Exhaust question? - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
Engine Mods Talk about Chevy Cobalt Engine Modifications here.

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old 10-19-2013, 06:02 AM Thread Starter
Staff Alumni
 
Join Date: Apr 2013
Posts: 279
Exhaust question?

So I got a small hole right behind one of the heat shields, I'm gonna take it to a local muffler shop and have them probably replace the whole exhaust pipe, what do you recommend I change? It's still gonna be on stock muffler. What would it sound like if I delete the cat? Go bigger pipe?


Sent from AutoGuide.com Free App
CamaroSS1969427 is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 10-19-2013, 07:13 AM
Forum God
 
Join Date: Feb 2010
Location: KCMO
Posts: 2,204
Garage
Bigger piping doesn't always mean MORE POWER.

I'd just have them patch it.

If you're looking to upgrade, get a ZZP downpipe and an EBay catback like I did...then welded on a Borla ProXS muffler...sounds great for an N/A four banger.

The Racekar - SOLD!: http://www.youtube.com/watch?v=fIW9XK_WMR4
2007 Cashmere Metallic Chevy Cobalt LT Sedan...totaled 04/11/2011
2010 VR Cobalt 2LT Sedan Debadged, ZZP Intake, Custom 2.5" Exhaust/Borla Pro XS, FE5 Bidnez with KSport Springs.
Previously dumped on BC Xtreme Low's...RIP LOWLYFE :(
bluegtp91 is offline  
post #3 of 10 (permalink) Old 10-19-2013, 08:41 AM Thread Starter
Staff Alumni
 
Join Date: Apr 2013
Posts: 279
Quote:
Originally Posted by bluegtp91 View Post
Bigger piping doesn't always mean MORE POWER.

I'd just have them patch it.

If you're looking to upgrade, get a ZZP downpipe and an EBay catback like I did...then welded on a Borla ProXS muffler...sounds great for an N/A four banger.
Not wanting power, just a little better sound. Post a video of how your car sounds
CamaroSS1969427 is offline  
 
post #4 of 10 (permalink) Old 10-19-2013, 08:52 AM
Forum God
 
Join Date: Feb 2010
Location: KCMO
Posts: 2,204
Garage
Option Racing 2.5" catback + the Borla muffler and a ZZP intake...otherwise stock.

926BEA31-421C-4E44-90AE-A8B7D386ED60-10330-00000810A0406080_zpsd247cb07.mp4 Video by bluegtp03 | Photobucket

FA0ADB3C-C537-4258-9452-AC2593B11A64-10244-0000080DEFC50AC0_zps12f012b1.mp4 Video by bluegtp03 | Photobucket

The Racekar - SOLD!: http://www.youtube.com/watch?v=fIW9XK_WMR4
2007 Cashmere Metallic Chevy Cobalt LT Sedan...totaled 04/11/2011
2010 VR Cobalt 2LT Sedan Debadged, ZZP Intake, Custom 2.5" Exhaust/Borla Pro XS, FE5 Bidnez with KSport Springs.
Previously dumped on BC Xtreme Low's...RIP LOWLYFE :(
bluegtp91 is offline  
post #5 of 10 (permalink) Old 10-19-2013, 09:05 AM
Super Moderator


 
Plain Jane's Avatar
 
Join Date: Mar 2013
Location: Montreal, Quebec
Posts: 3,860
Garage
An exhaust alone won't do much for power anyways, especially without a tune. It's illegal to run catless, and you'll actually lose power if the O2 codes aren't erased from the ECM/PCM. But if it's sound you want, go with what was stated above, best bang-for-the-buck I'm sure.

'07 Eclipse GT build thread - 280whp, 254wtq
Plain Jane is offline  
post #6 of 10 (permalink) Old 10-19-2013, 09:13 AM Thread Starter
Staff Alumni
 
Join Date: Apr 2013
Posts: 279
CamaroSS1969427 is offline  
post #7 of 10 (permalink) Old 10-20-2013, 05:03 AM
Cobalt Specialist


 
Join Date: Jun 2011
Location: Charlotte, NC
Posts: 1,145
Quote:
Originally Posted by Plain Jane View Post
An exhaust alone won't do much for power anyways, especially without a tune. It's illegal to run catless, and you'll actually lose power if the O2 codes aren't erased from the ECM/PCM. But if it's sound you want, go with what was stated above, best bang-for-the-buck I'm sure.
agreed sir. Catalytic Converters are not horsepower gobblers. The only reason to not have a cat converter is if your car is exempt from emissions (race setup only) and you pulled out the entire EVAP system.

