Mini-Cup

2023 MINI CUP Auburndale Mini Cup Rules Central Florida Mini Cup Rules at Auburndale Speedway is a driver development class. This class is committed to helping young drivers develop a solid foundation for their racing careers. This series allows anyone under 18 years of age to compete in point series. Drivers 18 and over can apply to run as a non-competitive driver. Drivers are required to demonstrate exemplary leadership and sportsmanship qualities, both on-and-off track. All drivers new to Mini Cup racing at Auburndale Speedway are required to contact Steve Smith 863-559-9865 prior to participation in their first race. No exceptions will be permitted. Any Mini Cup driver who has not previously competed at Auburndale Speedway must be cleared by the track’s race director prior to their first race. It is the responsibility of all new Mini Cup drivers to report to the race director personally (no crew members), prior to their first race. All drivers will be required to demonstrate consistency, predictability and comparative lap times to the satisfaction of the race director. Any driver unable to demonstrate these skills will be required to start at the rear of the field (including re-starts). The race director may also require additional driver training before a new competitor is cleared for competition. All novice drivers (as determined by the race director) are required to mark the rear bumper of their car with a yellow stripe of two (2) inches black stripe for yellow bumpers.

Driver and Team Conduct Conduct Each participant shall conduct himself to the highest standards of behavior and sportsmanship. Participant actions shall not diminish the reputation of the Auburndale Speedway, sponsors, or the sport of automobile racing. Failure to comply may result in penalties as specified by Auburndale Speedway officials. Assumption of Risk Automobile racing is a dangerous sport that can result in serious injury or death. Participation in all aspects of the sport are strictly voluntary. The ultimate responsibility for safety lies with the participants, whether vehicle owner, driver, or crew members. All participants must acknowledge they may suffer bodily injury or death, or loss or damage to property. All participants must further acknowledge that they voluntarily assumed the risk of bodily injury, or loss or damage to property and waive any claims for bodily injury or death, or loss or damage to property against Auburndale Speedway, its parent companies, directors, officers, employees, agents, event officials, sponsors, racetrack, and other participants; discharges such persons and entities from responsibility for such losses; and covenants not to sue such persons and entities for bodily injury or death, or loss or damage to property. Payout / Trophies Auburndale Speedway will provide payout based on the overall finish. Trophies will be awarded to drivers 18 and under only. Mini Cup Racing Safety Equipment Regardless of equipment, or approval in a prior inspection, compliance with all safety rules is mandatory for all cars, and inspection can be repeated at any time without prior notification. No expressed or implied warranty of safety shall result from the technical inspection or approval.

Radios & Race Receiver Two-way radios are required for drivers 18 and under when taking the track. Capable spotters are to assist the drivers in staging for starts and restarts as well as flags and track conditions and accidents. Race receivers are also required to be used either by the spotter and/or driver Seat All cars must be fitted with an aluminum racing seat that fits the driver’s physical characteristics. No homemade seats will be permitted. All seats must be securely mounted in the center line of the vehicle, so the seat center line is within 1/4 inches of the car centerline (the seat cannot be offset). Seats must be mounted using grade 8 hardware. Safety Harness All belts and harnesses must be of the five (5)-point type and meet the following minimum requirements: Have a minimum SFI rating of 16.1. Be at least two (2) inches wide. (three inches wide recommended). Be dated by the manufacturer and no more the (3) years old. A quick-release seat lap belt is required. Both ends of the lap belt must be fastened to the roll cage with grade 8 bolts not less than 3/8 inch in diameter. Shoulder harnesses must come from behind the driver’s seat. Inertia reels cannot be used.

