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I've read some threads about pulse and glide and the use of neutral to help gliding. I am wondering if that will damage the car. Here is my concern -- Toyota warns that the car should not be towed with the wheels on the ground as going over 42 will overspeed the motor/generator and may cause damage. Wouldn't that also be the case if you coast in neutral over 42 mph?

Thanks.

PS mine is an '02 classic if that makes a difference
 

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'D' neutral safe, don't know about 'N'.

Well, if you can 'feather' the gas pedal to have it go into 'no power' mode (no arrows going anywhere,) then it will effectively be in neutral, but without actually disengaging anything. If you exceed 42 mph in this mode, the gas engine will spin to prevent the electric motors from over-reving, even if it's not providing power. (The ICE will spin with no fuel in this case.) Over 42, it also becomes near-impossible to reliably use the 'feather the pedal' tecnique to stay in neutral. So if you just feather it so you alternate between generate and power, it's basically as good as neutral for the 'pulse and glide' technique. The upside is that if you leave the transmission in 'D', you run zero risk of damaging anything, as the transmission will take care of all of those concerns for you.

As for shifting into 'N' neutral? I don't know. I figured it actually disengaged the transmission from the drive wheels somehow, but I've never done any reasearch to support that hypothesis. Maybe some of our more technical bretherin can help.
 

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There is no disengagement in neutral. It just tells the computer how to control the electric motors or not.
 

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The priuschat reference given above lists a lot of other good reasons why coasting in N may not be such a good idea. However, fear of damage to the power train is almost never a concern. If you are already travelling over 42 MPH when you pop into N, the gasoline engine will already be spinning. It will be quickly configured to idle, thus will continue to spin even without help from the electric motors. This will avoid any possibility of overspinning the smaller motor/generator. If you are under 42 MPH when you pop into N, it is unlikely that you will end up over 42 MPH. However, on those rare steep hills where this is possible, you could very well end up overspinning the smaller motor/generator. If you're lucky enough to have a 2004 or later model Prius, the smaller motor/generator is actually rated at 10,000 RPM instead of 8,000 RPM, so you have to go quite a bit faster than 42 MPH before there's a danger of overspin. If the 71 MPH number in the priuschat reference is correct, I really doubt anyone is going to find a hill steep and long enough to go from under 42 MPH to over 71 MPH in N.

But there are some wierd places on this planet, so I won't claim its impossible to find such a place.
 

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Thanks Rob. I was second-guessing about being in N when Kirby mentioned the overspin. By the way, I thought the max RPM for MG1 was 6500 RPM for the classic.

But then, once the ICE is idling, I have found by tests I have done that it does stay running. I have discovered this by letting SOC go down to 2 bars, then putting the car in Neutral. The AC was running so the SOC went down to 1 bar. I was too chicken to let it go lower. When I put it back in Park, ICE started right up. Once started, it continued to run, at a different idle when placed in N again.

So, thanks again to Rob, if the car is running at a speed that would cause MG damage if the ICE was not spinning, then ICE would be spinning when I put it in N.
 

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Ray Moore said:
So does this mean that Neutral at any speed is ok as far as the car is concerned?
As long as you don't speed up.

Aside to Dan, I don't remember where I got the 8000 RPM number, but it was way back in a document I found in late 2000 or early 2001. I used that value in my nomograph description. Too bad I wasn't concientious enough to put in proper citations.

I see the 2004 Prius New Car Features says something about the 2001-03 MG1 not being able to put out max generation at above 6500 RPM. Also, 6500 RPM in the classic gives the magic number of 42 MPH with the engine stopped.
 
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