SCCA Time Trials

Max Category is a place for enthusiasts to maximize the street-worthy car of their dreams with minimal limits on engine, suspension and bodywork. Max Category vehicles must have all road-going equipment such as headlights, tail lights, blinkers and windshields/windscreens, if delivered with such. Other than specifically classed kit-cars which do not have headlights and such, Max Category vehicles must be able to be street driven.

Max Category is a restricted ruleset. If modifications are not specifically authorized in these Rules, it is not allowed. (If it doesn't say you can, you can’t.)

1. Vehicles running in Sport, Tuner 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 (4-points) may remove carpet, seats and trim (including convertible tops) behind the front seats. Vehicles that have an added roll cage (6-points) 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. Any replacement fuel cell should be constructed and installed to racing standards. (E.g., FIA/SFI approval, fuel cell enclosure, bladder, and foam baffling.)  

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

C. 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.

D. 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.

E. 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.

F. 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.)

Max Category is open to production cars and eligible kit cars using almost any automobile drivetrain and is meant to fit between the current Tuner and Unlimited Categories.

All of the general modification rules of Sport and Tuner Categories are allowed in Max.

Max 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.

Max 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.

The frame or unibody (from shock tower to shock tower or “ladder” frame) is sacrosanct. These must stay intact unless otherwise allowed in these Rules.

1. Body, frame and sheet metal (such as transmission tunnel) may be altered to the minimum extent required to allow engine swaps, transmission swaps and suspension modifications.

2. Subframes may be replaced or modified.

3. Vehicle perimeter and wheelbase must be full-scale to original model. Incidental wheelbase and overall dimension changes resulting from the allowed replacement of suspension components or modification of suspension design are allowed. This is not an allowance to shorten or lengthen the chassis/body (e.g., change the scale from the original).

1. Cosmetic interior components like panels, carpet and seats may be replaced (but not removed), as long as fire walls are retained and fumes are not vented into the cockpit. Panels may be added to insulate the driver from venting and exhaust. The driver’s normal seated position may not be relocated, unless it is a right-side drive conversion to match existing production cars.

2. Fuel tank/cell may be modified or replaced and must be separated from the driver/passengers as originally manufactured or by a metal panel/bulkhead if the OE structure is modified. If the fuel tank is moved from the OE location, it should be a motorsports-style fuel cell constructed of a housing, bladder and foam. Fuel must not vent into the driver/passenger compartment directly or indirectly.

3. As with Sport/Tuner Categories, there is a “safety loophole.” If you add a roll bar meeting Safety Level 2 Standards, you can remove carpet and trim (convertible tops included) from behind the driver and passenger seats and even replace an airbag-equipped steering wheel. If you install a full cage meeting Safety Level 3 Standards, you can remove all the trim and carpet other than the dash.

1. No portion of the vehicle or bodywork (other than exhaust/exhaust hangers) may be less than 3 inches from the ground.

2. Body panels may be modified or replaced in the original standard locations. Frame or Unibody may only be modified the minimal amount to account for allowed modifications. Subframes may be replaced or modified.

3. Body panels may be attached with removable fasteners (e.g., Dzus®).

4. “Side Skirts” sometimes referred to as “barge boards” may be added with the following restrictions:

A. No portion of the side skirts/barge boards may be less than 3 inches from the ground.

B. Horizontal portions of a side-skirt/barge-board may not extend more than 3-inches from OE bodywork when viewed from above.

C. They may not extend further than 12” inboard from the outer limits of OE bodywork.

5. Fenders and running boards may be removed from vehicles with a production year prior to 1946, as long as the removal of those parts does not expose the interior of the car or engine compartment.

Wings, wing endplates, spoilers, canards and splitters may be added, removed, or modified with the following restrictions.

1. Non-OE wings have the following restrictions: A rear wing may be added, removed, or modified with 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. The total surface area of rear wings shall not exceed 8.0 sq. ft. as calculated by multiplying the maximum chord by the maximum span. Definitions of the element (camber) and angle of attack when mounted on the vehicle will not affect the area measurement. The area for multiple element wings will be the sum of the individual areas of each of the elements.

D. The number of wing elements is limited to two (2).

E. Except for standard parts, wings designed to be adjustable while the car is in motion must be locked in a single position.

