Hey i had a question on test pipes.

1. How do they not throw CEL?
2. What happens when you have to go to emissions?

 

to not through a CEL get a test pipe with cel fix and with an emission test you fail.

 

there's an adepter you can buy from almost any auto part store to fix the CEL on test pipe.
something like this.... CEL fix

For emissions you will probably have to put back the stock cat.

 

The "CEL fix" Is just a type of spacer to keep the sensor further out of the pipe. and emissions depends on the state. In my state AZ they just plug in to your ECU so you would pass as long as you didint have a CEL.

 

Does putting on a test pipe make the car run more lean?

 

I guess you could say that, if you are going to get an aftermarket exhaust and it is loud and has a lot of drone the test pipe will also help with the drone. it will give you a few more ponies also since there will be better air flow to the exhaust.