RULES - NATIONAL COMPETITION RULES - PREPPED CATEGORY - PREPPED CATEGORY FULL RULES

PREPPED CATEGORY

These are the vehicle preparation rules for the Prepped Category of SCCA National Time Trials Competition. They are broken down into an Overview and then the "Authorized Modifications" (i.e., what you can do to your car and have it stay in Prepped Category).

Prepped Category, along with Sport, Tuner and Max are restricted rulesets. If a modification is not specifically authorized in these Rules, it is not allowed. (If it doesn't say you can, you can’t.)

1. Overview

1. Philosophy

Prepped Category is meant for street-drivable vehicles between Tuner and Max categories, with common OE engine swaps or aftermarket forced induction or camshafts. Vehicles in this Category may also install mild aero modifications and simple engine bolt-on parts.

2. Safety

1. Vehicles running in Sport, Tuner, Prepped and Max Categories must meet Safety Level 1 Standards.

A. Roll bars, cages, racing harnesses and other safety equipment may be added, and must meet manufacturers' guidelines for installation. It is highly recommended that they at least meet the minimum for Safety Level 2 or Safety Level 3 Standards.

B. Nothing in the rules prevents you from adding safety equipment; the minimum amount of modification to install safety equipment is allowed.

C. To facilitate safety, vehicles that have an added roll bar may remove carpet, seats and trim (including convertible tops) behind the front seats. Vehicles that have an added roll cage may remove carpet, seats and trim (including convertible tops) other than the dash.


2. Fuel cells may be used in cars with the following restrictions and allowances:

A. OE lines may be replaced in conjunction with a fuel cell provided they are shielded.

B. Any fuel lines—including gauge and vent lines—that pass into or through the driver/passenger compartment, shall be of steel tube or metal braided hoses or bulkheaded.

C. Drivers of cars with modified or replaced OE fuel lines or tanks must wear a suit, shoes, gloves and underwear as specified in SCCA Time Trials Safety Level 2 Standards.

D. Vehicles with modified or replaced OE fuel lines or tanks must have an on-board fire suppression (fire bottle or system) meeting SCCA Time Trials Safety Level 2 Standards.

E. Participants are cautioned that this is not an allowance to maximize fuel delivery by installing higher-performance parts than authorized by category rules. (E.g., installing an upgraded fuel pump if it's not otherwise allowed.)

3. Vehicle Eligibility

1. To be eligible for Prepped Category:

A. A minimum of 1,000 of that model must have been produced that model year for road use.

B. The vehicle must be capable of being licensed for normal road use in and delivered through the manufacturer's retail sales outlets.

4. General Rules

The following items are guidelines for modifications in Prepped Category:

A. Prepped Category builds on Sport and Tuner Rules—all of the general modification rules of Sport and Tuner Categories are allowed in Prepped Category.

B. Prepped Category vehicles are likely to be street-driven cars, and SCCA does not encourage or condone the breaking of laws governing pollution control systems or the alteration of street-driven vehicles contrary to state and federal laws regarding their use. It continues to be the responsibility of the individual to comply with such state and federal laws.

2. Interior, Chassis, Bodywork and Aerodynamic Aids

1. Interior

Everything legal in Sport and Tuner Categories, plus the items below.

1. Interior parts may be swapped with alternate market parts (JDM, EDM, etc.).

2. Chassis

1. Subframes may be modified the minimum amount to enable legal modifications in this section. Competitors are cautioned that modification is not replacement, and suspension geometry should not be modified beyond what is listed in this section.

3. Bodywork

Everything legal in Sport and Tuner Categories, plus the items below:

1. Hoods, fenders and bumpers may be replaced with OE parts and exact replicas from markets other than North America (E.g., JDM, Euro-spec parts).

2. Hoods and decklids may be replaced with replicas including those made of alternate material. Replacement pieces must retain any OEM lights and must be able to use OEM hinges and latching mechanisms as standard.

3. Hoods may have vents installed for cooling purposes. The maximum combined total area of all vents (including OEM) shall not exceed 200 square inches. The 200 square inches includes any area that deviates from the factory hood profile.

4. Hardtops may be replaced with replicas of alternate material. Replacement pieces must be able to use OEM hinges and latching mechanisms as standard.

