Sat,
I am going to try to take this on because you make very good points
... I hope this makes "some" sense. I was just at an exhaust coating
site and of course one of the advantages they claim ... quote "The
coating also contributes to faster exhaust flow and better cylinder
scavenging." Of course keeping the heat out of the engine compartment
is a biggie for them in regard to automotive applications as doing so
contributes to lower intake temperatures etc ...... possibly an
advantage for bikes too, (especially if you have body work), but thats
another story ...
However ... the claim for gains as a result of increased exhaust
velocity is true. Headers that radiate less heat, (everything else
being equal), will make more power .. because as exhaust gases cool
they lose velocity. Drawing exhaust into an area within the exhaust
system that is rapidly condensing may produce a scavenging effect of
it's own but sooner or later even the condensed gases have to exit the
exhaust system ... and if they aren't doing anything anymore they
usually have to be pushed out of the exhaust system. The insulation
helps move this "event" to the end of the exhaust system by delaying
the temperature loss. Reducing the speed at which heat is lost
maintains the velocity of the gases moving through the exhaust system.
An improvement of the velocity that the exhaust gases maintain,
(everything else being equal), will produce an improvement in it's
efficiency and the "increased scavenging" will occur as a result of
this "increased velocity". The heated gases that are expelled by the
engine do represent energy and the insulation provides a means to
utilize some of that energy as work that is beneficial to the engine.
Not to mention the fact that Kelly is much less likely to be burned as
severely as he would using a pipe with poorer insulation properties.
So .. just like intakes .. velocity is important and the "pulse of the
adjacent cylinder" to which you refer does indeed help the next guy ..
but only because it helps maintain the speed of the exhaust flow
.......
Would I lie ??
campbell
----- Original Message -----
From: Sat Tara S. Khalsa <[EMAIL PROTECTED]>
Subject: Re: Make a choice - Chrome vs JettHott - AIRBORN
> on 3/28/00 12:23 PM, Kelly Cash at [EMAIL PROTECTED] wrote:
>
>
> > o Performance is better. It's an insulator, so the
> > heat stays in your pipes. This increases scavenging.
>
>
> I've seen this said a few different times on this list, so don't
feel like
> I'm singling you out, Kelly. I'm just puzzled by this statement.
>
> Could somebody please explain to me how this makes the slightest bit
of
> sense?
> snip <
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