Leon:
I have used the stuff quite happily on my TR4A header. I have a thin
wall tuned header. The wrap greatly lowered noise as well as heat in
the engine bay. It is supposed to increase power because the hotter
exhaust gas flows faster and scavenges better, but I suspect that
benefit is minor. I have no experience with hard coatings, but my guess
is that they are more for header protection and appearance with little
heat or noise reduction.
If you have a standard exhaust, don't bother with the wrap. Benefits
will be much smaller but the work the same and the negatives. You have
to remove the header to wrap it, which is not difficult but takes a
while. It also complicates work on the carbs and starter because you
have to be careful not to bang it too hard. Also the wrap is somewhat
strange looking expecially when it gets scuffed up.
I bought mine from the JC Whitney catalog and can't remember what the
brand was. I think it was 2" by 50'. Wider covers better because there
is some overlap, but I think 6" would be too cumbersome for our
relatively small headers. You might get the 2" for the main wrap and a
1" roll for the detail coverage.
Some people say it accelerates rusting of the header, but mine has
lasted about 5 years already with no signs of damage. I don't think
rusting should be a general problem because it gets extremely hot under
the wrap which should boil off any moisture that works into there.
Cracking might be a problem on some cars because the header will expand
more at the higher temperature, putting a strain on it if the exhaust
system is clamped in place too rigidly. However, as a former heat
transfer engineer, I don't think the metal under the wrap will be all
that much hotter, and a wrapped header that cracks would probably have
cracked eventually anyway. In my car, the first exhaust clamp is at
the back of the transmission, leaving ample flexibility.
Alan
> Friends,
>
> I am thinking of applying heat proof wrap to my exhaust
> manifolding/headers,
> and am wondering if any of you have used such stuff, which type you have
> had
> success with?
>
> The object is to reduce the temperature of the air under bonnet/hood which
> is
> heading for my intake ports...
>
> The advertising bumpf says "reduces under bonnet temperatures up to 70%."
> The manufacturer is Design Engineering Inc, which I assume is American.
> It is available in 1" wide x 50 feet, 2" wide by 50 feet, and 6" wide by
> 100
> feet.
>
> Your opinions are as ever priceless...
>
> Léon F Guyot
>
> Triumph Sports Six Club
> International Liaison Secretary
> 1963 Triumph Vitesse 2-Litre Convertible
> Wimbledon, London, England.
>
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