Mini Cup Rules 2024
1. CAR BODIES:
a. All bodies must be mounted level and attached to the chassis at a minimum of four (4) places.
b. All cars, body and frame, must be a likeness of a Sprint Cup car and be in good condition and appearance. Any addition, alteration or modification to the body in an attempt to obtain an aerodynamic competitive advantage is not allowed.
c. Cars must have safe and suitable front and rear bumpers. Rear bumper must incorporate a push bar. The push bar shall be designed to prevent a car from being lifted off its rear wheels if hit by another car from the rear and additionally would allow a disabled car to be pushed back to the pits by a track service vehicle. The push bar shall be constructed of 3/4″ diameter pipe and shall not extend more than 1″ beyond the rear of the body and be no lower than 4″ about the track surface.
d. Cars must have front and rear windshields and side windows made from clear Lexan, not plexiglass. Complete tinting or painting of windows is not allowed. The painting of a 1” – 1.5” border around windshield, side and rear window is permitted. The painting of a 3”-4” sun shield strip at top of windshield is allowed.
e. Front and back windshields must be fastened to prevent windshields from being blown loose during race. Window brackets are permitted. No holes will be permitted in front and rear windows.
f. No right or left side windows, opening must be at least 20″.
g. Cars must have an easy access hatch made on top of car. Hatches must be hinged in front (opening from back to front). Hatches must be made of fiberglass or plastic. Hatch must be fastened with rubber locking strap, pins, or Velcro; as long as the hatch does not blow open while on the track. Track officials have the authority to black flag a car racing with the hatch not secured. Tethering of roof hatch to prevent opening in the event of a roll-over is recommended.
h. Cars must have numbers on both sides and on top of car, 12″ minimum on doors and 16″ minimum on roof facing grandstand. If car is numbered on windshield or right front bumper, numbers must be a minimum of 3″.
i. Riding Height: Minimum riding height is 1″ including all sides of car-front, rear, left side, and right side. From ground to highest point on roof of car: 28” Minimum.
j. Deck Lid Rear Spoiler Specs: Height- Minimum 2 ½ ” Max 4.0, Minimum thickness .0625 (1/16) aluminum or Plexiglas. Corners of spoiler must be rounded. Spoiler must be centered on car plus or minus 1″. C.O.T. spoiler is allowed.
k. Roof Rail, Rear Window Fin & Deck Lid Fin Specs: If utilized, they MUST comply with the following specifications. Maximum Height: 1″. Material: Aluminum .0625 (1/16″) Thick or a combination of Aluminum and Plexiglas. Vertical corners of roof rails, window and deck fins must be rounded. Deck Lid Fins are not recommended, but will be allowed as long as they comply with the intent of this paragraph.
2. FRAME :
a. Seats must be connected to the frame in an approved manor.
b. All parts must be fastened so as not to come loose.
c. A solid firewall is required to separate driver from engine compartment. Firewall must be metal only. No aluminum allowed. 2010 Chassis or newer must use a minimum of 18 ga. Steel.
d. Chassis: Full perimeter type frame and four- point roll cage is required. Grandfathered “straight-rail“ type chassis are allowed (see left side weight restrictions). Primary frames must be minimum 1″ round or square mild steel tubing, minimum .065 wall thickness. Cars built in 1994 or earlier may use 7/8″ tubing, but will be required to pass a general safety inspection. All welds must be sound. A full metal floor pan and firewall is required. 2010 or newer must use 18 gage steel for firewall.
e. Riding Height: Minimum riding height is 1″ including all sides of car-front, rear, left side, and right side.
3. SAFETY:
a. All cars to be equipped with a speedway approved roll cage. All cars must be inspected and approved by Dillon Motor Speedway Safety officials.
b. All Safety Equipment must be worn during Practice, Qualifying and Race.
c. An approved Racing Helmet is required (Full Face Recommended). Protective eye wear is REQUIRED if an Open Face Helmet is used. Head and Neck Protection: Neck Support Collar is recommended. The use of an Arm/Hand restraint tether is also recommended.
d. An Flame Retardant Fire Suit (1 Layer Minimum) is recommended. The suit must be in good condition without rips, tears, etc. If a racing suit is not utilized, a long sleeve racing jacket is required. Racing Gloves and Shoes in good condition are required.
e. Fire extinguishers are optional.
f. Safety belts must be Competition SFI Five Point Safety Harnesses. Harnesses must be SECURELY FASTENED TO FRAME OR OTHER PRIMARY ROLL CAGE MEMBER. Belts must be no older than 7 years recommended (based on date on belts, not date they were installed in the car). Regardless of age, belts must be free of any defects or damage and are subject to inspection and approval of CEMCA or Dillon Motor Speedway Safety Officials.
