Official 2017 THS Rules (amendment 3.16.18)

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Slow91z Helper
Staff member
Aug 7, 2003
2014 Turbo Hot Street Rules


  1. THS will be run with a “heads-up” .400 pro tree start and off of a pro ladder.
  2. No peer technical inspections relating to safety equipment rules by class participants or peers. The track safety personnel will make all final rulings on safety related items.
  3. Any vehicle is subject to being re-weighed and re-inspected (tech) immediately after the final round of eliminations or any other time deemed necessary by the Race Rules Administrator (RRA).
  4. Any entrant caught deliberately breaking the rules or deliberately attempting to break the rules or breeches that violate the spirit of competition will be disqualified from THS.
  5. All cars must enter the staging lanes under their own power.
  6. All rules subject to revision at the end of the race season.
Chassis & Exterior
  1. Lights, horn and windshield wipers must be operational.
  2. Aftermarket fiberglass or carbon fiber bumpers, bumper filler panels, Stock Appearing Hood, and Deck Lid are allowed
  3. MINIMUM vehicle weight including the driver MUST be at least 3550-pounds
  4. Complete stock and painted T-Type, Turbo Regal, Grand National or 1989 Pontiac Turbo Trans Am body required.
  5. No fiberglass or carbon fiber body parts (or any other material besides metal) unless otherwise specified.
  6. Stock wheelbase is required.
  7. The engine and the firewall must be in the stock location.
  8. Stock operable door glass windows, glass quarter windows (where applicable), glass front and rear windshields are required. No lexan.
  9. Factory stock suspension locations required with any type stock location shock absorbers.
  10. Any suspension stabilizer/ reinforcement bars or traction enhancing devices are allowed.
  11. Sway bars may be removed.
  12. No ladder bars or coil-over equipped rear suspensions.
  13. No coil-over equipped front suspensions.
  14. Stock style coil springs required.
  15. Outer frame rail notching is allowed. Inner frame rails must remain in the stock location.
  16. Reinforcement at the inner rear frame rail is allowed.
  17. No quarter panel modifications except rolled inner lips.
  18. Minor modifications to the stock rear wheel wells allowed but no mini tubs.
  19. Stock rear wheel wells can be “stretched” by adding material, but the majority of the tub material must be stock.
  20. Factory stock appearing front inner wheel wells required. Trimming for downpipe clearance is allowed.
  21. No wheelie bars.
  22. The brake system must be Power Master, Hydroboost, vacuum boosted, or manual brakes allowed.
  23. A brake system line-lock is allowed.
  24. The driver’s name on the side window is allowed. Sponsor or vendor decal(s) are acceptable on the rear window and rear quarter glass windows (where applicable).
  25. A maximum of two (2) hood mounted gauges are allowed.
  26. The Turbo Trans Am must use the factory production stock K-member.
  1. Any production Buick V6 engine that was available from the factory in a passenger vehicle is allowed.
  2. No Stage 1 or 2 iron or aluminum heads or engines are allowed.
  3. Any type of valve covers and oil pan is allowed.
  4. The factory stock intake manifold or cast intake manifold (i.e. Champion or BG Customs) are allowed. External welding, cold epoxy welding or puttying for performance enhancement is not allowed (to be determined by RRA of that race.) An EGR block-off plate is allowed.
  5. The factory coil pack bracket and right windshield wiper rod may be modified for clearance IF using an aftermarket cast intake manifold.
  6. The factory stock plenum with a spacer or aftermarket cast aluminum intake plenum is allowed.
  7. Any size single modified stock or aftermarket throttle body is allowed. Only a single throttle plate is allowed.
  8. Any type stock location exhaust headers are allowed. EGT guage probe bungs that are welded into the headers are allowed.
  9. **Any single or dual exhaust system (4” diameter max for either) is allowed. Systems used must be muffled and exit in the stock location(s). A closed (muffled) exhaust must be used during eliminations and qualifications. ((2018 Amendment 3.16.18))
  10. Any diameter downpipe size (from the turbo) is allowed. The downpipe must be routed through the stock location. No flex pipe is allowed.
  1. All turbochargers, including billet wheel turbochargers, meeting the below listed specifications available prior to January 1st of 2017 are allowed.
