What if any gains are made? It's a 2009 HHR SS so far I've only done the turbo upgrade kit from GMPP. I'm debating on putting one on my car. I don't want to change the exhaust system just the stock dp and I was thinking of going with either ZZP or Clear Image catless DP but would like to know what type of performance gains it would make if any? Anyone just running a dp did it make a difference? Thanks, Jason

 

yes the downpipe makes a difference the factory one is proly one of the most restrictive parts of the car, got my vote to go with the downpipe.... i have ADM, check them out.

 

ZZP Catted DP here to keep the Emission ****'s happy or I'd have got the catless one.

 

i have synapseturbo catless downpipe and deginitely a performance gain

turbo spools faster!

 

I have Clear Image Performance's Catless DP, NOTICEABLE gain.

 

http://www.zzperformance.com/cobalt_...1016&catid=155

full 304 stainless for as low as $199. Quality unmatched. ZZP is used on the forums fastest and only 11 sec LNF.


You can run catless with the O2 bung and not set a code.

 

Cool, Thanks for the info. I'm gona get me one soon