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Discussion Starter #1
Please humor a relatively new sports car owner/driver. I have some driving (well, stopping) questions that I would appreciate anyone's input on.

When driving my Lotus in 4th gear, for example, and am approaching an upcoming stop light, I typically take my foot off of the gas and (with the car still in 4th) let the engine do most of the braking until I hit around 15 mph. Apart from extending the brake life, this also allows the engine to make that low growling noise as it winds down through the low rev range that always makes me grin.

When the car reaches about 15 mph, the growling stops and the car feels like it slips into "neutral" and essentially idles. I assume this is normal for the type of clutch and minimizes the "lurching effect" that I am used to with other manuals. I then normally push the gear shifter into neutral at that point, without depressing the clutch, and then bring the car to a final stop using the brakes.

My admittedly novice questions are: Is there anything wrong with this type of stopping? Should I not let the engine "slip" into what seems like neutral on its own? Is it better to use the clutch when putting it into neutral in the few seconds before final stop?

Any meaningful input would be appreciated.
 

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I typically shift into neutral as soon as I start slowing down, and brake the rest of the way.

Imaginie it like this: A clutch is $$ to replace, an engine is $$$$ to replace, and brake pads are $ to replace. Just my $.02...
 

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You may wish to avoid lugging the engine too.
 

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You should always have positive control of your car.

You should downshift with a rev-match and you won't have lurching.

Downshifting from 4th to 3rd to 2nd will ensure you can accelerate out or manuver in case of an emergency.

Sounds to me you are just letting the car die and putting it into neutral.

There are many who will make the arguement that using the brakes is better than downshifting because it's cheaper to replace brakes than a tranny, but don't be fooled. Engine braking in combination with brakes is the proper way to drive a manual tranny.

It amazes me that anyone would drive a car such as an Elise/Exige and go neutral w/brakes.
 

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A clutch is $$ to replace, an engine is $$$$ to replace, and brake pads are $ to replace. Just my $.02...
You must feel like your saving a lot of $$$ when your stopping in an Auto tranny car with just the brakes.... :thwack:
 

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Discussion Starter #6
Sounds to me you are just letting the car die and putting it into neutral.
Thanks for the response. The car doesn't actually die (i.e. I don't have to re-start it). It acts and sounds as though I have the clutch in. It happens (regardless of gear) right before I would normally start to feel lurching in other manual cars. Are these trannys specifically designed to relieve the strain on the engine at low revs so as to eliminate lurching?
 

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Source? Are you a mechanic? Or did you just hear this through word of mouth?

You should always have positive control of your car.

You should downshift with a rev-match and you won't have lurching.

Downshifting from 4th to 3rd to 2nd will ensure you can accelerate out or manuver in case of an emergency.

Sounds to me you are just letting the car die and putting it into neutral.

There are many who will make the arguement that using the brakes is better than downshifting because it's cheaper to replace brakes than a tranny, but don't be fooled. Engine braking in combination with brakes is the proper way to drive a manual tranny.

It amazes me that anyone would drive a car such as an Elise/Exige and go neutral w/brakes.
 

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I often stop in a similar fashion but I gradually lift from the pedal and use the clutch when shifting to neutral.

I think I have felt what you describe. My guess is it has to do with variable valve timing.
 

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No. There is no witchcraft going on in our transmissions. What you experience is probably just simply idling along at 15mph in fourth gear. As long as you're on level ground the car probably isn't going to lurch. If you start up any slight incline whatsoever it's going to lug down the engine below idle speed, unless of course you finally push the clutch pedal in, which you do.

Personally I've owned a large handfull of manual transmission cars, and when coasting down to idle speed in gear I've never had one "lurch." They just slowly and smoothly reach the idle rpm range and stop providing any engine braking at that point. Now they might lurch if you keep slowing the car and don't push in the clutch AFTER you've reached that point, but there is no reason they would lurch prior to that point.

And since you're not working the clutch any more than you would have with another method, your clutch wear is not accelerated.

So the only real (possibly) arguement against your method is extra engine wear. I don't believe this argument myself. Sure, over the lifetime of the car you'll have used a tiny percentage of extra revs, but they're at a pretty low loading condition anyway.

xtn
 

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You should always have positive control of your car.

You should downshift with a rev-match and you won't have lurching.

Downshifting from 4th to 3rd to 2nd will ensure you can accelerate out or manuver in case of an emergency.

Sounds to me you are just letting the car die and putting it into neutral.

There are many who will make the arguement that using the brakes is better than downshifting because it's cheaper to replace brakes than a tranny, but don't be fooled. Engine braking in combination with brakes is the proper way to drive a manual tranny.

It amazes me that anyone would drive a car such as an Elise/Exige and go neutral w/brakes.
Source? Are you a mechanic? Or did you just hear this through word of mouth?
I've always heard both street and track driving instructors say that you should be in gear unless changing gears. The exception is, of course, when stopped, when you should be in neutral with the clutch engaged.

In short: clutch engaged unless shifting... in gear unless stopped (or very close to stopping).

Oh, yeah: both feet in if you spin...
 

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You should always have positive control of your car.

Downshifting from 4th to 3rd to 2nd will ensure you can accelerate out or manuver in case of an emergency.
If you're taking your driving test in the UK and you want to pass, do what the man says :)

Edit: Except for rev-matching, and clutch in while downshifting.
 