 

Head and Neck Restraint A head and neck restraint system designed specifically for auto racing (neck collar minimum) is mandatory for all drivers. No driver shall compete in any event with head or arm extended outside of the car opening. The top of the driver’s helmet must be at least one (1) inch below the top edge of the roll cage. This will be measured with the driver securely buckled in the seat. All drivers must wear a racing type helmet with a Snell rating of SA2000 or newer. No bicycle or motorcycle helmets are permitted. Drivers must also check local track regulations to ensure their helmet meets Auburndale Speedway regulations. All drivers must wear an approved driving suit, shoes and gloves. A single layer fire suit is the minimum permitted. A standard fire extinguisher mounted in driver’s compartment is mandatory and must be easily accessible to the driver. It is highly recommended that a built-in in fire extinguishing system, a minimum of the cold fire system type or equivalent is used. ENGINE RULES If any race car consistently double laps the filled in any 2 consecutive races or win 3 consecutive races the race car will be sent to tech prior to the next race to add weight, change gear and/or whatever may be decided to maintain a level playing field by the minim cup committee to maintain a level playing field not to intimidate other racers. GEAR RULE    4.29

 

Minicup Engine Rules 2022

Engine Platforms Permitted:  GX 390 Honda * For Sealed Class

*With the exception of some internal parts.

GX 390 Honda or Clone Block for MODIFIED

Sealed Class Rules:

This class is intended to be easy to tech at the track and is designed to keep a level playing field.  With that in mind, APPROVED engine builders are empowered to seal engines and keep record of the seals and engine numbers, to help expedite tech and assure quality racing! The approved engine builders of CFMC are:

VP Racing Engines   PH:352-262-4901            vpracingengines@gmail.com

Big Cheese Racing Engines   PH:863-860-2934           Bigcheeseracing3@aol.com

Seals may not be removed, nor serial numbers or stamped numbers be removed from block!

Engine must remain in stock location. Offsetting of engine is expressly prohibited

Detailed Engine Rules:

Due to a shortage of some parts, the following may differ from rules of the past!  The changes have been put into place in an effort to increase participation and to overcome some difficulties in obtaining replacement parts for rebuilds.

All GX 390 stock blocks are legal. Non electric start blocks may be prepped for an electric starter. Block must have no more than .005” piston pop up. Block may be repaired by use of welding, epoxy, or both due to failure of internal parts. Block may be sleeved.  Lifter liners may be installed into block and relived.

The governor must be removed, and holes can be plugged or vented.

The oil alert system may be removed, and hole may be plugged.

All Honda Factory heads allowed.   Large AND Small port heads ARE legal.

Any Dished Honda piston allowed.  Must meet specs on detail sheet.  Piston may be machined to meet spec.

Rings non tech except NO gapless rings.

May be bored oversize to a maximum of .030 + clearance and wear.

Crankshaft may be shortened a maximum of 1.250” and hole may be re-tapped. Crankshaft lobes may not me machined or polished.  Crankshaft may be reground .010 under size and appropriate rod journal bearing may be used.

ARC 6272 Rod may be used with insert bearing.  Minimum weight on detail sheet.

Honda rod may also be used with any bolts.

Must use stock style wrist pin and clips. May be lightened to meet spec on detail sheet.

Camshaft must be Honda or clone solid core design.  A reground camshaft must meet the following criteria:  Intake= .265” lift max ,  Duration at .050”= 260 Degrees

                               Exhaust= .265” lift max, Duration at .050” = 260 Degrees

All measurements taken at the lifter.  Camshaft must line up on factory timing marks.   Machining of face of camshaft to remove weight allowed to meet spec.

Must use factory balance shaft.

Bearings non tech except cannot be self-aligning.

Cylinder Head:  No porting of cylinder head allowed.  May be machined to spec thickness of 3.725”.

Three angle valve job allowed.

Valve seat must remain stock other than surfacing seat.

Valve guides may be replaced with factory dimensioned guides or liners may be installed.

Stock Honda valves must be used.  With or without rotator.  Must meet specs on detail sheet.

Valve springs must be single coil.

Retainers must be stock.

Valve shims may be used.  Valve seal may be used on intake valve.

Honda rockers (GX390 Stamped steel) must be used. Rocker arm may have hole elongated to prevent binding. Rocker contact patch may be ground to achieve proper geometry. Honda rocker stud, pivot, and nut must be used, and in stock condition.

Stock pushrods of stock length must be used. See specs on detail sheet.

Stock pushrod guide plate must be used.