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

G. No portion of the wing or its components (including endplates and mounts) may be more than 6 inches (15.24 cm) forward of the rear axle, more than 6 inches (15.24 cm) beyond the rearmost portion of the bodywork, and have the following restrictions on height:

1. On sedans/coupes/trucks the wing may not be more than 10 inches (25.4 cm) above the roofline of the vehicle. For convertibles/roadsters with no roof and targas with no rear window, the windshield frame, or windshield of any material shall be considered the top of the roofline.

2. On hatchbacks/wagons/Sport Utility Vehicles, the wing may not be more than 14 inches (35.56 cm) above the roofline of the vehicle.

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

I. All commercially available wings, splitters, air dams, and diffusers that are vehicle model specific and installed per the manufacturer’s directions are permitted with the following exclusions:

*There are currently no excluded products

J. I. Aftermarket spoilers and aftermarketrear wings are mutually exclusive such that a builder may add 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.

A. 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 10 inches (254 mm) from the original bodywork in any direction. Alternatively, in a hatchback, the spoiler may be mounted to the rear hatch lid at or near the top of the hatch; in such a configuration the spoiler may extend no more than 4 inches (101.6 mm) from 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. Angle of attack is free. The spoiler may not function as a wing.

B. C. Aftermarket spoilers and aftermarket rear wings are mutually exclusive such that a builder may add one or the other, but not both.

3. Canards are allowed with the following restrictions.

A. Canards may extend a maximum of 4 inches (10.16 cm) forward of front bodywork/fascia as viewed from above. 

A. B. No portion of the canard may extend past the widest part of the front bodywork/fascia as viewed from above.Canards may not extend beyond the OE vehicle width as defined by the outermost portion of the OE bodywork including mirrors, door handles, rub strips and trim.

C. Canard area will be measured in the same manner as wings. Canard area may not exceed 1.2 square feet (1114.8 cm²).

D. Canards may have endplates. The endplates may not connect to a splitter.

E. Canards may not be within 3 inches of the splitter.

4. A front spoiler/air dam/splitter is permitted, with the following restrictions.

A. Splitter blade shall be flat and installed parallel to the ground (within ±3° fore and aft) and may extend a maximum of 5 inches (12.7 cm) from the front bodywork/fascia as viewed from above. Blade may include up to two contoured ramps with a maximum area of 84 sq inches each, as viewed from the bottom. A front splitter, air dam, spoiler, and vertical members (e.g., fences, endplates) may be added below the top of the bumper. Components may extend a maximum of 6.0” (152.4 mm) from the front bodywork/fascia as viewed from above.

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

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

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

C.E. OE (factory) front spoiler/splitters are permitted, and if mounted in the stock location, have no height restrictions.

5. Diffusers are allowed with the following restrictions:

A. May not extend forward past the vertical centerline of the rear wheels.

B. May not extend more than 6” from the rear bodywork, as viewed from above.

C. No part of the diffuser shall be lower than 3 inches from the ground.

C.D. OE (factory) front diffusers are permitted., and if mounted in the stock location, have no height restrictions.

All aerodynamic modifications are subject to technical and/or safety inspections by Event Officials.

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

Tires must meet the following requirements to be eligible for use in Max 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 January 1 are not eligible for Time Trials competition until after the Time Trials National Championships of the year.

1. Original Equipment (OE) Tires
OE DOT-Approved Tires may be run providing the following conditions are met:

A. The tire size and model is as delivered from the factory on that model and trim level car. (E.g., The 100UTQG GoodYear Eagle F1 Supercar 305/30ZR19 (Front) and 325/30ZR19 (Rear) on the 2018 Chevrolet Camaro ZL1 1LE.)

B. The car is not prepped beyond Sport Category rules. (The car does not have to be classed in Sport Category, but its modification may not be beyond those rules.)

C. 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.

There are no tires currently listed.

2. Aftermarket/Non-OE Tires

A. Specification

1. Minimum UTQG Treadwear Grade of 200.

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

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

4. US Department of Transportation (DOT) approval.

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

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

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

2. 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.

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

4. 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.

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

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

7. 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)

- Vitour Tempesta P1

3. Tire Use

A. Scored Sessions
Unless a “wet session” is declared by event officials, vehicles must run on the same set of tires for all scored 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 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.)

B. Unscored Sessions
Vehicles are required to practice on tires which are legal for scored sessions in their class, but do not have to be the same set.

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.

Components, lines, hoses and method of attachment are unrestricted.

