RULES - NATIONAL COMPETITION RULES - UNLIMITED CATEGORY

UNLIMITED CATEGORY

Unlimited Category is for production-based vehicles prepared beyond Sport, Tuner and Max which means any vehicle on DOT tires with less than 200 treadwear or on non-DOT tires. We do not expect these vehicles to be streetable. This is where you will find Time Attack monsters, Tube Frame GT cars and race cars that don't fit with the street-driven philosophies of the other categories.

As with Max, Unlimited Category vehicles may only be driven, stopped and steered through the wheels and tires. When the word “unrestricted” is used in these rules, it is under the assumption that the modifications and controls are within this parameter.

Unlimited Category Overview

For National Events, Unlimited Category vehicles must be based on production automobiles and bear a noticeable resemblance to their production counterparts.

1. Kit cars and reproductions listed in Max Category are eligible for Unlimited Class.

2. There will be two classes in National Unlimited Category Competition—Unlimited 1 and Unlimited 2. Both classes must be production-based.

3. Full-scale tube-frame Grand Touring (GT), Production (P) and Prepared-Class cars are considered “production based.”

4. If Regions run under National Events Classing, and include a non-production class for Unlimited Category vehicles, it is recommended that Regions run the suggested classes for Formula Cars, Sports Racers and Specials.

Vehicles in Unlimited Category must meet Safety Level 2 or Safety Level 3 Standards, depending on tires.

A. Vehicles running on DOT-Approved tire will need to meet Safety Level 2 Standards.

B. Vehicles with non-DOT tires will need to meet Safety Level 3 Standards.

Unlimited Category - Authorized Modifications

Unlimited Category vehicles may do any modification listed in Sport, Tuner and Max Categories, plus allowances listed below.

Unlimited Category - Authorized Modifications

Interior and interior components may be modified, removed and replaced with the following restrictions:

1. There must be a sealed firewall between the engine and driver.

2. All fuel system components must be sealed off from the driver.

3. All exhaust components must be sealed off from the driver.

Bodywork and chassis components may be replaced or modified, with the following restrictions:

1. Bodywork must bear a noticeable resemblance to production counterparts.

2. Polycarbonate windows are allowed, with the following restrictions:

A. Rear, door, vent and quarter window glass can be replaced with a clear polycarbonate material having a minimum thickness of 3 mm. The windows in the rear door of a four-door car and quarter windows can be run in their stock open or closed position. Ducts can be installed in the door, vent and quarter windows or resultant door window openings, for the sole purpose of supplying cooling air to the driver.

B. If the windshield is replaced, the replacement must be of a polycarbonate material with a minimum thickness of 6 mm, be identical in size and curvature to the stock glass windshield and have a minimum of three (3) vertical inner supports to prevent the windshield from collapsing inward. Inner windshield supports must be a minimum of 0.75 inch by 0.125 inch straps of aluminum. The inner supports must be mounted a minimum of 8 inches apart.

Aerodynamic aids may be removed, replaced or added, with the following restrictions:

1. Except as OE, aerodynamic aids may not be adjustable while the vehicle is in motion.

Tires and wheels may be swapped with the following restrictions:

There are no restrictions at this time.

Brakes may be replaced or modified with the following restrictions:

A. Brakes must be functional and capable of stopping the car for the duration of any session.

1. Shock Absorbers
Shocks/Struts and their components may be swapped, modified or replaced with the following restrictions:

                        There are no restrictions at this time.

2. Suspension
Suspension components may be swapped, modified or replaced with the following restrictions:

A. Components may pass through any portion of the car with the exception of exterior body (unless OE).

3. Anti-sway (roll) bars
Anti-sway (roll) bars may be swapped, replaced or modified with the following restrictions:

                        There are no restrictions at this time.

Electrical components may be swapped, modified or replaced with the following restrictions:

There are no restrictions at this time.

Engines, drivetrains and all systems including cooling, intake, exhaust may be swapped with the following restrictions:

A. Non-electric engines must be internal combustion.

B. Vehicles may not be propelled, stopped or steered aided in grip by thrust.

C. Exhaust must exit from under the car.

In addition to fuels which are allowed by Sport and Tuner Categories, Unlimited Category may use any grade of gasoline, or federally-approved E85. Gasolines consist entirely of hydrocarbon compounds. Gasoline may contain antioxidants, metal deactivators, corrosion inhibitors, and lead alkyl compounds such as tetraethyl lead. Oxygen and/or nitrogen bearing additives are prohibited except for those originally present in fuel which is federally approved for use on public highways. Oxygen and/or nitrogen bearing oil additives are prohibited in two-cycle engine oiling systems.

Unlimited Category Classing

Unlimited is divided into two categories: Unlimited 1 (U1) and Unlimited 2 (U2). There is absolutely no guarantee of competitiveness for any vehicle in Unlimited Category, even though there will absolutely be a wide range of vehicle performance.

Unlimited Category Classing

Cars which are production silhouette, but are over the displacement limits or under the weight limits for Unlimited 2. (U2)

1. U1 minimum weight: None

Cars which are production silhouette and meet the following criteria:

1. U2 minimum weight:1,750 Lbs. (With Driver.)

2. U2 Maximum Displacement, 3.0 Liters corrected displacement.

To determine the corrected displacement for classing purposes, the following formulas will be used:

1. Rotary: Actual displacement X 2.0

2. 2-Cycle Engines: Actual displacement X 2.0

3. Forced induction: Actual or corrected displacement X 1.5

A. For each additional forced induction unit 0.5 should be added to the forced induction displacement modifier (e.g., twin charged, twin turbo: Actual corrected displacement X 2. Quad turbo: Actual displacement X 3).

If Regions run under National Events Classing, and include a non-production class for Unlimited Category vehicles, it is recommended that Regions run the suggested classes for Formula Cars, Sports Racers and Specials.

1. Time Trial Special (TTS)
For any open wheel, sports racer or other vehicle which doesn’t fit into any other class. Cars must meet safety requirements for SCCA HillClimb or GCR.

2. Time Trial Atlantic (TTA):
SCCA Road Race legal Formula Atlantic cars, Formula B/1000 cars, P1 and P2.

3. Time Trial Winged (TTW):
Time Trial Winged. SCCA Legal Formula Continental/F2000, Star Formula Mazda, Formula Enterprise, Sports 2000.

4. Time Trial Non-Winged (TTN):
SCCA Legal Formula F, Formula 500, Solo Vee, SRF3.

5. Time Trial V (TTV): TTV:
SCCA Legal Formula Vee, Formula First, SRF.