Exhaust System
Chemistry lab and silencer in one pipe
What leaves the cylinders is hot (900 °C), toxic, and as loud as a gunshot — 110+ dB pressure pulses. The exhaust system collects those pulses in the header, scrubs the gas in the catalytic converter, and cancels the noise in the resonator and muffler before releasing it at the tailpipe.
What it does
Routes combustion gases away from the cabin while cleaning them chemically and silencing them acoustically.
Runs under the floor, from the engine all the way to the rear bumper.
How it works
- The header merges each cylinder’s exhaust pulses into one stream, with runner lengths tuned so pulses help scavenge each other.
- Inside the catalytic converter, gas flows through a ceramic honeycomb coated with platinum, palladium and rhodium.
- The catalyst oxidizes unburnt fuel and CO into CO₂ and water, and reduces NOx back into nitrogen — converting ~98% of harmful gases once warm.
- The resonator is a tuned chamber that cancels specific drone frequencies.
- The muffler routes gas through perforated tubes and chambers where sound waves reflect and cancel themselves, cutting roughly 20–30 dB.
Key numbers
| Gas temp at header | 700 – 950 °C |
| Catalyst light-off | ~250 – 300 °C |
| Precious metals | Pt, Pd, Rh (3 – 7 g total) |
| Noise reduction | ~20 – 30 dB through muffler |
| Conversion efficiency | ~98% when warm |
Warning signs of trouble
- Sudden loud raspy exhaust — a hole or broken joint.
- Rotten-egg smell — catalyst overwhelmed or failing.
- Rattle from underneath — broken catalyst honeycomb or loose heat shield.
- Check-engine light with catalyst efficiency code (P0420).
Maintenance & care
- Fix misfires immediately — raw fuel melts catalytic converters.
- Take occasional longer drives so condensation inside the muffler evaporates.
- Check rubber hangers; a dangling exhaust cracks at the joints.
Frequently asked questions
What does the exhaust system do?
Routes combustion gases away from the cabin while cleaning them chemically and silencing them acoustically.
How does a exhaust system work?
What leaves the cylinders is hot (900 °C), toxic, and as loud as a gunshot — 110+ dB pressure pulses. The exhaust system collects those pulses in the header, scrubs the gas in the catalytic converter, and cancels the noise in the resonator and muffler before releasing it at the tailpipe.
What are the signs of a failing exhaust system?
Sudden loud raspy exhaust — a hole or broken joint. Rotten-egg smell — catalyst overwhelmed or failing. Rattle from underneath — broken catalyst honeycomb or loose heat shield. Check-engine light with catalyst efficiency code (P0420).
How do you maintain a exhaust system?
Fix misfires immediately — raw fuel melts catalytic converters. Take occasional longer drives so condensation inside the muffler evaporates. Check rubber hangers; a dangling exhaust cracks at the joints.