Re: [DML] free flow exhausts-legality?

[William T Wilson <fluffy@xxxx>]

On Sun, 12 May 2002, theshovel1224 wrote:

> Correct me if I'm wrong, but won't the PRV6, if tuned properly,
> pass emissions even without a catalytic converter?

You *might*. It depends on the test and the tuning. 

There are three kinds of emissions test - the visual test, the idle test
and the dyno test (where they put the car on rollers). What exactly
you're up against depends on where you are and, in some states, the year
of the car. In Colorado, for instance, 1981 model years and earlier get
the much less fussy idle test, whereas 1982 and newer get the dyno+visual
test.

Passing the visual test depends on the competence of the inspector. If
the inspector can't find where the cat is supposed to be, or doesn't have
the DeLorean in his computer - both of which are quite possible - he'll
just give you a pass on the visual test. However if he does manage to do
his job correctly, you will not pass if you don't have some sort of cat. 
Not all areas have a visual test.

You *might* pass an idle test without a catalytic converter. The PRV is a
very clean engine. Some states do not test for NOx in their idle test,
only hydrocarbons. You could pass such a test with a lean mixture and
possibly using oxygenated fuel. Even if they do test for NOx, they might
have very relaxed standards for older cars. It could work out - I
probably wouldn't bother and would just get a high flow cat. Or a turbo
kit. :}

There is no way you will pass a dyno test without a cat. It's hopeless.