Question on Steve Wong dyno chart

[Maxhouse97]

See the chart below:


When the chart references "pre muffler, 2-2 sport muffler, chip 91 oct", I take that to mean a two in, two out muffler. My question is with a pre muffler, it is implied that the stock HEs remain, which by definition conflicts with a 2 in 2 out muffler, no? The pre muffler (or cat) is there to route the exhaust from both banks of the engine through a common pipe - what sense would it make to split them back up after in order to fit into a 2 in muffler?

I am asking to better understand the chart and to see if there is better exhaust configuration with a pre muffler as opposed to SSIs.

[Elombard]

Good Catch I bet that is a mistake and should say 1 in 2 out. Some great numbers there on some of the set ups.

[Maxhouse97]

Yes I thought he must have meant 1 in 2 out but just wanted to be sure.

[gliding_serpent]

This is a great chart, and i always took it as 1 in 2 out. The next question is, what makes a sport muffler?

[jeffbottman]

Interestingly, my 3.2 dynoed out at 240 HP with premuffler, 1 in/1 out muffler, and Steve Wong chip. I would have expected a 2 in/2 out muffler to produce more power, but no. From the chart, I'm doing about as good as you can do given relatively mild but nice sounds.