Shifting into Neutral to Save Gas?

[Even Steven]

Originally Posted by JCL12

Back to the initial topic -

Bottom line: Is going from D-->N to eliminate engine braking for gas saving purposes (down hills and red lights) going to be bad on the tranny or not?

Did you read my post? You will not save gas by going into neutral...you'll actually use more gas by doing that.

[Even Steven]

Originally Posted by JCL12

To Clarify: you are saying that when you coast in drive, all fuel flow ceases and engine RPM is maintained by absorbing the cars kinetic energy, effectively slowing it down faster but using zero gas?

Yes, in a nutshell. It's not quite that simple, but the fact remains that a modern fuel management system has the ability to shut off the fuel pulse completely when a vehicle is coasting. Think of it this way--Why should the engine management system waste fuel by sending it to engine engine in a car coating down a hill? Fuel isn't required in such a situation, so it can simply be turned off. If you put the transmission into neutral while coasting, you are forcing the engine management system to start sending fuel to the engine to keep it idling. Therefore, it is more economical to leave the car in gear and coast down a hill instead of popping it into neutral and coasting down the hill.

Like I said earlier--do a little research and you'll learn all about it. I happened to learn this stuff in school

[rick3000]

Originally Posted by TriGem2k

Since your house is on a hill what are you going to do about premature brake fade?

I park in the garage.

[spark00]

Originally Posted by Even Steven

Yes, in a nutshell. It's not quite that simple, but the fact remains that a modern fuel management system has the ability to shut off the fuel pulse completely when a vehicle is coasting. Think of it this way--Why should the engine management system waste fuel by sending it to engine engine in a car coating down a hill? Fuel isn't required in such a situation, so it can simply be turned off. If you put the transmission into neutral while coasting, you are forcing the engine management system to start sending fuel to the engine to keep it idling. Therefore, it is more economical to leave the car in gear and coast down a hill instead of popping it into neutral and coasting down the hill.

Like I said earlier--do a little research and you'll learn all about it. I happened to learn this stuff in school

This is interesting. Is this same for manual transmission also? I tend to leave my shift on neutral when I'm coasting to stop. I would like to save gas for environmental reason if I can. haha.

[Dr. Kill]

Originally Posted by TriGem2k

AHAHAHHAHA good one Grizz. I'll take my chances though, the A/C sure keeps the car cool in the heat.

This is a risk. You might want to consult your insurance policy. I am under the impression that mine will not cover theft if I have left the keys in the car, or left the car running.

[Even Steven]

Originally Posted by spark00

This is interesting. Is this same for manual transmission also? I tend to leave my shift on neutral when I'm coasting to stop. I would like to save gas for environmental reason if I can. haha.

Yes, it works the same for manual trans cars too. I wouldn't be too concerned about putting it in neutral when coasting to a stop. The difference in fuel economy would be absolutely minimal. If you were always coasting down long hills in neutral or in gear, then you may notice a tiny difference in fuel economy, but even then it would be so small that it would be hard to accurately measure.

Either way, I'm sure that the differences would be hard to measure, but I was just trying to point out that coasting in neutral doesn't save gas....