Aftermarket spark plugs of a different heat rating, UIM
UIM answers this part for 16 of its classes, and publishes no rule for it in 8 more. 16 of those answers permit the part outright and 0 permit it with stated conditions, leaving 0 that do not. 8 are inherited from a parent class the rulebook points at.
This page is UIM only, and the bodies do not
agree. The same part under IHRA and IJSBA. Which one applies to you is decided by whoever sanctions the race you enter.
This is one body's answer, not the sport's. You are bound
by whichever body sanctions the event you enter. If you race more than one
series, build to the stricter answer. The differences are set out in
the rulebook comparison.
24 classes, grouped where the same rule gives the same
answer rather than listed one by one, because an answer that holds for a class usually holds for every class
that borrows its rules.
8 of them borrow another class’s rules and are marked below; for those, the link to the parent class is read from the categories table rather than stated in the rulebook. 8 publish no rule for this part and name no parent to borrow one from, and are grouped together at the end.
Keep it. The rules permit this part in this class.
No rule published for this class
Unanswerable here. This class publishes no rule for the part and names no parent class to borrow one from, which is an absence in the rulebook and not a permission.
Legal 16 classes
Aftermarket spark plugs of a different heat rating are allowed in every class that addresses them.
No component rules are published for this class and no single parent class is named, so this part cannot be answered for it. That is an absence in the rulebook, not a permission.
Aftermarket spark plugs of a different heat rating: 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.