Truth be told, the diesel engine wasn’t very loved by the majority of petrolheads; partly because it was heavy, low-revving, noisy and not that refined, and partly due to its lack of pleasant exhaust notes – among other key differences.
Modern cars with diesel engines generate more noise from the engine itself than from the tail pipe. Engines are also getting smaller as manufacturers try to cut fuel consumption without sacrificing power, a trick they pull off by using exhaust gases to help drive the engine through turbochargers. That can give three- and four-cylinder engines the sort of oomph but not the noise once associated with bigger engines.
In general, the exhaust system includes the following components:
- Aftertreatment devices (catalytic converters, particulate filters) to reduce emissions of pollutants,
- Mufflers, which provide noise attenuation,
- Decoupling elements, which connect the exhaust manifold with the rest of the exhaust system.
- Piping and hangers.
In general, today’s diesel the exhaust systems are almost inaudible, even in high-performance engines, such as the diesel twintubo BorgWarner Saab TTID (180hp). Today, there are various systems for improving car sound, but they are generally more expensive and require additional investment.
However, there is a cheaper option… In this case, the owners removed “unnecessary” parts, such as DPF, EGR, silencers, etc. This parts are not really functionally necessary (also increase the cost of vehicles) but they must be built in the car because of the legal provisions (Air Pollution, Noise…)
So, some owners like this Saab 9-3 TTiD Owner who decided to remove unneeded components. This is 2008 Saab 9-3 Aero Sportcombi 1.9TTiD 180bhp, with DPF and EGR delete with software update, deletion of twin rear silencers for straight pipes with 4.5″ slash cut tailpipes, K&N drop in panel filter also added… In the factory version, this exhaust system is almost totally silent: