I just EOCed down a gradual 2 mile hill in my 93 Civic. It is an automatic.
I used to do a lot of engine ON coasting in my last car, a 94 civic DX 5 speed, but anyway I figure if I EOC in the automatic on this hill which I travel about 7 times per tank of gas. 7X2 miles = 14/10gallon average fill, then I should increase my MPGs 1.4 gallons. or 4% at 35mpg avg.
I engine-on-coast a LOT in my automatic, but not engine-off coast (except in town at speeds well below 30mph).
Also, in my Bluebird (inefficient 2.0i 8-valve engine), I get about 100mpg doing 30mph in neutral (coasting), and about 200 doing 60mph (coasting), so, overall, engine-off, engine-on doesn't make much difference.
What has made a difference, when I do it, is to accelerate (what I think is, as I don't have Lambda feedback yet) at a level just below the enrichment point, and also to ease off briefly to get the gearbox to change up as quickly as possible. Also to go at e.g. 90km/h up a hill, and go into neutral uphill, rather than maintain 80km/h to the top of the hill.
Be very careful of engine-OFF coasting in Autos, and definitely don't do it above 30mph.
__________________ Team GasMisers5 - #1 for first three rounds of the original GS Fuel Economy Challenge
Miles displaced by e-bike since 1 Jan 2008: 62.6 (0 kWh used)
I'm a big fan of coasting. I coast a lot with my auto tranny.
Did you to check your owners manual to see if your car can coast with engine off? Many auto transmissions are designed so they will be damaged if coasting with engine off.
Look in the "towing your car" section. Usually the manual will state whether it's OK to "flat tow" the car, that is, with the drive wheels on the ground, transmission in neutral. Some cars will let you do that up to maybe 10 mph. Mine can do it up to 40 mph and 40 miles distance.
If your car won't EOC safely you can coast in neutral with engine idling. Not as good a deal as with engine off of course, but it does work.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.
The car never came with an owners manual. So I don't know if it is okay to coast. I went 2 miles starting out around 50 and by the end of the 2 miles I was going about 35.
The car is decent mechanically, I wouldn't want to damage the trans, but it does have 196K on it and the body is pretty rough, so it would not be a world ending catastrophe if the trans went. So that is why I decided to risk it.
The car handled fine through all of it. There was no noticable difference in the power steering and I made sure not to pump the vacuum out of the brakes until I turned the car back on.
Some Honda transmissions are ok to EOC. A friend in northern IL has a 2005 Accord and it's ok with that car. Most Saturn's auto-transmissions aren't damaged by EOC either. In fact, in our area, there are many RV transport companies and the Saturn SL series is a popular choice for a tow vehicle.
Horsepower is how hard you hit the wall, torque is how much of the wall you take with you.