g. All cars must be fitted with an Approved Aluminum racing seat mounted securely to the chassis. Fiberglas or plastic seats are not allowed. Both right and left side Seat Head Rests are highly recommended.
h. Window Nets: Car must have safety nets on both side window openings of the car.
i. Mirrors: Cars must have a left side mirror, mounted inside on the chassis. Right side mirror is optional, but highly recommended.
f. Battery and Fuel Cell must be firmly secured in the engine compartment behind the fire wall. Battery must be firmly secured by a metal strap across the top of the battery and attached to the chassis.
g. Fuel Cells to be foam filled and with fittings to prevent spillage during a roll-over.
h. Steering wheel must be “quick release” type. All steering, brake (including pedal assembly) and hub components must be secured by cotter pinned, double nut or lock nut.
i. Rear Axle must have snap rings in place, both ends.
j. Hydraulic brake connections must be tight and free of visible leaks. Brake lines should be safely routed to prevent possibly of being worn through or pulled loose.
k. All cars to be fitted with net or other approved covering over the leg and foot compartment (under the hood to keep legs and feet inside of car in case of a roll-over). Side crush or dirt panels in the leg and foot compartment are also required.
l. Radios are allowed and recommended.
4. SUSPENSION:
a. Suspension: RIGID…. Adjustable wedge suspensions are allowed, steel recommended. No type of adjustable suspension that can be adjusted by driver while driver is inside car is allowed. The car must be rigid with no rubber to be enforced by Dillon Motor Speedway tech official. As defined at the January 8, 2012 CEMCA Meeting, a rigid chassis car’s chassis and tire movement must be identical when the car is jacked up. When down force is applied to the car, that force must be absorbed by the tire and not any suspension component.
b. Steering: All steering and suspension parts shall be secured by cotter pin, double nut, lock nut or snap ring. Steel recommended. Steering wheel must be quick release type and must lock into place when attached. Kart type or rack & pinion allowed. Steering column padding is optional.
5. REAR END:
a. Axle: Minimum OD is 1″. No aluminum, carbon fiber or titanium axles allowed. Hollow or solid axles are optional. Axle must be rigid with no rubber to be enforced by Dillon Motor Speedway.
6. SPRINGS and SHOCKS:
a. No shocks or springs allowed
7. BRAKES:
a. Rear hydraulic brakes are required. Must be caliper/rotor type, not strap type brakes. Only ONE single brake rotor/caliper is allowed.
b. The utilization of brakes on the front wheels is optional and will be allowed, There will not be any weight concession, overall car maximum weight or left side weight requirements, if front wheel brakes are utilized.
8. WHEELBASE, WIDTH and LENGTH:
a. Wheelbase: Minimum wheel base of 58″, maximum wheel base of 61″ measured between centers of a rear axle to center of front spindle when front wheel is straight.
b. Width and length: Minimum of 38″, maximum of 50″ measured from outside to outside of both rear and front tires. Overall length minimum of 96″, maximum of 118″ measured at longest possible dimension.
9. ENGINE:
a. Only Honda GX390 13 HP, GX 340 11HP or approved “Clone” engines will be used in competition.
b. Engines cannot be altered from stock Honda specifications unless otherwise noted in this rulebook. No light weight parts unless otherwise specified.
c. All parts must be Honda or clone parts designed for the GX390 and will be checked against Honda parts unless otherwise noted in this rulebook. All decisions by Technical Director are final.
d. Internal and external governor system may be removed. Hole must be resealed.
e. Zero piston pop-up is allowed. Bore may be clearanced. Bore may be oversized by 10 thousandths (.010), 20 thousandths (.020), or 30 thousandths (.030) with Honda replacement 3 ring pistons only. Top piston ring may be oversized. Stock or aftermarket rings permitted. No gapless rings. Rings must be same thickness and width with no collapsing. Piston MUST have three rings.
f. Crankshaft must have stock stroke. Crankshaft may be turned or shortened to accommodate various clutches. No lightening, polishing, or balancing of the crankshaft is allowed. Crankshaft may be ground .010 and the use of a .010 replacement rod is permissible.
g. Piston and connecting rod must remain standard stock size with no grinding or sizing modifications allowed. modifying of oil lubrication hole is allowed. OEM ARC connecting rod OEM length allowed. Rod inserts allowed.
h. Piston must not extend above top of block. Top of piston crown may be sanded to ensure “0” piston pop out. Dish in top of piston must remain a minimum of .065 measured in the dish.
i. Blocks may be decked to achieve “0” deck. Clearance will be checked across the wrist pin.
j. Rotating the piston or rod is expressly forbidden. Any replacement rod bolt is allowed. Piston Pin must be in stock location and stock length. Wrist pin OEM inside hole diameter = .600. Stroke must not be altered (2.530) +/-.
k. Side cover locating pins may be solid dowels and cover bolts can be replaced with studs.
