So down pipe tune and gut 2nd cat should be good then
​​thanks for the help much appreciated

 

Go in this link, click on send message, then select send PM , and type out your interest

https://www.chevyhhr.net/forums/memb...chracing-4515/


this member had these results from testing DP


https://www.chevyhhr.net/forums/hhr-...t-power-43170/

 

If you are in E-town, Louisville is right up the road. (I used to live in Radcliff)
That is a big enough city that there should be some tuners there that can take care of you.

I understand that the canned tunes you can get from Trifecta and ZZP, etc. (including the GM Stage 1) are pretty limited compared to what a speed shop with a dyno can do.
Make some calls and find someone up there with an HPTuners setup who tunes turbo Cobalts (much more common than our cars) and you will probably be set.
To really dial it in, you must log, then tune and log some more, then adjust the tune.
Gutting the cat won't hurt, but don't change anything else until you are getting tuned as you could throw codes unless tuning for the DP, for example.

Disclaimer: I am NOT an expert on this, but I read EVERYTHING from a lot of guys who do a lot of this stuff.

 

If you can get the cat off to gut it, you can get it off and replace it with a straight pipe. Destroying a good cat could come back to bite you in the future. They aren’t cheap. Don’t think short term.

 

The GM stage kit is still out there

19369111 GM STAGE KIT

but wasn’t there something about the K&N elbow to the stock air filter an improvement?

 

I have just the K&N elbow from stock air box to turbo.
I did feel a slight difference by the "seat dyno"
I bought it new from K&N. They asked me why and I told them the original pipe got run over before I could install it. At the time it was like $45.
Buy the silicone reducers also when you buy the pipe if you can.
I bought the connectors off of Ebay.

 

I see the price really went up on the kit. I got mine for $400. Dealer installed it for $200. I would have, but since the car was under warranty I figured they could deal with any issues. Been fine for 10 years. No doubt the adapters would have been nice but mine's been solid.

 

It appears that kit doesn't include the reflash with the actual tune either!
They say you have to get it from the dealer.

 

Same as it always was. You are paying for a firmware serial number that only a GM dealer has access to.

Somebody recently posted the process:
install hardware
take serial number from the box to a dealer
wait a week or 2 for them to get access to the flash from HQ
take the car in to have it flashed

 

Step 5: Pay through the nose for something that takes a couple of minutes!

ZZPerformance will sell you a flashed PCM (and TCM if needed) to go along with the 3-bar MAP sensors, if you already have them. They also sell those for about $115 for the pair.
They will let you ship them your modules, sell you a new one, or do an exchange with core charge/refund.
https://zzperformance.com/products/zzp-lnf-turbo-pcm