Coasting is illegal in Kentucky?????

[Volones]

Hey rwyler,
If you see a dark blue Mazda MX-3 going downhill with really dim headlights, please don't report me, OK?

Vol

[scubascooby]

Coasting is illegal in Gt Britain and I suspect in European countries too.

HID headlights are illegal here too, either OE or aftermarket but the EU forbid us to stop them being sold. Fascists.

Most post 1980's cars shut off the injectors when the throttle is closed above a certain rpm, only starting them again to stop the engine stalling.

Coasting will burn more fuel than leaving it in gear.

[dcb]

Originally Posted by scubascooby

Coasting will burn more fuel than leaving it in gear.

I believe the correct response is "it depends".

[Andyman]

Originally Posted by scubascooby

Most post 1980's cars shut off the injectors when the throttle is closed above a certain rpm, only starting them again to stop the engine stalling.

Coasting will burn more fuel than leaving it in gear.

I agree with dcb.

On a car with closed throttle fuel shutoff, coasting will burn more fuel than staying in gear but will allow you to go farther before needing to accelerate (and burn fuel) again. If you need to have some braking anyway, keeping the transmission in gear is best. If not, coasting is more efficient overall. If you know you will gain speed while going down a hill, you may be able to start coasting early near the top of the hill to lose some speed, then gain some speed while descending the hill without exceeding the speed limit or the highest reasonable and safe speed. On hills that are both long and steep, it won't be useful to coast the whole way down, since the car would go too fast. The strategy to save the most fuel would be to coast early at the beginning of the hill, slow down (because the beginning of the hill is not steep enough to maintain speed), gain speed when the hill gets steeper, then shift back into gear when the speed is near the speed limit. On cars that don't shift smoothly from neutral to drive (such as some Mercedes), it would be best not to shift to neutral so the car is not at risk of skidding when engine braking is needed again. Speeding allows a longer coast after the hill but increases the risk of wasting money on tickets or having an accident. If we had regenerative braking we would be both safe and efficient in hilly areas without having to slow down a lot before going down hills.

Cars with a lot of engine braking will get the most benefit from coasting. Modern cars with overdrive transmissions usually don't have as much engine braking as older cars because of lower engine speed. Cars with low wind resistance and rolling resistance also get more benefit since they can coast a longer time before slowing down too much.

[azraelswrd]

As with anything done to our cars, checking the local laws and regulations is a good idea. I believe "coasting" is illegal in most states but as already mentioned, next to impossible to enforce. Just use some common sense and care, don't give people a reason to care about you (police or otherwise) and go about your business. I remember everyone telling me that when I put on wheel well covers and blocking the front grille that those were somehow "illegal".

I proved them wrong and I have the law/DMV ordanances on my side (and the lack of any citations or pullovers from police since I started doing the mods).