jczboy

I had a catless DP on, so it's makes less sound. I do think it runs better in the low and mid range. I do not think it makes much difference on the top. Did you find a piece of pipe?

Nightwalkerhemi

No I was thinking doing what you did with hole saw think I have one in the garage somewhere.im complete stock so might sound better,only thing I have is a tune,I like free mods though.

breds2k

Are you going to get that nice increase in sound that you get with a 3" dp? With this core setup?

jczboy

No, sound is very close to stock

Waynejwj

Good morning,

I have read the modifications and testing on the cats on the HHR SS and I must say that I am impressed with 2005HHRauto's persistence in the pursuit of power and performance. I am not clear on this one modification. After I core the second cat should I tack weld a piece of pipe in the cat.

Thanks for your help
Wayne

firemangeorge

Hey Wayne,
You may want to send a PM to 2005HHRauto and get his experienced opinion. I don't think he cruises this forum on a regular basis and he may miss your post.

2005HHRauto

Hi Wayne,
No pipe needed , after "coring", as the remaining cat-guts are quite
strong, & will stay in place...

Waynejwj

Thanks for your help. I think that the wealth of hands on experience that you bring to this forum has helped many owners of this little unappreciated hot rod or as my daughter calls it (Hip Hop Ride)

Waynejwj

Thanks for your reply. I did try to send him a message through this forum but his mail box is full.

paperboy72

i would think you want that "core" hole bigger than that small hole saw can do though.....