Modern direct injection (DI) engines are known for their power and efficiency—but they come with a catch. Over time, oil vapors and crankcase gases recirculate through the intake system and begin to form carbon deposits on the intake valves. Unlike port injection engines, DI systems don’t spray fuel across the valves, which means there’s nothing to wash that carbon away. Left untreated, the buildup only gets worse.

 

Common Vehicles We Service

We regularly perform valve cleaning on popular direct injection platforms, including:

• Subaru WRX (2015+)

• BMW turbocharged direct injection engines (N54, N55, B58, and more)

• Mazdaspeed3 / Mazdaspeed6

• Volkswagen GTI / Golf R (MK7 and newer)

• Ford Ecoboost engines

• Lamborghini Gallardo (direct injection models)

• Audi R8 Gen 1 (V8 & V10 DI engines)

• Mini Cooper S / JCW (Turbocharged DI models)

• Kia direct injection engines (Soul, Forte, Optima, and others)

• And many others

If you’re running a direct injection engine, it’s not a matter of if carbon buildup will happen—it’s when. We’ve seen some engines start to show symptoms as early as 20,000–30,000 miles.

 

Why It Matters

Even a light layer of carbon can disrupt airflow through the intake ports, hurting both performance and drivability. As buildup increases, it can cause:

• Reduced horsepower and throttle response

• Decreased fuel efficiency

• Rough idle and hesitation under load

• Increased knock activity due to turbulent airflow

This isn’t just about peak power—carbon buildup can hurt your engine’s performance even during daily driving.

Our Process

At The Shop Houston, we use the walnut media blasting method, a safe and proven solution for removing carbon buildup. This process uses finely ground walnut shells to blast away deposits without damaging internal components. We also take extra precautions to ensure that any residual media is thoroughly cleaned out of the ports.

Unlike chemical solutions or DIY shortcuts, walnut blasting gives you a factory-fresh result without the risk.

Pricing

Pricing varies depending on the platform, as the intake manifold must be removed and reinstalled with new gaskets. We’ll provide a clear estimate before any work is done, and we always use OEM or better-quality gaskets during reassembly.

Want to find out if your engine needs a cleaning?
Give us a call at (866) 735-RACE or (866) 735-7223 or shoot us an email at sales@theshophouston.com. We’ll get you booked for an inspection and let you know if it’s time to give your valves some attention.