Eric B’s modded out E93 BMW 335i Cabrio came in the other day to see Sr Mod Expert Alan Wei about one of the specialized services we offer for BMW N54 and N55 engines – Walnut Media Blasting. As we explained in our post introducing the N54 Walnut Blasting service (currently available for $495, the lowest price in town- Dealers ask $1200+), it’s recommended by BMW itself that the Walnut Blasting Intake Valve Cleaning service be done every 40,000 miles, more often if tuned. The reason for this is because of two features of the BMW N54 and N55 engines – direct injection fuel injectors and turbocharging.
Stay with us for a moment, we’re going to explain WHY you need the walnut blasting service done and what the benefit is in the simplest terms possible.
With traditional multi-point fuel injection, there’s an injector mounted IN the intake, ahead of the cylinder head, which sprays atomized gasoline (an excellent solvent) constantly on the intake valves as they operate, which keeps the intake valves clean and free of carbon deposits – check out the illustration below.
Throttle Body Injection vs Multipoint Injection vs Direct Injection
So to recap, that means on direct injection cars carbon build up accumulates much faster than traditional fuel injection engines. That’s part one.
The other half of the problem is the fact that all turbocharged cars, even brand new, will have some oil blow-by when the car makes boost. Oil blow-by gases then get into the intake tract, coating the intake, chargepipes, intercooler and yep, the intake valves too, with a sheen of oil, which attracts and traps any dirt particles in the air.

The combination of the facts that the engine traps dirt and oil in the intake more quickly than traditional EFI and also does not actively keep itself clean like EFI does translates into your N54 or N55 being one dirty engine after 50,000 miles. Which is why Erick brought the car into see Alan.

Erick’s done quite a bit to the car – some of it done here, some of it not, so let’s take a look at some of the goodies this Cabrio sports.

BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-4With a set of bright red custom RECARO seats and a Cobb AccessPORT V3 tuner for N54 mounted where it’s easy to read, the tuner nature of Erick’s E93 means that it needs the intake valves cleaned more often – though we didn’t install this upgrade. It’s worth saying that Cobb Tuning recommends that any BMW being tuned have the walnut blasting service done BEFORE tuning, and will outright turn your car away if you show up for Dyno tuning without having it done.
BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-6 The Recaro seats and Takata harnesses give this E93 a very unique interior.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-7 BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-8 Under the hood there’s a performance N54 Intake, we can see the recently-installed Mishimoto Baffled Oil Catch Can, set up to keep the intake tract of this turbo six nice and clean, helping to keep future walnut blasting services far apart.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-32Here’s a closer look at the Mishimoto Baffled Oil Catch Can as it appears outside the engine bay.
If you look carefully, just below the Mishimoto Oil Catch Can, you’ll find an Evolution Racewerks N54 Chargepipe with HKS SSQV Blow-Off Valve as well, eliminating boost leaks as well as offering that awesome SSQV BOV sound.
The Evolution Racewerks N54 Chargepipe can be ordered with a Tial BOV or an HKS SSQV as seen here.
Here’s a closer look at the HKS SSQV.
You can just barely make out the COBB Intercooler for BMW 335i hiding behind the front grille.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-27 Since we’ve done quite a few walnut blasting services now, we’re getting pretty quick at it – our techs had the intake manifold off the car before we could say “Bob’s your Uncle”.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-36 It takes a fair bit of equipment to perform the Walnut Media Blasting service, which would set you back more than $400 if you wanted to do it yourself, making our pricepoint of $495 an even better value. And as you can see, we take great pains to ensure that your paint is unharmed as we do our work.walnut-blasting-before-after700px2Check out these before/after comparisons of actual engines we’ve performed walnut blasting services on.walnut-blasting-before-after700px3Here’s a closeup of an intake port before and after the service. On the left, you can see there’s a thick coating of crap on the intake valve, gumming it up and hampering performance and response. Now check out the intake port on the right – looks brand spankin’ new – and performs as such.

Here’s how this E93’s engine looked after we completed the service. We can see the heads of every intake valve that’s not covered by shadows – so you can see for yourself this isn’t something BMW or some service shop made up just to charge for the service – it really is a necessity to keep your N54 (or N55) performing its best.

As our techs buttoned up the E93, we took the opportunity to appreciate the other mods Erick’s done to his 335i.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-20 Out back, the car sports a Vanguard Cat-Back Exhaust system for BMW E92/3 335i peeking out from the custom Carbon Fiber Diffuser mated to the M-Sport Rear Bumper for BMW E92/E93, delivering a muscular exhaust note and sharper response.
BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-25 On a black car, a set of gloss black kidney grilles might disappear, so a set of Carbon Fiber Kidney Grilles for BMW E92/E93 was in order.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-26The Carbon Fiber Kidneys aren’t the only CF accent – a set of Carbon Fiber Eyelids for BMW E92/E93 and an H Style Carbon Fiber Front Lip helps lend a more aggressive aesthetic to the E93.
BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-42 Giving Erick’s E93 BMW 335i its stance are a set of KW V3 Coilovers for BMW E93 Cabrio, giving the car the drop to go with the wheels.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-43 Everything about the front end of this car screams aggression, yet the black manages to keep it all still somewhat subtle.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-46The M3 Style Side Skirts for BMW E92 also give the car a nice side profile and the winglets on the H style front lip tie nicely into the contours of the side skirts.
BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-50 A Carbon Fiber Trunk Spoiler for BMW E93 Cabrio is a nice accent that ties together all that carbon fiber.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-52 The yellow tire paint letting you know that he’s rolling on Falken Azenis 453 tires and also gives the car a bit of extra flair to keep it from disappearing into a mass of all black.BMW_E93_335i_ER_Chargepipe_HKS_BOV_Mishi_OCC_Vanguard_Catback_Falkens-53All told, Erick’s put together a pretty sick package with a bit of help from Alan. We hope you enjoyed the photos – thanks again for joining us, and we’ll see you next time.

Not sure what the best mods for your BMW E92/E93 are? Check out our guide here! Need to schedule an installation for Walnut Blasting or anything else? Talk to our team of Mod Experts like Alan, give us a call at 714-582-3330 (x8006 for Alan), shop online at or come by the ModAuto showroom in La Habra, CA between 8-5 M-Sat and talk to a Mod Expert in person.

Story & Photos by Nick Gregson


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