I'm looking at something that won't be too aggressive or expensive for my automatic-equipped SS. I have been piecing some things together from everyone's favorite auction site and came up with the following. Please let me know what you think and if I should see a rise in performance and sound. I'm looking for best bang for the buck for performance, sound and aesthetics. Also, I am hoping these are warranty-friendly because I purchased a 5 year bumper to bumper when I got my car a month ago. Also, the muffler and tip would just be welded into the stock locations since I heard the factory system isn't bad? I do have the GMTU and a drop in K&N filter. Thanks in advance!

ZZP catted 3" downpipe...$220 shipped

Magnaflow muffler with following stats...~$59 shipped
* Part #: 12216
* Inlet: 2.5" Center
* Outlet: 2.5" Center
* Overall Length: 20"
* Body Length: 14"
* Body Type: 5" x 8" Oval

Magnaflow tip with following stats...~$35 shipped
Material: 100% Stainless Steel - Mirror Finish
Length: 5in.
Inlet Diameter: 2.5in. Inner
Outlet Diameter: 4in.
Layer: Single-wall
Application: Weld-on
Style: 15-Degree Angle-cut Rolled Edge


Brian

 

I've never seen any proof that anything but a catless downpipe will add anything HP wise and then IMHO all you really get is more noise. It does not add enough HP, by itself, to justify the expense. And sound only puts you into the 'ricer' crowd.

 

The stock downpipe looks restrictive with the bends and I think double cats? I'm not sure how you couldn't pick up some sort of HP gain from the new pipe with a single cat.

Also, my Vette has an SLP cat-back and I don't know if I picked up much HP from it. It's much louder now and I hope that isn't considered tacky.

 

i say if you want max hp and GOOD quality,don't be cheap. unless you live in cali or somewhere where they do a visual inspection,go with a hahn catless DP. no cel. to get the full effect of the system, i advise a full 3inch exhaust. you will see 15-20hp with a full exhaust system and yes it will sound nice. the reason i advise going 3inch all the way is because if one day you decide to get tuned,you are gonna want it!!. oh,welded systems imo are not that great. just do section at a time. in the end you will be happy you did.

 

I agree with this one but with the HHR SS, has anyone dynoed with a dp/stock catback vs. a dp/aftermarket catback. When you start adding mods it can help but I've seen that the stock catback hasn't become a restriction before 350 fwhp on the cobalts. Cutout's also gain high end power as well but kill the low end. Sound is one thing but justifing a $500 catback for 5-10hp is not really a bang for the buck mods. That's the reason I didn't do any catback on my SS. It really didn't make sense cost/gain wise. If you plan on going to a bigger turbo, then do the 3 inch exhaust. You'll see bigger gains than the stock turbo with the aftermarket exhaust. Not saying you can't add it to the stock turbo but is it worth the cost/gain? Best bang for the buck is a Trifecta/Hp tune!

Dave

 

I got rid of the cats on my old Mustang and it was loud and the exhaust had a strong odor. Since this is my daily driver, I'd like some gains in performance and sound, but not go all out. I have the Vette for that. Lol.

Also, I'm hoping to keep it close to stock because I have 4 years and 11 months left on my warranty.

Brian

 

Unless you know someone at your dealership, then keep it stock. I had a tech with a Cobalt T/C with the same dp work on mine everytime it went to dealership. Never had a problem! It's up in the air if they void your warranty for something with your mods. With my catless dp, you could smell a little fuel outside but nothing inside the vehicle. A catless downpipe will give more sound and performance with the stock catback. I would suggest doing the dp first and see how you like it. You can always do a catback later. A dp will give you the most gain for your money.

Dave

 

Brian, I noticed on your shopping list that most of the parts are 2.5", most upgrades go to the 3" for less restriction. If you collar it your building pressure, it comes 3" off the DP, to go to 2.5 is outlet is not the answer.

 

Can I use 3" pipes with the stock cat-back piping? If so, then I would definitely go that way. I was under the impression that the stock cat-back was 2.5".

 

you can,but to a point you are defeating the purpose of having a 3inch dp. like foolmoon said, it's like bottle necking the system. if you were in band() think of blowing into brass mouth piece. that's what you are doing. or pinch the end of a straw and make it flat and blow on the open end.