Active Autowerke F3X M235i/335i/435i N55 AFlow Downpipe

This is the AFlow version of the Active Autowerke Signature N55 downpipe for the BMW F22 M235i, F30 335i, F32 435i and 2016-2018 F87 M2. It uses Active Autowerke's own 4.5 in AFlow high-flow cat with 3.5 in stainless piping, at a lower price than the GESI version.

The single-turbo N55 in the F-chassis 3 and 4 Series, the M235i and the first M2 is held back by the factory downpipe and its restrictive cat.

The Active Autowerke AFlow catted downpipe for the BMW M235i F22 2014-2016, 335i F30 2012-2015, 435i F32 2014-2016 and M2 F87 2016-2018 delivers a measurable improvement in exhaust flow and turbo response while remaining fully OBD2 compliant with no check engine light. The Active AFlow high flow catalyst uses advanced substrate technology to maximize flow while keeping emissions within OBD2 thresholds. Paired with 304 stainless steel mandrel-bent piping, this is a bolt-on upgrade that improves throttle response, reduces turbo lag, and adds a more aggressive exhaust note — all without triggering a CEL. OBD2 compliant — no check engine light (CEL)

What It Does

A freer downpipe lets the turbo spool sooner and gives a tuned N55 room for more power, with a deeper sound. Active Autowerke replaces the AFlow cat in full within the first two years of ownership.

Materials and Construction

Full TIG-welded 304 stainless steel. The 400 cpsi substrate is furnace-brazed to the mantle. Bolt-on, no cutting or welding.

Features

• 4.5 in Active AFlow high-flow cat with 3.5 in piping
• 400 cpsi stainless catalyst substrate
• Full 304 stainless steel
• AFlow cat replacement within the first two years from Active Autowerke

Specs

• Part number: 11-040A
• Brand: Active Autowerke
• Type: catted downpipe
• Catalyst: Active AFlow, 4.5 in, 400 cpsi
• Piping: 3.5 in
• Engine: BMW N55 3.0L turbo inline-six
• Shipping weight (Active Autowerke): 30 lb (13.6 kg)

Fitment Notes

• Active Autowerke says this downpipe fits F-chassis N55 cars built from 09/2013 onward only. Early 2012-2013 335i cars (built before 09/2013) may not fit, so check your build date or send us your VIN.
• 5 Series N55 cars need a different model; contact us.
• Active Autowerke covers the shell and tube ends for 5 years / 50,000 miles and the catalyst core for 2 years / 25,000 miles, for the original buyer. The warranty is void if the car runs excessive burble (more than stock), because that physically destroys the catalyst core.
• Active Autowerke states fitment for US-model cars only.
• Questions before you order? Call or text (310) 231-0292 or email Online@AutoTalent.com.
• Shop all Active Autowerke downpipes, every catted downpipe we carry, or the full Active Autowerke range.

FAQ

Is this a catless downpipe?
No. It has a high-flow catalytic converter built in.

Do I need a tune?
A tune is recommended to get the most from any downpipe. Ask us if you are unsure which tune suits your car.

GESI or AFlow?
Same downpipe, different cat. AFlow costs less; GESI is 11-040.