Components, lines, hoses and method of attachment are unrestricted.

Components and method of attachment are unrestricted.

Intakes are unrestricted. Forced induction may be added.

Cooling systems for engine, transmissions and differentials are unrestricted.

1. Allowed Engine Modifications
Components (internal and external) may be modified or replaced, other than the following restrictions:

A. Engines must be derived from production automobiles. Motorcycle, snowmobile, marine or other engines of non-automobile design are not permitted.

B. The engine orientation and the general engine bay location must not be changed from OE. (E.g., Vehicles with transverse engines may only install an engine in a transverse orientation, vehicles with longitudinal engines may only install an engine in a longitudinal orientation, front-engine stays front-engine, rear/mid-engine stays rear/mid-engine.)

2. Engine Modification Definitions
The following criteria is how "modified" or "unmodified" engines are defined for Max Category classing criteria.

A. Modified Combustion Engine
The following criteria are used to define “modification” of an internal combustion engine: 

1. Modification or replacement of OE (or OE equivalent) head gasket, head bolts or parts in the valve train, or rotating assembly. (E.g., valve springs, lifters, rockers, camshaft(s), pistons, rods, crankshaft, balance shafts, rotors, etc.) This restriction does not include oil pumps or water pumps.

2. Modification or machining of the engine block, head or rotor-housing beyond factory shop-manual limits. 

3. As well as #1 and #2 above, modification or replacement of the following OE (or OE equivalent) parts of a forced-induction engine will be considered modified:

a. Turbocharger, including turbine wheel, turbine housing, compressor, compressor housing, intake manifold and any fastening hardware. 

i. Where a non-US market vehicle may not have come with specific emissions equipment (e.g., TGV) forced-induction engines may remove that equipment or, if the ability exists, replace it with a part which does not increase performance relative to the O.E. part. (e.g., TGV deletes which do not increase the diameter or length of the intake.)

b. Supercharger, including housing, phasing gear, rotors, intake manifold and any fastening hardware. 

B. Modified Electrical or Hybrid Engine
The following criteria are used to define “modification” of an electrical engine or hybrid drivetrain:

1. Increase in voltage output of electric motors by any means.

2. Change in number, type or discharge rate of OE batteries.

The transmission, differentials and transfer cases may be changed with the following restrictions:

1. The units must be from production-vehicles (no race-specific applications).

2. The internals of those cases may be modified or replaced, as long as it is not a dogbox or sequential conversion.

3. The reverse gear must be functional.

Exhaust is unrestricted other than it must exit from under the vehicle. It may exit through the bodywork.

1. Fuel System

Max Category vehicles fueling system components including injectors, lines and tanks are unrestricted provided they meet all safety rules. 

2. Allowed Fuel

1. 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.

For a PDF of the redlined version of the previous Max 1 rules, click here.

1. Max 1 eligible vehicles include production vehicles and eligible kit cars powered by the following OE engine displacement or KW-rated motor(s) and not weighing less than the corresponding minimum weight (with driver):

A. Naturally aspirated 4-cycle engines 3.0L and greater OE measured displacement: 2500lbs.

B. Naturally aspirated rotary or 2-cycle engines greater than 2.0L OE measured displacement: 2500lbs.

C. Unmodified single-unit forced-induction engines between 4.5L to 6.4L OE measured displacement: 3000lbs.

D. Modified, Unmodified, or added forced-induction engines up to 4.5L (4-cycle) or 1.5L (Rotary/2-Cycle) OE measured displacement: 2500lbs.

E. Electric vehicles with greater than 400KW OE rated motor(s): 2500lbs

2. Any vehicle underweight or built beyond above allowances goes to Unlimited. (I.e., any Modified FI motor above 4.5L, or any Forced Induction motor over 6.4L)

3. Max 1 eligible vehicles include the following low-production vehicles (less than 1,000 examples), and kit cars otherwise underweight for their indicated OE engine displacement and aspiration:

A. Vehicles which meet power, displacement and configurations for the classes below, not weighing less than 1600lbs (with driver).

For a PDF of the redlined version of the previous Max 2 rules, click here.