  2. One (1) 3-bolt turbo mounted and oriented in the factory stock position is allowed.
  3. The largest turbo compressor available up to and including 67mm is allowed. The maximum opening size anywhere on the compressor housing inducer must be less than 68.5mm. One (1) single compressor opening only is allowed. No internal ported shrouds are allowed.
  4. The compressor housing must have a three (3) inch INLET and a two (2) inch OUTLET (i.e. 3” x 2”).
  5. The turbine housing must be a 3-bolt housing that was commercially available on or before January 1st of 2017. The factory stock appearing turbine exhaust to downpipe connection must be used.
  6. Any wastegate configuration is acceptable
  1. Any stock location or front mounted air-to-air intercooler is allowed.
  2. A front mounted intercooler may not extend below the bottom of the stock located radiator support. This does not apply to the front mounted intercooler piping.
  3. No liquid intercoolers, intercooler external spray cooling or add-on cold boxes are allowed.
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Engine Management & Fuel System
  1. A stock or modified stock ECM or an aftermarket engine management system (i.e. FAST XFI, Accel DFI, MoTec, etcetera) is allowed.
  2. A factory stock appearing (Type I or Type II) DIS cam position sensor is required.
  3. Individual coil-per-sparkplug type ignitions are allowed.
  4. No distributor ignitions are allowed.
  5. Any air induction system is allowed but no hood scoops.
  6. Any type of fuel pump(s), pump(s) configuration and location(s) are allowed.
  7. Voltage increasing and fuel pump “hot wiring” devices are allowed.
  8. Factory stock or aftermarket fuel rails are allowed. Modification to rails (either type) is allowed.
  9. Any type of fuel pressure regulator is allowed. Any fuel injectors are allowed up to a maximum of seven (7) injectors. The seventh (7th) injector MUST get its fuel supply from the fuel rails.
  10. Factory stock fuel tank required, a sump addition is allowed. Factory tank must be installed in stock location
  11. Fuel Pump and Fuel Filters cannot be visible from the exterior of the vehicle.
  12. Alcohol injection is allowed. It must enter the engine through the “up-pipe” of the air intake system.
  13. Gasoline fuel only is allowed. E85 is ok
  14. The use of nitrous oxide is NOT allowed.
Engine Compartment
  1. The power steering must be operational, with the belt, in the stock location.
  2. The stock alternator must be operational, with the belt, in the stock location.
  3. Any engine compartment “dress-up” item is allowed.
  4. The battery must be in the stock location.
  5. Any stock or replacement radiator mounted in the stock location is allowed.
  6. 1984-1985 Grand National/ T-Types, i.e. “Hot Air” cars, running in hot air configuration, may compete without factory installed air conditioning components. The factory heater box or a factory heat only replacement must be intact.
  7. Any car configured as a 1986-1987 Turbo T/ Grand National or 1989 Turbo Trans Am MUST have all factory installed air conditioning and heater components.
Transmission & Differential
  1. Vehicle must use a GM transmission to transmit power from the engine to the differential.
  2. Any torque converter is allowed.
  3. Any transmission cooler and transmission pan is allowed.
  4. A transmission brake is allowed.
  5. Vehicle must use the factory 8.5” 10-bolt differential housing with a +/- allowance of one (1) inch. Turbo TransAms must use the factory production differential their vehicle was originally equipped with (with a +/- allowance of one (1) inch).
  6. Use of a limited slip differential or a spool is allowed.
  7. Any gear ratio with the factory stock or reinforced differential cover is allowed.
Tires & Wheels
  1. Rear drag slicks with a sidewall designation of up to and including 28”x10.5” are allowed. No “W” tires are allowed. Rear DOT street tires with a sidewall designation of up to and including 28”x12.5” are allowed. Rear DOT radial tires with a sidewall designation of up to and including 295-55 are allowed.
  2. Rear tire footprint when installed on a rim and mounted on the vehicle cannot exceed a maximum width of 10.9” for DOT radial tires and 10.6” for drag slicks and rear DOT street tires, at 10 PSI checking pressure. Tires may not be shaved at the tread edge to meet the 10.9”/10.6” maximum tire width rule.
  3. Front tire footprint must be at least 3.5” wide.
  1. A full stock appearing interior is required.
  2. Race seats are allowed only if the seats are attached to the rear crossbar of the roll bar (where applicable) AND the seats are painted and upholstered to match the factory interior.
  3. Any transmission shifter is allowed.
  4. Any type and number of additional gauges are allowed.
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