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Discussion Starter #12
What you experience is probably just simply idling along at 15mph in fourth gear.
What you are saying makes sense. However, when the engine reaches that approx. 15 mph range, there is a definite sound as though something has disengaged (at least partially) the tranny. In other words, the growling does not simply get lower and lower until I finally depress the clutch. Instead the lugging noise reaches a low point and then makes a clear transition to an idle sound. Like you said, I assume that if I left it in gear until the car actually stopped, it would start to lurch and then die.
 

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What you are saying makes sense. However, when the engine reaches that approx. 15 mph range, there is a definite sound as though something has disengaged (at least partially) the tranny.
You are probably just hearing the difference in "fuel delivery". Basically, when you let off the gas with the revs up, the fuel injectors are shut off - no fuel is being injected to the engine. As the RPMs drop down to idle speed, the ECU starts injecting fuel again so that the engine will idle. At this point, the engine is no longer "engine braking" so you stop slowing down as much.

I the "old days" with carbs, there was always at least idle mixture being delivered to the engine, so there was never any coasting with all the fuel cut off. Modern fuel injection has changed that.

By the way, you indicate that you just slip it out of gear without using the clutch. That's a good skill to have (along with up-shifting without a clutch) for cases when the clutch hydraulics fail, but under normal circumstances, you will be doing your synchros a favor by using the clutch when you shift into neutral.
 

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What you are saying makes sense. However, when the engine reaches that approx. 15 mph range, there is a definite sound as though something has disengaged (at least partially) the tranny. In other words, the growling does not simply get lower and lower until I finally depress the clutch. Instead the lugging noise reaches a low point and then makes a clear transition to an idle sound. Like you said, I assume that if I left it in gear until the car actually stopped, it would start to lurch and then die.
What's happening is your car is reaching the same speed that the engine would drive the wheels in that gear at idle if there was no load (i.e. on a lift). At that point the gears in your transmission are no longer under any significant load, and the noise they make undergoes a subtle change. And since there is no load, you can take the car out of gear easily without using the clutch.
 

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You should always have positive control of your car.

You should downshift with a rev-match and you won't have lurching.

Downshifting from 4th to 3rd to 2nd will ensure you can accelerate out or manuver in case of an emergency.

Sounds to me you are just letting the car die and putting it into neutral.

There are many who will make the arguement that using the brakes is better than downshifting because it's cheaper to replace brakes than a tranny, but don't be fooled. Engine braking in combination with brakes is the proper way to drive a manual tranny.

It amazes me that anyone would drive a car such as an Elise/Exige and go neutral w/brakes.

I agree with the first statement. I think the rest is bad advice.

Brake pads are sacrificial; made to wear out and be inexpensive to replace. Moreover, their sole function is to stop the car.

This has been discussed b4 here (search). Then, I stated that R&T covered this very question and came to the opposite conclusion than this poster.

Rev matching is not the answer, as stress is still applied to the (expensive) drivetrain for no good reason.

I try to shift (up or down) so there is no shock to the drivetrain, which takes practice.

One could idle up to a light in neutral with hand on shifter, ready. Given that one can keep the car in gear to a very low speed, this isn't much of a concern. The odds of some incident requiring quick acceleration in these circumstances are quite low, but the d/t stress is unavoidable.

Usually, someone will now mention that race cars downshift for each turn. But, they are racing and rebuilt much more frequently than street cars.
 

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Rev matching is not the answer, as stress is still applied to the (expensive) drivetrain for no good reason.

I try to shift (up or down) so there is no shock to the drivetrain, which takes practice.
...Practice at rev-matching :)

Usually, someone will now mention that race cars downshift for each turn. But, they are racing and rebuilt much more frequently than street cars.
Someone should now mention that the whole point of this car is to DRIVE it, not to make it last forever. Rev-matching at every opportunity is safer (I agree with the argument that it is safer to be in the [proper] gear at all times), allows you to practice the technique, is fun, and sounds cool :).
 

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gears

Advanced driving taught here in the Uk, ( police/military) will always say this...... when you are down shifting, always match your gears and revs to the speed you are traveling i still, and always will double de-clutch in my lotus and in every other car, always be in the gear that will get you out of a problem.....no expert, just my £1 ($2) worth.
 

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...Practice at rev-matching :)



Someone should now mention that the whole point of this car is to DRIVE it, not to make it last forever. Rev-matching at every opportunity is safer (I agree with the argument that it is safer to be in the [proper] gear at all times), allows you to practice the technique, is fun, and sounds cool :).
The whole point of this car is to DRIVE it, not to make it last forever.

You're welcome. ;)
 

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I agree with everything you said. It's interesting that modern EFI cars can actually save fuel (albeit a small amount) compared to their carb counterparts due to the injectors shutting down, which makes an arguement for coasting in gear for efficiency's sake.

But somehow methinks you're not using synchros to shift into neutral. I only come to this conclusion because on all the non-synchromesh gearboxes I've driven, it's quite easy to shift into neutral without the clutch (it's obviously more of a shock to the gears when under hard load, of course.) Heck some transmissions will pop into neutral on their own as they get knackered. That and the synchros are only really designed to help match gear speeds when shifting *into* a gear. So, I believe you can strike synchro wear from the coast down methodology along with clutch wear.

If we get pedantic, argueably, using the clutch to shift into neutral all the time will increase the wear on the clutch release bearing. Kind of the same reason you don't hold the clutch in at a light. But for shifting into neutral, the wear to the bearing is relatively small. More than not, though. :)

That's a good skill to have (along with up-shifting without a clutch) for cases when the clutch hydraulics fail, but under normal circumstances, you will be doing your synchros a favor by using the clutch when you shift into neutral.
 
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