upstate wrote:I believe if you check with GM parts that the exhaust system has only one Cat, that being the one built into the exhaust manifold. Two O2s one up and one down stream.The other is a resonator that is removed when installing some of the after market Cat back exhaust systems out there. BB being one of them...
Interesting. My Gibson cat-back started behind what I thought was the rear cat. The header removes the manifold and front cat. This leaves the squashed mid-pipe with something in it that looks like a small cat. Like I said earlier, I didn't see any other O2 sensors along that mid-pipe. What is the purpose of the resonator? Reduce noise?
stubborn3: It's hard to say if it's worth it for you. It's worth it for me. You can see the mods I've done in my sig. There is a noticeable difference in the driving power. Not necessarily in the flat out 0 to 60 for me (maybe because of the 5 speed?), but in the driving on the highway where I no longer have to downshift to 4th gear to make it up hills.
daniel, I think pup has an auto tranny too. Maybe that's why he noticed more of a difference than I did, since it effected his shifting?
2007 H3 5 speed, Adv/Lux, Eaton TVS 1320 supercharger, Gibson tail pipes, Flowmaster 50 Series muffler, custom mid-pipe, Long tube header, Custom tune, Custom cold air intake, Coil pack mod, Ported throttle body, Ron Davis radiator, SAW torsion bars, Samco shackles, Fox shocks, Trail Duty bump stops, Rocky Road rock sliders w/Line-X coating, Tomp rear shock skids, 35" Dick Cepek Crusher tires w/Tactical Rims, Gobi Stealth Rack w/ladder, shovel/axe and Hi-Lift mount