Twin Turbo Update... (10/13)

[Tom Cloud]

>
>-> Actually, Pontiac only used aluminum exhaust manifolds for drag
>-> racing.
>-> Anything else, they would have melted.
>
> Not necessarily.  From reports they did okay for normal driving, though
>they were wont to drip molten aluminum after a hard pass.
>
> Aluminum pistons and cylinder heads don't melt, you know.  As long as
>you can pass the heat off somewhere fast enough you're okay.  The
>manifolds couldn't reject enough heat to keep up when run hard.

I think the exhaust manifold is subjected to more severe heat than
the cylinder -- as hard as that may be to see.  The cylinder and
head area are water cooled, the burning inside is "in process" and
swirling and is replaced by cool air.  The gases going into the
exhaust manifold are at their hottest point -- no cool air or water
cooling here.  I would think that a thick, cast aluminuminuminum
manifold would last a good while, but that it would ablate away
on the inside due to the blow torch exhaust stream directed at it.

Tom Cloud

     Madness takes its toll   .....   please have exact change