10. CYLINDER and HEADS:
a. Cylinder head must remain stock. No material to be added in port or taken out. Big port or small port head allowed.
b. Cylinder head may be resurfaced to a minimum thickness of 3.730 inches.
c. The Porting, polishing, sand, bead blasting, or sizing of any part of the cylinder head is NOT allowed. No acid baths allowed. Three Angle valve seats are not allowed. It will be the CEMCA Technical Director’s discretion to determine if a head has been altered. CC’s on head will be checked.
d. No multi angle on valves allowed (45 degree only). Multi angle valves are not allowed.
e. All cylinder head dimensions will be taken from stock Honda parts or Honda manual.
f. Studs may be added to replace cylinder head bolts.
g. Head gasket must be OEM (Fiber) .040 minimum. No metal head gaskets allowed.
h. Head cover shroud may be removed or replaced with homemade version.
i. Head must be mass produced, no one off. No “bump” heads.
11. CAM SHAFT:
a. Camshaft timing must be in place with notches in line. No advancing or retarding of cams. Stock type Honda steel
b. A OEM Stock Honda camshaft must be used meeting the following profile and must be checked at the lifter against the camshaft. Specifications are listed below. No visual tech on lobes. Cam must pass stock profile listed below. If 11hp motors is used must run 11hp cam. (see Technical Director for profile numbers).
c. All pressed gears shall remain in stock position. OEM Balancers cannot be removed. No shims of any kind. EZ spin must be unaltered. No alterations to cam of any kind.
LIFT DEGREES POSITION: (+/- 5 degrees) tolerance VMCRA Stock OEM Cam Profile
INTAKE EXHAUST:
.050 ATDC – 5 .050 BBDC – 30
.100 ATDC – 20 .100 BBDC – 12
.150 ATDC – 35 .150 ABDC – 6
.200 ATDC – 57 .200 ABDC – 28
.250 ATDC – 89 .241 MAX
.260 MAX .200 BTDC – 66
.250 BBDC – 49 .150 BTDC – 44
.200 BBDC – 15 .100 BTDC – 26
.150 ABDC – 6 .050 BTDC – 10
.100 ABDC – 22
.050 ABDC – 37
1.028 base circle minimum. No billet.
1. Intake maximum lift of .322 at valve with valve lash as ran in race. Lift will be measured at the retainer. This number is figured with rocker arms included.
2. Exhaust maximum lift of .292 at valve with valve lash as ran in race. Lift will be measured at the retainer. This number is figured with rocker arms included.
3. OEM Compression release (EZ Spin) @ 66* ABDC at .049
4. If anyone has a problem finding a stock profile cam listed above contact DMS Owner Ron Barfield at 8434964792
12. VALVE TRAIN:
a. All valves, lifters, push rods, and rocker arms must remain OEM stock.
b. One stock Honda GX390 k1shim allowed under both intake and exhaust springs.
c. Safety “O” ring may be installed and 1 keeper per valve to prevent valve failure.
d. Valve cover bolt may be replaced with a stud.
e. Stock or brass valve guide replacements are allowed in stock location.
f. Any Steel Valve Spring(s) are allowed. Valve springs stock measurements must be used as follows: spring wire diameter – .110-.118, spring free length – 1.590max, outside spring diameter – 1.020, inside spring diameter – .785.
13. CARBURETOR and SPACER:
a. Maximum size Honda carburetor or clone on venture of carburetor is .883, must pass Go-No Go Plug. Any other modifications are not permitted. Any attempt to pull outside air other than through the venture is not permitted.
b. Remote Carburetor adjuster allowed and recommended.
c. All carburetors and spacer plates must meet CEMCA specifications.
d. Fuel Filters: Inline fuel filters are allowed.
e. Stock unaltered insulators blocks must be run with stock gaskets (one per side, unaltered intact).
f. Fuel Pump: Only vacuum type fuel pumps are allowed. 1/4″ tubing can be added for vacuum access. Cars to be equipped with only one (1) fuel pump. Electric fuel pumps are not allowed.
g. The ducting of outside air into the engine compartment is strictly prohibited.
h. Carburetor may run with or without choke hardware in place.
