[fatty335]

Greetings all,

Just wanted to share my recent DIY walnut blast experience on the n55. Walnut blasting is certainly not as popular with the n55 platform as it was with the n54, due primarily to the vastly improved PCV system on the n55. However, as with all direct injection engines, the intake valves do get dirty after accumulating many miles. For me at 80,000, I was experiencing more timing corrections than my conservative tune, 93 octane, and relatively new plugs and coils should have allowed. After some research and investigation, I decided to take a stab at cleaning up the intake valves.

I ordered one of the all-in-one kits from a major online retailer and used my own shop vac and air compressor.





Some notes for anyone giving this a go:
- I bought and used the aluminum vacuum port adapter; you can buy cheaper 3D printed ones, but the aluminum one worked really well
- Cylinder 6 is the toughest to get to; you may need to use several blasting wands with different angles to get at both valves
- You can accomplish this job with any size compressor; it just takes longer with a smaller one
- I bought and used a remote starter button to "bump" the engine over while I watched to ensure the valves were closed - this is highly recommended for this job
- This job is messy! Keep the intake ports that you're not currently working on sealed
- You should take this opportunity to refresh the intake gaskets (mine were hard and deformed) and consider replacing the computer gasket that attaches to the back of the intake manifold (mine was seeping oil)
- Since I had it off anyway, I used some CRC to clean up the throttle body, which was pretty dirty

The jury is still out on the smoother idle and better fuel economy that most people report after doing a walnut blast, however, I can report that the timing corrections do seem to be back in check. This only took an afternoon and about $200 to knock out (I already owned a shop vac and compressor).

So, my recommendation to any high-mileage n55 owner who wants to keep the car for the long haul: just do it - you'll be glad you did!

[demrovskyN55]

Takes a while to remove everything, but once you're in there it's easy and straight forward, also cool and satisfying to see the difference
suggestion clean your intake manifold and throttle body just to be safe.

[Welcome to NBA Jam]

If I had an air compressor and room for it I would. Shop near me will do it for around $300.

[Turbod]

On my 335i I had it done at 50,000 miles. I didn't notice any of the changes you mentioned above and mine looked similarly to your photos. On my current car I started spraying methanol around 50,000 miles, at 58,000 now. I think the methanol will help to either mitigate the build up or even clean them.

I'd recommend most N55's do it around 100,000 miles.