Turbo Hot Street – THS
- Heads-up pro tree start and pro ladder.
- No peer technical inspections relating to safety equipment rules by class participants or peers, track safety technician personnel will make all rulings on track safety related items.
- Any car is subject to re-weigh and re-tech immediately after final round or any other time.
- Any entrant caught trying to deliberately break the rules will be disqualified from the THS class.
- Nitrous Oxide not allowed.
- Seat belts, lights, horn, and windshield wipers must be operational.
- Aftermarket fiberglass or carbon fiber bumpers and bumper filler panels allowed.
- Minimum car weight w/driver must be at least 3500 pounds with iron heads, 3650 pounds with aluminum heads.
- Complete stock, painted Turbo Regal/Grand National body required.
- Stock wheelbase required (108.0” measured)
- Engine/firewall must be in the stock location.
- Stock operating glass windows and windshield required no lexan.
- Factory stock suspension locations required w/any type stock location shocks.
- Any suspension stabilizer/reinforcement bars or traction enhancing devices are allowed.
- Sway bars may be removed.
- No ladder bars or coil over equipped rear suspensions.
- Outer frame rails notching allowed. Inner frame rails remain in the stock location.
- Reinforcement at inner rear frame rail allowed.
- No quarter panel modifications except rolled inner lip.
- Minor modifications to stock rear wheel wells (no mini tubs).
- Factory stock appearing inner front wheel wells required. Trimming allowed for downpipe clearance.
- No wheelie bars.
- Brake system must be Power Master or vacuum boost operated, or manual brakes allowed.
- Brake system line locks allowed.
- Driveshaft safety loop required.
- Driver’s name on side window allowed. Sponsor/vendor decal is acceptable on the rear and quarter glass windows.
- A maximum of 2 hood mounted gauges are allowed.
- Stock 109 casting block.
- No Stage 2 iron or aluminum heads allowed.
- Any valve covers and oil pan allowed.
- Factory stock intake manifold or cast intake (BG Customs or Champion intake). External welding, cold weld epoxy, or putting not allowed. EGR block-off plate allowed.
- Factory coil pack bracket may be modified and right wiper rod maybe be modified for clearance if using an aftermarket cast intake.
- Factory stock plenum w/spacer or aftermarket cast aluminum intake plenum allowed.
- Any size single modified stock or aftermarket throttle body allowed. Single throttle plate only.
- Any type stock location exhaust headers are allowed Welded in EGT gauge probe bungs are allowed.
- Any single or dual exhaust system allowed. Must muffle and exit in stock location(s) (3.5” max size). Exhaust must run through mufflers in competition.
- Any diameter downpipe size from the turbo allowed. Downpipe must be routed down through the stock location, no flex pipe allowed.
- One (1) 3-bolt turbo allowed and in the factory stock position/orientation.
- The largest allowable turbo compressor is up to and including 67mm. Maximum opening size anywhere on the compressor housing inducer must be less than 68.5mm. One single compressor opening only no internal ported shrouds.
- The compressor housing must be 3” inlet x 2” outlet.
- The turbine housing must be a 3 bolt housing that was available November 1 of the previous year. Factory stock appearing turbine exhaust to downpipe connection must be used.
- Any wastegate configuration acceptable, external wastegate(s) must be plumbed back into the exhaust system, no external dumps allowed.
- No billet wheel turbos allowed until the potential of these new turbos is known.
- Any stock location or front mount air to air intercooler is allowed.
- A front mount intercooler may not extend down below the bottom of the stock located radiator support. Not including the piping.
- No liquid intercoolers, intercooler external spray cooling, or add-on cold boxes allowed.
Engine Management & Fuel System
- Stock or modified stock ECM, aftermarket fuel management system (DFI, F.A.S.T., Motec, Etc.) are allowed.
- Factory Stock Appearing (Type I) or (Type II) DIS cam position sensor required.
- No individual coil per spark plug ignitions allowed.
- No distributor ignitions allowed.
- Any air induction system allowed, but no hood scoop.
- Any fuel pump(s) configuration/location allowed.
- Voltage increasing and fuel pump hot wiring devices are allowed.
- Factory stock fuel rail or aftermarket rails allowed. Aftermarket and stock fuel rails may be modified.
- Any type fuel pressure regulator allowed. Any fuel injectors allowed, 7 maximum. The 7th injector MUST get its fuel supply from the fuel rail.
- Factory stock fuel tank w/ sump addition allowed.
- Gasoline fuel only.
- Alcohol injection allowed, must be sprayed in through the air intake system “up-pipe”.
- All Air Conditioning and heater components installed and in the stock location w/belt in the stock location.
- Power steering operational w/belt in stock location.
- Stock alternator operational w/belt in stock location.
- Stock water pump operational w/belt in stock location.
- All engine accessories must be driven from the same belt.
- Any engine compartment dress-up allowed.
- Battery must be in the stock location.
- Any stock type/location electronic engine cooling fans allowed.
- Any stock or replacement radiator in stock location allowed.
- Must have 200-4R transmission.
- Any torque converter allowed.
- Any transmission cooler and pan allowed.
- Transmission brake allowed.
- Must have 8.5” differential housing, +/- 1” allowance.
- Limited-slip differentials or spool allowed.
- Any gear ratio with factory stock or reinforced differential cover allowed.
Tires & Wheels
- Any matched set of (4), 15” diameter chrome steel or aluminum wheels allowed.
- Rear drag slicks w/sidewall designation up to and including 28” x 10.5” – 15”. No “W” tires allowed. Rear DOT street tires with sidewall designation up to and including 28” x 12.5” – 15” size tires allowed. Rear DOT Radial tires with sidewall designation up to and including 275/60/15 allowed. Rear tire footprint when installed on a rim and mounted on the car can not exceed a maximum of 10.6” in width at 10 psig checking pressure. Tires may not be shaved at the tread edge to meet the 10.6” maximum width rule.
- Front tire footprint must be at least 3.5” wide.
- Full stock appearing interior required.
- Race seats are allowed only if the seats are attached to the rear crossbar of the roll bar and seats are painted and upholstered to match the factory interior.
- Any transmission shifter allowed.
- Any additional aftermarket gauges allowed.