I have question regarding gearbox and the engine for example i go downhill is it ok for the car to put the gear in neutral to save some petrol ? I no on my diesel it was not possible as turbo can damage it self but petrol is different right ?

It's an offence to throw the car into neutral and coast and anyway when you take your foot off the accelerator (whilst in gear) the car uses minimal fuel.

up vote35down voteaccepted

If the car is equipped with a modern fuel injection system, it will likely use less if left in gear and allowed to run against the transmission with no throttle as modern fuel injection systems can and do shut down the injectors completely thus use no fuel whatsoever. If the engine is at idle in neutral, the ECU will have to use a small amount of fuel to keep the engine turning.

your not saving petrol, your using more, when on overun, ie down a hill in gear, there is no fuel being injected in to the cylinders, until around 1000rpm approx. in neutral with nengine ticking over you are using fuel to maintain idle speed. 

As above.

You lose engine braking which is dangerous.

Most cars nowadays actually cut fuel to the injectors when coasting.

TBH, the amount of fuel you'd save by rolling in neutral is minimal, also you'll ruin your clutch and gearbox jamming it into gear while coasting at speed.

Sent from my SM-G930F

Thanks for the replies I take it on board that why I asked as I did not no 

Avoid, not a great practise to get into for reasons including those mentioned above.

You can't coast in neutral in the ST150 anyway, unless you can put up with the annoying idle bounce!  

As above though, it doesn't save you any fuel, just makes for a slightly lazier, smoother ride with fewer gearchanges - I probably coast more than I should, bad habit though!

21 hours ago, TomsFocus said:

You can't coast in neutral in the ST150 anyway, unless you can put up with the annoying idle bounce!  

As above though, it doesn't save you any fuel, just makes for a slightly lazier, smoother ride with fewer gearchanges - I probably coast more than I should, bad habit though!

Me too, and yes it is a bad habit.  If I can maintain my current gear I won't coast, because there is no reason to go near the clutch.  If I need to declutch though (slowing down in 5th for example) then I do coast for a while until I need to speed up again.

Deliberately going into neutral though is just downright dangerous as you couldn't quickly accelerate should you need to.

That is true guys its bad habbit 

Food for thought:-

http://www.dailymail.co.uk/news/article-3741536/Driver-21-killed-three-friends-coasted-hill-neutral-save-petrol-trip-McDonald-s.html

Pretty sure not much energy is wasted with ford these days anyway,. Fords have regenerative braking that also works when decelerating / going down hill. Fuel is cut to the engine saving fuel and ecxess energy from the engine is sent to the alternator to charge it on deceleration / downhill travel

at least that's what I read about the newer fords

This news article should answer your question.

http://www.dailymail.co.uk/news/article-3741536/Driver-21-killed-three-friends-coasted-hill-neutral-save-petrol-trip-McDonald-s.html