gm performance parts exhaust - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

JeffStein · 04-19-2011, 11:38 AM

Does anyone know if the GM Performance Parts axle back exhaut kit will fit a L99 automatic? The Chevrolet website only has part numbers for the LS3. Thanks!

Hired Gun · 04-19-2011, 01:15 PM

Yes it does. I have it on mine.

JeffStein · 04-19-2011, 02:44 PM

Does it sound pretty good? A lot better then stock?

Scott@Bjorn3D · 04-19-2011, 02:53 PM

Much deeper sounding. Car sounds pretty mean with mine. Then if you want to get meaner you can cut the big freaking resonator out and put a X-Pipe in like I did

butch32 · 04-19-2011, 04:10 PM

What GM part # did you guys use for the L99? Also did you get more drone when the afm kicks in?

Switchback700 · 04-19-2011, 05:52 PM

The reason GM does not offer the exhaust for the L99 is probably because when the AFM kicks in the drone is terrible. On the highway it would vibrate the whole dash, mirror, console... you get the idea. My AFM was tuned off pretty quick...... along with my warranty. I have the road version GMPP axle back.

Hired Gun · 04-20-2011, 02:09 PM

I do not remember the part number, but do know it was for an ls3.

Scott, how does yours sound with the X pipe?

slickmetal · 04-20-2011, 03:09 PM

Quote:

Originally Posted by Switchback700

The reason GM does not offer the exhaust for the L99 is probably because when the AFM kicks in the drone is terrible. On the highway it would vibrate the whole dash, mirror, console... you get the idea. My AFM was tuned off pretty quick...... along with my warranty. I have the road version GMPP axle back.

The flex pipes right before the cats are what takes care of the vibration. The drone is taken care of by the stock resonator/mufflers. I chopped my mufflers off completely and really didn't have any drone, just could hear the drop down to 4cyl. more - so it felt like a bog...When I slapped on my LT headers, the vibration/noise was horrid - because they eliminated the flex pipes right above the cats. On another test subject, the AFM was removed and all vibration ceased.

Switchback700 · 04-20-2011, 03:38 PM

Quote:

Originally Posted by slickmetal

The flex pipes right before the cats are what takes care of the vibration. The drone is taken care of by the stock resonator/mufflers. I chopped my mufflers off completely and really didn't have any drone, just could hear the drop down to 4cyl. more - so it felt like a bog...When I slapped on my LT headers, the vibration/noise was horrid - because they eliminated the flex pipes right above the cats. On another test subject, the AFM was removed and all vibration ceased.

Did you drive much on the highway at 72-75 mph? That's when my 4 cylinder drone got so bad it would make my ears bleed and the interior vibrate. Not sure what flex pipes you are talking about but mine was stock except for the GMPP axle back. Still some mild drone with AFM off but it's nothing like before. Headers and Borla X pipe coming in a couple weeks, be interesting what the sound level and drone go to then.

Switchback700 · 04-20-2011, 03:41 PM

Not sure of the part number but my GMPP's are not the offroad version, they are the quieter version (supposedly same as Borla Touring). When I got mine they were listed for the L99...... I don't think there's a difference, it's just that GM does not want them advertised for the L99 because of the AFM noise problems.

JeffStein · 04-20-2011, 04:44 PM

Does the road version of gmpp exhaust sound much different than stock?

Switchback700 · 04-20-2011, 04:59 PM

Quote:

Originally Posted by JeffStein

Does the road version of gmpp exhaust sound much different than stock?

Yes it does... sounds more agressive at startup, gets almost as quiet at idle as stock (still a little more bass), but when getting on the throttle it sounds much better. Just sucks when the AFM kicks in.

nancygrl · 04-20-2011, 05:24 PM

The Borla touring is a lot of fun in a manual, it has an even nicer sound after I installed my rotofab cai. Sucks you have to deal with AFM, couldn't imagine how awful that must sound.

Switchback700 · 04-20-2011, 05:31 PM

I will have a Diablosport Predator for sale in a couple weeks after I get my Dyno Tune. Easy to turn off AFM and install stock tune back if needed. It was much more enjoyable to drive without AFM after modifying the exhaust.

04-19-2011, 11:38 AM	#1
JeffStein Drives: 2011 camaro 2SS Join Date: Apr 2011 Location: Ohio Posts: 14	gm performance parts exhaust Does anyone know if the GM Performance Parts axle back exhaut kit will fit a L99 automatic? The Chevrolet website only has part numbers for the LS3. Thanks!

04-19-2011, 01:15 PM	#2
Hired Gun Wild Man Drives: 2010 Camaro Join Date: Sep 2010 Location: Milford, Ky Posts: 516	Yes it does. I have it on mine. __________________ 2010 Camaro Black with White Stripes, Jannetty Racing Roto-Fab CAI, VMAX Ported Throttle Body, Long Tube Headers, GMPP Axel Back, Emblem Pros Custom "VOODOO" Under hood Bow tie, Chrome Gill Inserts, HUD plate, Sparks Performance White SS front and rear Plate MPD-1 Spoiler

04-20-2011, 02:09 PM	#7
Hired Gun Wild Man Drives: 2010 Camaro Join Date: Sep 2010 Location: Milford, Ky Posts: 516	I do not remember the part number, but do know it was for an ls3. