I know there are 2 cats on the stock ss down pipe , but the other skinnier round cylinder half way to the rear -Is that not a resonator ? Its welded in & as well as the muffler - Is a resonator that restrictive ?
already have catless down pipe -- so from the down pipe back there are no bolt up to flanges , So To get rid of the resonator ,would have to get the whole thing including the muffler ? just dont know how restrictive a resonator is if that is what that is

 

Yes that is a resonator, you could cut it out and weld in a straight pipe, or a cherry bomb style muffler, It won’t effect the power very much , but will increase the noise level of the exhaust.

This Magnaflow 16811 cat back deletes the resonantor completely



16811 for the 2.0 HHR SS

https://performancepeddler.myshopify...ducts/mag16811

 

Thank you - exact info I wanted !

 

Gee, and I don’t even own an SS! But I read a lot!

 

Or, you could just trust the engineers that calculated the optimum back pressure for the engine. There are good reasons for resonators.
Maybe you are smarter than them.

 

Don `t doubt
he is very clever