Track Rules and Regulations
2013 Rule Book
2013 MOD-LITE DWARF RULES
2013 TUSA RULES for Engine Specs
1. BODY STYLES
Any car specifications not covered in these body specs are subject to officials
interpretation. Any significant performance advantage will be addressed on an
individual basis. Officials reserves the right to determine what constitutes an unfair advantage.
(a) 1928-1948 American-made production vehicles only, 5/8 scale, two-door sedans, coupes, or pickup trucks. These are to be known as Classic Modified body styles.
(b) Modified appearing body style such as IMCA or DIRT modified. These are to be known as Modified Lite body styles.
(c) All chassis specifications are the same for both body styles.
2. BODY REQUIREMENTS AND SPECIFICATIONS
(a) Body must be 5/8 scale, stock appearing. Maximum outside tire width 60", Cars must pass freely through a hoop 60 1/2” wide by 50” high, 73” wheelbase plus or minus 1".
1. Must have grill shell or simulated open radiator matching original body style, any material.
2. Doors, windows, and cowlings must retain stock appearance. Hood louvers
allowed for cooling, but must maintain stock contours.
3. Engine compartment must conform to scale and match contour of body. Hole may be cut for breather clearance only. Ram air induction system prohibited.
4. Must have closed trunk lid or fully enclosed trunk access panel conforming to original bodylines. Louvers allowed no holes.
5. No fenders.
6. No wings or spoilers.
7. Ram air induction system prohibited.
(b) Body will be metal construction, 26-gauge steel or .040" aluminum minimum. Fiberglass or plastic grill shells allowed. All exposed edges must be folded or trimmed over. Legends cars may be allowed . No lips or spoilers of any kind.
(c) NO open top cars (roadsters, convertibles). No panel trucks, station wagons, or specialty cars.
(d) Classic Modified Overall Dimensions
1. NO car over 50” tall, top to ground. Body height maximum 44”, bottom edge to top (including frame rail).
2. Maximum body width: 38” Maximum frame width 34”; min 30”
3. Body contour must follow frame and roll cage. Roof hatch entrance allowed.
4. Frame ride height must not let car bottom out on track.
5. Drivers door must be operational and equipped with secure latch.
6. Fasteners on hood, trunk, or panels must be positive, locking type.
7. 124” maximum total length, bumper to bumper.
8. Kick outs or side nerf bars must be mounted at three points and run full length between tires. 1 ¼” max .125 wall thickness. Cannot stick out beyond 1” from the side of the tire.
The intent of these preceding specifications is to follow the bodyline and design of an exciting IMCA or DIRT modified racecar.
1. 84" max - Door and rear quarter length.
2b. MODIFIED LITE
(a) OVERALL DIMENSIONS
A. 42" min 50" max from ground - total car height.
B. 124" maximum total length, bumper to bumper
C. SIDES AND REAR QUARTER PANEL
1. 84" max - Door and rear quarter length.
D. 30" min 38" max - side height of rear quarter panel from the ground. 30” max height of quarter panel.
1. 20" min 27” max - hood height excluding breather protectors (bottom of frame rail to top of hood). Ram air induction system prohibited. Rear of hood becomes part of windshield area rules. No part of nose section (in front of spindle centerline) may be wider than a maximum of 24”. Hood may taper out to door panels at the rear.
F. ROOF PANEL
1. 40" min 48" max - length of roof panel. 36" min 42" max - width of roof.
No part of roof panel may have more than 14o of angle rake. No deflector of any type on upper sides or rear of roof panel. Roof entrance hatch optional. Front visors are allowed
G. REAR UPPER QUARTER PANEL
1. 20" min 38" max rear upper side panel may contain Plexiglas. Side panels maybe no higher than 3" at the rear of the straight line of quarter panel top edge. Side panel may be no higher than an imaginary line from the rear edge of roof panel to 3” above the top edge of the rear quarter panel.
H. SIDE WINDOW
1. 18" min side opening length. 10" minimum side opening height front and rear.
1. 46" min 50" max - width of rear shelf and body panels. Rear shelf may have no more than a 5o max rake and may not be concave or convex in design. No lips or spoilers of any kind. The rear frame area from the rear shelf downward a minimum of 16” must be completely enclosed the width of the frame. Louvers allowed, no holes.
J. ADDITIONAL INTERIOR SPECIFICATIONS
1. 36" min 56" max - length of right side pod area with max 30o. Left side pod may be altered for driver access.
2. Rear quarter distance from center of rear 20" min 30" max.
3. Cockpit cover with a max of ½” lip will be permitted providing the on/off cutoff switch is reachable from outside the car by safety personnel.
4. Deck lid height from ground 30” minimum, 36” maximum with NO rear lip
5. Side pod may not extend rearward past the centerline of rear axle.
6. Body must be centered on chassis.
7. If windshield is used, it must be flat.
8. All body dimensions will be teched + or – ½” unless otherwise specified.
3. BUMPER DIMENSIONS
(a) Front maximum width 30", Bumper height 6” to 8" with 2-bar loop. Ground to top of bumper: 12” minimum,
16” maximum. Bumper may not extend more than 12" forward of front tires.
