40 CFR 85.524 – Legacy standards
Prior to April 8, 2011, the following emission standards applied for conversions of vehicles/engines with an original model year of 1992 or earlier:
(a) Exhaust hydrocarbons. Light-duty vehicles must meet the Tier 0 hydrocarbon standard specified in 40 CFR 86.094-8. Light-duty trucks must meet the Tier 0 hydrocarbon standard specified in 40 CFR 86.094-9. Otto-cycle heavy-duty engines must meet the hydrocarbon standard specified in 40 CFR 86.096-10. Diesel heavy-duty engines must meet the hydrocarbon standard in 40 CFR 86.096-11.
(b) CO, NO
(c) Evaporative hydrocarbons. Vehicles/engines must meet the evaporative hydrocarbon emission standards that applied for the vehicle’s/engine’s original model year.