Stock Lifters must be used.  May be machined to meet spec.  Liners may be installed in lifter bores.  Bores may be chamfer relived.

Flywheel must be stock Honda.  Minimum weight is 11 pounds 10 oz.  Weight must be removed from the outside perimeter of flywheel only.  Evidence of machining elsewhere on flywheel is grounds for disqualification.  Magnets may be removed.  Charging system must be removed.

Stock flywheel fan, nut, and retaining washer must be used.

Timing Non-Tech

Stock Honda or clone ignition coil must be used.

Spark plug boot may be of any style except spark intensifier!

Any Spark plug allowed.

Starter must be in working order.

Starter cup and rotating screen must be removed and replaced with a protective Cover. This cover may be of ¼” mesh, solid metal, or solid plastic, WITH HOLES.  Holes may be no larger than ½” to retain a level of safety.  Cover may be taped or covered to obtain engine temperatures desired.  Must be fastened securely to the blower housing. A hole may be cut in center of mesh to allow the use of an external electric starter.

Stock Blower housing mandatory.

Sheet metal over cylinder is optional.

All gaskets must be Honda style.  All gaskets must be present.

All bolts are non tech besides Head bolts.  Head bolts must remain stock.

Studs may be used anywhere besides the Head bolts.

Valve cover must remain stock.  Vent may be modified to accept a durable connection to prevent leakage onto track.  Must be connected to a catch device of some type.

Exhaust pipe non tech, except must be securely mounted and safety wired, and cannot be adjustable under way.  Brace recommended but not mandatory.

****Carburetor*****

Carburetor options:

Honda Kehin cast carb body.  Venturi bore max no-go .960”.  Epoxy allowed.  No other tech requirements besides Cannot be a pressurized closed loop Fuel System.  Adjustable high-speed needle allowed.

Tillotson HL360A: Stock venturi and bore. Venturi .945” and bore 1.060”.  Use with manifold and velocity stack.  Fuel pump must be pulsed from intake manifold.  No other technical inspection.  Cannot be a pressurized closed loop fuel system.  Any manifold allowed.

 

 

Mini cup Sealed Stock Engine Parts Detail

The intent of the following list of measurements is to make clear what is a legal “stock” part.  This is a logical approach to truly leveling the playing field.  All Measurements must be within tolerance stated and measured to the level of precision as stated.  As a rule, there is no rounding up or down of any measurements.  Actual measurements as to comply with a GO/NO-GO mentality will be followed as grounds for disqualification.  All Measurement tools and GO/NO-GO gages have been calibrated and can be checked at the location of inspection. The following parts, as listed in detail, must meet the following criteria to be deemed legal.  Parts may be machined to meet the stated values but may not surpass the boundaries of the rules.

Parts to be measured in .001 thousandths of an inch, or to be measured to (0.1) Gram resolution:

