being frustrated w/ the FE of my civic lx, i'm considering a return to EOC. you guys that use this, if you would, give me specific application how and when...
for example: i don't have the opportunity for compiling a great amount of EOC miles, but when i do(or have in the past), it's typically on a back road with little or no traffic. so, i'll pick a speed of say 35mph, turn the car off, then coast to 10-15 mph before bump starting.
i drive mostly hwy miles, in the dark morning hours and afternoon rush hour. so, i don't feel comfortable doing this procedure w/ lights on or in heavy traffic.
I EOC when I am at the top of a hill that is at least 1/4 mile long and there are no other cars directly behind me that will get annoyed if I end up 5-10 mph below the stated speed limit when I finally bump start at the bottom of the hill. I don't really care about cars in front of me because they are usually speeding anyway (the distance will widen as I travel down the hill).
One more thing- I usually only EOC during the day when the pavement is dry.
I EOC all the time. For a 10 second coast or a minute plus coast. I think it's especially beneficial when the engine is cold since the engine uses a lot of fuel trying to get to operating temp. 35 down to 10mph seems a little slow for optimum results. You're probably better off EOCing from 41-43mph down to 29 or 30mph. If your battery is good, you can EOC with lights on. If your battery has been completely drained it may be compromised (not sure on that, tho). Of course, if your battery is old, then that might also be something you want to think about.
When the engine is cold, I turn off the engine whenever I do not need to be on the gas. I think this is a more efficient way to warm the engine up, but who knows if it's bad for the engine. I have been doing it a lot for the last two years and I do not think my actual engine has really suffered. One thing you do want to be careful of is if you climb a steep hill and the engine gets hot, you may want to go into neutral for 15 seconds or so before turning the engine off to give the cooling system a chance to move all the heat away from sensitive parts. One time I went high revving up a hill and then immediately killed the engine--I think that was the reason shortly later a hose bulged and I had to replace it immediately.
And, yes, you have worse traction when there is no power going to the wheels. Always keep that in mind when cornering when in neutral or when the engine is off.
EOC is an extension of neutral coasting. Therefore, to understand when I would choose to EOC we can look at when I coast. My commute consists almost entirely of rolling mild to medium grades which are perfect for coasting down and powering up while staying near the speed limit.
EOC is effective by time, not by distance, since the difference is idling. Therefore when I think I would neutral coast for a decent amount of time I EOC. Exactly how long that is depends on a number of conditions:
- How well my engine shuts down and restarts; if my Buick is dieseling then I only do it for long coasts (60+ seconds) but if it's shutting off well I might do it for a 20 second coast
- Traffic (as Erik does)
- Visibility and traction
I disagree that you have less traction while coasting than while applying power. While coasting you are asking less of your limited traction than while also putting power through the tires. However, while in gear you can use power to adjust your balance, or at an extreme you can use it for a powerslide (or what I call a "FWD powerslide", which actually works surprisingly similar to a classic RWD powerslide except for the attitude of the car and the steering angle).
When the goal is fuel economy I don't see a need to run on the ragged edge of traction where balance (or a powerslide) becomes an issue. I carry as much speed through a turn as I can safely do with whatever conditions I've got.
Of course when the engine is off and you don't have power steering (and limited power brakes), you might want to consider that. Even a macho big-armed man won't steer as fast with depowered steering...I do fine but certainly not as fast as with power. Does the LX have power steering anyway?
I EOC mostly on the long downgrades and when coming upon a long light. It's four lanes so people can pass me, but because of grades of the rolling hills, I tend not to go much slower than the traffic. Too slow and I lose much of my momentum in areas.
Bump starting isn't an option, plus the battery is nearing it's end of life, so I don't use the technique as much as I can. I have the scangauge on volt to keep an eye on the battery.
I wait for the engine to warm up. I figure I would be doing multiple starts with cold oil otherwise. The programing prioritizes emissions, but it can't be the only reason the Prius goes through a warm up stage.
I too EOC, all the time.
I do not P&G ever. I tried it several times and had worse FE than trying to maintain a speed. Probably has to do with the fact that when lean burn isn't active, the car gets worse FE than other civics.
I've learned all of my normal routes pretty well. I actually pick landmarks that a stop and start by. I decide what landmarks to use when traffic is light and I can go slower than I might otherwise go later.
I use the E-brake for braking unless a cop/erratic driver is tailing me during EOCing. The exception is when I'm coming to a final stop at a traffic light or something.
