Ian, I really think you should get the Thermal :):D:burnout:
… I dunno why tho :shrug: 
archivethis
That’s really a cool chart. Now my question, does this equation take into accounts the catalytic converter, resonator, muffler, and bends throughout? All these affect exhaust velocity. Therefore, although 3" piping is not ideal in this equation, I would think with the added restrictions through your typical streetcar exhaust setup, larger diameter piping helps balance it out more. Just a thought. I agree totally with what your saying about Tuner magazines altering dyno’s to promote advertisement, but I’ve seen in REAL world applications larger exhausts increasing performance. Not only at the track but at dyno sessions-without magazines.
i can tell you from experience that when i switched from my custom 2.5" mandrel bend exhaust with a thermal muffler to my 3" thermal i noticed a difference not really on the top end (though i was only boosting 8psi at the time), but the low-end response was much better. many other people on other boards such as honda-tech will also attest to good gains from an exhaust switch. it’s not all about dyno charts in magazines & conspiracy theories.
and to construct a custom 3" exhaust won’t cost much more then having a custom 2.5" exhaust made. in fact, there’s a couple group buys on honda-tech for 3" piping right now. i just bought the premade thermal because i liked the fact that it is full-stainless & will hopefully last longer then a custom one if i had one made from aluminized steel.
Originally posted by integracon
That’s really a cool chart. Now my question, does this equation take into accounts the catalytic converter, resonator, muffler, and bends throughout? All these affect exhaust velocity. Therefore, although 3" piping is not ideal in this equation, I would think with the added restrictions through your typical streetcar exhaust setup, larger diameter piping helps balance it out more. Just a thought. I agree totally with what your saying about Tuner magazines altering dyno’s to promote advertisement, but I’ve seen in REAL world applications larger exhausts increasing performance. Not only at the track but at dyno sessions-without magazines.
The extra velocity under 250 ft/sec on 2.5" (67 ft/sec) should have no problem over coming the current high flow, straight through, mufflers that are on the market and mandrel bends help too of course…
I guess physics equations aren’t REAL world enough…I’d better let NASA know :crazy: