Bad Driving Habits (M/T)

tonybui

Please xcuse my low knowledge on this but why is this a bad habit?

11Thumper

I believe lack of lubrication to the internal transmission components. It's also illegal in some states to coast in neutral.

Masa

Well the way I was taught - if you are going at a speed like that it's always safer to be in gear so you are ready to move and react if something should arise.

Also, coasting at speed in neutral - oil starvation + waste of gas. Leaving it in gear while coasting wastes no gas and your car is read to move if needed.

Neutral has throttle body on idle speed = fuel being used
In gear while coasting = throttle body shut so no gas being wasted on idle

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BMW 340i
Jeep Cherokee Trailhawk

Bleek

In no way, shape or form is putting the car in neutral wasting gas. Infact, if you're cruising at a "higher speed" (IE 80mph) and go into neutral, the car reads you're getting a higher MPG simply because the engine is not cranking/producing RPM's.

kenchan

coasting in neutral fuel is sent to the engine to keep it running.

coasting in gear while the engine is mechanically turned by the drivetrain, fuel is cut.

therefore you save fuel if you DONT put into neutral while coasting...

shadoquad

Makes sense to me, although I don't coast long enough for that fuel loss to matter. Maybe 50-100 ft at most.

Bleek

Source?

Red__Zed

Well known fact. No source needed.

Masa

Like others have said - it's pretty common knowledge.

Car in neutral at ANY speed = throttle body is default to idling to keep engine running. Idling uses fuel regardless if your car is stopped or coasting since it makes the engine stay at a certain rpm.

Car coasting at speed in gear means the throttle body is actually shut off at this point if you are coasting and have your foot off the gas. Coasting in gear wastes no gas since the throttle body is completely shut.

You can actually test this out yourself in the 370z if you put our little computer thing to the real time mpg bar. Coast in idle then coast in gear - Coasting in gear will yield a higher mpg than coasting in neutral.

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BMW 340i
Jeep Cherokee Trailhawk

jayl

Thanks Ron. I used to do this till I read your post... I was under the impression it would be the other way around! but i do recall seeing this when I was kid with the difference that the ignition would be turned off when the car was coasting in neutral... and then without the crank just pop the clutch to start it back up...

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-Jay

The BlueMax

Its not

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The Blue Max