Walnut Shell Blasting

What Is Walnut Shell Blasting?

Walnut shell blasting involves "shooting" a mixture of compressed air and walnut shells into the intake ports to clean the carbon deposits and buildup that occur slowly over time on the intake valves. It's a scheduled maintenance service required only on engines with Direct Injection (DI) fuel systems. Many vehicle makes and manufacturers have modern Direct Injection vehicles that require this cleaning at a specified interval — not just BMWs.

Modern BMWs all use Direct Injection fuel systems, which — as the name implies — directly inject fuel into the cylinder combustion chamber. This makes the vehicle more gas-efficient, allows more power with lower octane fuels, and helps manufacturers meet efficiency requirements. While it provides many benefits, one drawback of Direct Injection is that the intake valves aren't cleaned with fuel or detergents, which creates the need for walnut shell blasting as a regularly scheduled maintenance service. If you have a stock or tuned vehicle and this service hasn't been completed yet, it's a good idea to get it taken care of!

Do You Have Videos Showing the Before & After Results?

We sure do! We're confident in our results on every car that gets this service performed in our shop. Here are before & after video results from a client with a 2008 BMW 335i (N54 engine) with 60K miles on a stock vehicle prior to this service. The after results clearly show the intake valves and the dramatic difference from the walnut shell blasting service — we see this visually, but it's also felt in power, response, and gas mileage.

How Often Do I Need Walnut Shell Blasting?

The service should be completed based on a balance of how the car was driven and any modifications made over that time. If the vehicle is completely stock, walnut shell blasting should be completed as scheduled maintenance every 50K miles. With elevated heat cycling and levels from a modified or tuned vehicle, the need for this scheduled maintenance becomes more important, and should be completed every 30–40K miles depending on use. Many owners have more mileage than these recommendations, a previous owner responsible for a large portion of the mileage, or drive the vehicle lightly — any of these circumstances may call for slightly different intervals. If you have any specific questions, feel free to reach out and ask — we're happy to answer questions specific to your application.

What Are Symptoms of a Vehicle That Needs Walnut Shell Blasting?

• Car is due for scheduled maintenance cleaning (every ~30–40K tuned, every 50K stock)
• Vehicle has misfires in one or more cylinders
• Rough idle (may occur during idle or cold start)
• Car has sluggish response overall

What Is the Cost of Walnut Shell Blasting?

$300 for BMW N54, N55, and N20 engines — includes replacement of the OEM BMW intake manifold gaskets during the service.

What's the Difference Between Speed Logic and Other Shops Offering Walnut Shell Blasting?

Experience and quality. We've performed over 1,000+ walnut shell blastings for enthusiasts within the Southern California area and beyond. But don't let the number of cars we've walnut shell blasted fool you — we take our time and treat every car as if it's our own, during cleaning and careful reassembly. We won't reassemble a car unless it looks like the videos above, and we mean it — we have hundreds of videos we're happy to share to prove this isn't an anomaly. Every car that comes through our doors for this service gets cleaned with this expectation. And if you're still not sure, go ahead and ask other shops for their before & after results — we promise our work is unmatched, and we have the videos to prove it.