Name of part:	Min Weight if applicable:	Minimum Size:	Maximum Size:	Special***
All Pistons	Min 250 Grams	NA	Approx .030”Oversize	Machining Allowed
Piston Dome Shape	Top of Piston must have at minimum a .060” Depression Measurable in 3 places	Must remain similar in shape to factory dish	Must have radius of minimum .0625” /Maximum .25”, on transition	Raised section to have radial section width less than .380”
Rings	Any ring besides gapless allowed	Non tech	Lapping and gapping allowed	Must use factory style oil rings (3 piece)
Wrist Pin	70 Grams	Factory O.D. .787” +/- .003”		Machining allowed
Circlips	2 must be used	Non tech	Non tech	Non tech
Rod (ARC) #6272	265 Grams	Must remain as produced besides clearancing	Bearing/ Bolts, non tech	Truing and providing side clearance allowed
Crankshaft	Honda Only!  Must remain as prepared from the factory.  Broken Key Damage may be repaired. Hole in end may be re tapped.	May not remove more than 1.250” from end	Clearance for bearings and regrinding of up to .010” undersize permissible	Stock Stroke only !!
Cam	675 Grams , INT & EXH: .265” Max lift at lifter, Max Duration at .050: lift INT & EXH:  .260”	Cam gear may be lightened to meet spec	Compression release must be in place	Machining allowed
Lifters	26 Grams	May be straightened and trued to spec	Must compare to Factory design	Machining allowed
Pushrods	22 Grams	May be straightened and trued to spec	Must compare to factory design	Machining allowed
Rockers	20 Grams	Standard Honda Rocker ratio and length	May be ground to spec on weight	Machining allowed
Rocker nut/stud/ and jam nut	Must be Honda Stock	NA	NA	NA
Retainers and rotator	9 Grams Honda Style ( no 2 piece keepers)	Rotator is optional	Stock dimensions	Machining allowed
Valves	40 Grams Must be Honda Stock Stock 45 Degree Only!	1.230” Int Max 1.390” Exh Max	Length Non tech	Machining allowed No Knife edging!
Valve Seats	Three angle Valve seats permitted.  I.D. of seat must remain stock	NA	NA	NA
Valve Springs	Any Single coil springs and shims allowed	No rules on springs	Only visual for single coil design	Machining Allowed
Flywheel	11lbs. 10 Oz minimum Stock Honda Only Puller holes may be enlarged and retaped for flywheel removal	Must be machined on outside perimeter only!	Balancing also allowed	Machining allowed
Fan and cup and Nut	Must use factory flywheel fan	Any flywheel retention nut allowed	Fan retention cup may be trimmed down	Moving screen must be removed
Ignition	Must be Honda Style All Honda Coils are allowed	Ignition Wire and Boot may be replaced	No spark intensifiers	Any Spark plug and any timing allowed
Balancer	Must be present	Must remain in stock condition	May be modified slightly for rod bolt clearance	Machining allowed
Bearings	May be replaced with similar style No self-aligning bearings	No Ceramic bearings	NA	NA
Bolts	All bolts non tech besides Head bolts.  Head bolts must remain stock!	Studs allowed	Safety wire on bolts is recommended	NA
Gaskets	Gaskets must remain stock styles.  No solid aluminum or copper gaskets allowed.  Sealant allowed	Minimum 1 gasket required on Cylinder head and side cover	Sealant only on the exhaust manifold flange is allowed	NA
Valve Cover	Must be used.  Can be modified to accept permanent fitting to prevent leaks	Stock Honda style only	NA	NA
Starter	Must use an electric starter	Block may be machined to accept starter	NA	Machining is allowed
Sheet Metal	Must use factory shroud around flywheel.  Top cover optional.  Lower head cover optional.	Must use permanent non-rotating flywheel screen bolted to housing	Screen may be of any RIGID design to prevent a safety hazard	Holes in screen may be taped or non existent.  Hole may be cut in center for electric starter
Cylinder Head	Any Honda factory cylinder head may be used!  No porting or grinding in ports allowed.  Small port heads have some factory grinding that is tolerable.	Surfacing to spec is allowed for thickness:  Min 3.725”.  No addition of material in ports!	Valve Seats and Valve guides may be replaced.  Guides may have liners inserted.	Guide must be inserted completely to stop ring.  Must use dowels to block.
Block	Honda GX 390 only! Any Honda GX 390! Can be bored up to .030”oversize with wear and clearance	Welding or epoxy for repair is allowed.  Welding to plug governor holes or oil alert holes is allowed.	May be sleeved	Deck may be machined to a piston pop up of MAX: .005”
Carburetor	Tillitson HL360A with manifold ( manifold non tech)     Stock Honda style ( stock appearing rules ) with epoxy	No Go: Venturi=.945” Bore=1.060” No GO: Venturi=.960”	No pressurized fuel systems!	No other tech on carburetor
Air cleaner	Any air cleaner system allowed and recommended!	Must be passive	No other rules	NA
Fuel Lines	Must be rigidly secured at all connections.	Must be in good working order!	Fuel Filter recommended	NA
PCV system	Must route all crankcase ventilation vapor to canister	Ventilation can originate anywhere on block as needed	NA	NA
Exhaust Pipe	Pipe must be securely supported and attached.  Safety wire should secure bolts from manifold as well as tie pipe to car in case of a breakage.	Length, size, and material are non tech.	May use EGT system	May be used without gasket.  Any support is allowed.
Oil	Any oil besides an oil containing “Hot” additives.	May not be leaking onto racing surface	NA	NA
Fuel	Gasoline Only!!! 87- octane to 110 race fuel allowed No additives or dangerous oxidizers allowed.  Fuel must be able to pass all standard fuel Digitron standards, hydrometer, as well as water tests	No methanol or alcohol No blending of these fuels into your race fuel	NA	No poisons or banned chemicals in fuel!

