When you coast down a hill and you gear down to slow down, do you end up using more gas?

Question

I was wondering because i gear down in my car going downhill to save my brakes. Does it use more gas to do that? I wouldn't think so because your not feeding the engine more gas its just using gravitational force to make the engine run at higher RPM, isn't it? Thanks for the help!

Answer 1

yes it lowers the gas because you are not using your brake

Answer 2

YES you will use more gas.  The only way around it would be for you to cut off fuel to the engine.  an engine is going to try and use an even air/fuel ratio of 14:1  If it is supplying 2.0L worth of engine a 14:1 mix at 1800 RPMS with no load it is using half the gas that the same 14:1 ratio requires are a no load situation at the 3600 RPMS you're putting it at by downshifting.  I guess its a simple matter of whats cheaper. the little bit of added fuel you're going to use by downshifting or the added cost of replacing your brakes a little sooner by using them more.  the raw truth is every time that cylinder fills on the intake cycle, gas goes into it.  By downshifting and running higher RPMS you actually are causing your vehicle to be less fuel efficient as the energy created by that engine cycle is not utilized

Answer 3

I would say no. The fuel delivery is controlled by an electronic system and the fuel injectors.  The only way might be that a common method of downshifting is to open the clutch, get the rpms up, then close the clutch. So you are revving the the engine a bit.

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Answer 4

yep you kind of do used more because the car is in a lower gear... just let off the gas sooner brake and shift til you stop but just remember that a chutch cost more than brakes so the way your doing it will just wear the chutch out faster

Answer 5

the higher the rpms the more gas you use plus its not good on ur engine