Baffle (DBkiller) science?

[Big Block]

On my modern GS (Bandit 1250). It came to me with an obnoxious Two Brothers muffler. It's annoying and cop bait. I have a stock muffler coming but they are pretty darn big. Anyway I built a baffle for it today. Exhaust outlet of the can is 2 inch ID. So I drilled 24x3/8 holes in the baffle I made which is about an area of 2.6496 sq in. The 2 inch comes to 3.142 sq in. Online calculator says a 100HP engine requires a 1.9 inch exhaust so the 2 inch outlet is right inline. Question is do I just drill a few more holes in the baffle to equal the area of the 2 inch pipe or is some flow lost doing the turn (and quiieting the racket) into the baffle and should I overdrill a few more? Hopefully this makes sense to someone who knows something about this.

[Big Block]

Well: I ended up punching a total of 34 holes in the baffle and took it for a long test ride. There feels like no restriction on top end and the tone is really pleasing so I think it's fine although I am going to try to find a place to dyno it anyway just to make sure. The 34 holes in the baffle add up to 3.74 inches which is more than the 2 inch pipe area of 3.142 so I'm pretty sure I am not choking it now. baffling.jpg

[rphillips]

Well done and with waaay more thought put into it than I've ever heard of before. Wrapping the baffle with fiberglass matt, as many come with, will lower the tone of the exhaust note, make it less crackly. Knowing your 3/8" holes will make the matt not last very long, if you try it and like the sound, wrapping a layer of screen wire, tied on with fine wire, before installing the fiberglass matt will make it last a lot longer

[Big Block]

Yes the wrap and screen were on the radar as well. I'm kind of lazy so I was hoping to find some guideline to follow and I never found one. I think other people do what I do and just wing it. I was pretty relieved when it wound up to 9K today without falling on it's face. I made the baffle long so I had plenty of room for more holes if need be. I actually think doing the area calculation got me pretty close, I originally drilled 24 but when I did the math the area was less than the 2 inch pipe so I drilled out an extra 10 to make sure. I was quieter with the 24 but it's quiet enough with the 34.

[rphillips]

Glad it's all good...Congrats.