5. Bumpers may be trimmed or cut for fitment or aerodynamics.

6. Fenders may be flared, or cosmetic over-fender flares may be added. OE fenders may be trimmed or cut to facilitate the additions. Flared fenders may not be trimmed or cut for drag reduction. Fenders must taper into the OE bodywork.

4. Aero

Wings, spoilers, splitters and air-dams may be added, removed, or modified with the following restrictions:

1. Non-OE wings have the following restrictions:

A. May not be added in addition to an OE wing.

B. Only one wing may be added.

C. May only be attached behind the centerline of the rear axle and may not attach to suspension components.

D. The total combined surface area of all wings shall not exceed 5.75 square feet (0.5341 m2) as calculated.

E. The number of wing elements is limited to one (1).

F. Wings designed to be adjustable while the car is in motion must be locked in a single position.

G. Wings—and any component thereof—may not extend beyond the vehicle width as defined by the outermost portion of the bodywork including OE mirrors, door handles, rub strips and trim.

H. No portion of the wing or its components (including end plates and mounts) may be more than 6 inches (15.24 cm) forward of the rear axle, more than 6 inches (152.4 mm) beyond the rearmost portion of the bodywork, or more than 6 inches (15.24 cm) above the roofline of the vehicle, regardless of body style.

I. Reinforcements to the wing mounting area may be used but may serve no other purpose.

J. Wing endplate surface area is limited to 165 square inches (1064.51 cm2) each and the number of endplates is limited to a maximum of two (2).

K. For convertibles/roadsters with no roof, and targa tops with no rear window, no portion of the wing may be higher than 12 inches (30.48 cm) above the wing’s point of attachment to the body of the vehicle.

L. For convertibles/roadsters with no roof and targa tops with no rear window that retain the OE windshield frame, a windshield of any material that meets the top of the windshield frame shall be considered the top of the roofline, and the car may use the wing mounting rules for a closed car.

M. Spoilers and rear wings are mutually exclusive such that a builder may use one or the other, but not both.

2. A spoiler may be added to the rear of the car provided it complies with the following:

A. It is a production rear spoiler which is standard or optional equipment of a US model of the vehicle or an exact replica in an alternate material.

B. It is a non-production rear spoiler which is mounted to the rearmost portion of the rear hatch, deck or trunk lid. The spoiler may extend no more than 8 inches (203.2 mm) from the original bodywork in any direction. Alternatively, on a hatchback, the spoiler may be mounted to the rear hatch lid at or near the top of the hatch; however, in such a configuration the spoiler may not extend more than the original bodywork in any direction. The spoiler shall not protrude beyond the perimeter of the original bodywork as viewed from above. The use of endplates is prohibited. The angle of attack is free. The spoiler may not function as a wing.

C. Spoilers and rear wings are mutually exclusive such that a builder may use one or the other, but not both.

3. A front spoiler/splitter is permitted, with the following restrictions.

A. Splitter blade shall be installed parallel to the ground (within ±3° fore and aft) and may extend a maximum of 3 inches (7.62 cm) forward of the front bodywork/fascia as viewed from above.

B. No part of the front spoiler shall be lower than 3 inches from the ground.

C. Splitters may not extend rearward past the vertical centerline of the front wheels.

D. No portion of the splitter may extend beyond the widest part of the front bodywork including the top of the wheel arch or further than 3 inches from the edge of the bumper—whichever is less.

E. Openings in the front spoiler are permitted for the purposes of ducting air to the brakes, cooler, and radiator.

F. OE (factory) front spoiler/air dam systems are permitted, and if mounted in the stock location, have no height restrictions.

3. Wheels, Tires and Brakes

1. Wheels

Any width or diameter wheel and wheel spacers may be used provided it complies with the following:

1. Non-metallic wheels must be certified/approved from an appropriate, recognized standards organization. (E.g., FIA, SFI, SAE, TUV, etc.)

2. Wheel spacers are permitted.

3. Wheel studs, lug nuts, valve stems (including pressure-relief types) and/or bolt length may be changed. Wheel bolts may be replaced with studs and nuts, but the number of fasteners may not be changed.

4. Tire pressure monitoring sensors may be removed.

5. Centerlock/spline drive/knock-off type hubs may be converted to lug-type hubs.

2. Tires

Tires must meet the following requirements to be eligible for use in Prepped Category. No tire model will be eligible for Time Trials competition until it meets all requirements of this section. Tire models not meeting the requirements by April 30 are not eligible for Time Trials competition until after the Time Trials Nationals of the year.

