The following items, discussed during class meeting on 29 Nov
06, have been added to the former MMSP rules: 1) Hoosier tires;
2) Aluminum heads; 3) mounting of power steering pumps; and 4)
weight location for cars running aluminum heads.
FRAME & BODY - MODIFIED
Effective May 30, 2009 – NO raised
frame rails are allowed. Any other alterations to the front clip
is subject to inspection and approval.
No part of racecar can be
lower than four inches from the ground (exception is front cross
member and oil pan).
Frames may not be widened or narrowed and must be able to
support roll cage on both sides. Must be full and complete both
sides. Front cross member must remain full and intact; center of
cross member may be notched and boxed for radiator and/or
steering clearance only.
Minimum wheelbase, 108 inches, both sides. Maximum overall width
(front or rear) shall not exceed 78 inches from outside of tire
to outside of tire.
Engine compartment will remain open, no side panels; hood sides
may have maximum four-inch drop and must be enclosed at rear of
hood; maximum hood scoop height - six inches.
Passenger side of body must be no further forward than rear of
block.
Rear of bodies to be solid panel at least eight inches high,
No panel in front of right door to engine compartment. No inner
panels. No car covers.
Any driver slamming brakes on while on scales will be
disqualified and may be subject to loss of points and winnings.
No spoilers allowed.
ROLL CAGES - MODIFIED
Must consist of continuous hoops not less than
1.666-inch outside diameter with a wall thickness of at least
.O95-inch. Low carbon, mild steel tubing is recommended.
Must be frame-mounted in at least six places. No brazing or
soldering allowed.
Must consist of a configuration of front and rear hoops
connected by tubing on the sides or side hoops. Driver's head
must not protrude outside cage with helmet on and strapped in
driver's seat. Must have minimum of one cross bar in top halo of
roll cage. Roll cage must be securely supported and braced.
Protection of feet is mandatory. Bar across back of engine with
vertical bars and rub rails, or similar protection. No brace
bars forward of cage may be higher than stock hood height. Main
cage no further forward than engine plate.
DOOR BARS - MODIFIED
A minimum of three driver side door bars, at least
l.5-inch O.D., must be as parallel with the ground as possible,
and located perpendicular to the driver so as to provide maximum
protection for driver, but without causing undue difficulty in
getting into or out of vehicle. The side bars must be welded to
the front and rear of the roll cage members. Must have at least
one cross door bar, minimum 1.25-inch O.D., on passenger side of
car, either horizontal or angled.
Steel doorplates, 18-gauge or .O49-inch minimum thickness metal,
must be securely welded to outside of door bars on driver's
side. Plate must cover the area from the top door bar to the
bottom door bar and from the rear down post to five inches in
front of the seat. Must be visible for inspection.
BUMPERS - MODIFIED
Center of bumper, front and rear, must be 18 inches,
plus or minus two inches, from ground.
Steel bumpers must be used both front and rear at all times and
securely mounted with minimum .375-inch bolts. Must be made of
minimum 1.25-inch OD tubing, .065 wall thickness on front - .095
wall thickness on rear, and must be able to support car if
lifted by wrecker. Two-bar front bumpers must be mounted frame
end-to-frame end, no wider than the width of material outside
frame horns, with the bottom loop parallel to the ground. Top
bar must be directly above bottom bar, minimum 6.5 inches apart,
measured center to center at front of bumper (see P in body
diagram), so bumper is perpendicular to ground.
Rear bumper, steel nerf bars and bodies must not extend beyond
width of tires, and must not contain any sharp edges. Rear
bumper no more than two inches wider than body on each side.
Rear bumper must resemble one of three configurations, see
diagram on page four.
WEIGHT - MODIFIED
Car must weigh a minimum of 2,450 pounds with driver in
the car after race.
Cars running aluminum heads must place 25 pounds on each side of
the frame, ahead of the engine plate.
Top three (3) finishers must weigh in after each Feature.
Weight may be added to cars at the tech inspector's discretion
to allow non-conforming cars to participate.
All weight must be painted white with the car number clearly
marked on it. Weight added must be bolted to chassis. No weight
may be added to the bumper of any cars.
No lead pellets or liquid weights may be added to any car.
SUSPENSION AND STEERING - MODIFIED
Front suspension and steering must be unaltered approved
OEM and be in stock location, and must be replaceable by stock
parts. Outer tie rod end and adjustment sleeve may be replaced
by a minimum .625-inch rod end and steel tube. Weight jack must
be in original center line of spring. Stock passenger car
spindles only; no fabricated spindles. Spindles can be ground
for brake caliper clearance only. Bottom A-frames cannot be
altered or moved (exception: can weld shock mount on A-frame).
No offset or bearing type lower control arm bushings. Tube-type
upper A-frames allowed and can be moved. Front sway bar must be
approved OEM. Suspension, steering, and rear end parts must be
steel. Steering box must be steel approved OEM and must remain
within original bolt pattern for type of frame used. No rack &
pinion allowed. Steel steering shafts and knuckles only.
In-cockpit steering may be modified to suit driver's taste, but
must be kept on left side of cockpit. No center steering
allowed.
Steel or aluminum I.M.C.A. type coil-over assembly with 5"
minimum diameter springs allowed on rear only – one per side.
