Date: Thu, 27 Dec 2007 11:41:40 -0800
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Overcooling Hypothesis--Long
In-Reply-To: <4773E4DB.7020407@comcast.net>
Content-Type: text/plain; charset="us-ascii"
Yes but, descending long grades in neutral isn't very safe in terms of
vehicle stability. There are some serious long grades in the west coast.
Like there's one here, about 7 miles long, if you cost in the top 4 miles of
it, you'd be doing 80. And it curves. And you wouldn't want to be breaking
to keep speed under control there. . And it's technically illegal to coast
in some states I think.
And you sure wouldn't want to be in gear holding the clutch in going 60 or
so down a big hill. Trick it electrically I say.
Scott
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Kenneth Wilford
Sent: Thursday, December 27, 2007 9:46 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Overcooling Hypothesis--Long
Yes the injectors are only off above 2000 rpms on deceleration. Below
that they come back on. I have a digitool and have observed this myself
many times. So if you can somehow get the rpms down a bit this would
help (like having the engine at idle by depressing the clutch pedal
should work).
Ken Wilford
John 3:16
www.vanagain.com
Allan Streib wrote:
> Geza Polony <gezapolony@SBCGLOBAL.NET> writes:
>
>
>> Here's my idea. When you're coasting downhill, you're using the
>> engine as a brake. This means that above 1500 RPM, with the idle
>> switch closed, the engine isn't getting any gas, as the ECU has shut
>> the injectors down. If it isn't getting any gas, it also isn't
>> producing any heat. The engine is functioning as a brake, but there
>> isn't any combustion, and so, after a period of 10 minutes or so in
>> freezing temperatures, the coolant loses temperature, and your gauge
>> is way off the edge of the scale.
>>
>
> Makes sense. Not only is there no combustion but you are flushing
> cold outside air through the cylinders, which has a further cooling
> effect.
>
>
>> I tested this by going downhill, engine warm, and taking my foot off
>> the gas to coast. I could see the gauge move colder before my
>> eyes. Give it a little gas, and the engine warms up. This is kind of
>> tricky from a driving standpoint, but it works.
>>
>
> Now, repeat the experiment with the clutch in, so the engine is
> idling, not being overrun. See if it stays warmer.
>
> Allan
>
>
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