(b) Rear maximum width 56” with 3 vertical bars. Bumper height 6” to 8" with 2-bar configuration. Ground to top of bumper: 12” minimum, 18” maximum. May not extend more than 8” behind rear body panels.
(c) Bumpers must be hollow with max wall thickness of .125
(a) Must weigh a minimum of 1240 lbs, with driver after race unless stated otherwise .
(b) No weight outside of car body, i.e. on nerf bars
5. NERF BARS
(a) Full length nerf bars between front and rear tires mandatory. Maximum outside diameter of 1.25” and .125 maximum thickness, must be hollow and may not extend out beyond tread width more than 1" at the rear only.
(a) Firewall must be metal and must completely separate engine compartment from cockpit. Engine protruding
into cockpit must be enclosed.
(a) Windshield must be wire mesh, or protection bars. No Glass. All other cockpit areas must remain open. Deflectors may be used in front of driver. May be no wider than roll bar area.
(a) Seat must be high-backed aluminum, racing type. All cars will have a permanent bar located behind top of seat at shoulder level. Bottom of seat will not be more than 63" back measured from upper ball joint. Seat may be tilted back for added driver head clearance, however, no portion of the seat may be back more than 70" as measured above.
9. NUMBERS AND GRAPHICS
(a) Car number must be minimum 12" in height and 2" stroke. Must be displayed on each door and roof or trunk. Numbers in 4" size should be on front and rear of car to help with line-ups.
(b) All cars must have a cartoon character
10. WHEELS AND TIRES only NON TUSA WILL GET BONUS MONEY$
(a) Steel wheels only, minimum wall thickness .090", 13" only, Wheel width max. 8".
(b) Hoosier Racing Tires only Modlites running Soft 40-durometer minimum before race must weight 1350#, All cars running Medium 48 durometer minimum must weight no less than 1240# for dirt (TUSA stamp not required)
(c) Bead lock rims are optional Right side only.
11. BATTERY, FUEL SYSTEM
(a) Battery and fuel pump must be mounted outside driver compartment. Battery must be secure and held with non- rubber strap. Electric fuel pump allowed.
(b) Fuel cell mandatory, maximum 5 gallons, located in trunk.
(c) Gasoline only, no fuel additives allowed.
(d) Reinforced or steel braided line must be used in all high-pressure areas.
(e) A direct manual cutoff switch wired to ground circuit will be installed on the right rear shelf or rear fire wall within 6” of the corner formed by the rear deck and rear fire wall. Switch will be located over the right shoulder of the driver. The emergency electrical cut off switch will be clearly located and marked.
12. DRIVE TRAIN
(a) Must use steel drive shaft from transmission to automotive rear end. Minimum 2.50" x .083" or 2" x .120".
(b) Quick change rear ends allowed with steel tubes only.
(c) Drive shaft tunnel must have minimum of 2 (3 recommended) 360-degree hoops between firewall and seat back. Must be fabricated of minimum .1875" X 1.5" steel bar. 1" X .095" steel tube highly recommended.
(d) Rear must be locked or have a solid spool.
13. FRAME AND ROLL CAGE
(a) Main frame members will be minimum of 1" X 2" x .120" wall rectangular steel tubing only. Mainframe rail consist of the length between the front lower a-arm cross member and the rear main roll bar upright. No aluminum allowed in cage or frame.
(b) Main frames will have a minimum of 3 cross members between firewall and back of seat fabricated of same material as frame rails. Alternate material may be steel angle, min. .125" X 1.5" X 2". Cross-bracing in floor under driver strongly recommended. Rear frame rails at rear roll bar must be 34” max and 30” minimum outside dimension. Rear roll bar must meet same dimension as the frame it is mounted to. Frame may taper forward of driver seat area. Front engine area frame width must be 24: max and 20” min outside dimension. Left and right frame rails must be the same + or – ½”. (c) Roll cage must be DOM steel minimum 1.25" x .083" (.095 recommended) in all cars manufactured from 12/98 on. Clubs may grandfather older cars with 1" x .065" tubing. Cross-brace or diagonal strongly recommended in hoop over driver's head.
(d) All cars must have cage bars installed across door openings on both sides. Bars should be welded in place as part of roll cage. Minimum size 1" x .065". (1.25" x .095" recommended) cars with bars mounted on doors should have full doorframe and minimum of 2 horizontal cross bars. Minimum 1” x .083". Cars with bats mounted on doors must have 1/4" x 2" steel stops welded in on each side of opening, totaling a minimum of 4" on each end of door.
(e) It is required to have a steel bar with a minimum size of 1" X .065" from doorpost to doorpost, under the dash. Steel plate on driver's door bars recommended
(f) It is recommended that, if using rivets, body panels attach to tabs welded onto cage instead of drilling multiple holes into cage bars.
(g) No down tube frame cars allowed. Any bars going from cowl area to snout must remain below the upper line of hood.
(h) Classic pickups may have two (2) bars going from upper rear roll cage down to rear clip.
