Variable Restrictiveness Exhaust

[Shannen Durphey]

Vacuum operated valve, WOT= bypassed cat.
Shannen

David A. Cooley wrote:
> 
> How about a test pipe for the cat...
> when you need to get it smogged, bolt the cat back in.
> 
> ----- Original Message -----
> From: William T Wilson <fluffy at snurgle.org>
> To: <diy_efi at efi332.eng.ohio-state.edu>
> Sent: Thursday, May 13, 1999 2:40 PM
> Subject: Variable Restrictiveness Exhaust
> 
> > Okay, this seems to be the best place to talk about random, goofy car mods
> > that just might work. :}
> >
> > Suppose I have a car that I want to pass emissions, but I also want it to
> > gogood.  Why couldn't I make some sort of cat-bypass system which would
> > allow the exhaust to flow openly at high revs, but flow through the cat at
> > more "normal" RPM?  Maybe a solenoid-activated valve attached to the tach,
> > or perhaps just a flap on a spring like at the top of a big-diesel
> > smokestack.
> >
> >