Cut It Out

Cut It Out

Today, we return to the saga of Kris Boss’s Phoenix Yellow M3 with a bit of exhaust work.

When we last looked at the M3, the second section of the exhaust was removed in order to add the cutout. Here’s the cutout in question, the same brand we used for Nick’s M3, along with almost every other cutout we’ve done. The first step in the process is to give the exhaust piping a nice ovalesque hole to connect to the cutout. So we drilled the hole in the pipe, which we then smooth out to the intended size (shown by the marker outline). It’s then tacked in place.


Then, with the tacks holding the cutout where it should be, we welded it into its permanent resting spot.


After the welding finished, we put together a small dump tube to angle the exhaust gas away from the differential and towards the ground instead.


At this point, we cut out a chunk of his midsection closer to the middle. There was a slight point of contact between the exhaust piping and the heat shield, so we reengineered the pipe to bypass that issue.


And of course, with all weld jobs at work comes everybody’s favorite type of pornography — weld porn!


So here she is, all put back in place with no contact and some extra loudness to boot.


You may find yourself asking, “What’s next for this Bavarian beast?” Well, as we all know, power is addicting. Once you get some of it, if you have the means, you’ll want more of it. And that’s exactly what we’re helping Kris to set up right now. Stay tuned for the next round of work to take place!


  • christian
    Posted at 19:10h, 26 June

    oh my god.. i want this 1) and 2) i want to hear it

  • Ciarán
    Posted at 09:43h, 27 June

    “How much to ship my car to you and do all of the above” …an email I wish I could send you 🙁 Someday…someday…

  • Sam
    Posted at 14:32h, 30 June

    By putting a cut out in the exhaust, with the extra bit of piping into it etc, aren’t you disrupting the air flow quite badly?

    Also when the valve is open, won’t a large proportion of the gases still flow past it as the flow would have to change directions? Or does the lower air pressure of the fast flowing air under the car mean that the gases exit through the valve?

  • fluidmotorunion
    Posted at 07:16h, 02 July

    It wasn’t done with the intent of causing additional airflow underneath the vehicle; Kris wanted the cutout for one reason and one reason alone — to get louder than he can without a muffler, without having to have that noise 24/7. The location we’ve chosen allows for the best level of growl and rasp — any further upstream, and the sound isn’t really that desirable. The lower air pressure does contribute to pulling the exhaust gas out, as it’s following the path of least resistance out of the system.

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