BOLLOCKS. Compete and utter s**te. If the engine is on overrun, the supply is cut off no matter what you're doing. If you're using the gears and braking, there's no fuel going to the engine until it gets down to the level the anti-stall kicks in, around 800 RPM.
DING!
*IF* the engine is on overrun.
If you go down through the gears, every time you change it uses fuel for a few moments. Stay in top and brake, it doesn't.
Which uses less?
That uses *less* fuel? Care to rethink that one?
I think you've confused yourself into a corner.
Staying in top and braking clutch up uses less fuel than going through the gears.
Not to mention the other advantages of approaching an obstacle that way, like having a much lower driver workload, the car being more stable, being able to choose the right gear to go through at exactly the right time, two hands on the wheel...
There's a reason that RoADA and the IAM teach one change per hazard. And it isn't fuel economy, that's just a useful side effect.
The message from Conor contains these words:
IAM and the police teach that gears are for going, brakes are for slowing. The idea of "having to be in the right gear in case you need to accelerate out of trouble" is a fault with forward thinking and the ability to read the road properly, not with gear changing.
I never thought this was helpful until I had to use it. Twice now ive avoided serious rear-end impacts by being in an appropriate gear to dodge round the car in front to avoid someone sliding up behind me in the wet. If I'd stuck in 4th/5th id never have moved (did get rear ended when i did that, by a tractor!).
In message , Guy King writes
We need a phrase instead of "using engine braking" which differentiates between "lifting off early to avoid having to brake" and "jamming it down through the gears instead of braking".
Maybe you do. But _we_ don't know that you know. And since you didn't tell us, the easy option when asked why your fuel economy is so poor, was to check you aren't as stupid as you're now making yourself out to be.
In the grand scheme of things does any aspect of the fuel economy of your vehicle make any difference to any of us?
If you measured your fuel economy incorrectly, don't you think that would go some way to explaining why you got unexpected results?
No, it's a bit like saying "My printer doesn't work, but I'm sure it has ink left. Why doesn't it work?", then responding indignantly when asked "Why do you think it isn't out of ink?"...
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