Project E46 M3: Part 11 – Castro Motorsports air box installed and dyno tested!

This is where it splits into a twin 3-in system.  The fab work looks very clean.

The twin 3-in piping routes its way out to the tail pipes.  Since the exhaust tips themselves look nothing out of the ordinary, this car is a total sleeper.  The only tell-tale sign of heavy upgrades will be the sound of the exhaust, since it's got no mufflers.  It will be loud, even on a turbo car.  Hey that rear diffuser looks similar to the Khoalty unit we installed on our Project E46 M3 last time in Part 10.

If you were curious about how our new Castro Motorsport intake plenum sounds, I took a quick phone video as I climbed through a couple of gears, in order to give you a taste.

 

In this second quick clip, you can hear the what it sounds like approaching you.  It's quite the roar, and reminiscent of an E36 M3, only slightly louder.

Lastly, stay tuned as we tinker with this sleeper BMW E46 M3 sporting a Horsepower Freaks turbo kit worth over 700whp!