Quick Info
Model
450, 452
Estimated Cost
50-60€
Difficulty
Beginner
Time Required
5-10 min
Safety Notes
READ BEFORE STARTING: Changing the air filter is a simple task, but working in the engine bay requires caution to avoid injury or damage to the intake system.
Cool Engine: Always ensure the engine is cold to the touch. The airbox sits very close to the turbocharger and engine block, which retain extreme heat for up to an hour after driving.
Intake Protection (Mandatory): Once the airbox is open and the filter is removed, the engine's intake is exposed. Never start the engine without a filter in place. Even a small stone or screw falling into the intake pipe can cause catastrophic engine failure.
Avoid Over-Oiling: If you are installing a "washable" sport filter (like K&N), do not over-oil it.
Hand Protection (PPE): The clips on the airbox and the surrounding engine components can have sharp edges. Wear light mechanic gloves to prevent cuts or scrapes during the fiddly removal of the airbox cover.
Secure the Airbox: Ensure the clips are fully "clicked" back into place during reassembly. An improperly sealed airbox will draw in "dirty" air and road grime, shortening the life of your engine.
Step-by-Step Guide
Introduction
Smart Roadster 0.7 Turbo: Installing a DNA High Performance Air Filter
The 698cc Suprex engine in the Smart Roadster thrives on efficiency and turbo response. One of the simplest and most effective ways to let that engine breathe is by replacing the restrictive factory paper element with a DNA High Performance Air Filter.
In this tutorial, I’ll walk you through the 5-minute process of swapping out your standard filter for a precision-engineered upgrade that utilizes DNA’s unique Full Contour Design (FCd) technology.
Why Upgrade to DNA?
While the stock filter is a "one-and-done" paper part designed for basic filtration, the DNA unit is a lifetime performance tool. It features four layers of high-grade surgical cotton gauze sandwiched between epoxy-coated marine wire mesh.
By installing a DNA filter, you are unlocking up to 37% more airflow while maintaining a staggering 98-99% filtration efficiency. This means your turbo doesn't have to work as hard to pull in air, resulting in a noticeably crisper throttle response and a slightly more mechanical induction sound when you’re on boost. It’s the perfect foundation for any 452 owner looking to improve engine longevity and performance without modifying the airbox itself.
Access the Airbox
Open the engine cover and locate the black plastic airbox on the left-hand side of the engine bay. Ensure the area around the lid is free of loose dirt.
Release the Housing Clips
Locate and undo the four metal retaining clips holding the airbox lid in place. For some models, you may need to slide the internal locking rod to fully release the tension on the filter.
Remove the Old Filter
Carefully lift the airbox lid or slide the rod away from you to expose the filter. Pull the old paper filter out of the housing and inspect it for heavy contamination.
Clean the Internal Housing
Before installing the new filter, use a damp cloth or vacuum to remove any dirt, grit, or salt from the internal surfaces of the airbox. A clean housing prevents contaminants from bypassing the new filter.
Install the DNA Filter & Reassemble
Slide the new DNA High Performance filter into the housing, ensuring the rubber seals are properly aligned for a airtight fit. Reposition the lid, re-engage the locking rod, and snap the four clips back into place.
