Which B58 Downpipe should I get for the BMW B58 Engine? The BMW B58 is a very capable engine, featuring huge tuning potential for those who are seeking more power. Generally if you're upgrading your BMW B58 Downpipe, especially if you're from Europe or countries that have OPF filters installed from the factory, the first consideration you have to make is which fitment you have got in your vehicle. With simple bolt ons like B58 Downpipes, Intakes, Fuel System Optimisation and a proper remap, these cars push well over 500 horsepower and even more if you go crazy with the mods. In this guide, we will purely focus on the Exhaust system, mainly the downpipe. Especially for Europeans, this guide will be very useful. With our experience with the B58 Downpipes and engines, we are excited to guide you through the proces.

The downpipe is the exhaust part that directly connects to your turbo. The downpipe guides exhaust gases away from the engine and turbo. In most stock applications, the stock downpipe will also feature a Catalytic Converter. A downpipe is commonly regarded as one of the most cost effective ways to gain power together with a remap. It allows the turbo of the engine to be more effective and due to the reduced back pressure, you will also have less turbo lag. An aftermarket downpipe is commonly supplied in two options, Catless and with a High Flow Catalytic Converter. Aftermarket solutions are less restrictive than the stock downpipes. Installing a less restrictive Downpipe together with a remap (usually called a Stage 2 Remap due to the exhaust modifications), you can easily push high horsepower numbers while being relatively friendly to your wallet. A Stage 2 Remap for your BMW B58 is the best bang for buck tuning mod for those who aim for higher performance numbers.

In addition to changing the B58 Downpipe to a less restrictive version will also increase the exhaust sound levels. To most of us who chooses to go with a B58 Downpipe, this is also an added benefit. Generally, changing the downpipe while keeping the stock cat-back in place will not dramatically increase sound levels to an ear-deafening degree. Usually the downpipe modification remains silent until you increase the engine load. It will also be more noticeable during a cold start. If you choose to change the cat-back as well, we recommend to go with a Valvetronic system that is designed for Catless or High Flow Catted applications as these usually also filters out drone from a less restrictive downpipe and can be loud when you want to, but nearly as silent as OEM when you do not want the car to be as loud. They come with Flaps that can open and close with a push of a button to increase or decrease sound levels.

The BMW B58 Engines has been used in a lot of applications. For this guide, our downpipes will be applicable to the following cars, ranging from the 1 Series to the 7 Series (see below). All these vehicles have the BMW B58 Downpipe installed.

• BMW 1-Serie F20 M140i - 2016-
• BMW 1-Serie F21 M140i - 2016-
• BMW 2-Serie F22 M240i - 2016-
• BMW 2-Serie F23 M240i - 2016-
• BMW 3-Serie F30 340i - 2016-
• BMW 3-Serie F31 340i - 2016-
• BMW 4-Serie F32 440i - 2016-
• BMW 4-Serie F33 440i - 2016-
• BMW 4-Serie F36 440i - 2016-
• BMW 5-Serie G30 540i - 2016-
• BMW 5-Serie G31 540i - 2016-
• BMW 6-Serie G32 640i - 2017-
• BMW 7-Serie G11 740i/Li - 2016-
• BMW 7-Serie G12 740i/Li - 2016-

• BMW 2-Serie G42 M240i 374hp - 2021+
• BMW 3-Serie G20 M340i 374hp - 2020+
• BMW 3-Serie G21 M340i 374hp - 2020+
• BMW 5-Serie G30 540i 340hp - 2018+
• BMW 5-Serie G30 545e 394hp - 2020+
• BMW 5-Serie G31 540i 340hp - 2018+
• BMW 6-Serie G32 640i 340hp - 2018+
• BMW 7-Serie G11 740i/745e - 2019+
• BMW 8-Serie G14 840i 340hp - 2019+
• BMW 8-Serie G15 840i 340hp - 2019+
• BMW 8-Serie G16 840i 340hp- 2019+
• BMW Z4 G29 M40i 340hp - 2019+
• Toyota Supra MK5 A90 GR 3.0 340hp - 2019+
• Toyota Supra MK5 A91 GR 3.0 382hp - 2021+

The BMW B58 engine was first introduced in the BMW F-Series Generation of BMWs, approximately around 2015-2016. At this time, BMW did not install OPF filters into their vehicles yet, so for the 2016-2018 generation of vehicles, the United States and EU versions were similar in fitment. This is the BMW B58 Downpipe that features the Slip On connection to the cat-back exhaust. At this time of writing (January 2023) it is still the version of downpipe that the US cars come equipped with from the factory. For the United States, the Slip On Versions still fit. It was when the OPF filters were mandatory in Europe and other parts of the world that the fitments started to change.

