Open Stock & Open Improved
All snowmobiles must follow ISR rules and weights in stock form.
2 Stroke - Any stock qualified snowmobile as outlined in ISR rules.
4 Stroke - Any stock production 4stroke, no modifications to engine,turbo. Oem waste gate and blowoff valve required.
Modifications allowed include
- ecu flash or boondocker
- charge tubes may be changed but must remain oem diameter
2 Stroke - Improved Stock 1000 qualified sleds allowed (maximum of 1010 cc's )
4 Stroke - Any production 4 stroke turbo sled allowed. OE engine and turbo for the model (ie. no engine or turbo swaps). No turbos added to sleds not originally equipped. Max CC for 3 cylinders is 998, two cylinders is 1100. Internal engine modifications allowed. All intake and exhaust modifications allowed. Intake must be under hood and not alter OEM appearance (exception: mountain style intakes pointing straight upward from hood). Electrical and ignition changes allowed. Electrical stutter boxes, launch control and traction control allowed (as per Improved 1000 rules). Minimum combined sled/rider weight 825 pounds.
As per Improved rules, OEM for the model frame, suspension, fuel tank and seat must be used. Track drive axle, chain case, and brake system must remain OEM for the model and remain in OEM location. SSRA rule of no traction products in Improved classes still applies.
The guiding principal for this class is to apply Improved 1000 rules to the factory four stroke turbo sleds.