1. Specification

A. Minimum UTQG Treadwear Grade of 200.

B. Minimum molded tread depth of 7/32 inch as specified by the manufacturer.

C. Listed in a current year or prior two years of the “Tire Guide®” and/or the “Tread Design Guide®” (www.tireguides.com).

D. US Department of Transportation (DOT) approval.

E. Tires must be designed for highway use on passenger cars.

2. Eligibility Requirements:
The following are prerequisites before a tire can be used in competition at Time Trials Events.

A. Tire availability: Tires are considered available when competitors can take possession through retail channels. Pre-orders are not considered available.

B. Tires must be equally available to all competitors. Tires that are in short supply do not specifically violate this section. Extensive shortages may result in the tire being placed on the exclusion list until supply is replenished. Tire variations differing from standard specification, delivered only on a limited basis, or only to selected competitors may not be used.

C. Tire models must have tires available in at least four (4) rim diameters and in at least six (6) sizes which meet these requirements.

D. Material Change: Tires which previously met the eligibility requirements that undergo a significant compound change, tread pattern change, or other significant redesign reset the requirement for eligibility described in this section.

E. A tire model which was previously allowed by these rules continues to be eligible for competition until specifically disallowed.

F. Reintroduction: Models that were once discontinued will be considered a new model once reintroduced and must meet all the requirements of this section.


3. Tire Use
Unless a “wet session” is declared by event officials, vehicles must run on the same set of tires for all competition rounds, and the tires should be marked with a stamp on grid of the first competition. Tires may also be replaced at the discretion of the Technical Chief in cases of safety issues such as damage or excessive wear. (Entrants are warned that damage caused by deliberate abusive handling or deliberate shaving should not be given a replacement allowance.)


4. Other

A. Tires may be shaved evenly and parallel to the axis of rotation, but may not otherwise be siped, grooved or modified.

B. Tires must have a minimum tread depth of 2/32nds at two (2) points 180 degrees apart.

C. No recap and/or retread tires may be used.

D. Excluded tires: Tires may be excluded for, but not limited to, low volume production, extensive availability limitations and specialty design.

E. The tire must not appear on the following exclusion list, which may be altered at any time by the Time Trials Board (TTB) upon notification of membership.

- Kumho V720 ACR (less than minimum molded tread depth)

3. Brakes

Brakes may be modified or changed within the guidelines of Sport and Tuner Categories, plus the allowances below:

1. Proportioning valves may be added.

4. Steering and Suspension

1. Steering

Proposed Category vehicles may have any modifications allowed in Sport or Tuner Categories, plus the allowances below: 

1. Right-side-drive conversions to left-side-drive vehicles may be performed and vice-versa, provided that: the vehicle was delivered in retail sales locations, the converted configuration is OE, and the conversion is done with OE parts for the vehicle.

2. Shocks and Struts

1. Shocks and Strut Replacement Allowances:

A. Any shock absorbers may be used.

B. Shock absorber mounting brackets which serve no other purpose may be altered, added, or replaced, provided that the attachment points on the body/frame/subframe/chassis/suspension member are not altered. This installation may incorporate an alternate upper spring perch/seat and/or mounting block (bearing mount). The system of attachment may be changed.

C. The number of shock absorbers shall be the same as standard.

D. No shock absorber may be capable of adjustment while the car is in motion, unless fitted as original equipment.

E. MacPherson strut equipped cars may substitute struts and/or may use any insert. This does not allow unauthorized changes in suspension geometry or changes in attachment points (e.g., affecting the position of the lower ball joint or spindle). It is intended to allow the strut length changes needed to accommodate permitted modifications which affect ride height and suspension travel.

2. The following additional allowances apply to cars originally equipped with separate spring and shock absorber assemblies.

A. Coil springs may be relocated so they encircle the body of the shock absorber in a “coilover” configuration.

B. Coil spring perches may be modified, added, or replaced and their position may be adjustable.

C. Additional bolt holes may be drilled for coilover assembly mounting brackets. This does not permit any modifications to the frame or unibody beyond the allowed mounting holes.

