A gasoline detergent manufacturer must perform testing using one of the methods specified in this section to establish the lowest additive concentration (LAC) for the detergent.

(a) Top Tier-Based Test Method. Use the procedures specified in ASTM D6201 (incorporated by reference in § 1090.95), as follows:

(1) Use a base fuel that conforms to the specifications for gasoline-alcohol blends in ASTM D4814 (incorporated by reference in § 1090.95). Blendstocks used to formulate the test fuel must be derived from conversion units downstream of distillation, with all processes representing normal fuel manufacturing facility operations. Blendstocks must not come from chemical grade streams. Butane and pentane may be added to adjust vapor pressure. The base fuel should include any nondetergent additives typical of commercially available fuel if they may positively or negatively affect deposit formation. In addition, the base fuel must have the following properties:

(i) 8.0-10.0 volume percent DFE that meets the requirements in § 1090.270 and conforms to the specifications of ASTM D4806 (incorporated by reference in § 1090.95).

(ii) At least 8.0 volume percent olefins.

(iii) At least 15 volume percent aromatics.

(iv) No more than 80 ppm sulfur.

(v) T90 distillation temperature at or above 143 °C.

(vi) No detergent-active substance. A base fuel with typical nondetergent additives, such as antioxidants, corrosion inhibitors, and metal deactivators, may be used.

(2) Perform the 100-hour test for intake valve deposits with the base fuel to demonstrate that the intake valves accumulate at least 500 mg on average. If the test engine fails to accumulate enough deposits, make any necessary adjustments and repeat the test. This demonstration is valid for any further detergent testing with the same base fuel.

(3) Repeat the test on the same engine with a specific concentration of detergent added to the base fuel. If the test results in less than 50 mg average per intake valve, the tested detergent concentration is the LAC for the detergent.

(b) CARB Test Method. Use the procedures specified by CARB in Title 13, California Code of Regulations, section 2257 (incorporated by reference in § 1090.95).

(1) A detergent tested under this option or certified under 40 CFR 80.163(d) prior to January 21, 2021, may be used at the LAC specified for use in the state of California in any gasoline in the United States.

(2) The gasoline detergent manufacturer must cease selling a detergent immediately upon being notified by CARB that the CARB certification for this detergent has been invalidated and must notify EPA under 40 CFR 79.21.

(c) EPA BMW method. Use the procedures specified in ASTM D5500 (incorporated by reference in § 1090.95), as follows:

(1) Prepare the test fuel with the following specification:

(i) Sulfur—minimum 340 ppm.

(ii) T90—minimum 171 °C.

(iii) Olefins—minimum 11.4 volume percent.

(iv) Aromatics—minimum 31.1 volume percent.

(v) Ethanol—minimum 10 volume percent.

(vi) Sulfur, T90, olefins, and aromatics specifications must be met before adding ethanol.

(vii) Di-tert-butyl disulfide may be added to the test fuel.

(2) The duration of testing may be less than 10,000 miles. Measured deposits must meet the following specified values to qualify the test fuel and establish a detergent's LAC:

(i) Measured deposits for the fuel without detergent must be at least 290 mg per valve on average.

(ii) Measured deposits for the fuel with detergent must be less than 100 mg per valve on average.

(d) Alternative test methods. (1) An EPA-approved alternative test method may be used if the alternative test method can be correlated to any of the methods specified in paragraphs (a) through (c) of this section.

(2) Information describing the alternative test method and analysis demonstrating correlation must be submitted for EPA approval as specified in § 1090.10.