Sound Requirements

Sound Levels & Mufflers

Mufflers are required for all ChampCar events, regardless of track policy. Some facilities, including Atlanta Motorsports Park, NCM, Thompson, and Laguna Seca, may enforce limits lower than ChampCar’s series maximum.

Pass-Sound Checklist Current Limits Parts & Resources

Three strikes = parked for the weekend.

Sound violations are cumulative from Friday testing through Sunday. Tracks may remove non-compliant cars without repeated retests. Fix the car after the first hit.

Sound Limits

Current limits

ChampCar cars must not exceed the series limit and must also meet any track-specific limits when lower. Always check the Event Supplemental Rules for the official number and meter location.

Facility Typical limit Notes
ChampCar series maximum 96 dBA Or lower if the track requires it.
Atlanta Motorsports Park Below 96 dBA Prepare a quieter configuration, extra muffling, and turn-outs.
WeatherTech Raceway Laguna Seca ~90 dBA Strict enforcement. Meter location can catch intake and exhaust noise.
NCM Motorsports Park Below 96 dBA Event Supps will specify. Bring a quieter setup.
Thompson Speedway Below 96 dBA Check meter location. Intake roar can trigger hits.

Examples only. The Event Supplemental Rules govern.

Checklist

Pass-sound checklist

  • Mufflers installed: plural recommended on higher-output builds. No open pipes.
  • Exhaust orientation: exit up and toward driver’s left when possible. Avoid pointing at meter locations or walls.
  • Quiet the intake: keep filters under the hood, baffle front inlets, and avoid open stacks or ram-air without attenuation.
  • Seal the system: no leaks at flanges, collectors, or slip joints.
  • Test under load: dyno or safe road test. Free-revving in the paddock does not predict pass/fail.
  • Carry a quiet kit: turndowns, turn-ups, extra muffler, packing, clamps, flex joints, and basic repair tools.
What Works

Best practices

Exhaust hardware

  • Use two mufflers in series on stricter tracks.
  • Stagger case sizes or resonance frequencies when possible.
  • 2.5-inch tubing often balances flow and noise better than oversized pipe on mid-power builds.
  • Use ball-and-socket or V-band joints that seal well and are serviceable.
  • Add a turndown or turn-up elbow to redirect energy away from the meter.

Installation and routing

  • Keep clamps tucked up and away from curbs or off-track hazards.
  • Skid the muffler face with a small ramp plate where exposed.
  • Support exhaust weight with proper hangers.
  • Use flex joints for movement, not flanges.
  • Double-nut or safety-wire hot-zone fasteners.
Muffler ramp concept to prevent impacts

Ramp plates help prevent impacts on curbs and off-track moments.

Laguna Seca sound focus area

Meter orientation matters. Some locations can “see” both intake and exhaust noise.

Trackside Fixes

At-track fixes and tools

If you get a sound hit, act quickly. Do not risk a second or third strike.

  • Add or swap in a second muffler or resonator.
  • Extend the tailpipe and redirect it with a turndown or turn-up.
  • Seal leaks at flanges, collectors, and slip joints.
  • Re-orient intake tubes under the hood.
  • Carry a basic flux-core MIG kit, gloves, wire, brushes, clamps, and spare material.
Resources

Parts and resources

FAQ

Quick answers

Do stock exhausts always pass?

No. Even quiet OEM systems can fail on strict days or with certain meter placement. Bring backup muffling and turn-pieces.

Is there re-testing?

Tracks control testing. Do not count on retries. Fix the car immediately to avoid strikes.

Who should I contact with questions?

Email media@champcar.org. We want you on track all weekend, so set up to be quiet and fast before you arrive.