Best way to eco-drive an automatic
 

I'm starting this thread in the hopes that it can become a 'sticky' that helps those of us crippled with automatic transmissions.

Besides shifting into 'N' ( neutral ) when coasting down a long hill*, what else can we all do ?

* engine running

Shutting off the engine on an automatic, and trying to restart while moving doesn't seem to work, at least not with the car I drive - A 1993 Civic.
I have to pull over and apply the brake before shifting back into 'D' ( drive )

I haven't tried lightly tapping the brake with enough pressure to let me shift, but then this wouldn't be practical in any sort of traffic anyhow.

Is there anything we can do to increase the efficiency of our transmissions, such as adding lower weight fluid ( Hey - it works for manual transmissions :D )

If any of you have any tips please share them here. Thanks !

I like the idea of this thread. with automatics being so popular it is getting harder to find used cars with manual shift transmissions.

Synthetic trans fluid is available and can be used in most makes of car cd.

I always wondered about coasting. If I coast in gear my engine revs is 200rpm lower than if I am in nuetral. Once I stop the rpms go right back to the factory set idle. My question is.. Is the engine load of being in gear (foot off pedal) worse than the additional rpm caused by (I am assuming) a ram air effect of the car moving forward. I have seen this in a few cars even my old 95 civic.

I don't think it's a ram air effect so much as a computer compensation.

I think what happens is that the VSS tells the ECU that the car is moving, but the engine is not under load, so the ECU opens the IACV to help compensate for where the engine should be, in case it gets a sudden load.

I could be spitting canal water, here, but that's what I've always thought was happening, cuz it never happened on any of my carbies.

That sounds like a better reason to me.. LOL I'll use that one.

Yeah I pretty much am in neutral about 10% of each drive I take. If I drive 8 miles, I'm probably in neural about 2 miles of it..(which I know is 20%~~leave me alone~~)

The most efficient thing to do would be to shut the engine off so no fuel is being burned.....The safest thing to do is leave the motor running so you can steer easier saying you have power steering.....Most newer vehicles when coasting down hill in gear with very low load will actually go into fuel cut which means that the motor is still running but no fuel is being injected. This can be seen with an air/fuel monitoring device. and a scan tool or something similar to monitor load. I have no clue if the older vehicles do this as well.....The down fall to coasting in gear is that the vehicle is slowing down vs not slowing or actually gaining speed when in neutral. So will you slow down too much to make it over the next rise? So you see this can get quite involved.....Cd, Can you make the car think that the brake is pressed at all times so that you can start up on the go vs having to stop?

Quick, for our cars it makes a difference if you're neutral coasting or in-gear coasting. I do better neutral coasting downhill, unless there's a stop sign or another impediment to slow down for. I find I actually gain speed going down a steep enough hill, and gradual declines are enough to let me maintain speed. We don't have a fuel cut, it simply uses less. Where our air boxes are isn't much good for ram air. Sure does a good job drawing in ambient air. I'm blocking the frame opening off this winter for higher air temperatures and reduced knocking. My car doesn't like 15*F air...

For our cars, once they're warm idling in gear or in neutral uses the same amount of gas. 0.45 gph according to my ScanGauge.

Also, upgrading to lighter-weight ATF ought to make a difference. For us GM drivers, Dexron-VI has much better cold-flow properties than Dexron-III. And it's part-synthetic to meet the spec. I'm going to do it one of these days when I have nothing better to do.

Have you ever lost your power steering at >30MPH? There's no need for power steering when you're moving. It was invented for scrawny kids in parking lots.

I coast in neutral as much as possible, usually up to 25% of my commute. I also Pulse and Coast (as I call it) on flat ground or slightly rolling terain. When I can't coast, I just keep the speeds down low enough to not make other drivers too mad. I also accelerate briskly to get torque converter lock asap. When I am coasting, I will re-engage the gear at a speed above torque converter lock, so I can get it locked asap again then pulse and repeat. I just coast as much as is possible. I have found, just thru observation not with any instrumentation, that the pulse and coast for my car is extremely effective at any speed below 60mph. My car will idle at 1000-1100 rpm when coasting in neutral, it's normal idle is 750rpm, my presumption is that the IAC is attempting to rev things up a bit in case I drop it back into gear. Also, a tackometer is vital in rev. matching to coast as much as I attempt to. You can check my fuel log to see the results once I started to coast more and then as I have gained skill at at it.
I also run full synthetic (generic brand) ATF, it didn't seem to make much of a difference to mpg, but I do have trans overheating problems when coasting a lot and having a full grill block, the syn. deffinatly helps relieve those heat related issues.
I also have a trans pan heater to get things warm for the morning, it deffinatly helps get things shifting quicker in the morning.
I also have upped the line pressure in my trans for firmer/quicker shifts. It doesn't seem to have helped mpg any, but it is more reasssuring feeling the shifts.

