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Old 05-21-2008, 06:13 PM   #1
Kevfra
Registered User
 
Join Date: Mar 2008
Location: San Francisco
Posts: 66
Cool Need your input on bypass pipes

For those of you not living in California allow me to explain something about our smog test. The test equipment is connected via modem to a State of California computer such that all readings during a test are sent to this computer. This was an evolution in the smog test saga, and was designed to avoid fraud. In the past it would be common to slip a guy twenty bucks and he would make sure you pass the test, or he would enter your VIN info and then tailpipe a known clean car, rather than your nasty beast.

Now the emission stats are in the CA computer and it is pretty savvy as to what kind of readings to expect from what type of car. So if you are running a big V8 ford and the computer sees readings appropriate for a Pinto – flares are going to go off. And more important – you don’t get do-overs. The State knows you just failed, and now you have to fix your car before you can test again. Yes – it’s all spelled $$$ more than spelled clean air. Ask me about the custom engine I’m getting approved right now, regardless of emissions…

However there is something called a ‘dry board’. This is where they tailpipe you but not connected to Big Brother. It’s a chance to see your readings before a true test. Generally we don’t do this because it runs about fifty bucks, and so we just go with the test and mostly pass. But if you’ve been fussing with your car in some fashion…a dry board is a good thing to do.

I have the four cat exhaust on my 3.2 and want to install the bypass pipes to replace the second set of cats. No headers, and leaving the first cats intact. No O2 sensors on the rear cats, so this is simply going to have an effect on the emissions…but what effect? My engine is clean and just passed its regular smog test nicely, so now is a good time to do a mod and go for the dry board to see if this is going to hang me up next time I do the real thing.

So I’m going to install the bypass pipes (test pipes) and then run a dry smog check to look at my readings. I will know if the elimination of the second cats increased my emissions, and by how much, and if over the limits. If under the limits I might be able to keep the pipes on the car, as they never seem to do a visual check. If over the limits…well then I know for sure I have to make things right before I exhale in Arnold’s face two years from now.

I’ll post my results for your reference. Meanwhile I need some pipes! What do you folks recommend as a good set, reasonably priced, for an ’01 S ?
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