Engine Coolant Rules

[Viper_Race_HQ]

VIPER COMPETITION COUPE

TECHNICAL SERVICE BULLETIN

NUMBER 07 - 4

Date: May 7, 2007

Subject: Engine Coolant Rules for Racing. Blocked Open Thermostats.

Please refer to section 2.9.3.16.2 of the 2007 SCCA PRR. Viper Competition Coupe engines ARE NOT to be run in competition with any glycol based coolant. This rule also applies in virtually any racing series. In any case, plain water is a far better coolant than 50/50 glycol in terms of ability to absorb heat. Typically the system should be filled with clean water with a small amount of water pump lube and water wetter (if desired).

In addition, the thermostat should be permanently blocked open as a reliability measure. All engines sent back for overhaul in the future will have this done to the thermostat as standard procedure if required.

Another option would be to place a restrictor orifice in the thermostat housing in place of the thermostat. An orifice opening of 1.125 inch is suggested.


Irv Zwicker
Dodge Motorsports
Email: ikz@damilerchrysler.com