Car Handling

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Tue 24 Apr 2007 22:59
Car Handling - ziggy
When a driver loses control, swaps ends and ends up going backwards, what happens to the transmission..? E.g. if you do not declutch..? Does this
wreck the engine/gearbox..? It seems to happen a lot on the telly during road tests.

Just curious.


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Tue 24 Apr 2007 23:05
Car Handling - bell boy
it usually stalls
someone will be along in a minute to make a 200 word thesis on the back stall pressures of an engine in the urban enviroment in a paramedical way

(no i havent been drinking)
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Tue 24 Apr 2007 23:29
Car Handling - David Horn
Perhaps the engine would stall and then restart going backwards? I've wondered this before.
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Tue 24 Apr 2007 23:51
Car Handling - bathtub tom
No.
The ignition and valve timing would be all wrong.
I did have a two-stroke bubble-car that was reversed by stopping the engine and re-starting it backwards ( the ignition was controlled by a second set of points). It was supposed to have a cut-out on the gears to stop it going beyond first, but that seemed to be missing on mine, great for scaring mickey- takers! How would you like to be a passenger in a bubble-car that was reversing up through the gears, and with rear-wheel steering?
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Tue 24 Apr 2007 23:56
Car Handling - Lud
Keep the 7 litre V8 on the boil and rotate amid billowing clouds of tyre smoke... stall indeed. Tchah!
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Wed 25 Apr 2007 00:02
Car Handling - Number_Cruncher
>>Perhaps the engine would stall and then restart going backwards?

In a 4 stroke petrol, no. The inlet manifold would be behaving as an exhaust, and so, no fuel would get in to the cylinder.

2 strokes, yes, they will run in whatever direction you set them off in.

In an old fashioned diesel, then, it's possible for them to run backwards, and it wasn't completely unusual to see a truck briefly running backwards, blowing exhaust out through the air filter! Typically this would be after stalling going up a steep hill on-site, or in a quarry, and the truck then running back, and starting to run backwards. There were anti backfire cams on the injector pumps supposed to stop this, and they did run a bit rough when it happened.

While running backwards, of course, the oil pump is also running backwards, sucking oil away from the crank and the cam - lovely!

Of course, even if an engine doesn't actually run backwards, there's nothing to stop it being forced to turn backwards at high speed. Every part of the car just obeys Newton's laws (in the case of an engine, the rotary equivalent of F=ma).

Number_Cruncher
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Wed 25 Apr 2007 00:32
Car Handling - Pugugly {P}
All in a 189 eloquent words.
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Wed 25 Apr 2007 00:42
Car Handling - Number_Cruncher
Like a moth to flame PU! There are some threads I just can't resist.



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Wed 25 Apr 2007 00:45
Car Handling - Pugugly {P}
ditto- that's why I counted your words. Brilliant.
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Wed 25 Apr 2007 16:21
Car Handling - yorkiebar
Have been in a car travelling backwards, after a high speed handbrake turn, in first gear, accelerating madly, trying to find find grip and go forwards, with the wheels tramping and smoke coming from tyres.

It was in a rally mind but still a vivid memory.

Gearbox and engine were fine after, couple of bushes were a bit shot though !

Will only stall if you allow it too, ie not keep accelerator pressed. As car slides sideways it will stall the engine unless you are quick enough to press the right pedals. And as an after thought. The sideways motion slows a car quicker than any brake system can! And they dont flip unless unsettled by a kerb/hole/object etc!
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Wed 25 Apr 2007 17:51
Car Handling - ziggy
.. well I wasn't so worried about stallling, just couldn't understand why
the engine/transmission wouldn't be totally shot. Of course I would instinctively
de-clutch if it happened.

I did once select reverse at 50mph, but fortunately did not release the clutch (so the experiment was incomplete..)
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