Rear of frame may be altered to accept leaf or coil springs; any
coil spring must be at least 4.5 inches outside diameter. One
steel coil spring per wheel only. No torsion bars allowed in
rear. Progressive springs allowed only on pull or lift bar.
No devices allowed that would enable driver adjustment to alter
wheelbase or for weight jacking while car is in competition. No
air shocks or air bags allowed.
One shock per wheel only. One additional shock and spring
allowed on rear suspension of vehicle. No adjustable shocks. No
covers on suspension parts except clear cover on slider and a
shield to protect the shocks. This shield can cover no more than
the front half of the shocks. No Schrader valves allowed.
ENGINE - MODIFIED
No aluminum blocks or oil pans. No magnetos.
Aluminum heads allowed. See weight rule for placement of weight.
Any American make engine may be used as long as rear of engine (bellhousing
flange) is mounted at least 72 inches forward from the center
line of rear axle. Engine offset must be kept within 2 inches of
centerline of front crossmember with engine level. ll-inch
engine height minimum from ground to front center of crankshaft.
All engines used in competition must be able to be used in
conventional passenger car without alterations. Motor mounts
cannot be removed or altered. Castings and fittings must not be
changed. No machine work on outside engine.
Wet oiling system only. Oil coolers must not protrude above
interior. Accumulators cannot be mounted between driver and
left-side door.
Cooling system may be modified. Any overflow tubes must be
directed to the ground, between frame rails. Radiators to be
mounted in front of engine only.
Conventional air cleaner housings only. No top flow air cleaner
housings allowed.
One 2- or one 4-barrel carburetor allowed; must be naturally
aspirated. No fuel injection; No electric fuel pumps.
BATTERIES - MODIFIED
One 12-volt battery only, must be securely mounted and
shielded.
Batteries must not be located in the driver's compartment.
ELECTRONICS - MODIFIED
No transmitting or listening devices. RIS is exploring
the possibility of using Race-ceivers.
No electronic monitoring computer devices capable of storing or
transmitting information except tachometers.
No digital gauges, timing retard controls or oxygen sensors
allowed.
One 12-volt non-adjustable ignition box and coil allowed - must
be out of driver's reach. No additional ignition accessories
allowed.
The only change that can be made with ignition box is
rev-limiter setting, and only one high-end setting is allowed.
This setting can be changed through one chip, or an internal
setting inside the box.
TRANSMISSIONS - MODIFIED
Must have at least one gear forward and one reverse,
plus a neutral position,
Quick-change transmissions will not be allowed.
Bert & Brinn transmissions will be allowed.
With motor running and car in a still position, driver must be
able to engage car in gear and move forward, then backward.
Power steering pumps may be mounted on transmission, driveline
or engine.
BRAKES - MODIFIED
Must have a working caliper and rotor on each wheel and
must lock up all four wheels,
Front rotors should be within 15 degrees temperature of each
other after all races.
No brake shut-off or pressure sensitive devices allowed.
One proportioning device allowed, front to rear only.
Brake lines must be outside frame rails and visible.
Vented rotors only, no scalloped rotors. Rotors cannot be
lightened.
Rotors may be re-drilled for different bolt pattern or larger
studs. Must be steel, approved OEM calipers, and they cannot be
lightened.
REAR END - MODIFIED
Any approved OEM passenger car type or truck rear end
may be used.
No aluminum allowed, except lowering blocks, axle cap, and drive
flange. A one-inch inspection hole in center section is
recommended. Full steel spool, steel mini spool or welded
rearends only.
Steel axles only.
Quick-change devices ARE allowed.
No cambered rear ends. One-piece drive
flange only. No electronic or mechanical traction control
devices allowed.
Minimum 19 inch long panhard bar
(J-Bar). Measure straight line center to center.
FUEL & FUEL CELL - MODIFIED
May be either gasoline or alcohol. No Nitrous Oxide.
Racing fuel cells required and must be mounted by at least two
solid steel straps, two inches wide around cell. Fuel cells must
be enclosed in steel container and must be mounted securely
behind rear axle and between the rear tires, no lower than six
inches off the ground, protected by roll- cage tubing.
Protective tubing must cover the rear and extend past both sides
of fuel cell.
Fuel cell must be a minimum of four inches ahead of rear bumper
and no part of fuel cell shall be lower than protective tubing.
Fuel cell vents, including cap vent, must have check valves, and
bladders are highly recommended.
Fuel cells are limited to 32-gallon maximum capacity. Pick-up
must not be underneath fuel cell. A limit of one standard fuel
filter allowed between the fuel cell and carburetor.
No performance-enhancing fuel additives of any kind.
TIRES AND WHEELS - MODIFIED
Hoosier Racing Tires I.M.C.A. type G60-15 on all 4
corners.
All tires must maintain a minimum durometer hardness of 50 after
race.
Cannot soften, condition or groove tires.
8” steel wheels only allowed.
No wide-five wheel adapters allowed. Aluminum or steel spacers
allowed.
May use bead lock, on right rear only. External, steel bead lock
only and it cannot make the wheel any narrower than 8 inches and
no wider than 8.75 inches.
Must use only steel bolts.
One foam type or plastic mud cap per wheel allowed on right
sides only.
Rim-mounted bleeder valves are allowed.
Tires may be ground or sipe within
confines of tread (not past factory straight line). No re-caps
allowed.
