BMW B58 40i (140i to M340i) Exhaust Guide

2 min read

The B58 is a turbocharged inline-six used in the 140i, 240i, 340i, 440i and M340i. KHH lists made-to-order downpipes for the first four, and exhausts for the 340i, 440i and M340i. This guide explains the choices.

Which parts KHH lists for the BMW B58 40i cars

Delivery is free worldwide.

What each part does on the B58 engine

The downpipe is the first section of exhaust after the turbo. Every exhaust gas leaving the engine goes through it, so it is a key part of the system. Each car has its own downpipe listing, and all four are priced the same.

The exhaust is the rear section. It carries the gas to the tips and sets how the car sounds. Valved exhausts are quieter when the valves are closed. KHH lists an exhaust for the 340i, one for the 440i and one for the M340i. Read each product page to see which valves, tips and finish are used.

Gas leaves the engine, spins the turbos, then flows through the downpipes, the midpipe and the exhaust to the tips. Each section is a separate part, which is why you can buy them in steps. Every part is made to order, so it is built after you place your order.

How to choose: one part or the full system

If you are new to this, start with the downpipe. It is one part, and it is the lowest priced item on this list. The exhaust costs more and changes the rear of the system.

Choose both when you want the whole path from turbo to tips to match. You can buy the downpipe now and add the exhaust later. Delivery is free either way.

What to check before you order

Write down your chassis code, model year and engine before you start. Keep your registration card close, so you can compare it with the Fits list. If the list does not match your car, do not order that part. If you are unsure, ask us on WhatsApp first.

  1. Exact chassis and years. Open the product page and read the Fits list. Match your chassis code and model years to it before you buy. Each listing is for one model, so a 340i buyer should not order the 440i part. The M340i has its own exhaust listing, so check the Fits list on that page.
  2. Tune. A tune may be needed after a downpipe, and some cars show a check-engine light without one.
  3. Road or track. Some parts are for road use and some are for off-road and track use only. Check the rules where you drive.

Questions? Chat with us on WhatsApp.

Next step

Browse all BMW B58 40i cars parts. For more background, read Downpipe, midpipe or exhaust: what is the difference and Is a downpipe legal in the UAE?.