40 Below Water Additive / Coolant. Mix 1/2 gallon of CTX-2 into 4 1/2 gallons of racing gas. Mix 1 gallon of CTX-2 into 4 gallons of racing gas. Specific gravity: 1 gallon of CTX-2 in 4 gallons of racing gas increases the S.G. about. 035, which should keep it under the limits of most sanctions.
