Are aftermarket modifications contributing to altered emission profiles?

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Are aftermarket modifications contributing to altered emission profiles?

Discuss the impact of non-OEM air filters, performance exhausts, o r ECU tunes. Do owners installing such modifications observe higher emissions, o r cleaned-up throttle response?

Qalb E Momin asked on 10 Jun 2025 17:46:44 pm

1 Answer

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Car Mechanic Expert - on 10 Jun 2025 17:50:23 pm

Yes—common aftermarket mods affecting emissions:

Non-OEM air filters → turbulence → poor MAF readings → rich running → black smoke.

Performance exhausts → reduced back pressure → MIL lights P0420.

ECU tunes:

Some raise fueling under boost, increasing HC/CO.

Others improve throttle response but disrupt emissions compliance.

Owners often observe:

Improved throttle but higher soot.

CEL lights after installing free-flow exhausts.