3. Springs

Springs must be of the same type as the original (e.g., coil, leaf, torsion bar, bellows) and except as noted herein, must use the original spring attachment points. This permits multiple springs, if they use the original mount locations. Coil spring perches originally attached to struts or shock absorber bodies may be changed or altered and their position may be adjustable. Spacers are allowed above or below the spring. Coil springs may incorporate spring rubbers. Suspension bump stops may be altered or removed.

4. Anti-Roll (Sway) Bars

Substitution or removal of sway bars (at one or both ends of the car) and supporting hardware (brackets, end links, bushings, etc.) is permitted. Tow hooks may be removed for the instillation of sway bars.

5. Strut Braces

Strut bars are permitted with all types of suspension, subject to the following constraints:

1. Strut bars may be added, removed, modified or substituted.

2. Lower suspension braces must be attached to the lower suspension pickup point locations on the chassis within 2 inches (50.8mm) in any direction of the actual suspension attachment to the chassis.

3. Except for standard parts, no connections to other components are permitted. Additional holes may be drilled for mounting bolts. Only “bolt-on” attachment is permitted. Interior trim panels may be modified to allow installation of strut bars. Holes or slots may be no larger than necessary and may serve no other purpose. This does not permit any modifications to the frame or unibody beyond the allowed mounting holes.

6. Suspension

Prepped Category vehicles may have any modification allowed in Sport or Tuner Categories, plus the allowances below:

1. Ball Joint Extenders/Bump Steer Adjustment

A. Parts which bolt directly to OE parts may be installed.

2. Control Arms/Camber Adjustment

A. Control Arms
Control arms for vehicles that have integral bushing/arm assemblies may be replaced subject to the following restrictions:

i. The replacement arms must attach in the original standard mounting points. All bushings must meet the requirements of this section. Intermediate mounting points (e.g., shock/spring mounts) may not be moved or relocated on the arm. The knuckle/bearing housing/spindle assembly cannot be modified or replaced.

ii. The replacement arm length must be the same as OE.

iii. The replacement arm may not be adjustable unless it meets the restrictions for camber kits as outlined below.

iv. The bushings of the replacement arms may not be spherical.

B. Camber kits (also known as camber compensators) may be installed. These kits consist of either adjustable length arms or arm mounts (including ball joints) that provide a lateral adjustment to the effective length of a control arm. Alignment outside the factory specifications is allowed. The following restrictions apply:

i. On double/unequal arm (e.g., wishbone, multi-link) suspensions, only the upper arms OR lower arms may be adjustable, but not both. Non-integral longitudinal arms that primarily control fore/aft wheel movement (e.g., trailing arm(s) or link(s) of a multi-link suspension) may not be replaced, changed or modified.

ii. On arm-and-strut (MacPherson/Chapman) suspensions, the lower arms may be adjustable OR other methods of camber adjustment as allowed by the previous sections may be used, but NOT both.

C. Leaf spring cars may be converted to a coilover design.

7. Sub Frame Connectors

Longitudinal (fore-aft) subframe connectors (SFCs) are permitted with the following restrictions:

1. They must only connect previously unconnected boxed frame rails on unibody vehicles.

2. Each SFC must attach at no more than three (3) points on the unibody (e.g., front, rear, and one point in between such as a seat mount brace or rocker box brace).

3. SFCs must be bolted in place and not welded.

4. No cutting of OE subframes or floorpan stampings is permitted. Drilling is permitted for mounting bolts only.

5. No cross-car/lateral/triangulated connections directly between the driver’s side and passenger’s side SFCs are permitted. Connections to OE components such as tunnel braces or closure panels via bolts are allowed and count as the third point of attachment. No alteration to the OE components is permitted.

6. SFCs may not be used to attach other components (including but not limited to torque arm front mounts or driveshaft loops) and may serve no other purpose.

5. Electrical

1. Electrical

Prepped Category vehicles may have any modification allowed in Sport or Tuner, plus the allowances below:

1. Wiring harnesses may be replaced or modified in order to accommodate further allowances in these rules.

2. Coil packs and other engine electrical accessories (e.g., sensors) may be swapped to accommodate further allowances within these rules.

6. Engine and Drivetrain

1. Engine Control/ECU/Electronics

1. Engine Control/ECU/Electronics

A. Engine Control/ECU may be replaced or modified without restriction.

B. Distributers may be replaced by alternate same-manufacturer OE units.

2. Intake

Competitors may perform any Sport- or Tuner-legal intake modification, plus the allowances or restrictions below, based on engine options listed further down.

