OEM part required 1 class
Supercharged four-strokes to 2000 cc are admitted, but no article opens the supercharger, so its internals, clutch and pulleys stay original under the class's stock clause. · 502.03-02, 502.03.01-01
UIM · Forced induction
Supercharger internals, clutch and pulleys, UIM
No UIM class prints a supercharger article, so each answer comes from the class stock clause or the open-list reading of GP1.
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.
Runabout GP2 is the class to check: superchargers are legal there, but the blower stays as the manufacturer built it.
Where it stands, class by class
21 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. 6 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.
What each answer below means
- OEM part required
- This comes off. Only the part the manufacturer fitted is allowed here.
- Not permitted, not listed in the rules
- Treat it as coming off. The class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list, so this is our reading rather than a rule we can quote at you.
- The rules do not say
- Unanswered. The rules do not settle this, so ask the club before you rely on it.
- No rule, this is an open class
- Probably keep it. The class carries no stock clause at all, so anything unlisted appears to be open. The rulebook does not say so in terms, and this is our reading rather than a permission anybody wrote down.
- 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.
Not permitted, not listed in the rules 6 classes
Not listed in this class. Illegal under the class's own stock clause.
- Runabout GP4 · 502.01
- Ski Division GP4 · 501.01
- Runabout GP3 · 502.02
- Runabout Juniors GP4 · 302.01 · borrows another class
- Runabout Ladies GP4 · 302.01.01 · borrows another class
- Ski Juniors GP4 · 302.01 · borrows another class
Not permitted, not listed in the rules 1 class
Ski GP2 lists atmospheric engines and turbocharged ones to 750 cc but no supercharged configuration, so there is no supercharger to rebuild. · 501.03-02, 501.03.01-01
The rules do not say 3 classes
Ski GP1's capacity limits name turbocharged four-strokes and no supercharged ones, and no article covers supercharger parts, so whether a supercharged engine may run here is not settled. · 501.04.01-01
- Ski Division GP1
- Ski Ladies GP1 · borrows another class
- Ski Veterans GP1 · borrows another class
No rule, this is an open class 2 classes
No article covering this part. Free under the open-list reading of GP1.
- Runabout GP1 · 502.04
- Runabout Veterans GP1 · 302.01.05 · borrows another class
No rule published for this class 8 classes
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.
- Endurance · 317.03
- Freestyle Amateur · 312
- Freestyle Free · 312
- Jet Raid · 317.01
- Offshore · 317.02
- Parallel Slalom · 313
- Ski Future Electric (SFE) · 302.01
- UIM Hydro-Fly · 900
Supercharger internals, clutch and pulleys: 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.
Every UIM class · where the rulebooks differ · checks on parts the shop sells · how this site reads a rulebook.
Forced induction · four stroke · legal in 0 of 13 answered