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What car parts give the most horsepower?

When it comes to increasing horsepower in a car, there are several key components that can make a big difference. The engine, exhaust system, air intake, turbocharger or supercharger, fuel system, and ECU tuning are some of the most impactful upgrades for gaining horsepower.

Engine Modifications

The engine itself offers great potential for horsepower gains. Here are some of the most effective engine modifications:

  • Bigger displacement – Installing a larger bore and stroke crankshaft, along with bigger pistons, can significantly increase the engine’s horsepower potential. This allows more air/fuel mixture into the cylinders.
  • Cylinder heads – Upgraded cylinder heads with larger valves and free-flowing ports optimize airflow and allow the engine to breathe better, making more power.
  • Camshaft – A more aggressive cam profile with increased lift and duration keeps the valves open longer, improving airflow. This allows more air/fuel mixture into and out of the cylinders.
  • Intake manifold – A free-flowing intake manifold gets more air into the engine. Manifolds with larger runners and plenums improve airflow.
  • Headers – Less restrictive exhaust headers allow more exhaust to be scavenged from the cylinders, reducing back pressure. This optimization allows the engine to make more power throughout the RPM range.
  • Forced induction – Adding a turbocharger or supercharger compresses more air into the engine for bigger power gains.

With the right combination of these and other engine upgrades, power increases of 25-50% or more are possible.

Exhaust System Upgrades

The exhaust system plays a key role in engine power production. Reducing back pressure allows the engine to expel spent gasses faster and optimize cylinder filling. Here are some effective exhaust upgrades:

  • Headers – Aftermarket headers have smoothed out bends and larger diameter pipes to reduce flow restrictions.
  • High-flow catalytic converter – A less restrictive cat frees up exhaust flow for better scavenging.
  • Cat-back exhaust – Larger diameter piping with reduced bends compared to stock exhausts reduce back pressure.
  • Muffler delete/upgrade – Eliminating the muffler or installing a high-flow model reduces flow restrictions.
  • Exhaust cutouts – Manually opening cutouts bypasses the muffler at higher RPMs, reducing back pressure when the engine needs it most.

The cumulative effect of these upgrades reduces exhaust back pressure, allowing the engine to breathe better and make more power throughout the RPM band. Gains of 15-30 horsepower are common.

Air Intake Upgrades

The engine air intake pathway is another vital system impacting power. Optimizing airflow here allows the engine to swallow more air for making power. Here are some top intakes mods:

  • Cold air intake – Pulls cooler outside air from the front bumper area, increasing density for more oxygen.
  • Short ram intake – Removes the stock airbox for a short, straight path to the throttle body.
  • Open element intake – Uses an oiled cotton gauze filter for high airflow with minimal restriction.
  • Port matched intake – Smooths and matches intake port edges to the manifold opening to optimize airflow.

These intake upgrades reduce turbulence and restriction, optimizing the engine’s ability to ingest air. Intake gains typically provide an extra 10-20 horsepower.

Forced Induction

Forced induction substantially increases engine power by packing more air molecules into the cylinders. A turbocharger uses wasted exhaust gases to spin a turbine that drives a compressor forcing more air into the engine. A supercharger uses a belt-driven compressor for the same effect. With greater air density crammed into the engine, more fuel can be added proportionally for massive power gains. Here are some key forced induction mods:

  • Larger turbo – A bigger turbocharger flows more exhaust and air for bigger power gains.
  • Lower boost threshold – Adjusting wastegate spring pressure brings max boost on earlier for quicker spool up.
  • Intercooler upgrade – A larger intercooler or water/methanol injection cools the compressed intake charge for denser air.
  • Blow-off valve – Recycles boost pressure between shifts for faster spool up.
  • Supercharger pulley – Smaller supercharger pulleys drive the compressor faster for higher boost pressures.

Turbo and supercharger upgrades commonly produce horsepower gains of 50-100% or more. This makes forced induction one of the most powerful ways to increase engine horsepower.

Fuel System Upgrades

When increasing engine airflow and power output, the fuel system needs to keep up with greater fuel demands. Here are some key fuel system mods to support big power:

  • Fuel injectors – Higher flow rated injectors supply more fuel for the extra air airflow.
  • Fuel pump – A higher output fuel pump feeds the engine enough fuel at higher outputs.
  • Fuel pressure regulator – Bumps up fuel rail pressure for adequate fueling under boost.
  • Fuel lines – Upgraded lines handle the increased fuel flow rates.
  • Fuel cell/tank – Larger capacity fuel tank or cell prevents fuel starvation.

Properly upgrading the fuel system ensures the engine has enough fuel to take advantage of airflow improvements from other bolt-on mods. This fuels bigger power numbers.

ECU Tuning

The engine’s computer controls fuel maps, timing advance, boost pressure, shift points, and other parameters. An optimized custom tune tailored specifically to your mods and fuel takes advantage of all your bolt-ons for maximum horsepower. An ECU tune offers these benefits:

  • Optimizes fuel for more power – Increased injector flow rates and pressure for big airflow gains.
  • Optimizes ignition timing – Carefully calibrated timing maps produce best torque throughout the RPM band.
  • Raises RPM limit – Removes factory RPM limit for power gains higher in the band.
  • Optimizes boost – Calibrates turbo wastegate duty cycle for peak boost curves.
  • Improves drivability – Smoothes out throttle mapping and gear shifts.

A professional dyno tune is like tying all your mods together to work in harmony, optimizing your unique setup for big power gains. Expect an extra 20-30 horsepower from ECU tuning.

Choosing the Right Parts Combination

Here are a few example packages for mild to extreme horsepower gains:

  • Daily Driver Bolt-Ons – Cold air intake, cat-back exhaust, and ECU tune. Good for an extra 30-50 HP for minimal cost.
  • Weekend Warrior – Intake, full exhaust, ECU tune, injectors, and headers. Around 75-125 HP more for serious power.
  • All Out Package – Built motor, big turbo, race fuel system, and engine management. Can double HP or more at high cost.

Choose parts optimal for your power goals, budget, and usage. Aim for packages that work synergistically together. Prioritize mods that remove restrictions first before adding more airflow.


Here are some key takeaways on the best bolt-on car parts for increasing horsepower:

  • Engine build upgrades like displacement, cylinder heads, cams, and intake manifolds directly increase power potential.
  • Reducing exhaust back pressure with headers, high-flow cats, and muffler upgrades optimizes cylinder scavenging.
  • Cold air intakes, short ram intakes, and port matching reduce intake restrictions for more airflow.
  • Turbocharger and supercharger upgrades force more air into the engine for tremendous power gains.
  • Fuel system upgrades supply adequate fuel for the engine’s increased demands.
  • An ECU tune ties everything together for maximum horsepower from your package of mods.

Focus on removing intake/exhaust restrictions first, then add more airflow, fuel, and finally optimize with tuning. Combining the right mods can safely increase horsepower substantially. Just be sure to upgrade brakes, tires and other components to handle the extra power.

Car Parts Power Comparison Table

This table summarizes the potential horsepower gains from various bolt-on car parts:

Mod Type Parts Typical Gains
Engine Cylinder heads, camshaft, displacement increase 25-50%
Exhaust Headers, high-flow catalytic converter, free-flow muffler 15-30 HP
Intake Cold air intake, short ram intake, port matching 10-20 HP
Forced Induction Turbocharger, supercharger, intercooling 50-100%
Fuel System Injectors, fuel pump, fuel pressure regulator Supports added airflow
Tuning ECU tuning, engine management 20-30 HP