1.Max 2 eligible vehicles include production vehicles of more than 1,000 examples and eligible kit cars powered by the following OE engine displacement or KW-rated motor(s) and not weighing less than the corresponding minimum weight (with driver):

A. Modified naturally aspirated 4-cycle engines of up to 6.4L OE measured displacement: 3300lbs.

B. Unmodified naturally aspirated rotary or 2-cycle engines of up to 2.0L OE measured displacement: 2800lbs.

C. Unmodified single-unit forced induction 4-cycle engines between 4.5L to 6.4L OE measured displacement: 3800lbs

D. Unmodified, Modified, or added, forced induction 4-cycle engines between 1.9x to 2.9L OE measured displacement: 2700lbs.  

E. Modified or added forced induction engines up to 1.9L: 2350lbs.

F.  Unmodified, Modified, or added forced induction Rotary engines up to 1.5L: 2800lbs.

G. Electric vehicles with unmodified OE batteries and up to 400 KW OE rated motor(s): 3000lbs.

H. Electric vehicles with modified/replaced batteries or modified motor(s) up to 250 KW of OE rated motor(s) 3000lbs.

2.  All Max 2 eligible cars underweight go to Max 1 up to the Max 1 minimum weights. Lighter than that, welcome to Unlimited!

For a PDF of the redlined version of the previous Max 3 rules, click here.

1.  Max 3 eligible vehicles include production vehicles of more than 1,000 examples and eligible kit cars powered by the following OE engine displacement and not weighing less than the corresponding minimum weight (with driver):

A. Unmodified naturally aspirated 4-cycle engines of up to 6.4L OE measured displacement: 3800lbs.

2.  All Max 3 eligible cars underweight by up to 800lbs go to Max 2.

For a PDF of the redlined version of the previous version of the Max 4 rules, click here

1. Max 4 eligible vehicles include production vehicles of more than 1,000 examples and eligible kit cars powered by the following OE engine displacement or KW-rated motor(s) and not weighing less than the corresponding minimum weight (with driver):

A. Unmodified naturally aspirated 4-cycle engines between 3.7x and 4.5L OE measured displacement: 3000lbs.

B. Unmodified naturally aspirated 4-cycle engines between 3.0x and 3.7L OE measured displacement: 2700lbs.

C. Modified naturally aspirated rotary or 2-cycle engines of up to 1.5L OE measured displacement: 2700lbs.

D. Modified naturally aspirated 4-cycle between 1.9x and 2.9L OE measured displacement: 2700lbs.

E. Unmodified single-unit forced induction 4-cylinder, 4-cycle engines between 1.9x and 2.46L OE measured displacement: 3000lbs.

F.  Unmodified single-unit forced induction 3-cylinder, 4-cycle engines between 1.5x and 1.9L OE measured displacement: 3000lbs.

G. Electric vehicles with unmodified OE batteries and up to 250 KW of OE rated motor(s): 2800lbs.

H. Electric vehicles with modified/replaced batteries or modified motor(s) up to 175 KW OE rated motor(s) limit: 2800lbs.

2.All Max 4 eligible cars underweight by up to 300lbs go to Max 2. 

For a PDF of the redlined version of the previous Max 5 rules, click here

1. Max 5 eligible vehicles include production vehicles of more than 1,000 examples and eligible kit cars powered by the following OE engine displacement or KW-rated motor(s) and not weighing less than the corresponding minimum weight (with driver):

A. Unmodified naturally aspirated USDM 4-cycle engines between 1.9x and 3.0L OE measured displacement 2550lbs.

B. Modified naturally aspirated 4-cycle engines of up to 1.9L OE measured displacement: 2200lbs.

C. Unmodified naturally aspirated 4-cycle engines of up to 1.9L OE measured displacement: 1900lbs.

D. Unmodified naturally aspirated rotary or 2-cycle engines of up to 1.25L 1.5L OE measured displacement: 2550lbs.

E. Unmodified single-unit forced induction 4-cylinder, 4-cycle engines of up to 1.9L OE measured displacement: 2650lbs.

F. Electric vehicles with unmodified OE batteries and up to 100KW 175KW of OE rated motor(s): 2550lbs.

2. All Max 5 eligible cars underweight by up to 300lbs go to Max 4. Lighter than that, welcome to Unlimited.

The following kit cars are eligible for Max Category:

1. Shelby Cobra Models

2. Shelby Daytona Coupe Models

3. Corvette 1963 Grand Sport Models

4. Ariel Atom

5. Exocet

6. Noble M400/M12 and Rossion Q1

7. Brunton Auto - Stalker

8. Factory Five 818/818C

9. DF Kit Car Goblin