I guess when you think about the intake manifold, it really does not have
time to heat the intake air very much anyway, as you said, very little
resistance and high velocity.
Ed
-----Original Message-----
From: Randall Young [mailto:ryoung@NAVCOMTECH.COM]
Sent: Friday, October 12, 2001 2:12 PM
Cc: triumphs@autox.team.net
Subject: RE: Intake manifold on an early TR-6.
Ed :
It's true at least in theory, if you can cool the intake charge you can get
greater density which usually means more power at full throttle. But, the
coolant is actually warming the intake manifold, and that actually has
relatively little effect on the charge temperature at full throttle. There
just isn't enough surface area, and the air moves too fast, to change it's
temperature by much. Plus, a street driven car engine has to operate under
a wide variety of conditions, with full throttle being one of the rarest
ones. As Barry noted, those who are only interested in full throttle power
usually disconnect the carb/manifold heat. I've done it on my own
street-driven cars, and honestly the only difference I can tell is a
tendency to suffer from carburetor icing.
I've seen various naturally aspirated race cars try to cool the intake air
below ambient (buckets of ice and whatnot), but it usually winds up being a
lot of complexity, weight, and intake restriction, with relatively little
benefit. The situation is, of course, a lot different with a supercharged
engine, where you're only trying to cool down to ambient, and a little
restriction doesn't hurt (since you can turn up the boost to compensate).
Plus generally, the amount of boost you can use is inversely proportional to
the charge temp when it enters the cylinders.
Randall
>
> Not to stir the pot, but for my own interest.
> If the coolant is actually cooling the intake during running,
> would this not
> result in better mass flow. In other words if you ran another
> radiator and
> further cooled the intake, could you theoretically get better performance.
> Higher density therefore greater mass of air....sorta like an
> intercooler/precooler.
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