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Is coasting in neutral a problem?

Discussion in 'Gen 2 Prius Main Forum' started by aarons12, Apr 17, 2004.

  1. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    i dont believe that anyone thinks coasting is really risking the mechanics of the car. however, coasting is not the accepted method of operation of the vehicle and if something should go wrong or you get into an accident, i believe you may have problems filing a claim.

    coasting is not recommended for ANY car and never has been. but people have been doing it for years.

    i can remember many many times towing a car that had an automatic tranny to jump the vehicle because it had to be going about 25-35 mph to work.

    that is against auto policy too, but it works.
     
  2. Frank Hudon

    Frank Hudon Senior Member

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    only on automatics with a rear pump. most went away from using rear pumps in the 60's
     
  3. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    sorry, but im not that old and i did this MANY times.

    when i was a kid, most of the people i knew had cars that wouldnt start on a regular basis. most of these cars were of the early 70's models. some were 60's like most of mine.

    of course, maybe doing things like that contributed to the problems we had keeping them cars running...

    ah the good ole days!!... funny though, it only took one time walking home after being stranded in a Michigan snowstorm for me to be very happy that the good ole days have past!!
     
  4. Ray Moore

    Ray Moore Active Member

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    Well Dave, I'm not sure what you meant about voiding the warranty, but I'm even more confused about the risk of a denied insurance claim that you are now raising. I should probably just let this go but I do wonder what you are thinking. Do you believe that there is even a remote possibility that an insurance company would know that I was coasting in neutral? Coasting along on back country roads at less than 50 mph is not the part of my commute when I'm at risk. The risky part of my drive is near the college campus when I become a target for teenagers justifying their high insurance rates.
     
  5. jamarimutt

    jamarimutt New Member

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    I coast in N for short distances every day. I go down a long hill that is not steep enough to maintain a constant speed in D and which is followed by a hill. By coasting in N I can pick up momentum to climb the hill with less gas. I have yet to see a convincing argument against coasting in N.
     
  6. tag

    tag Senior Member

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    If you lived here, it's prohibited by §11-1410 of the Illinois Vehicle Code. Don't ask me how any cop could enforce that one, though.
     
  7. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    not operating the car in the way it is intended may void your insurance policy is all im saying.
     
  8. fred

    fred New Member

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    serious answer for a change from me. it is never a good idea to coast in neutral in any car.it was one of the first rules instilled in me at driving school many, many years ago. its true that brakes are much better than they used to be but its still not a good habit to get into. having been into sportscars etc all my life i have learned that control and anticipation are key to no accidents. another key lesson is for every 10 miles per hour be another car length behind the car infront of you. that way you almost never have to slam on your brakes. one other thing is to go the speed of the predominant traffic. when everyone is going 75 dont drive at 55. the whole idea is not to be in or cause an accident . well, enough pontificating for now.

    fred from nashville with over 40 yrs driving, no accidents (knock on wood) and no tickets. 8)
     
  9. jamarimutt

    jamarimutt New Member

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    I understand your points, but they still contain no convincing argument against coasting in N for short distances. In an emergency situation you're much more likely going to brake than to accelerate, and for the former being in N or D should not make a difference.
     
  10. fred

    fred New Member

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    you are probably right. its just that like playing musical instruments the results are what you practice. so if you coasted once inawhile for short distances its not likely to be a big deal. but... if it became a habit thats another story . for sure it does not give you more control than not doing it. its the little things that add up
     
  11. tomdeimos

    tomdeimos New Member

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    I learned to drive it a car that always coasted. A 2 cycle Saab. It had free wheeling built in to save on gas. The free wheel could be locked out for engine braking down a mountain but that was the only time it didn't free wheel. So coasting in a Prius just seems the only proper way to drive: either with the accelerator controlled precisely for no arrows or by using the neutral gear, which really serves no other purpose.

    Now if only somebody would dis-assemble the source code and make it available. The first 2 things I would modify would be to make it simulate free-wheeling with foot off the accelerator, and eliminate the forward creeping that tries to simulate a bad automatic transmission. Both should be easy to do.
     
  12. richard schumacher

    richard schumacher shortbus driver

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    Certainly there are many times when no regeneration would help economy. I expect Toyota's testing showed that, averaged over a typical set of urban driving profiles, fuel economy is better when some mild regenerative slowdown is present. The batteries can only absorb charge at a smallish maximum rate; the benefit of coasting with no regeneration at all may, on average, be overwhelmed by the friction losses of subsequent braking.

