IJSBA answers this part for 20 of its classes. 20 of those answers are permissions, with or without limits attached, and 0 are not.
This is one body's answer, not the sport's. You are bound
by whichever body sanctions the event you enter, and where both govern you,
you are held to the stricter of the two. The differences are set out in
the rulebook comparison.
Where it stands, class by class
20 classes, grouped by the answer rather than listed one by
one, because an answer that holds for a class usually holds for every class
that borrows its rules.
Legal, within limits 20 classes
Fixed-type or automatic valves only. Thermostats, pressure regulators and solenoids qualify. Manual actuation of any kind during operation is prohibited everywhere.
Aftermarket thermostat, pressure regulator, cooling solenoid: if the rule your class applies reads
differently to you, or the rulebook has changed since this was read, ask.
We answer with the section we read it from, or that we have not read it.
Ask a rules question.