I failed the noise levels for my emissions test. I have SLP shorty headers w/ a carsound 3" hi flow cat and a brand new hooker catback system. I have a couple questions...how can I make the system more quiet?? If I take off the dual tipped hooker tips and have just single tips, does that make a difference? Maybe if I temporarily replace the hooker tips with some crappy smaller diameter tips, would that quiet the engine down enough? I am at 99dB and I have to get alllll the way down to 93dB. That's a big step. ANY help would be greatly appreciated! Any other ideas besides replacing the entire muffler just to pass sound levels???

Thanks.

 

Potato in the tailpipe

 

Striaight through bullet or twister bullet in the I pipe.
The twister will definately do it by 10 db. Then you can take it out.

 

I believe it is dynatech that makes a perforated cone called the vertex. Summit sells them.The weld in the collector and they are a perforated cone with the surface area of the cone equals to approx. 3.5 diameter so virtually no backpressure is developed, yet it quiets the exhaust note. I welded one in each collector,(you can also bolt them in) and my car no longer sounds like a winston cup car( Nextel sounds to weird and gay).