UIM · Ignition

Aftermarket standalone ECU, UIM

UIM is stricter than IJSBA here: no production class allows one.

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.

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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.

IJSBA Runabout Limited and Superstock both allow a modified or aftermarket ECU. UIM allows one in no class below GP1. A customer running both series needs the UIM answer, which is the binding one.

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

Not legal

This comes off. The rules refuse it in this class.

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 legal 6 classes

ECU must be original. Aftermarket ECU prohibited.

• Runabout GP4 · 502.01.05-02
• Ski Division GP4 · 501.01.05
• Runabout GP3 · 502.02.08-02
• Runabout Juniors GP4 · 502.01.05-02 · borrows another class
• Runabout Ladies GP4 · 502.01.05-02 · borrows another class
• Ski Juniors GP4 · 501.01.05 · borrows another class

Not legal 1 class

NO AFTERMARKET UNITS ARE ALLOWED - stated expressly. · 502.03.08-02

• Runabout GP2

Not legal 1 class

Sensors and actuators must remain original; no aftermarket ECU allowance. · 501.03.08

• Ski Division GP2

No rule, this is an open class 3 classes

No ignition article at all.

• Ski Division GP1 · 501.04
• Ski Ladies GP1 · 314 · borrows another class
• Ski Veterans GP1 · 302.01.05 · borrows another class

No rule, this is an open class 2 classes

No ignition or electronics article.

• 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

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Aftermarket standalone ECU: 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.