I really hope that you are joking about making your sled 'LOUD!!!' with all the stuff going on in the sledding world these days, meaning that we are losing riding areas and having more restrictions put on us all the time. Intentionally making your sled louder is not doing your fellow sledders any favors. There are lots of ways to gain performance without making more noise. I see that CatWoman already provided the appropriate link, please take the time to read it and then make an informed choice. Your fellow sledders will thank you.