Project E46 M3: Part 2 – Cat-back Exhaust and Pulleys


MKC technician, Nelson, quickly got to work on our pulley installation.  You’ll want to allow a few hours for this.  Notice the intake system is gone, and now he’s getting to work on removing the fan shroud and fan.

Removing the shroud is a more complicated procedure on an E46 than it is on an E36 M3.  We won’t bore you with the details but, as a previous E36 M3 guy myself, I’d much rather have to work on an E36 M3 than E46 M3.

A view of the VAC water pump pulley going on.  It’s possible to do this job without removing the radiator or alternator, but it is a tight fit.

With the pulleys installed we felt a noticeable difference.  And, while our peak horsepower numbers only went up by a handful, there were several areas between 7000-8200rpm where the gains surpassed 8whp.  Not a bad, uncompromised bang for your 250 bucks in the M3 world!

All told, we gained 12 horsepower at 7000rpm and 5 lb-ft of torque at 4300 rpm with our new Corsa cat-back and VAC pulleys installment.  The car feels stronger—like on a colder day—with a 4whp gain throughout the midrange and an average 7-8whp gain in the upper revs.

While we couldn’t get good torque readings, we had to plot against vehicle speed.  However, looking back at the broken-up graphs we could see peak torque figures rising from 248 lb-ft (from our baseline) to over 252 lb-ft, with the largest gain being 8.2 lb-ft at around 3200 rpm (54mph) with our exhaust and pulleys combo.


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