B58 Downpipes for BMW M340i, M240i & GR Supra | AutoTalent

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A B58 downpipe is the biggest single bolt-on for the BMW 3.0L turbo six. It replaces the restrictive factory catalytic converter right after the turbo, cuts exhaust back-pressure and lets the turbo spool faster. We stock catted (GESI and high-flow) and catless B58 downpipes for the M340i, M440i, M240i, 340i,...

A B58 downpipe is the biggest single bolt-on for the BMW 3.0L turbo six. It replaces the restrictive factory catalytic converter right after the turbo, cuts exhaust back-pressure and lets the turbo spool faster. We stock catted (GESI and high-flow) and catless B58 downpipes for the M340i, M440i, M240i, 340i, 440i, 540i, X3/X4 M40i, Z4 M40i and Toyota GR Supra.

Active AutoWerke B58 downpipes

Our best-selling B58 downpipe is the Active AutoWerke GESI catted downpipe for the G20 M340i / G22 M440i. For F-chassis cars, choose the Active AutoWerke AFlow catted downpipe for the M240i / 340i / 440i. 2025+ cars use the B58N GESI downpipe with GPF. See all Active AutoWerke downpipes.

Fabspeed sport cat downpipes

Fabspeed builds sport cat downpipes for the BMW Z4 M40i and the Toyota GR Supra A90.

VRSF downpipes

VRSF covers the G20 M340i / M440i, the F-chassis M240i, 340i, 440i and 540i and the GR Supra. See all VRSF downpipes.

AMS Performance Supra downpipes

For the A90 Supra, choose the AMS street downpipe with GESI cat or the AMS race downpipe.

A downpipe needs a tune: see the Bootmod3 B58 tune and all B58 performance parts. Finish the system with an M340i exhaust or a Supra exhaust.

FAQ

Do I need a tune with a B58 downpipe?

Yes. A downpipe changes exhaust flow and the O2 sensor readings, so pair it with a tune to avoid check-engine lights and get the full power gain.

Catted vs catless B58 downpipe: which should I buy?

A catted downpipe (GESI or high-flow) keeps a catalytic converter, so it's quieter, avoids a raw fuel smell and is the right choice for street cars. Catless downpipes are for off-road and competition use only.

Which downpipe fits my M340i?

2019–2024 G20 M340i and G22 M440i cars use the G-chassis B58 downpipe; 2025+ cars use the B58N version, and OPF/GPF cars need the matching OPF version. Check the title, or text us your VIN.

Do M240i and 340i downpipes fit the M340i?

No. The F-chassis M240i, 340i and 440i use a different B58 downpipe than the G20 M340i. Pick the product that names your chassis.