IJSBA · Forced induction

Supercharger rebuild internals, clutch, belt, pulleys, IJSBA

The commercially important tier below a whole blower.

This page is IJSBA only, and the bodies do not agree. The same part under IHRA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.

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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.

Runabout Stock is the case to check: IJSBA-approved aftermarket internals are legal, OEM gear ratio is not negotiable. Check the IJSBA approval of each part.

Where it stands, class by class

14 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.

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.

Legal, with conditions

Keep it, but measure it: the rules permit this part only inside stated limits.

Legal

Keep it. The rules permit this part in this class.

OEM part required 1 class

No modifications to the turbo/supercharger system.

• Runabout Naturally Aspirated · RNA

Not permitted, not listed in the rules 6 classes

Not listed in this class document. Illegal under the closed-list principle.

• Fixed Steering Ski Stock · FSSK
• Runabout Rec Lites · RRL
• Ski Stock · SSK
• Four Stroke Ski Lites · FSKL
• Ski Modified · SKM
• Ski Superstock · SKSS

Legal, with conditions 1 class

Clutches, belts and internal replacement parts need not be OEM provided they are IJSBA-APPROVED, and OEM gear ratios must be maintained. Shafts may be welded or reinforced FOR SAFETY PURPOSES only. · RAS.9.2

• Runabout Stock

Legal 3 classes

The original turbocharger or supercharger may be modified, or an aftermarket unit fitted, so its internals, clutch, belt and pulleys are open, and all hoses and pipes may be modified or aftermarket.

• Runabout Superstock · RSS.6.1
• Freestyle · FREST.9.1
• Runabout Open / GP · ROP.8.1

Legal 2 classes

Forced induction is allowed only on four-stroke engines of 1100cc or less, and there the original turbocharger or supercharger may be modified or an aftermarket unit fitted, so its internals, clutch, belt and pulleys are open.

• Ski Grand Prix · SKGP.9, SKGP.9.1
• Sport GP · SPGP.9.1, SPGP.9.2

Legal 1 class

ALL internal supercharger or turbocharger parts may be modified or aftermarket. Pulleys and tensioners too. A spacer may be used to fit a larger impeller. · RAL.5.1

• Runabout Limited

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Supercharger rebuild internals, clutch, belt, 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 IJSBA class · where the rulebooks differ · checks on parts the shop sells · how this site reads a rulebook.