Sorry for the delay in responding I don't think my notifications are setup correctly.
Anyway I did not understand you reply to my post?

"it can be to to an ls or lt"

Could you please further explain?

Thanks again

 

The ls or lt are model designations. Basic LS, LT (there is a LT1 = 2.2L engine & a LT2 = 2.4L engine - major differences ) & SS , IIRC ...

 

Easiest way is to cut off that restrictive garbage can sized stock muffler and replace it with a small performance style one. It won't "mess" with the computer.
This is what I went with on my SS. No drone sound that you get with some aftermarket mufflers. Saves some weight also. Description is in my signature.

 

The stock muffler ISN'T restrictive...
It's a straight-thru muffler, using 2.75" tubing...
The stock resonator, uses 2.5" tubing, & the tubing to the muffler is also 2.5".

GM did a wonderful job with the HHR SS exhaust system.
The restriction point, for all out performance, is the 2nd cat...
By simply 'coring' the 2nd cat, I ran 12.4s at the track, with the mods in my signature...

 

Sorry 2005HHRauto.
I should have been more clear about who I was talking to. My answer was for "n0m0n" who has a LS 2.2.

I know all about the unrestrictive SS muffler. Even the difference between the 5 speed and auto versions. ( the number of rows of perforations in main tube)

Sorry again for the confusion, I do regard you as an expert on the in and outs of our SS exhaust systems. Lord knows, you've done enough tests on them.

 

whoaaaa ! That's one fast car!

 

Ah, the pipes are called, ole' Danny boy! Listen to them echo thru the highlands of the Tail of the Dragon or any other twisty road area in the USA or Canada

 

I know this seems to be a thread that has died out, but it appears to have been resurrected a number of times already...I will do the same...

Does anyone have any audio clips (or videos) of the stock exhaust with the Cat/Resonator deleted? I haven't found any good ones.