Turbocharged vehicles love free flowing exhaust. The most restrictive
part of the exhaust on the CLA 45 and A 45 cars is the downpipe. The
factory downpipe contains a catalytic converter and has a very
restrictive cross section where it passes between the engine and the
subframe. The Weistec M133 Downpipe for the CLA 45 and A 45 is designed
to have the best possible flow without any permanent modification to the
engine or chassis and even makes use of the factory exhaust hanger.
Countless hours were spent designing and testing the downpipe to ensure
OEM fit and finish as well as prevent any check engine lights.
Right off the turbo, the downpipe has a 3.5” diameter, perfectly
matching the outlet of the turbine housing. The 3.5” pipe routes down
under the engine to a flex section. After the flex section the piping
tapers to 3” diameter. This section of the pipe uses a V-band connection
to mate with midpipe that runs between the engine and the subframe. The
midpipe mates to the factory or AMG sport catback exhaust.
The upper portion of the downpipe comes standard with external
Titanium Ceramic Coating and internal Copper Ceramic coating to keep
heat inside the piping, maintaining exhaust velocity and reducing engine
Additional to the Exhaust System is the M133 Heat Sheild
which features 100% stainless steel construction with interlocking side
panels to ensure solid fit and finish. Providing function as a heat
shield while improving under hood appearance. Testing shows under hood
temps at the turbo drop as much as 15 degrees F compared to the original
Some cars will experience a check engine light if Exhaust System is
installed without proper ECU tuning. For maximum performance and gains, a ECU Software upgrade is highly recommended.