14. ENGINE SPECIFICATIONS
(There will be 2 weight divisions:
(A. “STOCK” ENGINES - weight requirement 1250#
1000 cc or less Water-cooled engines produced between 2000 and 2008
may compete in this program Engine must retain its stock fuel induction system with no other form of fuel delivery.
Engines eligible for this program, Suzuki GSXR 1000, Honda CBR1000RR,
Yamaha YZFR1, and Kawasaki ZX10. All other engine requirements apply from section
(1) No interchanging, swapping or changing the specifications of any part with the
1. Air Box – aftermarket air filter assemblies are allowable. No ram type are
2009 and newer engines are not eligible for competition but will be REVIEWED for competition for the 2013-racing season with restriction of competing in the stock division only.
(B) Open Motor” - weight requirement 1375#
1. Side draft motors 1250cc (+1%)
2. Down draft motors limited to 1200cc maximum with no variance.
3. Water-cooled engines 1100cc and below can run carburetors or fuel
i. Engines above 1100cc OEM must remain in their original
stock configuration of carburetors or fuel injection.
4. No engine can be or be bored to more than 3mm over OEM specifications stock .
5.. Carburetors and cams optional. (Except ZX12)
8. Porting, grinding, polishing or changing stock configuration of intake
or exhaust ports allowed for oil & air cooled motors only
Absolutely head work allowed on any water cooled engines None Casting part lines must be visible upon inspection.
Only Cars running the Stock sealed engine are eligible for bonus Money.
(C) “General engine” Specifications for All Engines:
Four cycle, four cylinders maximum only. Must remain stock bore and stroke, no altering rod or piston Specifications, All head components must remain stock, (except cam sprockets may be adjustable type). Cams must be as per original equipment, Must have working transision , and starter with all parts in place.
Complete Clutch assembly must remain in engine. External reverse boxes allowed. No 2009 engines or newer No air controlled shifting devices.
2. Charging system optional. Battery powered ignition system only. Alternator cover allowed.
3. Only OEM stock ignition with OEM ECU box may be used. Only one fuel monitoring device, wired into the harness, with no other connections, will be allowed during competition. No fuel monitoring control devices allowed in the drivers - reach or driver cockpit area. Bizzaz systems or any other electronic control system that has the ability to add modules that alters any program except fuel monitoring is strictly prohibited
4. Engines must be front mounted in engine compartment
5. Engine setback: The "square of the engine" (rear fins of the jugs) may not extend rearward more than 17" from the center of front spindle. No part of the engine or transmission may extend rearward more than 21 inches from center of front spindle.
6. No Aftermarket cylinder & cylinder heads, No after market fuel injection No auxiliary starters, and no turbos. nitrous oxide. OEM fuel injection must remain stock.
7. Engine must be cooled by original intent. May use extra fan or oil cooler.
8. No increasing or decreasing of stroke in any way No engine can be modified to be less than original stock configuration OEM specifications
9. Oil pans maybe cut or modified, Oil systems may not include a dry sump system.
10. Carburetor/Fuel injection boot must fasten directly to head in
the stock intake port location Engine exhaust Header must attach directly to head in stock exhaust port location, must include muffler and exit rearward.
MUFFLER SEE MANDATORY MUFFLERS PAGE 10.
(a) Front suspension must not extend rearward past the most forward panel of the firewall.
1. Aluminum modular Spindles allowed must be steel spindle shaft.
(b) Rear trailing arm/radius rod specifications: Arms may have a maximum length of 30”.
2. Torque-absorbing devices are permitted.
3. Maximum 3 radius rods or 3 link suspension
(c) Wheel offsets are allowed.
(d) Hub offsets are NOT allowed. Hubs front and rear must be within 1/2” distance from mainframe rail on either
side of car, measured from center of rotor to vertical plane of frame rail.
(e) Coil-over shocks are the only allowable means of supporting the chassis. One shock and spring per wheel only. Shock and spring must remain as one unit.
(f) Shocks must be of all-steel construction, non-adjustable type any make.may not be of a type that allows user to disassemble claimable for 110.00 each less coil over kit.
(g) No driver shall have the ability to adjust suspension from inside car.
(h) Straight front axles are prohibited.
(i) No leaf springs.
(j) No birdcage type rear linkage.
(k) Anti-roll (sway) bars permitted front or rear. Must be connected without
adjustments to arm location allowed
(l) No torsion bar suspension system of any type allowed.
(m) The use of carbon fiber or titanium in any way is prohibited.
(a) All steering components must have safety fasteners such as cotter pins or
(b) Manufactured quick-release steering wheel hubs mandatory.
(c) Rack and pinion steering is mandatory.
(a) All four wheels must have working calipers and rotors.
(b) Rotors and calipers:
1. Steel rotors mandatory, .250 minimum thickness.
2. Steel OEM calipers or aluminum calipers.
3. Cutting & scalloping of rotors will be allowed with no rotor surface being less than 3/4” in width.
4. Drilling of rotors is permitted.
(c) Adjustable brake bias and wheel shut offs allowed.
(d) Competition-type master cylinders allowed
18. Courtesy Rule: See Courtesy Rule Page 9 Rule 28.