No More Exhaust Myths

Indycars

Indycars

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I found this Youtube video on exhaust systems and found it very
informative. I'm looking to replace my headers with something
new and different if possible. If the cost doesn't get out of hand.

I also need to understand how sound energy is decreased by a
muffler so I can install the right kind in the header extension.

 
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I watched this video again, and I was reminded of things I'm sure I learned before, now I'm learning
it again. Richard Waitis talks really fast, so be prepared to stop and rewind a few times.

- Exhaust gases don't like to turn, especially coming out of the exhaust port.
- Passive vs Reflective muffler design, starts at 15:37.
- Sound velocity in the exhaust port is ~~ 1100 ft/min.
- "4 into 1" is good for peak TQ/HP curve, think drag racing.
- "4 into 2 into 1" OR Tri-Y is good for a broader curve, think road racing.
- Exhaust system primary diameter is based on 2 cfm/hp.
- Assuming a dual exhaust for a V8, 500 cfm is the break point between a 2-1/2 and a 3 inch exhaust pipe, starts at 12:38.
- An absorption muffler can flow more than a straight pipe.

And ..... keep watching to learn more!
 
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I wish they would have taken the 3 inch and test at each joint. Another words, leave everything
off from the muffler back including the muffler. Then put the muffler on and test, then add the tail
pipe and test.
 
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Ive seen similar tests,
(no tail pipe rear of the muffler vs longer tail pipe)
and to many people amazement, the added tail pipe length added, after the muffle if it was still a dual full length exhaust of 3" diam.
rarely cause much of a drop in power and in one test it even allowed about 1 -2 extra ft lbs below 3500 rpm.
with no big upper rpm loss.
and as with most parts , careful accurate measuring before you buy parts will tend to reduce mistake and reduce wasted time and effort,
and yeah, owning a decent TIG or MIG welder and knowing how to weld is a huge advantage
https://www.jegs.com/i/JEGS/555/306...MI-_nu5ayV5gIV7ffjBx3SwgpBEAQYBCABEgLQa_D_BwE



 
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