Drive to Reverse at 55 MPH
Thread Starter
Member
Joined: Aug 2011
Posts: 1,278
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From: Cleveland, MN
Coasting in neutral is basically running at idle levels fuel consumption.
Coasting in drive goes into deceleration fuel cut that is zero or near zero fuel consumption. This is primarily to protect your cats, since on deceleration the throttle plate closes leading to low oxygen and incomplete burn of any fuel injected. But it also saves fuel and uses less than coating in neutral. If you can feel engine braking, you are probably in deceleration fuel cut, though it isn't universally true.
Your technique has probably costed you gas over the years, not saved it. This has been on cars for a long time. Though I can't guarantee it was on your old truck, it probably was.
Any scan guage can show injector pulse width in real-time.
Coasting in drive goes into deceleration fuel cut that is zero or near zero fuel consumption. This is primarily to protect your cats, since on deceleration the throttle plate closes leading to low oxygen and incomplete burn of any fuel injected. But it also saves fuel and uses less than coating in neutral. If you can feel engine braking, you are probably in deceleration fuel cut, though it isn't universally true.
Your technique has probably costed you gas over the years, not saved it. This has been on cars for a long time. Though I can't guarantee it was on your old truck, it probably was.
Any scan guage can show injector pulse width in real-time.
Based on the "maximum MPG people", this isn't true. I wish I could remember what they call themselves, but neutral coasting is one of their mainstays...along with aerodynamic body panels and full undercarriage skid plates, lol.
Those fruit loops are worse than the F15dy Boyz when it comes to MR looking mods.
Those fruit loops are worse than the F15dy Boyz when it comes to MR looking mods.
Resident Worm Drowner
Joined: Jan 2014
Posts: 6,778
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From: West Virginia
Call me a fruit loop if you like but at 178K miles on my last truck I had only changed brakes twice. I accredit that to all the coasting to a stop that I do. I had it to the point that more often than not I could judge my coast so that I came to a stop right at the sign with NO BRAKING REQUIRED.
Thread Starter
Member
Joined: Aug 2011
Posts: 1,278
Likes: 168
From: Cleveland, MN
Resident Worm Drowner
Joined: Jan 2014
Posts: 6,778
Likes: 90
From: West Virginia
Senior Member
Joined: Dec 2012
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Based on the "maximum MPG people", this isn't true. I wish I could remember what they call themselves, but neutral coasting is one of their mainstays...along with aerodynamic body panels and full undercarriage skid plates, lol.
Those fruit loops are worse than the F15dy Boyz when it comes to MR looking mods.
Senior Member
Joined: Dec 2012
Posts: 2,964
Likes: 584
The only way fuel could be shut off completely is if the torque converter is in lock-up to keep the engine turning. If this is so, then engine braking is occurring which in turn will slow the vehicle much faster thus decreasing the distance of coast. That being said, throttle must be applied to make up for that decrease in coast distance. I am willing to bet that the throttle required to make up that distance uses more fuel than coasting in neutral at idle for the longer distance.
There are cases where coasting in neutral or with engine brake can come out on top mpg wise. It depends on terrain. But if you are really into it coast with the motor off in neutral. That can't be beat.
Texas Aggie
Joined: Mar 2013
Posts: 2,344
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From: Houston and College Station, TX
My opinion: It's bad for the automatic transmission to do this to it, just like manual down and up-shifting frequently with an auto is hard on it.
And then lastly, my truck coasts far as hell in gear because it doesn't let the RPM fall immediately to idle, so left to its own devices, it should "coast" pretty far.