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Is a Cold Air Intake Legal in the UK?

Legal

A cold air intake is road-legal in the UK. It sits before the engine, leaves the emissions system untouched, and there is no dedicated MOT check for it.

Why?

An intake replaces the standard airbox or panel filter so the engine breathes more freely. Because it sits ahead of the engine and does not touch the catalytic converter, DPF or any other emissions equipment, no UK rule stops you fitting one.

The two things that keep it legal in practice: the car must still pass its MOT emissions test, so the airflow sensors have to keep working properly and the engine must not smoke or throw a warning light; and, like any modification, it should be declared to your insurer.

Induction noise itself is not a tested item, so a louder intake roar does not fail anything, though a car that is clearly obnoxious can still attract attention under the general noise rules.

What decides if it's legal

  • An intake sits before the engine and leaves the emissions system untouched.
  • The car must still pass the MOT emissions test (keep the MAF and sensors working).
  • No specific MOT check exists for the intake itself.
  • Declare the modification to your insurer.

Does it depend on your car?

The legality is the same everywhere; what varies is the value. On most modern cars the factory airbox already flows well, so the gain is sound and response more than power. Your car's page lists the intakes confirmed to fit.

Related UK legality guides

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Sources

This page is general guidance, not legal advice, on UK rules for cold air intake. The detail varies by exact vehicle and changes over time - confirm with your insurer and the latest DVSA/GOV.UK guidance before modifying.