    Still it is tempting to try to coast long distances when possible. Rather than risk the (admittedly rare) emergencies which call for speeding up in a hurry rather than braking, I practice glancing at the MFD and modulating the pedal to keep the arrows off.
     
  13. DanMan32

    DanMan32 Senior Member

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    I'd rather have the MFD source code disassembled. We could do a lot of neat things with that.

    Sometimes, esp over 40MPH, I can't get it to coast/dead-band. Either it regens (green), or powers by electric (yellow).
     
  14. BorisSlo

    BorisSlo New Member

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    <div class='quotetop'>QUOTE(Ray Moore\";p=\"16166)</div>
    As others have mentioned, having the accelerator pedal depressed only slightly to prevent regeneration but to not give any power would perform exactly the same as going to neutral. Look under 'feathering'.

    The only time I would use neutral is when stopping i.e. at speeds below 12 km/h where no regeneration takes place and electric motor is actually consuming power.

    Boris
     
  15. Ray Moore

    Ray Moore Active Member

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    I use neutral alot on my commute and I wondered how much so I monitored it the other day and was suprised by the results. My commute is 33 miles one way. I use neutral on back roads when I know that a consistent downhill or flat section will allow me to maintain speed without added power. I don't use it if the engine will be on for a warmup as I don't want to waste the charge benefit. When checking the miles in neutral I included some of the slowdown time in drive as I will sometimes shift to drive in the middle of a long coast to slow down a bit and get a charge out of it before shifting back to neutral. I also use neutral for long coasts up to red lights since it doesn't reduce speed much if that is called for.

    On the way to work, I spent 7.5 miles in neutral, including 3 stretches for a mile or more. On the way home I used it for 4.5 miles. including one stretch for 1.5 miles. I have used this practice for 28,000 miles now with no ill effect. I limit the speed in neutral to 62 mph.

    My last two tanks were 654 miles at 58.9 MPG and 660 miles at 58.0 MPG.
     
  16. DanMan32

    DanMan32 Senior Member

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    Hmm. Then I CAN get 700 miles on a tank, even if I get the Add Fuel warning just before 600 miles. I have been getting 59-60MPG. How many gallons did you put in before and after those last 2 tanks?
     
  17. fred

    fred New Member

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    guys im in the minoirty but..... dont do it. it is a rotten non driver habit to establish over hardly any gain. that does not mean that i think you are a rotten person but he uses neutral as a habit is most likely to do other non driver stuff which equals increased accidents and lack of proper control. sorry, it sounds like im alone in my feeling ont his one.
    your friend fred from nashville (still 0 accidentsd, 0 tickets in 40 yrs)
     
  18. Ray Moore

    Ray Moore Active Member

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    Fred-

    It is a pro-driver thing to do that is not lackadaisical in any way. The amount of attention that I pay to my driving in the Prius is far and away more than with any car I have ever driven. I enjoy driving the Prius and am therefore constantly aware of the way that I am driving it. Shifting the car back and forth to neutral is no different than shifting gears in a standard transmission from a driver stand point and I'm sure that you don't consider that to be a rotten non-driver habit. I don't do anything without weighing the risks and rewards. The rewards for coasting in neutral are substantial in the high mileage game I play, but not that great in a strictly dollars and cents context.

    And I still love you. Your opinion doesn't change that.

    Dan-
    I fill it to the top. Last fill 11.4 gallons. One before that, 12.3 due to a short fill the time before that. On my first 700 mile tank, I carried a gallon with me toward the end, but not anymore. I may carry a gallon when I try for 800.
     
  19. fred

    fred New Member

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    btw ray, when i had my harleys i felt exactly the same way. that is as an adult i weighed the risks and accepted them as they might be. that was very well put by you, ray. i still as a stick in the mud dont agree but its more that im a true car guy where driving with the ultimate control is very important. i hope i did not come across as attacking you personally. its just as someone who was brought up on sportscars and driving the hell out of them i have a little old fashioned view. so... respectively i just can never do the neutral thing.
     
  20. Ray Moore

    Ray Moore Active Member

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    It's just another gear Fred.