I'm ready to swap to a manual transmission, the ATX is a big limiting factor for taking my car much further up the mpg charts. I have made a switch box to maually shift my automatic so I can hit gears sooner, but it doesn't have much of a possitive effect on mpg and is difficult to use in traffic. I've tried about all there is I can do with the ATX and have gotten some good results.

I'll have to try brisker acceleration. It's not a problem for my car. I just hate the low numbers on the ScanGauge while accelerating. Also my Tcc locks at ~30 mph. Is that too high to accelerate briskly to?

My TCC doesn't lock until I'm past 40mph.

Mine locks at 38-40MPH, depending on throttle position, it can go all the way up to never.

Ahh. Mine's pretty aggressive about locking up.

I'll have to try accelerating at a good clip to 30 tomorrow on the longer stretches of my all-city commute and see what numbers I get. I usually accelerate at a leisurely pace, ~1500-1700 RPM tops. Breaking 25 LOD and 2000 RPM on the SG, anyone?

I usually accellerate between 2000-2500 rpm and about 25 on the TPS, haven't looked at LOD yet. Just got the SG last night though :) Just kinda obseving what my usual drive results in. I noticed I pull about 25mpg on the 10 second pulses and between 200 and 500mpg on the coasts usually lasting more than double or triple the pulse. This is on the uncalibrated SG, I'm sure it's reading high right now because it's showing about 60mpg cruising at 55mph (however it's nice to think that might be true)

Cruise control is a good tool with an automatic. I find the sweet spot for a 3.8 liter Dodge Caravan to be about 42 to 44mph, just fast enough to keep it in highest gear. On hills, I disengage cruise control to just get over the hill and coast down. I have not tried putting it in neutral on the way down, it seems to freewheel pretty good on downhills as long as you turn off cruise control.

I've gotten the best mileage with my automatic so far just by going real easy on the gas pedal. Try to look far ahead and if you see a red light and stopped cars, get your foot off the gas and coast up to it (if no one's behind you).

Keep your RPMs as low as possible, especially going uphill. If there are no cars behind me, I listen to the engine and back off of the gas pedal to try to keep the RPMs low without the transmission downshifting and screwing up my plan. Then, if it downshifts and puts my RPMs through the roof, I swear at myself for not learning stick shift and buying one. Lol. If someone's behind me, though, I just accelerate enough to match the speed limit. And I won't coast down a hill and break the speed limit for an extended period of time, because I don't believe in going over the speed limit to get better mileage.

That being said, I won't drive below the speed limit and hold people up, either. That's the biggest problem for me... there's so much traffic in Connecticut and someone's always behind me, so I can't really experiment too much with all this coasting and what not, and I can't drive 55 on the 65 mph speed limit highway that's near my house, cause people drive 70-80 on it and I'd die before too long. I guess my only hope is fixing my aerodynamics somehow.

:rolleyes:

You think I'm kidding... people drive like their gas pedals are super-glued to the floor around here!

I don't think you're kidding, I think you're misinformed. Slower is Safer, and NHTSA and other organizations have conducted many studies to prove it, several times over.

I know how people drive in CT... I've been through there several times going between NYC and Boston, Mass. (Both of which are far worse, I might add.)

Of all of the states up that way, I prefer NH, honestly. No insurance laws, and no state tax. :thumbup:

Torque converter lockup switch.

Turns your auto into a manumatic. Takes some getting used to but the benefits are there. Just getting data together now. These are used for towing where the auto can overheat, the TCC lock switch overrides the ECT and lets you lock up on demand. Mine took ten minutes to wire. I can lock up at any time (RPM permitting) in any gear except first.

http://ecomodder.com/forum/showthrea...tch-10028.html

Also on Toyotas (and possibly other cars) there is a kickdown cable which should be tightened to give faster shifting and higher fluid pressure. Reduces wear on the tranny and (I think) a more secure TCC lock.

The Free Mod Series - Part I Quicker Transmission Shifting - Toyota Forums :: Toyota Nation

newhavenpatriot, I sympathize with you about CT drivers.

One technique I've been playing with lately is trying to load the engine more effectively by tricking the transmission into upshifting by lifting off the throttle, than adding as much throttle as I can without causing it to downshift back to the previous gear. It's really a half assed solution though, a manual is key to loading the engine effectively. I test drove a car with a stick recently, and fell in love with how easy it is to do. I'm itching to get a new (used) car with a stick, but I happen to be very picky with cars, so I have to be patient.

A trick I learned with non-e transmissions is to adjust/remove the kickdown device. This will disallow the transmission from downshifting at all, though, so whatever gear you're in, you're in, until the governor takes you down a gear. You can manually upshift at a much lower RPM, though.

The kickdown (TV cable, in come cases) relates the Throttle position (relative load) to the transmission governor.