2013 UMP Modified Rules

Transmission & Driveline

A.) The drive shaft must be made from magnetic steel. The driveshaft
must be painted white with the car number clearly labeled on the drive

B.) Aluminum, fiberglass, or carbon fiber drive shafts will not be permitted.

C.) A 1/2”-inch x 2”-inch 18-gauge steel drive shaft hoop is
mandatory. The drive shaft hoop must be at least six (6”) inches
behind the universal-joint. Two hoops are strongly recommended. A
single 1/8”-inch plate on the right side of the drive shaft tunnel is

D.) All competitors are encouraged to perform systematic checks on
their drive-train.

E.) Direct drives and/or any type devices will not be permitted.

F.) The transmission must be bolted to the engine. All cars must have
forward and working reverse gears and be able to shift to forward or
reverse with engine running.

G.) Clutch-type transmissions must be equipped with explosion-proof
steel bell housing. In lieu of an explosion-proof bell housing or if
one is not available for your engine, a shield of at least 1/2”-inch x
6”- inches covering the clutch area 360 degrees securely fastened in
place and fabricated from magnetic steel will be permitted.

H.) The steering box must be O.E.M. Any-type rack and pinion style
steering will not be permitted. The original bolt pattern that matches
frame type must be used. In the cockpit, steering may be modified to
suit the driver but must remain on the left side of the vehicle.
Moving the steering mechanisms to the center of the vehicle will not
be permitted.

I.) The minimum wheelbase permitted will be 108” inches. The maximum
wheelbase permitted will be 112” inches.


A.) All added weight(s) must be painted white with the car number
clearly labeled on each weight.

B.) All added weight(s) must be securely mounted to car with minimum
of two (2) 1/2”-inch bolts that pass completely through each weight
and the car. Weights that are mounted on the rear bumper or outside
the body of the car will not be permitted. All added weight must be
mounted below all windows and the interior sheet metal.

C.) The minimum weight of car with driver at all times including after
the race is 2,400 lbs.

Fuel Cells and Fuel

A.) All cars must have fuel cells. The maximum capacity for the fuel
cell will be 32 gallons. The fuel cell must be completely enclosed in
an 18-gauge magnetic steel container. Aluminum fuel cell containers
will not be permitted. All fuel cells must be completely visible. All
fuel cells must have a minimum of 2”x2” inch x 1/8”-inch steel straps
surrounding them. The fuel cell must be protected in the rear of axle
by securely-mounted (welded) roll cage tubing.

B:) All fuel cells must have check valve in breather and filler check valve.


See drawing diagram for reference – There may be dimensions referenced
in the drawing diagram that are not referenced in written rules and
vice versa. All dimensions whether written and/or referenced in the
drawing diagram dimensional are rule(s)

A.) All bodies must follow dimension(s) and the appearance as shown in diagram.

B.) The front windshield and rear window support must be stock
appearing. The front window support(s) may have a clear Lexan support
of no more than 16” inches including the roof post at the bottom and
going straight to the roof. The support must be securely fastened in a
positive manner.

C.) The front roof post must be in a straight line from top to bottom.

D.) The sides of the engine compartment will remain open. Any side
panels in the engine compartment area will not be permitted. A five
(5”) inch drop on either side of the hood will be permitted and it
must enclosed at the rear of the hood. The firewall on driver’s side
must meet the front of the door. The firewall must be a minimum of
16”-inches in length from top-to-bottom.

E.) The top of the doors must remain in line with the rear engine
plate. The bottom of the doors may extend a maximum of eight (8”)
inches past the motor plate toward the front of the vehicle. Any
material that exceeds 8”-inches will not be permitted.

F.) A maximum one (1”) inch flange on the outside edges (left or right
side vertically) for the purpose of strengthening only will be
permitted on the front nose only. Side fins and/or flanges of any kind
along the length of the entire car (hood, front, and/or roof) will not
be permitted.

G.) A maximum of one (1) stone deflector, for rear mounted oil pumps,
oil filters, and for the main oil tank will be permitted. The
deflector may be made of steel, aluminum, or heavy gauge wire. The
cover may only be mounted near the unit it is designed to protect with
a maximum size of eighteen (18”x18”) inches square and mounted only
from the upper right frame rail to the lower right frame rail.

H.) The minimum roof height is 42” inches with a maximum height of 52” inches.

I.) The minimum deck height is 28” inches with a maximum height of 38” inches.

J.) All cars must have a car number on both sides and the roof that
are at least 18” inches in height and 14” inches in width.

K.) The driver’s last name must be displayed under the car number in a
legible font that is a minimum of eight (8”) inch high letters.

L.) A minimum of two (2”) inches of tire clearance from the body is required.

M.) The minimum ground clearance will be four (4”) inches.

N.) The measurement from center of the hub to the rear top of deck
will be a minimum of 34” inches and a maximum of 48” inches.

O.) The maximum body width at the body’s widest part will be 72”
inches. The minimum of width at the body’s narrowest part will be 53”
inches. The top of the doors may have a maximum width of 67” inches.
The bottom of the doors may have a maximum width of 68” inches.

