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Engine basics => Engine set up tips => Topic started by: Motorman on July 14, 2016, 07:48:43 PM

Title: Tongue muffler Holes
Post by: Motorman on July 14, 2016, 07:48:43 PM
Venturi size gets talked about allot but what about the exhaust. Is there a formula for how many and how big to make holes in a tongue muffler? I've got an OS max S 15 side exhaust, the one made after the steel fin and before the FP, and I need to make a light weight muffler for it.

Should I calculate on the area of the exhaust port, copy it or reduce it? Not using muffler pressure but want to cut down the noise a little without loosing power.

Thanks,
MM
Title: Re: Tongue muffler Holes
Post by: RandySmith on July 14, 2016, 09:15:41 PM
Venturi size gets talked about allot but what about the exhaust. Is there a formula for how many and how big to make holes in a tongue muffler? I've got an OS max S 15 side exhaust, the one made after the steel fin and before the FP, and I need to make a light weight muffler for it.

Should I calculate on the area of the exhaust port, copy it or reduce it? Not using muffler pressure but want to cut down the noise a little without loosing power.

Thanks,
MM

You can use 12 -  5/64th  holes, you will still hve good power, and you can tweek it by tapping 4/40  and blocking up 1 or 2, or...  opening 1 or 2 holes to a larger  size, this will depend on venturie size

Randy