Just an academic musing

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Old 09-17-18, 08:56 AM
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Just an academic musing

When I start off from a stop position such as a traffic light I give the car just enough gas to start moving and gradually let the car come up to speed. I don't mean I hold up traffic but I don't push the car. Sort of like letting the engine push itself. As opposed to gassing it to get up to speed in a short time, like most people do. My question is do I get better gas economy or worse gas economy? Does it even make a difference?
 
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Old 09-17-18, 10:22 AM
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I used to like playing with "hypermiling" in my younger years and my guess would be better mileage but how much would depend upon how many stops and starts. The flip side is the road rage those ultra slow takeoffs can induce and IMO, being selective as to when you do so would be good.

I was pumping gar a few years back (higher gas prices) and watched to older gentleman on the next pump lifting the hose after he finished to drain out any extra he could. I suppose if some comes out it is free, but???

A good friend and co-worker and very conservative person always advised a stack of washers under the gas pedal to improve mileage. Might have to be a block of wood on today's cars, but same idea as your soft start.

Bud
 
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Old 09-17-18, 10:52 AM
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I'm sure we had similar conversations in this forum multiple times before.

I still do a lighter form of hypermiling. But I don't block or back-up the flow of traffic. I stay in the right hand lane and let faster traffic pass me or I go the faster if that is what current flow is like. I will slow or coast as I approach a traffic light. But my main question, am I gaining anything by doing a "normal" start vs a slow start and "let the car pull itself up to speed"?
 
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Old 09-17-18, 11:54 AM
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I believe the slow start does save some gas. Maybe a small cup of coffee each month, depending.
 
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Old 09-17-18, 01:09 PM
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Pretend you have a raw egg between your foot and the pedal. Press slowly and with a light enough touch to prevent cracking the shell.
 
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Old 09-17-18, 01:09 PM
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But I've also seen studies suggesting you save more by getting into high gear/cruising speed sooner. Not that you should floor it up the speed limit and then ease off, but I think a moderate acceleration is a good compromise.

There's probably more savings by watching your BRAKING. I see this all the time, people maintain speed until 50 feet before a red light and then brake hard up to a stop. Uses excess fuel AND wears out the brakes faster.
 
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Old 09-17-18, 01:11 PM
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Did Mythbusters ever cover this? They've done everything else.
 
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Old 09-17-18, 01:41 PM
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I've always been easy on/off the throttle and tend to get better fuel mileage than most. I had a Bronco once with a 460 cid that didn't care if you babied it or kept your foot in it - 8 mpg either way although it idled better if you drove it hard.
 
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Old 09-17-18, 01:47 PM
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Cars with ECO driving mode do just that - very slow acceleration. Figures, eggheads at design institutes agree with you.
Though hypermiler will tell you something opposite - fast acceleration and then roll, coast as long as you can.
 
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Old 09-17-18, 01:59 PM
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But I've also seen studies suggesting you save more by getting into high gear/cruising speed sooner.
That's what I was thinking.
 
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Old 09-17-18, 08:59 PM
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it depends on the car. best route is if it has an instant mpg try to keep it the highest at all times. if not, do your own math. use the same gas(something you should do anyways) fill up and drive one way, mark your miles and divide by how many gallons at next fill up(mpg). do it again only driving it the other way. But i feel you have to do this over a years time to really know which works for your car. too many factors in play. temp/humidity/traffic/unwanted idling. and then you are left with 1-2 mpg difference between the two(if the car is maintained and not 20 years old)
 
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Old 09-18-18, 05:42 AM
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LOL. Yeah, my wrecker gets 8 mpg no matter HOW I drive it.
 
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Old 09-19-18, 06:25 AM
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Originally Posted by Bud9051
I was pumping gar a few years back (higher gas prices) and watched to older gentleman on the next pump lifting the hose after he finished to drain out any extra he could.
Back in the 80s, before the 24 hour gas station was common, a highschool friend took a weekend trip to Atlantic City, made it there just about on empty. He lost his wallet but managed to get 100 miles home "the long way" by going from little town to little town and toppping off the tank from whatever was left in the hoses; although it took from midnight to around 4am to get home.

Originally Posted by the_tow_guy
Did Mythbusters ever cover this?
They did-

    I think the consensus is that, as slow an accelleration as you get away with is best;
    once at speed, then "tap and coast" to maintain speed - idea is to spend 10% accellerating at 15 mpg and 90% coasting at 99 mpg; is better than getting average 50 mpg.
     

    Last edited by Hal_S; 09-19-18 at 06:51 AM.
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