In Europe, the OPF filters were introduced around 2018. BMW Also made a change to the fitment of the B58 Downpipes. The connection to the cat-back exhaust has been changed from the Slip On Type to the V-Clamp Version and BMW OPF tubing to the downpipe as well. Generally, the European BMW G-Series (M240i, M340i, M440i etc.) will have the BMW OPF type B58 Downpipe, however, there are some late BMW F-Series B58 equipped vehicles that also have the OPF installed. If you’re not sure, the best way to find out which downpipe your car features is to actually check the connection to the cat-back exhaust under your car and check from above in the engine bay if you’re vehicle features OPF tubing on the B58 Downpipe.

If you're in doubt which B58 Downpipe you need, it is always possible to contact us for help regarding the fitment. Easiest solution is to send us the photos of the connections of the downpipe. Approximate location of the Downpipe to Cat-back Connection (under the vehicle, around the passengers feet location) and the OPF tubing (in the engine bay, passenger side of the engine, on top of the downpipe). Here you will find the information you need to get the correct B58 Downpipe.

Once you’ve determined which downpipe you will need for your B58 engine, you will now have to make a choice between a Catless B58 Downpipe or High Flow Catalytic Converter B58 Dowpipe. They come in a lot of different price ranges.

A Catalytic Converter decreases the harmful emissions from your engine. A catalytic converter contains a ceramic honeycomb or metallic core structure and is placed parallel with the exhaust direction. Modern catalytic converters are designed to maximize the flow of the exhaust gasses while also maximizing the surface area of noble metals that trigger the chemical reaction converting harmful exhaust gasses to cleaner air.

For most customers, the largest factor in choosing between aftermarket Catless and Catted B58 Downpipes is the difference in price and smell. We understand that the Check Engine Light will also be a consideration in this as 200 Cell Downpipes will less likely throw a CEL, but 95% of the people who choose for a downpipe, also opt for a remap in the future. While a High Flow Catted B58 Downpipe is usually cheaper than the OE B58 downpipes, the price of a good High Flow Catted B58 Downpipe is still significantly more than the Catless version. In terms of power output, it is a misconception that a Catless Downpipe automatically makes more power than the High Flow Catted Version. Modern catalytic converters are not as restrictive as they are used to be, especially the premium aftermarket solutions. 

When a customer chooses between a Catted or Catless B58 Downpipe, we advise our customers to take into consideration when running a Catless Downpipe comes with the downside of smelly exhaust gasses. The lack of a Catalytic Converter means that no harmful gasses will be converted and that they will directly leave the tailpipes and enter the environment. You will be able to smell these harmful gasses if you run a Catless Downpipe, which is not only harmful to the environment, but also to yourself and your passengers. You will also most likely fail your MOT and emission tests.

The positive is that the backpressures are significantly reduced, and it is possible to output higher power levels with less turbo-lag as it allows the turbo to spool faster. We recommend Catless B58 Downpipes for those who use their car offroad and are aiming for further tuning. Of course for those who like it, it usually is also a bit louder but also raspier than the catted version.

The High Flow Catted B58 Downpipe Versions reduces the smells of the exhaust gasses significantly, while also providing a huge improvement compared to the OE downpipes. Aftermarket B58 Downpipes usually come with 200 or 300 cell Catalytic Converters. Based on our inspections, the 200 Cell catalytic converters usually fulfil the requirements of the emission tests in most countries, but it is best to check if your local government. The 200 Cell is actually the best of both worlds for a daily driver because it most likely will not fail the emission testing, reduce a lot of the smell and also provide a huge improvement in terms of flow compared to the OE option. It also sounds about as loud as a Catless B58 Downpipe, but with a deeper note to the exhaust sound.