 

Engine Tech Procedure

The Purpose of this document is to detail a teardown procedure to assure fairness and a level playing field. The motor being described is a Honda GX390. This procedure covers what is acceptable from a technically measurable standpoint and from a Spirit and Intent rule. Cheating, or attempting to navigate around the rule set mentioned here, will be seen as probable cause for disqualification for the event currently being participated in. All measurements will be exact to the TOUSANTH of an inch or the THENTH OF A GRAM for weight. A tolerance of up to .001” of an inch in critical and .005” inch in non-critical measurements, and up to 1 gram on weight, can be applied by the technical inspector during teardown. This may allow a mercy rule for differences between measurement devices and is intended to be applied to promote fairness. Any other item in question can be compared to a known Honda production part or a “Suitable Clone part” that meets all specifications listed. The inspector must carry a 1.000” zero gauge and a tare weight, to show conformity of measuring equipment if concern may arise.

 

Tear Down Procedure:

Inspect visually on and around engine to for leaks and or visual safety issues. Check to assure throttle linkage is in working order and secure.

Check to see that the correct make and model of Honda engine are used. GX 390 block only.

Check to see if safety seals are intact and in an unaltered state. Any evidence of tampering is immediate grounds for disqualification.

Check records with the technical director to see if engine info and seal numbers match MASTER LOG.

Visually inspect air filter for and securing devices to assure safe working order. No filter also allowed.

Use No GO gage in carburetor venturi for correct corresponding carburetor.

Tillitson: BORE 0.945” VENTURI: 1.060”

Honda: VENTURI 0.960”

If NO GO Gage enters carburetor, competitor is deemed illegal.

If not, the carburetor is removed, and the bore is checked with no go gage (Tillitson).

If PASS, Valve cover is removed to inspect the valve train and lift.

Visually inspect to see if springs are single coil and check to see that rockers are stock type.

Install dial indicator to check max valve lift at push rod side of rocker. Zero indicator and assure the lift is no more than 0.265” on both the intake and exhaust.

If PASS, install a degree wheel to check cam duration. Zero wheel and check for no more than 260 degrees of duration at 0.050” lift on both the intake and the exhaust.

If PASS, the competitor may be deemed legal, and tech may be completed. If the technical director wishes to do a complete teardown, the following further steps should be taken.

Remove cylinder head and check minimum thickness to 3.725” in three places. Check to see if ports are stock and in stock condition.

Check to see if stock valves are used and if weight of each is within spec. Inspect the push rods for stock length and configuration. Inspect for stock style retainers (Non-Automotive) Required.

Install a long reach dial indicator and zero at top dead center. Revolve the motor in direction of rotation and check stroke. Stock stroke must be used. Check Piston Pop up for no more than 0.005” at center or wrist pin parallel and directly above the wrist pin.

Remove piston and inspect to see it is Stock Honda Dished style piston and check dome profile compared to specs.

Remove wrist pin, rings, circlips, rod, camshaft, balancer, and lifters and visually inspect for modifications. Check the minimum weight on these items.

Check the flywheel and ignition system. Stock Honda Flywheel minimum weight is 11 pounds, 10 ounces. Any Honda or clone coil may be used along with any coil wire and boot. Factory fan must be used. Spark plug non tech. Timing Non-Tech.

Check to See that Valve cover and sheet metal are being used and are in stock condition.

Check Oil to see if it passes flame test.

Check Fuel to see if it passes Digitron or Take Sample to Send to lab.

 

If all above rules are passed, Competitor is Deemed Legal.

 

If not, Competitor is Deemed Illegal and is Disqualified.