What increases horsepower the most?

If you hang around dyno shops or street race spots long enough, you’ll hear the same question over and over:

“What increases horsepower the most?”

Some people swear it’s a cam.
Others say turbo or blower.
Someone’s uncle still thinks it’s just a muffler and a “race chip.”

The truth: there’s no single magic part. Horsepower is the result of how well your combo moves air and fuel through the engine—and how safely you can spin that combo without blowing it up.

Let’s break down the mods that actually move the needle, and how to build a plan instead of throwing random parts at your LS.

1. Power Adders: Turbo, Supercharger, and Nitrous

If we’re being real, nothing increases horsepower faster than a power adder.

• Turbocharger – Uses exhaust energy to force more air into the engine. Massive power potential, very tunable, and great for street/strip combos.

• Supercharger – Belt-driven boost. Instant response and big midrange power, perfect for fun street cars and roll racing.

• Nitrous – The “instantly 150+ more hp” button. Cheap upfront, brutally effective, but requires respect with timing and fueling.

All three work because they push more air into the cylinders. More air + the right amount of fuel + good timing = more horsepower.

But there’s a catch…

If your fuel injectors, pump, and tune can’t keep up, that extra air just turns into melted pistons. That’s why serious builds pair boost or nitrous with:

• Correctly sized fuel injectors (60lb, 80lb, 120lb, 1200cc+ depending on goals)

• A fuel system that can maintain pressure at WOT

• A clean, reliable wiring setup and ECU that can control it all

2. Camshaft Upgrades

For naturally aspirated or mild boosted builds, a camshaft is one of the biggest horsepower-per-dollar upgrades.

A good cam:

• Keeps the valves open longer and higher

• Lets more air in and out at higher RPM

• Shifts the powerband into the range where you actually race

Paired with:

• Better valve springs

• Long-tube headers

• Proper tune

…you can see huge gains over stock. But again, if the fuel system is maxed out, you’re leaving power (and safety) on the table.

3. Intake, Exhaust, and Airflow

These don’t usually add the most horsepower by themselves, but they unlock horsepower when combined with other mods.

• Freer-flowing intake manifold and throttle body

• Cold air intake that actually pulls cool air

• Long-tube headers and a less restrictive exhaust

Think of this as reducing “breathing restrictions” so your engine can take full advantage of a cam or boost.

4. Tuning: The Hidden Horsepower Multiplier

You can bolt on the best parts in the world, but without a proper tune, your engine is guessing.

A good tuner can:

• Optimize timing for your fuel and compression

• Dial in air/fuel for power and safety

• Calibrate injector data, idle quality, throttle response, and shift points

Tuning doesn’t just add horsepower—it makes the horsepower usable and repeatable.

5. Fuel System & Injectors: The Unsung Heroes

Here’s the part a lot of people ignore until it’s too late:
Your fuel system can make or break every other mod.

Bigger injectors don’t “make” power on their own.
What they do is allow more power safely by feeding the extra air your combo is trying to use.

Examples:

• Mild NA or small spray: Deka LS 60lb injectors can support mid-600 hp range with the right setup.

• Serious turbo or blower: LS 80lb injectors are a popular step for 600–750+ hp builds and E85 conversions.

• Big-boy numbers: 120lb or 1200cc injectors and up for high-boost, E85, or four-digit power goals.

Matched, flow-tested injectors + clean wiring + a solid tune = power that’s consistent, not sketchy.

That’s why serious builders upgrade injectors and wiring at the same time as the big “horsepower” mods, not after something melts.

So… What Increases Horsepower the Most?

If we’re talking single biggest category of mods:

Power adders (turbo, supercharger, nitrous) increase horsepower the most.

But they can only do their job if:

• The fuel system (injectors, pump, lines) can keep up

• The wiring and ECU can control everything reliably

• The tune is dialed in for your combo

Think of it like this:

• Boost / nitrous / cam = potential horsepower

• Fuel system + wiring + tune = how much of that potential you actually get

The fastest cars don’t just bolt on a turbo. They build a complete system that moves air and fuel efficiently and safely.

Want Real Horsepower Gains, Not Just Noise?

If you’re serious about turning the power up, start where it actually matters:

• Choose injectors sized for your goal horsepower and fuel type

• Use a stand alone or LS swap harness that won’t freak out at the track

• Get a tune from someone who understands LS combos and boosted builds

👉 Upgrade your build with flow-matched injectors and LS swap harnesses at
HighPerformanceInjectors.com

💥 Use code Turbo at checkout for 10% OFF qualifying injectors and harnesses.

More air. Enough fuel. Clean wiring. That’s how you turn parts into real horsepower.