1. Vehicles with their OE naturally-aspirated engines may have replaced or modified any part of the intake manifold and throttle body.

2. Vehicles with their OE force-induction engines must keep their OE intake manifold turbo and throttle body.

3. Vehicles with a swapped naturally-aspirated engine may use either the OE intake manifold and throttle body, or the intake manifold and throttle body from the donor engine.

A. Minor modifications for fitment are allowed, provided the modifications serve no other purpose. 

4. Vehicles receiving a forced-induction engine must retain the OE intake manifold, turbo and throttle body from the donor engine.

5. Vehicles receiving a naturally-aspirated engine in place of a forced-induction engine must keep the intake manifold and throttle body from the donor engine.

3. Cooling

Prepped Category vehicles may have any modification allowed in Sport and Tuner, plus those listed below.

There are no further allowances at this time.

4. Engine Rebuilds/Service Limits

1. Engine Service Limits

A. Engines may be rebored to the manufacturer’s first standard overbore, not to exceed 0.020 inch (0.508 mm). Sleeving is allowed to repair to the standard bore. Only OE-type standard or first overbore pistons of the same configuration and of the same or greater weights are permitted. No interchange between cast and forged pistons is allowed.

B. Valve seats and guides in older engines originally designed for leaded fuel may be only substituted with alternate components if the dimensions are the same as those of the standard components.

5. Engine Swaps/Engine Modifications

There are three “either-or” options for engine modification. Engines may either be swapped or competitors may replace/modify items from the “ports out” plus replace the camshaft(s), or may add aftermarket forced induction, but may only pick one.

1. Option 1: Engines—including swapping OE Forced-induction engines for naturally aspirated and vice-versa—may be replaced with the following restrictions:

A. The engine must be from a production car of the same manufacturer, and that engine must have been produced and delivered in at least 2,500 vehicles per calendar year in any single market (USDM, JDM, EDM).

B. The “long block” (i.e., head and block) must be a matched OE pair.

C. Naturally-aspirated engines swapping for naturally-aspirated engines may use the intake manifold and throttle body from either the OE engine or the swapped engine. Minor modifications for fitment are allowed, provided the modifications serve no other purpose.

D. Vehicles receiving a forced-induction engine must retain the OE intake manifold, turbo and throttle body from the donor engine.

E. Vehicles receiving a naturally-aspirated engine in place of a forced-induction engine must retain the OE intake manifold from the donor engine.

F. An engine swap may not be performed on any vehicle taking advantage of Options 2 or 3, nor may items from Options 2 and 3 be performed on a swapped engine.

2. Option 2: Vehicles that keep their OE engine may take advantage of the following allowances:

A. On OE naturally-aspirated engines, items from the “ports out” plus camshafts may be replaced with the following restrictions:

1. Intake manifold, carburetors and throttle-bodies may be modified or replaced.

2. Camshafts may be replaced or modified, but cam gears may not be swapped.

B. On forced-Induction OE engines, components of the system may be modified or replaced with the following restrictions:

1. The OE intake manifold, throttle body, and supercharger or turbochargers may not be modified or replaced.

C. These allowances may not be performed on any vehicle taking advantage or Options 1 or 3.

3. Option 3: Aftermarket forced induction may be added and fuel injectors may be changed on an OE naturally-aspirated engine with the following restrictions:

A. Only a single unit may be added. (E.g., a single turbo or single supercharger; multi-turbo or twin-charged systems are prohibited.)

B. Aftermarket forced induction may not be added to any vehicle taking advantage of Option 1 or 2.

6. Transmissions/Differentials/Transfer Cases

1. Transmissions and drive-gear may be replaced as part of an engine swap, with the
following restrictions:

A. The transmission/differential/drivetrain components must meet category rules otherwise.

B. The transmission/differential/components of the drivetrain must have been packaged with the original car, or the car supplying the donor engine. Further mixing and matching of different models, option packages or trim level is prohibited.

