02-25-2008, 07:46 PM
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#21 (permalink)
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EcoModding Lurker
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I think the load under neutral on certain makes might have to do with some necessity to keep the trans slushing in order to prevent some kind of negative side effect.
I've decided to abandon N for my driving practice, and stick to basic in-gear coasting. The way I see it, using N wont save me enough $ to replace a prematurely busted slushbox.
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02-25-2008, 08:46 PM
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#22 (permalink)
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I"m not lurking!
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Quote:
Originally Posted by Whoops
I think that what they do is to open the throttle, or something, just a little bit, so that the car appears to coast farther when you have your foot off of the gas pedal.
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Yes! I found that when I borrowed my mother's Lincoln Continental. At first I thought "wow, this thing really coasts!". Then, after experimenting with coasting in neutral vs. in gear, I realized the stupid drive-by-wire computer was holding the throttle open for 15 seconds after I let off the gas, or until I touched the brakes. I figured it was to make a smoother ride for the throttley-challenged older drivers and their passengers.
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02-25-2008, 11:47 PM
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#23 (permalink)
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Giant Moving Eco-Wall
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I don't know guys. But All I know is that when I coast in gear, the Rpm's drop like a rock, I coast a lot farther, and even when I hit my brakes, it still coasts far. In neutral, it drops about half of what in gear does, I coast about half the distance, and I know it's using fuel. Plus my owners manual says not to go over 30 in neutral. So Basically, I only use neutral when I'm below about 17, where I'm coming to a stop and the brakes have to overpower the engine to stop it. It shifts into first if I put it in gear, which is the gear it's supposed to be in anyway.
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02-26-2008, 05:15 PM
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#24 (permalink)
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Yea, I'm not going to use neutral over 25 or so anymore. In my mom's van, the rpms drop when coasting, not so lucky on mine, they stick at around 2k at 40 mph. Idle is 700 rpm (what it drops to in neutral). But yea, not going to neutral unless I'm stopping at a red light or pulling into the driveway, with the car off.
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02-26-2008, 05:40 PM
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#25 (permalink)
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The only thing I have noticed with automatic transmissions is as follows:
Shifting in to N with my Camry results in more coasting ability, but it also uses, like was said earlier, a little gas to maintain it's idle.
Leaving the tranny in D when I coast results in a little more loss of speed because, I figure, it's using the wheels to keep the engine idling and adjusting the amount of spin getting to the engine by using the transfer case to modulate how much goes from the gears to the engine. I figure this because when I let off abruptly going down a hill, the RPMs will drop down to idle and then after a second they will jump to 1100RPM (from 800RPM). I have not gotten a scangauge yet however to confirm this idea).
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02-26-2008, 08:10 PM
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#26 (permalink)
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Camry's don't have transfer cases, at least not from the factory. I think what you're talking about is called the flash stall.
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02-26-2008, 08:12 PM
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#27 (permalink)
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maybe that's it, I'm not too up on cars so I was going on what I'd seen on other automatics (granted the only ones I've seen are automatic drag cars). I'm just thinking that there is something similar to a clutch between the tranny and the engine to keep it from spinning too much, otherwise it would certainly over-rev the motor...but now thinking about it, the RPMs do progressively increase with the speed of the car while coasting so maybe it's just a fixed gear to reduce the revolutions.
::EDIT::
AHA, just thought about it again, the word I was looking for was torque converter, not transfer case
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02-26-2008, 09:36 PM
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#28 (permalink)
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This is a good read on 'em IMO.
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02-26-2008, 10:57 PM
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#29 (permalink)
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Giant Moving Eco-Wall
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Quote:
I'm just thinking that there is something similar to a clutch between the tranny and the engine to keep it from spinning too much, otherwise it would certainly over-rev the motor...
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the transmission shifts gears in order to keep engine speed closest to idle. If you notice, go down a very slight hill degrade, but it's enough to speed up the car to around 30-40 before you can't go faster. Start in first at about 10mph, and as you go faster, you'll notice that the rpm's will go up over 1000, and at some point shift. and faster you go the more it will shift, and will downshift when you start slowing down.
NOTE: this is with my tranny. It might not work with other transmissions.
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12-03-2009, 10:15 PM
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#30 (permalink)
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In my wifes '04 trail blazer, when I tried coasting down a long grade, no matter how many seconds, the engine still maintains the RPM from the moment I shifted out of drive. Another words, I can be cruising along at about 2000 rpm and shift out of gear into neutral, and the engine still revs at 2000 RPM for the entire time Im in neutral. One thing I did notice is that by keeping the same RPM, the thing doesnt jerk when I put it back into gear like my old suburban use to. who knows, maybe its designed to hold RPM to keep from slapping the tranny into the wrong gear?
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