85.504—Applicable standards.
(a)
The emission standards applicable to conversions of 1993 and later model year vehicles and engines are:
(1)
All of the requirements that would apply if the conversion were being certified as if it were a new vehicle or engine.
(2)
If a vehicle or engine to be converted was originally certified to a NOX or particulate family emission limit other than the applicable new vehicle NOX or particulate standard, the family emission limit is the applicable standard.
(b)
The emission standards applicable to conversions of 1992 and earlier model year vehicles and engines are:
(1) Exhaust hydrocarbons (as applicable by fuel type).
The Tier 0 hydrocarbon standards, as applicable by vehicle class, contained in §§ 86.094-8 and 86.094-9 of this chapter, and the hydrocarbon standards, as applicable by engine class, contained in §§ 86.094-10 and 86.094-11 of this chapter ;
(2)
CO, NO
X
and particulate. The applicable CO, NOX and particulate standards or NOX and particulate family emission limits the vehicle or engine was originally certified as meeting;
(3) Evaporative hydrocarbons.
Any evaporative requirements applicable to the original vehicle or engine will remain applicable to the conversion if the converted vehicle or engine retains the ability to operate on the fuel which it was designed and certified to use.