>Subject: anyone know anything about the new smog test in CA?

[RonHorowitz <RonHorowitz@xxxxxxxxxxxxxx>]

> from what
>I've read,

Don't believe everything you read, obviously.

>it seems that ported heads are actually
>more efficient than the original spec heads.

Depends on how they were ported.

>Does this
>mean less CO? less particulate exhaust? fewer unburned
>fuel vapors in the exaust?

Probably the opposite. They way most knuckle heads "port" the intakes, the
opposite is likely to be true. "Hogging out," which is what most people do,
lowers the velocity in proportion to the square of the increased radius.
Think of it this way, cubic dimension divided by square dimension yields
linear dimension. A high velocity port can increase charge homogeneity
(sp?) and burn rate via turbulence, thus combustion efficiency. Conversely,
a "hogged out" port can do the opposite, especially at low rpms, where the
low cfm implies lower velocity through the larger port radius.

There are a lot of positive things you could do. The straight section of
the port can be raised and filled, the profile can be developed on a
Superflow for maximum velocity, you can do a reverse venturi at the bend
near the guide, you can port the maximum radius on the port floor, you can
fit a venturi seat dropped into the chamber a little with long-stem valves
and relieved pistons, you can neck-down the valve stems and flat-back the
valves, you can blend the valve grind and do a single-angle seat with an
assymetric hand-blend, you can fit the engine with custom, high-squish
pistons (kind of like a Fiat 124 only in reverse,) you can try to minimize
trapped volumes for end gas, you can tune the car up for a pre-smog on a
dyno of your own, and so forth. It's all stupid-expensive and it's a lot of
R&D for a car that's not wrth much, especially since your shooting for
lower emissions rather than just performance, but you could do it.

On the other hand, now that I think of it, hogging out the _exhaust_  might
actually _lower_ emissions. Decreased exhaust velocity should increase
reversion, which might work sort of like increasing the volume of the
exhaust gas recirculation, especially at lower RPM.  I'm going to have to
think about that one for a minuite!

>On the other hand, maybe someone would be interested
>in taking the car out of state if it does not pass...<

Sad state of affairs, isn't it? Wish me luck as I've got a '77 Alfetta to
get passed the new smog, also!

RON
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