It is illegal to modify the operating system of any emissions certified vehicle and that even includes the exhaust system. I agree is is rarely enfored but it certainly can be.
WARNING: In the U.S.A. Or Canada, federal law makes it illegal for ANYONE to tamper with, disconnect, remove or otherwise render inoperative ANY automotive emissions related control device. In general, the entire fuel system and all its individual components (including the EFI ECU) are considered 'emissions related control devices'. The penalties for tampering can be substantial. A violation may make you liable for a fine of $2,500 or even more!
"Tampering" means replacing or disabling any emissions related components (i.E. Any components that would, or could, affect any vehicle emissions) with an unapproved replacement part. It originally applied primarily to 'professional mechanics' operating from licensed repair facilities.
Revisions to the U.S. Clean Air Act in 1990 (40 CFR Title 2, Part A, Section 203) further broadened the definition of emissions tampering to include virtually ANY type of engine or exhaust system modification, performed by anyone, that alters, or might alter, what comes out the tail pipe. That means any nonstock aftermarket part that is installed on your engine must be EPA-approved and emissions legal (except on the exempt vehicles noted below) if you will be driving on public roads. Canadian federal clean air laws are very similar.
However, federal anti-tampering law does not apply to race cars that are not operated on the street, other full-time off-road vehicles, show cars that are not street driven, or vehicles not factory equipped with emission controls (most 1967 and earlier vehicles). So that exempts all antique cars, and many classic cars and muscle cars.
Sunday, November 3rd, 2013 AT 4:09 AM