14. AIR CLEANER:
a. All engines are required to have an air filter and air filter adapter. Air filter cannot act as a ram air device
15. FLYWHEEL ASSEMBLY:
a. Flywheel may be balanced. Minimum flywheel weight must be 11 lbs. 10 oz. Any flywheel that shows signs of machining on the inside area will be deemed illegal. Charging magnets on the inside may be removed. The CEMCA Technical Director will have sole authority on this matter.
b. Must have OEM flywheel key in place. No offset keys. No alteration to keys or key guides on the crankshaft or flywheel. Outside magnets must remain stock and in stock location.
c. External pull crank must be removed. Fan behind pull crank must remain stock. Manual hand rope pull may be removed. If removed the hole must be covered with acceptable screen (no solid plates). Screens must have openings, min ¼” diameter.
16. EXHAUST:
a. Exhaust pipe must be solid, may be stepped, and must exit behind rear tire.
b. Exhaust pipe wrap only is legal. No Coatings. Slip allowed for vibration.
c. Mufflers are Optional.
17. CLUTCH and CHAIN:
a. Only a dry centrifugal clutch is allowed. No transmissions, belt driven torque converters, torque converters, oil bath clutches or axle clutches. Only # 35 chain allowed. Live axle only.
b. No auto or manual chain oiling systems. No ratchet or free float hubs. All Sprocket keys in place.
18. TIMING and ELECTRICAL SYSTEM:
a. Oil alert system may be removed and hole resealed.
b. Charging magnets may be removed.
c. Altering the ignition timing from stock Honda GX390K1 specifications is not allowed.
d. No alterations to the starter coil, mounting bolts and holes or other electrical parts are allowed. No advancing or retarding crank gears.
e. No battery is allowed to be inside the driver’s compartment it must be behind firewall.
f. Any make or brand of spark plug may be used. Must be Compatible.
g. The electric self starter must be in working order. All cars must be capable of starting under
their own power.
19. OIL and FUEL SYSTEM:
a. Oil brands are optional. No flammables or explosives. No additive is allowed and random oil checks will be administered. Oil catch cans required on all cars and must be in working order.
b. Stock fuel tank must be removed and mounting tabs may be removed.
c. Fuel: For the 2018 Racing Season, racers must purchase 110 Octane Racing Gas from the Dillon Motor Speedway or from the other race tracks where the CEMCA Mini Cup Series will be racing. No additives, admixtures or mixing of fuel allowed. Fuel will be random tested by the CEMCA Technical Director in 2018 to insure that fuel rules are adhered to. Any fuel sampled and found to contain any type of alcohol, ethanol or admixture will result in disqualification.
d. Fuel containers must be metal or plastic. Fuel line must have a in line quick shutoff valve properly installed between the fuel cell and fuel pump
20. WHEELS and TIRES:
a. Wheels: Aluminum or steel rims allowed. Maximum wheel width of 8″on all 4.
b. The application of ANY tire treatment is prohibited. Sniffer and durometer will be used in 2015 to insure that no tire treatments have been used. The use of any tire treatment will result in disqualification. The decision by the CEMCA Technical Direction in this regard will be final.
c. The Official Tire of the CEMCA Mini Cup Series shall be the Hoosier MC780 Mini Cup Tire. Racers who have American Racer mini cup tires will be given a three (3) race “grace period” to get switched over to Hoosier.
d. All qualifying and race tires shall be in good condition with visible flaws.
21. WEIGHT:
a. Minimum Car and driver weight of 685 lbs. for Honda GX390-13 H.P. or its approved clone.
b. Minimum Car and driver weight of 610 lbs. for Honda GX340-11 H.P. or its approved clone.
c. The maximum left side weight shall not exceed 58% of the total weight of the car and driver. The maximum left side weight for “grandfathered” chassis cars shall not exceed 56%. Weight must be written on hood of the car.
d. All cars will be weighed with driver in a driving position.
e. All lead weight must be added to chassis securely and painted white with car number indicated.
22. AMMENDMENTS:
a. These rules are subject to amendments for competition when ample notice has been given by the CEMCA Technical Director. Any car that does not conform to the above rules may be allowed to compete with a weight and/or restrictor plate at the CEMCA Technical Director’s discretion.
b. CEMCA and DMS Speedway officials may use professional judgment for any infractions for a competitive race program.
c. Any driver or car that wins three races in a row maybe subject to a tear down & inspection of engine.
d. Unless specifically written in the 2018 CEMCA Technical Rules presented above, it is not allowed.
NOTE:
ANY RULES YOU DO NOT UNDERSTAND OR YOU NEED CLARIFICATION CONTACT CEMCA or DMS SPEEDWAY OFFICALS. Email tech@dillonmotorspeedway.com or call the CEMCA Technical Director Ronnie Barfield @ 843-496-4790 or Ron Barfield @ 843-496-4792.
