downpipe

  • What is a downpipe? 
Downpipe is a crucial component in the exhaust system of a turbocharged vehicle. Its primary function is to direct the exhaust gases from the turbocharger to the rest of the exhaust system and eventually out of the vehicle. 
  • Does a downpipe increase HP and How a Downpipe Increases Horsepower? 
  1. Improved Exhaust Flow: A downpipe replaces the restrictive factory catalyst, allowing exhaust gases to flow more freely from the turbocharger. In turbocharged engines, this reduces backpressure, allowing the turbo to spool more quickly and efficiently. The result is an increase in power output, especially at higher RPMs.
  2. Reduced Backpressure: Stock OEM catalysts often contain restrictive catalytic converters designed to meet emissions standards, which can hinder performance. Upgraded downpipes, especially "catless" or "high-flow catted" versions, reduce this restriction, allowing the engine to breathe better and operate more efficiently.
  3. Boost Gains: By improving exhaust flow, the turbocharger can spool up faster and achieve higher boost levels, translating into greater engine power. The faster the turbo reaches its peak boost, the more quickly the engine can generate additional horsepower and torque.
  4. Expected Power Gains: On turbocharged vehicles, including many AUDI, BMW and Mercedes models, downpipes can provide power gains in the range of 20 to 60 horsepower and more when combined with ECU tune. The actual gains depend on the car's engine, other modifications, and whether you use a high-flow catalytic converter or opt for a catless downpipe.
  • Is downpipe good for engine?
Downpipe can be very beneficial for your engine, by improving performance, reducing turbo lag, and lowering exhaust gas temperatures. However, it requires careful instalation and a proper ECU tune to avoid issues. If all done correctly, it can be a great upgrade without harming the engine.downpipe

Catted Downpipes

  • Emissions Compliance: Catted downpipes include a catalytic converter which helps reduce harmful emissions, making the vehicle more environmentally friendly and often compliant with emission regulations.
  • Less Odor: They reduce the sulfur smell commonly associated with catless.
  • Legal Compliance: More likely to pass emissions tests and inspections required by law in many regions.
  • Reduced Noise: They tend to be quieter than catless, as the catalytic converter also helps to muffle the exhaust sound.

Catless Downpipes

  • Performance: Offer the best performance gains as they are less restrictive, allowing for better exhaust flow and potentially more power and torque.
  • Cost: Generally cheaper than catted as they do not include the expensive catalytic converter.
  • Sound: Provide a louder and more aggressive exhaust note, which some enthusiasts prefer.

If the vehicle is mainly for street use, a catted option might be a better choice. For track use, where emissions regulations might be less stringent, a catless option could be considered.
Performance Goals: Determine how much of a performance gain you are seeking. Catless downpipes offer better performance but at the cost of emissions and legality.