This will probably end up being a question that only matt can answer...

But...

1) When coasting with the A/T in 'N' (with the engine ON), is ATF being pumped through the A/T?

2) When coasting with the A/T in 'N' (with the engine OFF), is ATF being pumped through the A/T?

I'm trying to figure out if these hypermiling techniques are good/bad for our 7thgens.

Thanks,

 

any time the car is on, the motor is spinning the input on the transmission. all you're doing is disengaging the drive gears by putting it in neutral when you're coasting with the car on. coasting at any speed in neutral with the car OFF is just plain stupid.

 

Just so you know in an auto, as long as you are coasting to a stop and the RPM's are above a specific threshold, the fuel injectors are cut off. If you put the car in neutral with the engine running, you burn fuel in order to keep the engine running. Shutting it off is another story, however I would think the AT is designed to be used in gear, not coasting in neutral. But that's just my .02.

So it's better to coast to a stop in gear, so the trans can keep the rpm's high enough to keep the injectors cut off. I have a scan gauge and you can watch the MPG jump to 9999 due to the injectors being cut off and getting infinite instant MPG numbers. I have a 5-speed so it's more under my control than in an auto.

 

Thanks for the answer guys!

The reason I asked about coasting with engine off, is when I'm approaching a light that just turned red that I know I'm going to be stuck at for a few minutes...I was pondering turning car off and coasting to the light as soon as I see it turn red, and leaving the car off till I see the light about to cycle for me to go.

I have a scangauge 2 as well! I try to coast down hills in gear b/c of the 9999MPG as opposed to the 100-120MPG in N. But sometimes I coast in N down hills to gain speed to make it over hills ahead of me...gotta love hypermiling and getting 40MPG around town

 

Ah but if you look at the gallons per hour, pretty much in neutral (I have a five speed so not sure about the manual) I burn around .28 of a gallon an hour. So if the light is 5 minutes long... you only burn around .0325 gallons, which even at 4 bucks a gallon it only cost you .094 of a dollar. So the wear and tear of putting it into neutral and using the starter over and over, not to mention, if something goes really wrong sitting at the light, you are screwed as far as possibly being able to get out of the way. I'd also think it would put a lot of strain on your battery, our civics come with some really small batteries and I doubt they would enjoy the extra starts.

THe only way that shutting it down works without much strain is when it's a hybrid, they have the battery capacity, not to mention a large generator/motor for restarting the engine quickly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by briq4 &raquo;</TD></TR><TR><TD CLASS="quote">Ah but if you look at the gallons per hour, pretty much in neutral (I have a five speed so not sure about the manual) I burn around .28 of a gallon an hour. So if the light is 5 minutes long... you only burn around .0325 gallons, which even at 4 bucks a gallon it only cost you .094 of a dollar. So the wear and tear of putting it into neutral and using the starter over and over, not to mention, if something goes really wrong sitting at the light, you are screwed as far as possibly being able to get out of the way. I'd also think it would put a lot of strain on your battery, our civics come with some really small batteries and I doubt they would enjoy the extra starts.

THe only way that shutting it down works without much strain is when it's a hybrid, they have the battery capacity, not to mention a large generator/motor for restarting the engine quickly. </TD></TR></TABLE>

True...Thanks for the advice!