In reading the proposed 9.3.15, I think its going to cause a lot of problems. Before I send this note to the CRB, can you Porsche and VW guys comment on your cooling systems. I know you have external pressure relief tanks, but I don't know if there are drain fittings on them. I don't think there were for Saabs. Also, I don't even know if there were pressure relief caps on them for sure. Please comment and mark up the proposed language so we get the best rule possible.

GCR
Item 1. Effective 3/1/09: Insert a new section 9.3.15 and renumber subsequent paragraphs:
Coolant Catch Tanks Cooling systems shall be equipped with coolant catch tanks with a minimum capacity of 1 US quart.

I think it needs to be reworked to clarify its intent as in regards to what is required and when this rule is applicable.

I assume the intent of 9.3.15 is for water cooled radiators, having a pressure relief cap, whose neck has a hose fitting for conduit of steam and fluid to a safe location. Most modern cars today have a catch tank of the type required by this rule, but some such as my '66 mustang had just a dump hose. For a '66 mustang and other cars with a pressure relief and neck with hose fitting, this rule is clear and easy to implement.

There are several cases where it is not so clear and easy;

1) The rule does not tell what the tank should be hooked to; I believe there are examples of cars where the radiator system has a separate pressure relief tanks of a quart or larger vapor space to capture coolant expansion. I believe its common practice for these systems to have no hose fitting in the pressure relief neck. I do not have the ability to confirm this, but I believe that 1980's Saab 99 and 900's, some VW’s, and Porsche 924/944s all have systems of this type.

If there are cars without hose connections, I think it becomes very difficult to implement this rule with the alternatives being
- Replace the OEM pressure relief tank with custom tank that has a relief fitting. (Expensive and difficult because this would be a custom built pressurized reservoir with multiple cooling hose connections)
- Replace the OEM pressure relief cap with one that has a built in relief fitting. (I don’t know of any available)
- Shroud the neck of the pressure relief cap and plumb that to a catch tank. (I think there would be space interference with the hood as the tank is at the top of the engine compartment)
To eliminate this problem, I recommend allowing pressurize relief tanks as an alternative to catch tanks as long as their vapor capacity is 1 quart or larger. (Note; the one quart rule may be tight for Saab and VW’s.)

2) The rule does not define what cooling systems this applies to; Does this rule apply to any fluid cooling system or just the engine radiator cooling system?
- My water cooled race car has an oil cooler as part of its lubrication system. It’s also
common for lubricant heat exchangers to be added to differentials and power
steering systems. As these systems are closed and have no external pressure
reliefs; how, where, and for what purpose would I connect the catch tank to them?
- My car has a cool suit system. How and where do I connect a catch tank to it?
To eliminate this problem, I recommend that this rule only apply to “radiator cooling systems with an pressure relief” per the GCR definition of Radiator.


I don’t think its SCCA’s intent to put catch tanks on oil coolers or make it very difficult for Saab and Porsche drivers to conform to the rule. As such, I think this rule should be held and studied further. An option to address my above concerns that SCCA may want to consider would be modifying 9.3.15 as follows
Radiator Coolant Catch Tanks
Radiator engine cooling systems having a means of pressure relief shall have either a pressure relief line connected to an coolant catch tank having a minimum capacity of 1 US quart or a pressure relief tank within the cooling system that has at minimum 1 US quart volume vapor space between the normal liquid level and the relief device during operation.