Turbochargers: Understanding the Basics

Introduction

• Turbochargers: Power adders turning average engines into high-performance machines.
• Purpose: Use exhaust gases to drive a compressor, bringing more oxygen into engine cylinders.
• History:
  • Originated over 100 years ago.
  • First used in marine diesel engines, then aircraft engines during WWI.
  • Automakers started using turbos in the 1950s; first production car in 1962.

How Turbochargers Work

• Engine Basics:
  • Engine acts as a pump: sucks in air/fuel, compresses, combusts, and exhausts.
  • More power = more fuel and air ("suck, squeeze, bang, blow").
• Turbo Function:
  • Uses exhaust gases to spin a turbine, which drives a compressor.
  • Compressor pushes more air into the engine, increasing power.
  • Functions like an on-demand displacement modifier.

Components of a Turbocharger

• Hot Side (Turbine):
  • Spins with exhaust gases, can reach over 100,000 RPM.
  • Generates high heat, causing rust and oxidation.
• Cold Side (Compressor):
  • Compresses incoming air, increases temperature due to friction.
• Intercooler:
  • Cools compressed air, increasing density and oxygen content.
  • Essential for engine performance.
• Wastegate:
  • Regulates turbo speed/boost pressure by bypassing excess exhaust gases.
• Blow-off Valve:
  • Releases excess pressurized air to prevent turbo damage.

Types of Turbos and Configurations

• Turbo Lag: Delay in boost response.
• Twin Turbos:
  • Parallel: One turbo per cylinder bank.
  • Found in early models like Maserati BiTurbo.
• Sequential/Twin-Stage Turbos:
  • Small turbo for low RPM, larger for high RPM.
  • Examples: Audi rally cars, Toyota Supra.
• Compound Turbos:
  • Small turbo helps spin large turbo; common in diesel engines.
• Variable Geometry Turbos:
  • Adjustable vanes to optimize flow and reduce lag.
  • Found in models like 911 Turbo.
• Electric Turbos:
  • Use electrical assistance to eliminate lag, recover energy.
  • Found in modern performance cars.

Pros and Cons of Turbochargers

• Advantages:
  • Increased power and efficiency.
  • Used widely in a variety of vehicles, from economy to supercars.
• Disadvantages:
  • Added weight, complexity, engine stress, and heat.
  • Despite challenges, reliability has improved.

Conclusion

• Turbos are prevalent in modern vehicles, enhancing both performance and efficiency.
• With modifications, even common turbo cars can achieve high performance.
• Encouragement to explore turbo modifications.

Further Learning

• Differences between turbochargers and superchargers.
• More content on engines, tuning, and vehicle technology available.

Presenter: Trav from AutoLab