On Sat, 2008-03-01 at 14:58 +1300, Apptech wrote:
> >> You could use heated air from the manifold when the 
> >> engine is running to
> >> the save energy otherwise used to heat the air while the 
> >> engine is running.
> 
> > Unfortunately when it's cold it can take a surprising 
> > amount of time for
> > an idling engine to get anywhere near warm enough to put a 
> > dent on
> > defrosting a windsheild. Trust me, I know, it was -25C 
> > (about -13F) last
> > night here...
> 
> >From startup, how long can you hold your hand on the top of 
> the exhaust pipe where it leaves the manifold? (We'll let 
> you not place it there until the pipe rises above 0 C to 
> save you some skin, but count those seconds into the period. 
> Hand off (new meaning to the term) occurs around 55C - 60C 
> unless you have asbestos hands.

Right, but what do you do when the temp of that pipe reaches 300 or 400C
or even higher? (I'm unsure of the exact temp, I do know that the O2
sensors need to be at about 800C to operate, and I also know from
experience that the pipes are hot enough to light transmission fluid on
fire instantly).

Frankly there are many MUCH easier ways to get heat then trying to build
something that can operate safely through such a wide variation of
temperature, which is why it is almost never done.

TTYL


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