In extreme cases, performance modifications will cause a vehicle to fail, but many modifications will keep vehicles well within the pass limits.
Performance exhaust systems, so-called “cat-back systems,” should not adversely affect emissions.
Removing a catalytic converter is illegal, subject to large fines, and not subject to repair cost limits, whether or not emissions are within pass limits. The same is true of any component of the emissions system.
Performance chips come in a variety of levels. While U.S. standards don’t apply from a regulatory standpoint, they are similar enough to offer a guideline for Canadian businesses. Chips marked “Not for Highway Use” may or may not surpass emissions limits; those marked as “For Highway Use” or with an Exemption Order (E.O.) number should be okay.
As far as machined or internal engine modifications are concerned, all customers should be advised of their potential impact on emissions. Speed shops may find it useful to align themselves with a facility willing to test vehicles off-line (testing not for licensing purposes), to minimize customer grief.
Engine swaps are treated differently. For 1999 and earlier vehicles, testing is done according to 1980 emissions standards. For year 2000 and later, testing standards applied are as per the vehicle year.