Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance info on gutting the precats

Hey. Just to clarify the catalytic converter thing.
Under full throttle or even greater than part throttle your catalytic converter is not going to oxidize all of the unburnt fuel. In fact it oxidizes very little of the unburnt fuel that is pushed through under heavy load. The catalytic converter is destroyed in most cases by significant amounts of unburnt fuel and it works most efficiently at operating temperature with little to NO unburnt fuel in the exhaust!
Its primary purpose is to convert CO to CO2. The primary reducer of unburnt fuel (HC's) is the combustion chamber and the combustion chamber process! Correct timing, A/F ratio, combustion temp and chamber design are the greatest factors in reducing HC emissions, NOT the catalytic converter.

So in effect, driving your car with CATs at full throttle is probably 90% as problematic with pollution of HC's as a car without CATS.
CO is another issue and results from partial combustion of the fuel. That should be the big winner with cats, but again the combustion process today with electronic fuel control actually plays a bigger part in controlling HC, CO, adn NOx emmissions than any other factor.

Do I agreet that having a cat is cleaner? Yes. Is it significant? In many cases yes. However am I passing the state emissions test? Yes. With the main cat in standard location but gutted precats I passed emission the same day that I first fired up my 3L engine. Extremely low emissions too.
Why did I leave my cat in place? I too wanted to do my part and minimize pollution when I understand that my car is not adversely affected by having a catalytic converter. If you look in my post history you will see that I am a proponent of keeping cats in favor of the emissions gain since there isn't a significant loss of power.
However, I also know that there was no measureable difference in my tailpipe emissions between when I had 3 cats and now have 1 cat. So I'll take the 1 cat to save the weight and allow better performance from headers.
Its all a matter of "gray area" You should learn that there are really no absolutes in this world except death and taxes...and that you sometimes have to pick the lesser of two evils based upon your wants/needs. You did in your own way, but you see people like me as evil because 50 ppm HC's is acceptable to me rather than 25 ppm HC's or more is for you.

If the shoe doesn't fit then stop being so high and mighty and leave room for a little broader interpretation. I really don't think our views are that far apart.

warmonger