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Discussion Starter #1
I'm trying to come up with a good explanation of why when you put the car in gear, and simply take you foot off the clutch without giving it gas, the car stalls. When I have a good understanding of most automotive mechanical systems, I forgot why this happens.
My brother wants to learn how to drive stick, and I want him to understand the mechanics behind the operation. Thanks for the help.
 

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Reading Topic: Why a Car Stalls

Here's a brief explanation...

The engine spins all the time and the car wheels don't. In order for a car to stop without killing the engine, the wheels need to be disconnected from the engine somehow, this is where the clutch comes in. The clutch will allow you engage a spinning engine to a non-spinning transmission by controlling the slippage between them. So if you take your foot of the clutch without giving it gas, won't allow the engine and the transmission to mate together causing the car to stall.
 

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Replying to Topic 'Why a Car Stalls'

QUOTE
Originally posted by Absolut


            Here's a brief explanation...

The engine spins all the time and the car wheels don't.  In order for a car to stop without killing the engine, the wheels need to be disconnected from the engine somehow, this is where the clutch comes in.  The clutch will allow you engage a spinning engine to a non-spinning transmission by controlling the slippage between them.  So if you take your foot of the clutch without giving it gas, won't allow the engine and the transmission to mate together causing the car to stall.[/b]
I'm with you up to this point, I guess I'm unclear why the engine cuts off when you release the clutch without giving it gas, I realize the engine spins even in neutral, hence the idle rpm, but I would think you would just get a jerky contact when you let the clutch out while in gear. Is the engine cut out a safety mechanism for the transmission or engine?
 

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Reading Topic: Why a Car Stalls

It's simpley because the engine is to week to get the car to move forward, so it stalls. The same as if you would brake the car to a stop without de-clutching.
Happens mostly to lowe-power cars. Our 166hp 6 2.3l does not stall if you release the clutch. Not on first gear at least. But our Laguna does. It's around 110hp. I guess it's really about tourque though.
 

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Reading Topic: Why a Car Stalls

It's pretty simple.

Say you are superman and you put your hand on the crankshaft of the engine. It is going to stall because you literally stopped the engine from "spinning at idle speed". On the other hand, it is harder for superman to stop a revved up engine at "above idle speed".

when u release the clutch without revving it, it is like superman (the weight of the car) stop the engine from "spinning at idle speed". Engine stall because of that.
 

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Reading Topic: Why a Car Stalls

Have your brother stand 1 ft away any have him try to stop you from moving forward. Then back up 15 ft, take a running start and have him try again. :D

Inertia, that's why they put heavy flywheels on on stock cars.
 

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Reading Topic: Why a Car Stalls

You can also explain to him that if you were on a flat road, and let the clutch out VERY slowly, you could probably get the car moving, albeit very slowly. :) Also, have him watch the tach when you drive the car, taking off from a standstill in 1st gear, and have him notice how, even though you don't let off the gas, as you release the clutch pedal, the engine speed slows down as the car starts moving until the clutch has fully engaged. It probably drops 500 RPM or so. If you were to do that with the engine at idle, which is usually around 500-700 RPM, the drop would be enough to take it almost down to 0 (i.e. stall).
 

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Reading Topic: Why a Car Stalls

future6owner : You can release the clutch normaly and the car will start to move. As said in the "Did you ever notice..."-thread - the enigne in the 6 seems to "rev up" by it self when you release the clutch, stopping it from stalling.
 

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Replying to Topic 'Why a Car Stalls'

I always found the easiest way to explain clutch operation is to just simply say think of it as brakes in reverse.

This is really dumbing it down, but your spinning rubber pad (clutch) makes contact with your flat, stationary steel wheel (flywheel) and if your spinning pad isn't spinning fast enough, it just skids to a stop on your steel wheel, and your car stalls. However, give it some gas, your spinning pad is moving fast enough, it sticks onto your wheel and starts moving the steel wheel along with it, presto, the car is moving.

Best way to explain it to someone younger, I think.

Cheers!

Bryan
 
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