Gutted 2nd Cat
Banned
Joined: 01-20-2014
Posts: 83
From: iowa
Just keep in mind that "gutting a converter" is illegal, and you could fail an emissions inspection and face fines under...
"Section 288 – Enforcement: (b) TAMPERING WITH VEHICLE EMISSION CONTROLS –
(1) Section 203(a)(3) (42 U.S.C. 7522(a)(3)) is amended to read as follows:
'(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or
'(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use."
It's better to look into certified performance converters, such as a unit by ZZP as mentioned above by SS fan.
"Section 288 – Enforcement: (b) TAMPERING WITH VEHICLE EMISSION CONTROLS –
(1) Section 203(a)(3) (42 U.S.C. 7522(a)(3)) is amended to read as follows:
'(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or
'(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use."
It's better to look into certified performance converters, such as a unit by ZZP as mentioned above by SS fan.
Deceased
Joined: 03-22-2012
Posts: 1,012
From: Rogers City, Michigan
Banned
Joined: 01-20-2014
Posts: 83
From: iowa
Haha Yup I'm in Iowa, they still let us have fun... For now
Senior Member
Joined: 02-13-2010
Posts: 698
From: HuskerNation
IIRC, I think that 2005hhrauto is gutting the first cat right after the turbo because the 02 bung would be in the way if you attempted to gut the second cat from the exit side of the down pipe. Yes, this would include removing the downpipe entirely. Anyway, would probably be a better idea to just buy a down pipe already manufactured with one cat UNLESS you are attempting to conceal the fact that the exhaust is modified. Not to mention, some catalytic converters are carcinogenic. 
I run a Clear Image Auto catted DP(300 cell cat). Ran it with GMTU for almost a year with no codes and still no codes for over a year on my current tune. ZZP 400 cell catted DP would also be a good choice if your trying to avoid CEL.
I too wanted a strong sounding exhaust note that wasn't obnoxiously loud, and I am very happy with the rumble I got from the catted DP.
Edit: after reading 2005hhrauto's link he is actually cutting out the second cat without removing the pipe.
I run a Clear Image Auto catted DP(300 cell cat). Ran it with GMTU for almost a year with no codes and still no codes for over a year on my current tune. ZZP 400 cell catted DP would also be a good choice if your trying to avoid CEL.
I too wanted a strong sounding exhaust note that wasn't obnoxiously loud, and I am very happy with the rumble I got from the catted DP.
Edit: after reading 2005hhrauto's link he is actually cutting out the second cat without removing the pipe.
Last edited by XtremeSS; Mar 18, 2014 at 09:07 AM.
Banned
Joined: 01-20-2014
Posts: 83
From: iowa
I really want more loud from my hhr ss, I had a 500whp big turbo 2005 Subaru sti with a full APS turbo back exhaust (this was the prettiest sound you'll ever hear) and then a 2012 mustang and so the quietness of this car is disheartening
But I don't want ricer weed wacker sound either
Might just have to take a shot on a custom muffler from the local shop cause I need much more noise from this baby! And I don't wanna spend a ton
If this gutting the second cat would help I'm down to try it
But I don't want ricer weed wacker sound either
Might just have to take a shot on a custom muffler from the local shop cause I need much more noise from this baby! And I don't wanna spend a ton
If this gutting the second cat would help I'm down to try it
Premium Member
Joined: 10-09-2010
Posts: 14,420
From: Tacoma
It didn't change the sound much, turbo spools faster though. Lots of second hand exhaust gets sold in the classifieds, that's where I got the ZZP downpipe, your welcome to it for a mere 150.00. I never took it out of the box, I'm happy with the gutted second cat mod. These Flowmaster HP2 shorties sound good to me. I think Foxtrot raptor found a inexpensive muffler that sounder good, might pm him.
Deceased
Joined: 03-22-2012
Posts: 1,012
From: Rogers City, Michigan
Wow that is pretty SS Fan.
Boydie
Boydie
It didn't change the sound much, turbo spools faster though. Lots of second hand exhaust gets sold in the classifieds, that's where I got the ZZP downpipe, your welcome to it for a mere 150.00. I never took it out of the box, I'm happy with the gutted second cat mod. These Flowmaster HP2 shorties sound good to me. I think Foxtrot raptor found a inexpensive muffler that sounder good, might pm him.