QHCE M135i / M140i Catback — BMW F20 / F21 (N55 / B58)
QHCE M135i / M140i Catback — BMW F20 / F21 (N55 / B58)
VALVETRONIC
Whisper to wide‑open.
Valves shut, it’s refined enough for a 6 a.m. start. Valves open, it roars. Flip the valves and hold the throttle — feel it climb.
Verify fitment with your vehicle
Confirm this kit is engineered for your exact car before checkout.
The M135i / M140i is the sleeper six-cylinder hot hatch — N55 then B58 turbo power in a shell nobody expects. This catback gives the straight-six its proper snarl.
FITMENT
| Chassis | F20 / F21 (M135i / M140i) |
|---|---|
| Years | 2012 – 2019 |
| Engine | 3.0L turbo inline-six (N55 / B58) |
| Trims | M135i, M140i |
| Mid-pipe flange | OEM, bolt-on — no cutting, no welding |
SOUND PROFILE
Closed: civil. Open: full B58/N55 straight-six howl with decel crackle.
Measured at 50 ft, idle, ambient temp. WOT pulls 8-12 dB higher.
MATERIAL SPECS
- Pipes: T304 stainless, 1.5mm wall, 3" mandrel
- Welds: TIG-welded, back-purged, X-ray inspected
- Muffler chamber: Twin-valve bypass
- Tips: Polished stainless quad
- Heat shielding: Multi-layer titanium foil + stainless wrap on muffler section
WHAT'S IN THE BOX
- Full catback assembly (mid-pipe + muffler + tailpipes)
- Pre-installed electronic valve actuators (CNC-machined billet)
- Wireless remote (anodized aluminum fob)
- Key-chain switch + cabin-mount controller
- All OEM-spec hardware, gaskets, V-band clamps
- Printed install guide + digital fitment notes
INSTALLATION
1.5-2 hours on a lift. Bolt-on, no cutting, no tuning. New gaskets and clamps included.
SHIPPING & LEAD TIME
| Production | ~7 business days — every kit is built-to-order, TIG-welded and QC'd before it leaves the floor. |
|---|---|
| Freight | 4–5 business days, continental US, fully insured + tracked. |
| Total time to door | Roughly 2.5 weeks from checkout to delivery. |
| Shipping cost | Free on orders $1,000+ in the continental US. AK / HI / international quoted at checkout. |
| Notes | You'll get a tracking number the moment the kit ships. Any production delays are flagged in writing the same day. |
WARRANTY
Lifetime structural warranty on the pipes. 2 years on electronic valve actuators and remote system. 1 year on cosmetic finish.
For off-road / track use only. Not CARB-certified. Loud — check local laws before street use.
PRODUCTION
Built-to-order, TIG-welded, QC'd before freight.
FREIGHT
Continental US. Fully insured + tracked.
FREE SHIPPING
Continental US orders over $1,000.
STRUCTURAL WARRANTY
Lifetime on pipes · 2 yr on electronics.
BUILT TO ORDER
ORDER TODAY. HERE'S YOUR TIMELINE.
BUILD SLOT RESERVED
Order locked. Your kit enters the fabrication queue same day.
FABRICATION COMPLETE
TIG-welded, leak-tested, QC'd, crated. ~7 business days.
FREIGHT
Insured + tracked across the continental US.
AT YOUR DOOR
Bolt-on install, no tune. First cold start that afternoon.
Dates computed live from today against the standard 7-day build + 4–5 day freight window. You get an email at every step.
WHAT'S IN THE BOX
EVERY KIT INCLUDES
- 01
FULL CATBACK SYSTEM
Mid-pipe, valved muffler, and tailpipes. Direct OEM flange fitment.
- 02
ELECTRONIC VALVE + ACTUATOR
Pre-installed and wired. Just plug into the included controller harness.
- 03
WIRELESS REMOTE
Glovebox-friendly fob. Open / close / auto.
- 04
KEY-CHAIN SWITCH
Smaller fob you can leave on the keyring.
- 05
IN-CABIN CONTROLLER
3M-mount it on the trim. Toggle from the driver's seat.
- 06
QHCE-LASERED CARBON FIBER TIPS
4-out tips with a subtle QHCE logo laser-engraved on the inside.
THE BADGE TAX, ITEMIZED
SAME ARCHITECTURE.
NONE OF THE MARKUP.
You're not paying less because it's worse. You're paying less because there's no importer, distributor, dealer, and ad budget between you and the workshop.
| QHCE | NAME-BRAND VALVED SYSTEMS | |
|---|---|---|
| This kit, delivered | $1,299.00 | $3,000 – $7,000+ |
| Electronic valve control | Remote + keyfob + cabin switch, included | Controller often sold separately |
| Construction | T304 stainless · carbon tips | T304 / titanium |
| Tune required | None — pure bolt-on | None |
| Structural warranty | Lifetime | 1–5 yr typical |
| Lead time | ~2.5 weeks, built to order | Frequently backordered |
Name-brand figures reflect typical published pricing and policies for electronically valved catback systems, mid-2026. Same valve architecture, same weld type — the savings come out of the middlemen, not the hardware.
