Originally Posted by afawaterpolo

curacaosfinest: Don't know if this will help but I have a complete vibrant 4 inch exhaust system.

The engine is a 13b-rew full bridge with a cosmo upper and lower thats been ported to the max along with extra porting on the engine to port match the runners. Exhaust ports have been opened up a lot as well.

I'm running a 4 inch down pipe, to a 4 inch vibrant flex section, 4 inch resonator, another 4 inch resonator, a 4 inch race muffler (the little bullet looking one) and finally the 4 inch regular muffler. All the pieces are vibrant.

It is not that loud at all. I can talk on the phone in the car while driving on the freeway doing 75mph.

Here are some pics of the exhaust and a video of it on the dyno (made 703RMHP at 23psi on a mustang dyno, E85) so you can see how loud it is. Oh by the way the dump tube is vented and thats actually the loudest (2.5 inch diameter dump tube).

I'm extremely happy with the exhaust in terms of still being able to talk and not have my ears ringing after driving it for a few hours. Hope this helps.

Here it shows the down pipe, flex section and first resonator



Here it shows the two resonators




Here it shows the race muffler and the last muffler.



Mazda 2 Rotor 703RWHP E85 @ 23PSI on Mustang Dyno 10,500 RPM @ PRT Performance - YouTube

Mazda 2 Rotor 675RWHP E85 on Mustang Dyno 10,500 RPM @ PRT Performance - YouTube