BMW Z4 M40i OPF Decat Downpipe B58 | MTC Motorsport

MTC Motorsport BMW M340i 440i 540i 640i 740i and 840i 4.5” stainless steel decat downpipe for B58 OPF engines only.

• The Z4 M40i downpipe is machined from SS304 aircraft-grade stainless steel and are tig welded in house
• The B58 downpipe is made of 3.5" stainless pipe straight out of the turbo providing a sharper throttle response due to faster spool of the turbo
• This downpipe will provide noticeable power gains and a much more aggressive exhaust note which sounds truly amazing
• It produces lower temperatures and less exhaust backpressure due to the relief of the turbocharger. Also, the cylinder charge is increased
• There is also a substantial weight saving in comparison to the factory catalytic converter.
• The decat is mandrel-bent for better gas flow and maximum internal size to ensure ultimate performance without the loss of mid-range torque.  

This downpipe will fit the following models with OPF/PPF only:

• BMW G20/21 M340i 3.0L 285KW/374PS 2019 OPF Model
• BMW G22 440i 3.0L 285KW/387PS 2019 OPF Model
• BMW G30/31 540i 3.0L 250KW/340PS 2018 OPF Model
• BMW G32 640i 3.0L 250KW/340PS 2018 OPF Model
• BMW G11/12 740i 3.0L 240KW/326PS 2019 OPF Model
• BMW G14/15/16 840i 3.0L 250KW/340PS 2019 OPF Model
• BMW Z4 G29 M40i 3.0L 250KW/340PS 2019 OPF Model
• Toyota Supra MK5 A90 GR 3.0L 250KW/340PS 2019 OPF Model

Original BMW part number 18329897313.

We have tested this product and found increases of around 20-25bhp.

Professional installation is recommended as some exhausts sit slightly different from others and can be tight although the feedback we have received from this product is that it is very easy to fit.

Please note, you will need to swap the gasket in the turbo end of the downpipe over or you will get a smell of fuel in the cabin.

We also recommend purchasing a Lambda Sensor Spacer(s) to prevent the engine light coming on in most cases. If you search our other items you will find these. 

If you would like this product fitted to your car in our Lancashire workshop please give us a call and we can arrange this and also do an exchange with your original cat which usually covers the cost of the downpipe and fitting from us.