at the end of the braking zone rather than ride each gear down along the way -- when you're concentrating on maximum-effort braking it does not pay dividends to worry about making each downshift perfect (and they would need to be to prevent loss of traction at max braking). Notable exceptions include sequential gearboxes in which you must go down in order. There's a great video of Hans Stuck in an M3 GTR at Nurburgring in which he downshifts through each gear in sequence in the braking zones -- and that's on an H-pattern gearbox too!


Whew, I'm deviating off-topic a lot. Makes me forget what I wanted to say...

Maybe some do (out of habit) but most pro drivers would prefer going down in a sequence. And it doesn't affect their braking bcos they don't have to concentrate on their foot work (it bcomes a part of their driving style).

[rks]

Originally Posted by Multiades

In any car, RWD, FWD, or AWD, "lift throttle" can cause oversteer.

And if you ever get into an oversteer situation on a FWD, you will need acceleration to provide the traction to get you out of the skid. If you are coasting in neutral on a FWD, approach a corner too fast, brake and find that your car oversteers, you will be left with insufficient traction to get you out of the skid.

I think it is safe to assert that you should *never* coast in neutral when you are overtaking on a two-way road, for you may find yourself in any of the following situations:

(a) The guy you are overtaking suddenly speeds up and/or starts to swerve into your path just as you begin to overtake and leaves you having to accelerate to avoid colliding with either the overtaken vehicle and/or an oncoming vehicle in your lane.

(b) An oncoming vehicle approaching you in the overtaking lane is either coming faster than expected and/or suddenly accelerates/swerves into your path, leaving you with no choice but to accelerate to avoid a head-on collision

(c) You may find that you need a burst of acceleration to avoid some obstacle in the overtaking lane, say a stone or a massive pot-hole -- all too common in India.

In India you are almost always driving on narrow two-way roads with a wide variability in the speeds of the vehicles (ranging from painfully slow trucks/two-wheelers to high-speed sedans), so you will need both braking and acceleration at unpredictable times to drive safely. This is in addition to what others have already pointed out.

I do agree with you that coasting in neutral in certain situations can be beneficial, but in Indian driving conditions it can become a bad habit that will let you down at crucial times.

[Shan2nu]

Here's a vid of Kurosawa "Gan San" from Best Motoring, driving the NSX R around the Nurburgring. Watch his foot work...it's so effortless.

YouTube - Honda NSX-R Time Atack in Nurburgring

Shan2nu