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Old 01-13-2019, 10:53 PM   #5 (permalink)
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Originally Posted by DeliveryGuy89 View Post
So if there's danger in putting it in neutral and coasting, why not leave it in gear and coast instead, beyond engine braking slowing you down a bit? I just turn it back to acc and the only things that I notice are the odometer quits and my headlights turn off.

What's a way around that happening?

And I'm really only aiming for about 28. I don't have any delusions about this car getting amazing mileage. I drive it because it's a tank. Deer heavy area. I have a close call probably 3x a week in my 50 hour work schedule.

I'd rather survive in this than be buried in a metro.
I'm not sure you're understanding the difference between DFCO and EOC. There's no advantage to turning the engine off if you are DFCO (leaving it in gear and letting momentum turn the engine). The engine already cuts fuel entirely when doing this, even when it's "on".

As I said, the 2 strategies have different purposes. EOC is useful for maximizing fuel economy when you don't want to slow down. DFCO is useful for maximizing fuel economy when you do want to slow down. EOC doesn't power the accessories on your car such as power steering and brakes, which is why it's more efficient. It's not trading vehicle speed to power these things (and spin the motor needlessly). DFCO robs the vehicle speed in return for providing power to accessories.

The way I would use EOC is if there was a long downhill section that allows me to coast near to the speed I want to travel. I'd turn the key to ACC, which would kill the engine, then I would switch it back to run (not start). That way when I do finally want the engine to start, I just let out the clutch.

DFCO happens any time you're completely off the throttle and the engine is still turning, and you're slowing down. I use that all the time, anytime I need to slow down or stop.

I'm not saying you've got a bad vehicle, and my favorite car I've owned yet was a 1996 Legacy 5-speed manual. Best I ever averaged was 28 MPG, and that was with a 2.2L engine and lower chassis. I'm saying you'll have a very difficult time getting to that average considering the larger engine and greater frontal area.


EOC (Engine Off Coast)- Used for minimizing momentum loss while coasting. Does not provide accessory power.

DFCO (Deceleration Fuel Cut Off)- Used when slowing is desirable, or losing accessory power is not acceptable.
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Last edited by redpoint5; 01-14-2019 at 04:59 PM..
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