2. Clutches may be replaced with those of different design.

3. Flywheels may be replaced with those of non-OE material.

7. Exhaust

1. Exhaust manifolds, headers, downpipes, catalytic converters and any associated EGR tubes may be replaced with alternate units. Exhaust exit may be relocated provided it meets safety requirements. Relocation of the oxygen sensor is permitted. Exhaust heat shields which cover only, and attach solely to, these parts may also be replaced, removed or modified. All other exhaust heat shields may be modified the minimum amount necessary to accommodate allowed alternate exhaust components. Mounting brackets/hardware which serve no other purpose are considered part of the exhaust components.

Note: The SCCA does not encourage or condone the breaking of laws governing pollution control systems or the alteration of street-driven vehicles contrary to state and Federal laws regarding their use. It continues to be the responsibility of the individual to comply with such state and federal laws.

8. Oil/Lubrication

1. Oil Pans may be replaced, and minor modifications to facilitate replacement may be performed as long as the modification serves no other purpose (e.g., removing the balance shaft or swapping an oil pickup because it won’t clear the new pan).

7. Other

1. Out of Production Vehicles

Where a car is out of production and the manufacturer is either out of business, stocks no parts or no longer has a required part, a part of any origin but as similar as possible to the original may be substituted.

1. The entrant must be prepared to show documentary evidence that one of the three circumstances above applies and that the substituted part is as similar as possible under the circumstances.

2. Substitute parts which provide improvements in performance (e.g., superior gearing, lighter weight, better camshaft profile, etc.) are not permitted under this allowance.

8. Fuel

1. Prepped and Max Category Allowed Fuel

1. Prepped and Max Category vehicles will use fuel which is “Federally approved for use on public highways.” This does not allow racing-type fuels which are available at service station pumps.The use of E85 is not restricted.

2. Propane or Compressed Natural Gas (CNG) fuel may be used in any category provided that the following conditions are met:

A. The tank must be located in a safe location on the car and be firmly and securely mounted. This does not permit the cutting of vehicle sheet metal (e.g., the trunk floor) for tank installation.

B. The tank must conform to Federal and local container standards and have an emergency relief/cut-off control.

C. For use of propane or CNG as a fuel, no changes to the induction system of the engine may be made with the exception of the necessary fuel lines to the carburetor or fuel injection. There may also be no other engine parts changed.

D. The entire system must meet local ordinances covering the use and transmission of compressed gas.

E. Propane or CNG may not be used in combination with another fuel.

9. Classing

1. Alternate Motorsports Series Classing

This is where we're going to class cars that might not quite meet the rules, but we think they can go in this category anyway.

1. Cars listed as eligible in and prepared to the SCCA Road Race Improved Touring National Rules are permitted to compete in their respective Time Trials Prepped Class, provided they run on tires legal for Time Trials. Vehicles with this allowance are not permitted to interchange preparation rules otherwise.

A. Improved Touring cars are not limited to the spec wheel sizes.

B. Regional-only Improved Touring cars—e.g., "ITE"—do not fall under this allowance.

2. Prepped 1 (P1)

Prepped 1 (P1) eligible vehicles include:

1. Naturally-aspirated vehicles with an engine displacement of no more than 6.5L, not weighing less than 3,000 lbs. (with driver).

2. Forced-induction vehicles with an engine displacement of no more than 4.334L, not weighing less than 3,000 lbs. (with driver).

3. Naturally-aspirated vehicles with an engine displacement between 2.995 and 3.9L which weigh less than 2,600 lbs. (with driver).

4. Forced-induction vehicles with an engine displacement between 1.997 and 2.6L which weigh less than 2,600 lbs. (with driver).

3. Prepped 2 (P2)

Prepped 2 (P2) eligible vehicles include:

1. Vehicles with a real or corrected displacement of no more than 3.9L, not weighing less than 2,600 lbs. (with driver).

2. Vehicles with a real or corrected displacement between 1.995 and 2.995L which weigh less than 2,200 lbs. (with driver).

4. Prepped 3 (P3)

Prepped 3 (P3) eligible vehicles include:

1. Vehicles with a real or corrected displacement of no more than 2.995L, not weighing less than 2,200 lbs. (with driver).

2. Vehicles with a real or corrected displacement of 1.995L or less which weigh less than 1,900 lbs. (with driver).

5. Prepped 4 (P4)

Prepped 4 (P4) eligible vehicles include:

1. Vehicles with a real or corrected displacement of no more than 1.995L, not weighing less than 1,900 lbs. (with driver).

6. Prepped, Max and Unlimited Displacement Modifiers

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).