I have only the HPT from Church, otherwise bone stock. Well, I got lucky and found someome else here who had the SAME tune at Church, only he has the following Bolt ons:
Intake and Charge pipes plus a down pipe.

HIS PM TO ME:
yeah I had all my parts on before I got it tuned so the baseline run is with all the parts no tune then after the tune is when I got a big difference, I have a dejon intake, ingen hotside piping, and a catless downpipe"


They *appear* to worth an adidtional 15HP and 20TQ.

Link to post:

https://www.cobaltss.net/forums/show...4&postcount=10

 

The gain is from the catless DP. The injen upper CP is nice, but the Dejon intake skews the fuel trims about -7%. Need the MAF tuned as well to compensate but you will see lurching coming out of Decel Fuel Cutoff (DFCO) from air turbulence. Wonder how I know???

Get the ZZP lower CP with the MAF relocate, tune for that and put any intake on it you want. See my mods in profile.

Second choice would be K&N SRI instead of the MAF relocate if you ever want to add Meth. Spraying with the MAF relocate is gonna be tough, hard to keep the MAF dry.

No mounting bracket on the Dejon intake so the install is quite critical to keep it in place without squishing the reducer into the turbo inlet vanes.

 

Yeah I figured the Catless DP accounted for the gains. I'm in CA, what gains would I get with a DP with cat?
Thanks for the response!

 

More than stock... Because you would get a Hi-Flow Cat. And it removes the restriction in your stock DP where it necks down to 2.5" Of course not as much power as fully catless, but much better than stock.

 

If you get a catted DP, get the spun metal one from ZZP or CIA, they tolerate the higher temps better than the ceramic (cheaper) cats. Still flow better than the stock pinched down abomination.

I just kept the stock cat in the attic for the two year inspection due for me in two more years.

 

Not worried about inspection..will it pass Ca smog emisions?