I EOC to almost all traffic lights. The only ones I don't EOC to are the ones I know change rapidly. This saves A LOT but takes the most practice/patience/skill.
I don't EOC when I'm going down a long hill that would make the car exceed the speed limit by 15mph or more. I use the braking of the engine and make sure I'm DFCO (by that I mean down shift so DFCO is active). If I see the road leveling out ahead of a long downhill, I'll then EOC about 1/3 of the way to the flat spot. Then I coast as far as I can down to about 15-20 below the posted speed unless there's someone behind me.
There is no gain to be had if you would have been in DFCO until the traffic light anyway.... Might as well keep the engine running for that reason.
As for restart, I try to bump start as much as possible. To do so, I use the next gear up from the gear I think I'll need once the motor is started. For example, at 30mph approaching a hill, I'll use 4th or 5th to bump start, then drop to 3rd or 4th to use the motor. On the highway after a long downhill, (I dont' get many worthwhile opportunities to EOC on the highway because I don't P&G), I keep it in fifth for both bumping and going.
To do it nicely, I quickly lift then push my foot back to the floor until the engine catches, all the while shifting to the driving gear, then let the clutch up as normal.
As stated, I EOC to most stop lights. I try to keep the car rolling as long as possible. The way I do that is to creep up to the light. Usually, the light will change before I get there and I have enough momentum to bump and go. This generally pisses drivers off behind me to the extreme. I try not to let it get to me. There's "MPG" in big block letters on the rear bumper. If they can't figure that out, too bad.
On the semi-rare occasions I get to the light red and must stop, I key restart.
I EOC no matter what the temp of the motor is. During winter/fall/early spring I use my block heater so the motor is almost always above 60df year round when I'm driving. However, if I have the option to DFCO when the motor is "cold" I will do that before EOCing. That way the internal friction of the motor/trans and the stored energy of the hills can heat up the motor to some degree without burning fuel.
I EOC regardless of day/night. I try to time my restart so oncomming traffic doesn't see the headlights brighten/dim, however. Not that it matters much anyway. I've been doing EOC for over a year on a now 3+ year old never start battery with no issues. I'm not running any extra electrical stuff though, like big speakers or anything. If I did, I'd get a second battery and still do it.
As far as wear and tear goes-
Starters are cheap. I still think the potential gain of FE outweighs the starter cost if I ever need a new one. Besides, I've got a spare on the spare motor anyway.
Clutches wear more with EOC. How much, I don't know. However, clutches also wear from downshifting. Assuming I get close with rev matching (which, during normal circumstances, I'm in the ball park) I'm still putting wear on the clutch and related components by downshifting. I hope and want to believe it washes or comes close to washing with bump starting. At least it allows me to sleep at night!
For me, ditto everything benfrogg does. My general rule of thumb is if there's someone behind me on a hill, I EOC if the hill is steep enough to maintain my speed down the hill. If there's no one behind me and the hill is not steep enough to maintain engine speed, I'll EOC and allow the car to drop below my original speed before bump starting. I EOC regardless of time of day or traffic conditions. It's so natural now that doesn't require any thought. I also EOC to traffic lights and most of the time I don't have to stop by the time I reach the light. If I'm at a traffic light that's longer than 20 seconds, I turn the engine off if I missed the opportunity to coast up to it.
I've been EOCing for 20 years starting with my 1986 CRX HF, before I knew there was a name for hypermiling and EOC. I never replaced a starter or clutch in my HF or my '95 VX (225,000 miles) from bump starting or turning the engine on more frequently (when stopped at traffic lights or in traffic). The worst that happened is the ignition tumbler in my VX started to get a little flaky at about 215,000 miles from the frequent cycling of the key (Honda owners know the key has to be cycled back to the position where all the dashboard lights are on so the odometer functions). I'd like to add an engine kill switch on my '95 DX so I don't have to cycle the key.
Forgot to add now noticing Cems70's comments-
I have an engine kill switch. It dramatically reduces the wear on the ignition, in my opinion. The switch I put in costs about $4. I haven't had to replace it yet. I probably cycle that 5-20 times per trip.
I try to EOC all the time, with the main exceptions being highway travel and uphills, when my glide time isn't double my pulse time. As THC says, the benefits of EOC are time dependent. I monitor battery voltage, and hook up a charger when I get home, or keep the engine running when BV drops to 11.8V