Putting a DCT in neutral when coasting
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I can't imagine why anyone would actually want to do this (it's not safe thing to do), but it shouldn't hurt the car at all. You can switch into and out of neutral while moving all day long.
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Exactly, why?
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Brake pads are cheaper than engines.
Probably not, but I don't see the reason unless you have few miles to go downhill. JMO
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10,950 Posts
You might confuse the software and cause it to some something crazy. I might not even let you do it. Going into neutral might not be a problem. But, going from neutral into a gear while moving might be.
In contrast, Porsche's PDK (DCT in Porsche lingo) has a "sailing" function that throws the car in neutral (for better fuel economy) if you gently let off the throttle.
In contrast, Porsche's PDK (DCT in Porsche lingo) has a "sailing" function that throws the car in neutral (for better fuel economy) if you gently let off the throttle.
If you are coasting the engine is not using any fuel.
If the engine is idling in neutral it is using fuel.
http://www.popularmechanics.com/cars/hybrid-electric/a5977/coasting-in-neutral-fuel-economy/
If the engine is idling in neutral it is using fuel.
http://www.popularmechanics.com/cars/hybrid-electric/a5977/coasting-in-neutral-fuel-economy/
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Popular Mechanics got it wrong.
It's true that modern cars use zero fuel when coasting in gear (engine being turned by the wheels). But that creates a braking effect on the car from the engine's compression and from the parasitic losses form the accessories (AC compressor, mechanical power steering and water pumps, alternator, oil pump, etc.) running at full speed. So, that car coasting in gear will coast less distance than a car coasting in neutral, and will therefore have to be under power for part of the distance that car in neutral would be coasting. Because it's under power part of the time the car in neutral is coasting, the car staying in gear uses more fuel.
Mercedes-Benz, in addition to Porsche, uses the "sailing" (coasting in neutral) function to save fuel.
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Coasting outta gear can be a way to optimize mileage. Personally the diff in expense doesn't mean much, I just like to see how high I can push the mileage readout.....
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I live on a barrier island. Gas in cheaper on the mainland. So, if I'm over there and near empty I fill up. There's a big bridge I go over to get back on the island. I reset the OBC MPG when I fill the tank. If I get a running go at the bridge, slowing down as I climb, it doesn't hurt MPG as much. Then I coast down the other side of the bridge for almost 3/4 of a mile. The MPG goes through the roof. Frau Putzer refuses to look at the readout when I point out my phenomenal MPG, though. She looks out the passenger window and says "Meow, meow, meow..." which roughly translates into "I'm not listening to you."
If I'm out in the boonies with no traffic behind me, I'll coast about a 1/2 mile to a stop sign.
Modern BMW's have super efficient wheel bearings. I can tell the difference between my 535i and my Chevy. I expect the rolling resistance to be even less when I dump the RFT tires. It's a dirty little secret that RFT's cut your MPG about 1-2%.
If you reset your MPG when you fill up, and compare the OBC MPG to the "gas pump" MPG (miles since last fill-up/gallons), you can figure out which gas pumps are ripping you off and which ones are giving away free gas. But, they eventually recalibrate the generous pumps.
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I've tried doing the 'right thing' and seeing what I can get but I just can't do it. My right foot gets in the way every time and I don't get through a tank in 'efficient' mode 
I have a real dislike of the coasting in neutral or clutch to the floor. I cringe when my wife does it. At that point you aren't driving the vehicle. Not really in full control - IMO.
I have a real dislike of the coasting in neutral or clutch to the floor. I cringe when my wife does it. At that point you aren't driving the vehicle. Not really in full control - IMO.
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It does wear out the throw-out bearing that disengages the clutch. I had a '76 VW Rabbit with 155k miles that had a noisy throw-out bearing.I've tried doing the 'right thing' and seeing what I can get but I just can't do it. My right foot gets in the way every time and I don't get through a tank in 'efficient' mode
I have a real dislike of the coasting in neutral or clutch to the floor. I cringe when my wife does it. At that point you aren't driving the vehicle. Not really in full control - IMO.
When I "sail," I do it in neutral.
I tried EcoPro mode... once. Once I figured out is screwed with the air conditioning, that was the end for me.
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