When you opt for a Catless B58 Downpipe , it automatically means you will need a ECU tune, piggy-back tuner or Cat-deleter to prevent the CEL from appearing onto your dashboard.

With the Non-OPF BMW B58 Engines, you might be able to get away with just going for the High Flow Catted Downpipe which in most cases will prevent the CEL from appearing. However, since the B58 is a very sensitive engine, in some cases it will still throw a CEL.

When you opt for a Catless B58 Downpipe , it automatically means you will need a ECU tune, piggy-back tuner or Cat-deleter to prevent the CEL from appearing onto your dashboard.

Please take into consideration that at the time of writing (January 2023) the 2020+ ECU have not been openly cracked for tuners to get into yet, which means the ECU have to be shipped physically to a tuner that is able to crack the ECU. Other solutions will be mentioned below.

With the OPF BMW B58 Downpipe versions, a High Flow Catted Downpipe is likely not enough to prevent the CEL due to a reduced back pressure in the exhaust when you're just changing the downpipe. While this brings performance benefits, the downside is that the ECU will measure a reduced back pressure and throw a CEL. 

Possible solutions for the OPF equipped vehicles with a 2020+ ECU are the LEIB OPF and CAT Deleter, which is essentially a small connector which tricks the ECU in thinking the OPF and CAT is still present. The LEIB solution is Plug & Play installation in about 60 minutes without cutting or soldering. It is not detectable for the BMW dealer and also reversible for those who want to remove it afterwards. We recommend this solution for those who want a more aggressive sound, but not necessarily want to tune the engine yet.

• LEIB OPF and CAT Deleter (no Performance Tune, only prevents CEL)

• Piggy-back ECU Tuner with OPF and CAT Deleter (Performance Tune Possible)

We have plenty of BMW B58 Downpipes available in our store. See our recommendations for the Non-OPF Versions below:

Photo taken at DB Autotechniek - BMW / MINI Specialist - www.dbautotechniek.nl 

DCE Parts offers a cost effective and high quality non-OPF version downpipe with great fitment.

DCE PARTS - B58 4.5 INCH DOWNPIPE - F & G CHASSIS - BMW M140I, M240I, 340I, 440I, 540I, 640I, 740I & XDRIVE - (SLIP ON CLAMP TYPE - NON-OPF)

VRSF B58 DOWNPIPE UPGRADE 2016+ BMW M240I/340I/440I/540I/740I & XDRIVE

MASATA BMW B58 CATLESS DOWNPIPE (M140I, M240I, 340I, 440I & 550I)

See our recommendations for Downpipes for vehicles with the BMW B58 with OPF below:

DCE Parts offers a very cost effective OPF version downpipe and in the market, our actual go-to solution due to the great fitment and great OPF solutions.

DCE PARTS - B58 4.5 INCH DOWNPIPE - F & G CHASSIS - BMW M240I, M340I, M440I, 540I, 640I, 745E, 840I, Z4, SUPRA & XDRIVE - (OPF & V-BAND FLANGE TYPE)

ARMYTRIX B58 OPF DOWNPIPES

Catless B58 Downpipes are the least restrictive and offer the most performance benefit if tuned correctly with accommodating parts. The difference for street applications is not always hugely noticeable and for daily driven cars, we'd recommend 200 Cell High Flow Catted B58 Downpipes in most cases due to the reduced smell and MOT and Emission requirements. Catless B58 Downpipes are also technically against the law for street applications, so the 200 Cell HFC B58 Downpipes offer a great balance between performance. 

For tuning, opting for a High Flow Catted B58 Downpipes will allow you to push high horsepower numbers and your exhaust system will still be able to handle the increased air flow from the accommodating performance parts and tune. 

For the B58 vehicles without OPF, it is a straight-forward Downpipe swap that require a tune for those who go full Catless. Those with a High Flow Cat will in most cases be able to get away without a tune and not get a CEL. This varies from vehicle to vehicle though. For B58 vehicles with OPF installed, there are many ways to prevent the CEL, however, this always come with added costs, for example the LEIB OPF and CAT delete or a piggyback tune. For vehicles with a tuneable ECU (Pre-2020), you're able to flash the ECU for the CEL. 

Please note that any modifications to the engine, downpipe or ECU will void factory warranty unless stated differently.

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