Just as a data point: The top ITS guys in the Northeast run the Dynomax Ultra Flo in 3" format with the tip pointe dthe appropriate direction. 99-100dB is common.
The ISC system is pretty nice. They make stuff for 1st and 2nd gens. Check here:
I use the same brand muffler as Andy only I use (2) Dynoflow 2 1/2" I/O, I have (2) 2 1/2" pipes from my header flange straight back to the pumpkin, where they split going under the rear end to either side of my fuel cell. from the pumpkin back there wrapped with heat wrap to keep fuel pump/ diff/ fuel cell from getting hot, works too you can touch them after a session. this setup is around 97-98 DB which allows me to run laguna without black flag worries should I hold a gear going past the sound station cause the guy in front of me is backing off a bit for it.
[This message has been edited by 7'sRracing (edited February 13, 2004).]
Eddie started the thread, Andy added some & Daryl threw some more into the mix.
I am going to convert my Spec-7 to ITA/7 & have many questions of knowledgeable rotary folks. With the Spec-7, cast iron header & 2 1/8 O.D. all the way back, straight out/no turn on a 45* day it blows 100db.
Andy, do you have the complete ISC system including the expansion chamber in the section after the header ? IIRC from Karting in the early 90's the expansion chamber speeds up the exhaust draw out of the motor.
What are the thoughts advantages/disadvantages of a single pipe exhaust or a 2 pipe system like Daryl uses ?
I built this exhaust system at the same time I did some intake swapping so I didnt get any idea of which netted me 9 HP on the chassis dyno but the gain was there, then EEEEEEEEEUUUUUUUUUOOOOOOOOOOO.....silence