Thunder Mountain Speedway


Site Under Construction




Updated:  January 2013

 (Clarifications in red)


            The rules set forth herein are designed to provide fair parameters for competition and a high level of safety. NO expressed or implied warranty of safety shall result from publications of or compliance with these rules and regulations, they are intended as a guide for the conduct of sport and are no way a guarantee against injury or death to a participant, spectator or official. Driver/ Car owner is legally responsible for all crew signed in under car.

It is the Driver/ Car owners' responsibility to ensure his or her car is legal, if there is a question about the rules, email or phone tech committee before you show up, non conforming cars will not be allowed to run except for minor variations. Tires and Safety rules are only subjected to review by Tech only.

Refer to the safety rules for the basic building rules (Roll cage, Bumpers, Fuel cell, Approved clothing, etc.)

2014 Safety Rule Change***Bone Stock Mini’s will have a minimum Safety requirement and a Maximum Safety Requirement in regards to their Roll Cages.  Cage Diagrams (on Page 37 in the Street Stock Rule area) are the minimum Requirement; with the addition of a Petty Bar; a bar that runs diagonally from the center bar down to the Right Front of the existing roll cage.  A maximum and suggested cage design will allow drivers to run bars out the firewalls of their cars and tie their strut or shock towers together.  Rear Wedge bars are also a minimum Safety Requirement for the 2014 season as well. If the Fuel Cell is mounted on the rear differential hump then the bars only need to run to the rear shock towers.  If the fuel cell is mounted where the spare tire would have been located then bars must be ran to the furthest most point of the trunk to safely protect the fuel cell in case of a collision from the rear.

The emphasis is on keeping this class of cars inexpensive to build as well as providing for the safety and fun of the participants.  All cars will be extensively inspected for both safety and STOCK COMPONENTS.  Failure to follow the intent of the rules or class will result in disqualification of a car and or driver from the class.  Cars must be stock in every aspect with the following exceptions.  When the word “stock” is used it means as it came from the factory for the particular year and model in question.  This also includes replacement parts by part number.  Any question on parts need to be directed to the Board of Directors.



1.    Any four-passenger sedan produced with a 2.5 liter engine or smaller. --Maximum 125 hp; no sport cars. 

2.    Body shape must remain stock. If the original bumpers are replaced, new bumpers may be fabricated, but must maintain original ride height and openings. No Racing Style Nose or Tail Cones.

3.    Lexan rear windows or quarter windows allowed.

4.    No four wheel drive vehicles.


1.    All suspension components must remain stock to make and model of car.

2.    All pivot points and mounting points must remain in stock location.

3.    Springs must remain stock, no spacers allowed, no aftermarket springs or shocks allowed.

4.    Shock must remain in stock location

5.    May modify mounting point on upper right front strut tower ONLY for camber adjustment.  Maximum 2” negative camber allowed.  NO REAR CAMBER ALLOWED. 


1.    Must have stock points or stock electronic ignition only.

2.    No aftermarket or high performance coils allowed including any spark enhancers.

3.    Single kill switch required to both dis-able the ignition and electric fuel pumps on fuel-injected cars. All switches to be clearly marked and within easy reach of Safety Workers. (Refer to Track Running Rules for any further clarifications.)

4.    Ignition and fuel pump also to be connected to fuel pressure reduced sending switch mount on rail or in fuel line (inertia switch for roll over in Fords may be accepted).



1.    Stock exhaust manifolds only.  Exhaust maximum 2” OD tube.

2.    Exhaust to exit behind driver.

3.    Muffler required.



1.    Any stock auto or standard transmission for make and model of car.

2.    Only stock flywheel and clutch to be used for make and model of car.

3.    Only stock torque converters allowed transmission coolers allowed but must be mounted away from drivers compartment.



No metal to be removed inside car.

1.    Front doors may be gutted for three bar clearance into the doors.





1.   Approved fuel cell mandatory. Plastic Fuel Cells must have a steel cover over top of them to protect them from any collision from the rear.

2.   Fuel cells mounted in the trunk, fuel cell to be above trunk floor (on the rear hump) but may be mounted in spare tire well; only if rear roll bars are extended to protect the fuel cell in the event of a collision from the rear.

3.  No matter where the Fuel Cell is mounted a full firewall/guard made from sheet metal must cover all and any opening between the driver and the fuel cell.



1.    Any gear ratio allowed.

2.    Rear end and transaxle must remain stock to make and model of car.

3.    No positrack or welded rear ends allowed.



1.    All brakes must be in working order.

2.    No aftermarket brake bias allowed.

3.    All brakes must be stock to make and model of car.



1.   Only 60 series or larger street legal tires allowed; no NuTreads or any other racing tires allowed, no Drifting Tires.  All 4 Tires must be the same size and profile, no mixing of Tire Sizes.

2.    Maximum of 7” rim width.  Stock rims only.  No Racing Rims allowed!

3.    All 4 wheels and tires to be either 13”, 14”, or 15” no mixing of tire sizes or wheels.

4.    Wheels and tires not to protrude past fenders.



1.    Must be make to make, no Rotary engines.

2.    Fuel injection allowed (STOCK ONLY).

3.    Any push rod or single overhead cam type engine allowed.

4.    All engine components must remain stock – only OEM replacement parts allowed.

5.    Stock camshaft only, stock rods only for engine (no aftermarket rods allowed).

6.    Must use stock crank for that engine.

7.    No mixing or matching of parts to achieve any non-stock configuration.

8.    No decking of block.



1.    Any stock make-to-make carburetor.

2.    Only single carburetors allowed.

a.    Twin carbs allowed if stock to make and model of engine, max hp rule applies

3.   No performance carburetors allowed.

4.    No air boxes allowed.



1.    Must be stock intake, no machining or grinding allowed, no adapters or spacer plates allowed.



TMS, its Tech Official and its Executives reserve the right to add weight penalties to any Bone-Stock Mini if it is deemed necessary in regards to Safety.

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