For the 02 sensors, your car will be in limp home mode, in which a p0420 code will generate (catalyst efficiency). Your car defaults to open loop status, making your car dump more fuel and pull in more air. The only problem to this, is that your ECT (Engine Coolant temp sensor) will read a default below normal operating temperature, causing the engine efficiency not to be at its peak of performance and fuel efficiency.

This will also cause problems for your emissions, ever hear people say "that car is running rich" with a smell of fuel out the exhaust pipe? That is nothing more than excessive hydrocarbons (fuel) not being broken down in the cat converter or lack of a cat. This will eventually lead down to a mechanical misfire in the engine after time, your PCM relies on air/fuel control from the rear 02 sensor heavily on STFT and LTFT (short and long term fuel trim). Im not gonna explain that stuff cause there's a lot to it. So, if your car is running rich, your PCM is trying to increase more air to balance the ratio correctly, but no cat, no go. If you think a wideband would be a solution, dead wrong. Wideband is the front 02 before the cat (just a tip to remember in the future).

2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille

Last edited by 5t3alth; 10-20-2013 at 05:12 AM.
5t3alth is offline  
post #8 of 10 (permalink) Old 10-20-2013, 03:04 PM Thread Starter
Staff Alumni
 
Join Date: Apr 2013
Posts: 279
Quote:
Originally Posted by 5t3alth View Post
agreed sir. Catalytic Converters are not horsepower gobblers. The only reason to not have a cat converter is if your car is exempt from emissions (race setup only) and you pulled out the entire EVAP system.

For the 02 sensors, your car will be in limp home mode, in which a p0420 code will generate (catalyst efficiency). Your car defaults to open loop status, making your car dump more fuel and pull in more air. The only problem to this, is that your ECT (Engine Coolant temp sensor) will read a default below normal operating temperature, causing the engine efficiency not to be at its peak of performance and fuel efficiency.

This will also cause problems for your emissions, ever hear people say "that car is running rich" with a smell of fuel out the exhaust pipe? That is nothing more than excessive hydrocarbons (fuel) not being broken down in the cat converter or lack of a cat. This will eventually lead down to a mechanical misfire in the engine after time, your PCM relies on air/fuel control from the rear 02 sensor heavily on STFT and LTFT (short and long term fuel trim). Im not gonna explain that stuff cause there's a lot to it. So, if your car is running rich, your PCM is trying to increase more air to balance the ratio correctly, but no cat, no go. If you think a wideband would be a solution, dead wrong. Wideband is the front 02 before the cat (just a tip to remember in the future).
I'll probably just put a new pipe on it to stock muffler
CamaroSS1969427 is offline  
post #9 of 10 (permalink) Old 10-21-2013, 07:57 AM
Forum God
 
Join Date: Feb 2010
Location: KCMO
Posts: 2,204
Garage
Catback will be fine.

Won't mess with anything emissions wise...hence the CAT BACK.

The Racekar - SOLD!: http://www.youtube.com/watch?v=fIW9XK_WMR4
2007 Cashmere Metallic Chevy Cobalt LT Sedan...totaled 04/11/2011
2010 VR Cobalt 2LT Sedan Debadged, ZZP Intake, Custom 2.5" Exhaust/Borla Pro XS, FE5 Bidnez with KSport Springs.
Previously dumped on BC Xtreme Low's...RIP LOWLYFE :(
bluegtp91 is offline  
post #10 of 10 (permalink) Old 10-21-2013, 08:53 AM
Veteran
 
Batmobile's Avatar
 
Join Date: Apr 2011
Location: Western Maryland
Posts: 658
Garage
If all you want is sound, get a muffler. And get the leak fixed obviously.
Before I got a full exhaust, I only had a "fart can" and it sounded pretty good for only costing me $30 to have it welded on.
Batmobile is offline  
Sponsored Links
Advertisement
 
Closed Thread

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome