Tried my first EOC today - Fuel Economy, Hypermiling, EcoModding News and Forum

comptiger5000 · 08-08-2010, 11:14 PM

Today, I realized that I have a good stretch of road to EOC on when returning from work. So, I went out and tried it. It's only a little over 1/3 of a mile from the time I can disengage and kill the engine to when I have to fire it up and go through the re-engage sequence and be in gear before I have to turn.

EOCing the beast requires certain conditions, where I can end the glide either at a stop, or can get to 20mph +/- 1 mph to re-engage while moving. Being that it's an auto, I EOC with the t-case in Neutral so it doesn't kill the tranny.

Of course, the t-case has no synchros, so it can be engaged back into gear either stopped with the tranny in Neutral, or rolling at 20mph with the engine idling, tranny in drive. Lower speeds while rolling could be done by holding the tranny in a lower gear (1st or 2nd), higher speeds would require rev matching and would be too hard to do.

This makes my shutdown and startup a little clunky, but not too bad. To shut down, put tranny in Neutral, put t-case in Neutral, kill engine. To restart (rolling @ 20mph), fire up engine, put tranny in Drive, shift t-case back into gear quickly while watching the speedo for the right timing.

She's not too bad without power steering (unless < 5mph). It's a little stiff, but perfectly manageable. I have enough power brake reserve for 2 full applications. Any more, and it's time to fire it up. She takes A LOT of pedal pressure to stop without vacuum assist (hard to stop 1 footed, a panic stop would be 2 feet on pedal, lifting me out of seat). Fortunately, I don't need the brakes on this glide until after I fire it up (downhill right before my turn, and it's a tight turn). If I were to need them for an emergency stop, I'd have enough vacuum reserve to be fine, and just fire it up after.

C3H8 · 08-11-2010, 02:30 PM

why do you have to put the transfer case in neutral, to reduce rolling resistance? or is there some special reason?

i once had an old subaru with a transfer case. it has neutral, 4wdhi and 4wdlo and 2wd. when coasting in any of the ranges, i never had to put it in neutral to eoc..

on my dads landrover with a blazer diesel 4wd running gear we just pop it into neutral when going down a hill or whatever and it works fine like that.

comptiger5000 · 08-11-2010, 02:33 PM

EOC with the tranny spinning in this thing is bad for it, as with most autos. No fluid circulation unless the engine is running, so I'd kill the tranny bearings after a while. By putting the t-case in neutral, I do get slightly less rolling resistance, as there's less stuff spinning, but the big benefit is that the tranny doesn't spin.

Unfortunately, I can't do any more EOC testing as I drive around at the moment, as I had to park the Jeep for a couple days last night when the water pump started leaking. Should have it back on the road for the weekend, gotta wait for parts.

C3H8 · 08-11-2010, 06:48 PM

honestly i don't think it is all that bad for an auto tranny. look at tow trucks as an example. ever seen a fwd car being towed somewhere with the car being pulled backwards, so the front wheels are turning in reverse and the rear wheels are up on the tow truck? or rear wheel drive car being towed with the rear wheels on the ground and the front's up in the air. i've even seen AWD subaru's being towed with 1 set of wheels on the ground and the other set up on the tow truck.

i am guessing that if moving vehicles like that was at all bad for the tranny's, the tow truck drivers would get fired for blowing up customers trannies. where are all these recently fired tow truck drivers? tbhey are not around...

that is why i guess that eoc is not too bad for a automatic. i wouldn't want to pull a car thousands of miles with the engine off but coasting around town shouldn't hurt anything.

i have actually towed my car using a tow strap and a friend's car 50 miles home with the engine off when the engine quit running a year ago. thats 50 miles of eoc on my auto tranny.

maybe you praticular trans has some issue i don't know about but automatic in general does fine with eoc.

comptiger5000 · 08-11-2010, 10:33 PM

Some auto trannies allow flat towing for a short distance at low speed. Mine specifically states it can be flat towed ONLY with the t-case in neutral.

As far as the tow companies, it depends on the vehicle, and also the nature of the problem. In some cases, depending on why the vehicle is being towed, they may leave it idling in Neutral to keep the tranny lubed. For a RWD car, they may drop the driveshaft.

Plus, spinning an auto tranny with the engine off probably isn't going to kill it. However, it does wear the bearings some, and over time, it could cause issues. Basically, I have a workaround for it, so why risk it? Plus, it's rare that it's safe to EOC around here, due to the speeds people drive (get pissed if you do less than 35-40 in a 25, will cut around you on the wrong side of the road if you're doing 30 or less). In addition, there aren't a whole lot of places where EOC is practical anyway, and I don't think it gains a lot in my Jeep. At 30 or so, it actually coasts slightly better in gear, as the engine has quite a bit of idle torque.

mikeross · 08-28-2010, 12:03 AM

Quote:

Originally Posted by C3H8

why do you have to put the transfer case in neutral, to reduce rolling resistance? or is there some special reason?

i once had an old subaru with a transfer case. it has neutral, 4wdhi and 4wdlo and 2wd. when coasting in any of the ranges, i never had to put it in neutral to eoc..

on my dads landrover with a blazer diesel 4wd running gear we just pop it into neutral when going down a hill or whatever and it works fine like that.

We tow our Jeep behind our motor home, and need to put the transfer case in Neutral to do so. Other than that i didn't know that it could reduce rolling resistance.