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Old 02-24-2008, 08:48 AM   #1
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EOC in Gear?

Does anybody else here EOC in gear?

For my commute in the Escort, with 35-40 mph speed limits and multiple lights, it seems to be more practical to just leave the car in gear (5th) for the majority of coasting. Typically the opportunity to do a true EOC without having to anticipate stopping or at least using the brakes is a rare thing, so I don't see a significant sacrifice of efficiency there. Plus, in 5th gear the amount of drag from the engine is virtually unnoticeable. (My Tercel loses speed faster in neutral.) As such, I've adopted the practice of not using the clutch or taking it out of gear for my EOCs. And depending on the light timing, I either turn the ignition back on at the lowest practical bump start speed or just leave it off to manually restart when the light changes. But I very rarely have to use the starter this way.

This obviously avoids virtually all of the driveline wear and tear from clutch assisted bump starts, and likely still beats the wear of just leaving the ignition on while coasting down.

Does anybody else do this?
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Old 02-24-2008, 10:08 AM   #2
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I've never done it. Have you tried holding the throttle open while coasting to reduce drag further?
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Old 02-24-2008, 10:37 AM   #3
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Snax -

This is definitely on my todo list for my LA freeway commute, because I need "full power" in that context. I intend to copy Skewbe's momentary off-switch to make it happen.

In the meantime, I have been experimenting with what you are doing when I leave the house because I am going downhill. I am doing it in 3rd or 4th gear because of the slope, so I am using it as an engine brake.

Because the engine is cold when I leave the house, the California gizmo that helps emissions at startup keeps turning on when I turn the engine back on, so I won't like it until I get the momentary off-switch online.

Also, without the momentary off-switch, the odometer doesn't change, so it doesn't count on my gas-log.

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Old 02-24-2008, 08:41 PM   #4
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Quote:
Originally Posted by landon View Post
I've never done it. Have you tried holding the throttle open while coasting to reduce drag further?
I tried that, it doesn't make any difference. Here's how it went; key off, tranny in gear ( I tried a few different gears), traveling downhill around the speed limit, then open and close the throttle. If it did help I couldn't tell.

On my car the ecu shuts off the fuel injectors when coasting in gear if the engine is above 1200rpm and the throttle is closed, so I don't really need to turn the key off. From reading this forum, other fuel injected cars have this feature, too.
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Old 02-24-2008, 09:27 PM   #5
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just to add, I seen horrible mileage while doing this and have complete stopped doing it...... just my experience, i dunno if there's more to it or if your supposed to compression start or what. me just attempting it with no real research on the technique.
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Old 02-25-2008, 10:08 AM   #6
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i find it odd that you would lose speed faster with the car in neutral than in gear. There should be less friction in neutral?
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Old 02-25-2008, 07:46 PM   #7
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Originally Posted by Snax View Post
Plus, in 5th gear the amount of drag from the engine is virtually unnoticeable. (My Tercel loses speed faster in neutral.)
There are a lot of things you can do to help distance with both "in gear" and "out of gear" coasting. For example, good synthetic grease in the wheel barrings, good synthetic oil in the engine, properly adjusted/lubed brakes, etc. However, no matter how good your "in gear coasting" is, you will always have some extra drag vs an "out of gear" coast. If you think you are getting better "coasting" in gear, then you are actually fooling yourself (likely having your engine continue to use gas to give you that illusion).

However, that said I will frequently do "in 5th gear coasting" (with the engine ON), when I am slowing down from highway speeds (highway off ramp, coming up to a red light on a secondary highway, etc). With my CRX, the ECU fuel cut (for no throttle "in gear" coasting) seems to work very well in 5th gear, allowing me to coast "for free" until I get down to around 30mph (at which point a feel the slightest "bump" as the ECU automatically restarts my FI). And so if/when I'm going to slow down anyway, I'll often stay in 5th gear until I feel that "bump" (indicating that I'm again using fuel), and then shift to neutral for the remaining coast (for example, up to the red light I'm slowing down for).

However, even as my 5th gear coasting got better and better (work on my car means that I can now coast in 5th gear further than I used to be able to coast in neutral), the neutral coasting went up even more. So if I really want coasting distance, I still go with neutral coasting.

However, in my case, I don't feel comfortable with engine OFF coasting in my car, so when I coast it is always a judgement call as to which is better distance (best with neutral coasting) and fuel savings (best with 5th gear coasting, due to the ECU cutting the fuel use as long as I'm moving "fast enough").
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Old 02-25-2008, 08:18 PM   #8
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Escort's EEC-IV should be doing the injector cut thing, I have heard down to 1800rpm as general for the EEC-IV but that might be application specific (higher for autos, lower for standards etc.)

Sounds like you're having to try too hard to get MPG out of that 'scort though. Mine I got it all tuned up, all maintenance done, (95 auto) and I'd have to beat the living snot out of it, with the AC full blast, all the electrics on, to get less than 29MPG, seems really sensitive to tire pressure though, keep on top of that. One thing made a big difference was cleaning the MAF and replacing the breather element (oil clagged and disintegrating) and PCV valve. Blast the MAF with brake cleaner, don't poke it or touch it though, and if it's black, replace those other things to keep it clean. If you don't get 35mpg+ after doing that with a standard, I'll be surprised. Airhog airfilter seemed to make a good improvement on mine. (K+Ns reputed not to be very good though)
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Old 02-25-2008, 08:20 PM   #9
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Originally Posted by DracoFelis View Post
. . If you think you are getting better "coasting" in gear, then you are actually fooling yourself (likely having your engine continue to use gas to give you that illusion).
Nope, not what I was suggesting either. 'Engine off' means no ignition or fuel in an EFI vehicle. Carbed and MFI engines however are a recipe for mufflers blowing off.

The distinction here is where a full neutral coast would provide more of a coast than one can use before needing to stop for a light or other reason. Leaving it in top gear merely provides an unbroken connection to the drivetrain, eliminating excess wear on the clutch if a bump start will be used before coming to a complete stop. In my case, it allows me to carry engine rpms to well below the fuel cutoff rpm.
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Old 02-25-2008, 09:33 PM   #10
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Originally Posted by RoadWarrior View Post
Escort's EEC-IV should be doing the injector cut thing, I have heard down to 1800rpm as general for the EEC-IV but that might be application specific (higher for autos, lower for standards etc.)

Sounds like you're having to try too hard to get MPG out of that 'scort though. Mine I got it all tuned up, all maintenance done, (95 auto) and I'd have to beat the living snot out of it, with the AC full blast, all the electrics on, to get less than 29MPG, seems really sensitive to tire pressure though, keep on top of that. One thing made a big difference was cleaning the MAF and replacing the breather element (oil clagged and disintegrating) and PCV valve. Blast the MAF with brake cleaner, don't poke it or touch it though, and if it's black, replace those other things to keep it clean. If you don't get 35mpg+ after doing that with a standard, I'll be surprised. Airhog airfilter seemed to make a good improvement on mine. (K+Ns reputed not to be very good though)
Thanks for the tips, but I think it has more to do with infrequent short trips in cold weather than anything else. I'm thinking it will be worth inspecting the coolant bypass however.

Just this last two weeks we have had significantly less rain, it's about 5-10 degrees warmer, and already I'm seeing closer to 33 mpg for this tank if I can trust the gas guage. On the highway it gets mid to upper 30s easily.
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