P.) On the left side the rear of the door may flare out six (2”)
inches for tire clearance.

Q.) The bottom of the flare must be curved and rounded not pointed in
any fashion.

R.) The maximum rear width of car must be 67” inches at the widest point.

S.) The maximum roof width will be 50” inches with a minimum of 44” inches.

T.) The maximum roof length will be 56” inches with a minimum roof
length of 41” inches.

U.) The maximum height on rear roof post vertical is 5” inches.

V.) The nose piece must not exceed 45”-inches in width, centered
between the frame rails and must not extend past the leading edge of
the front bumper. The nose piece must have a minimum of six (6”)
inches from the ground to the bottom edge of the nose piece.

W.) The composite, Dominator 2012 “Modified Nose” is the only approved
composite “Modified Nose” for competition. To be eligible for
competition the Dominator 2012 “Modified Nose” must meet all
manufacturer specifications and/or rules as stated within the 2013
DIRT car UMP Modified Rule Book.

X.) The spoiler shall be a maximum of 5” inches tall. Any spoiler
angle will be permitted. Three (3) spoiler supports may be used; this
includes side spoilers. The spoiler supports and side spoilers shall
be 5” inches tall in the back and 2” inches tall in the front with a
maximum total length of 12” inches at the bottom.

Y.) The spoiler may be fabricated from lexan or aluminum. You may use
the roof post/spoiler kit. The kit has the roof post and spoiler
fabricated in one piece. If the kit is utilized the spoiler height
must remain 5” inches.

Interior and Driver Compartment

A.) The maximum slope/rake of the interior sheet metal “shelf”
front-to-rear is 4”-inches when measured from the firewall to the base
of the spoiler. A maximum of 2”-inches of slope/rake will be permitted
in front of the rear of the seat to the firewall and a maximum of
2”-inches of slope/rake will be permitted from the rear of the seat to
the base of the spoiler.

B.) The top of the interior must be flush with the top of door and
quarter panels.

Roof & Roof Supports

A.) All roofs must be full size. Half-moon roofs will not be
permitted. The roof may not be mounted more than 12” (twelve inches)
past the rear axle.

B.) Wings, roof spoilers or ground effects of any kind will not be permitted.

C.) All flat type roofs will be allowed a maximum 3”-inch difference
in height between the front of the roof and the rear of the roof. This
measurement may be taken from the interior and/or the ground up in any
circumstance. The rear of the roof must maintain the same height from

D.) Wedge roofs will not be permitted.

E) Dished roofs will not be permitted. Roofs must be rounded
side-to-side. Bead rolls will be permitted.


A.) Any “live axle”-type rear ends will not be permitted.

B.) Quick change rear ends will be permitted. Only magnetic steel
tubes will be permitted.

C.) Aluminum birdcages will not be permitted.

D.) Independent rear suspensions will not be permitted.

E.) Only floater hub assemblies will be permitted.

F.) Steel coil-over eliminators and/or steel/aluminum coil-over kits
will be permitted. The coil-over eliminators and/or coil-over kits
must conform to the shock and spring rules. In the rear of the car a
minimum 5”-inch spring is required.

G.) All springs must have a tethered and/or cable system in place to
securely fasten them in position in the car.

H.) Aluminum shocks, shells, aluminum hubs, aluminum A-frames,
aluminum rear-end, aluminum tubes and/or other aluminum suspension
parts will not be permitted.

I.) Only steel body, one piece non-adjustable shocks will be
permitted. Adjustable shocks, including cockpit adjusters will not be

J.) Coils over shocks of any type on the front of the car will not be permitted.

K.) Only one shock per wheel will be permitted.

L.) Only stock passenger car spindles will be permitted. Fabricated
spindles will not be permitted.

M.) Alterations and/or relocation of the lower A-frames will not be
permitted. DIRTcar approved after-market lower control arms, which are
mounted in the OEM location and maintaining the OEM Manufacturer will
be permitted. All after-market lower control arms must have an
official DIRTcar-approved and numbered decal displayed for ease of
inspection at all times. On January 1st, 2014 only stock OEM DIRTcar
approved lower A-frames will be permitted in competition.

N.) Tubular-type upper A-frames will be permitted. The upper A-frame
mounting locations may be altered. Aluminum cross shafts will be


A.) All cars must be equipped with a working braking system on all
four wheels and all four wheels must be able to stop/brake at all

B.) Only magnetic steel rotors will be permitted. Carbon fiber and/or
aluminum rotors will not be permitted. Drilling, lightening and/or any
alteration to the brake rotors or calipers will not be permitted.

C.) Only stock O.E.M. and/or DIRTcar approved aftermarket calipers
will be permitted. Only the Wilwood P/N # 120-7197 is DIRTcar

D.) Only stock O.E.M. rotors will be permitted. Single disc brake
rotors or scalloped rotors will not be permitted.

Wheels and Tires

A.) All wheels must be conventional one-piece magnetic steel and must
be mounted with lug nuts. Aluminum, plastic and/or carbon fiber wheels
will not be permitted.

B.) All wheels must be fastened to the hub with five lug nuts.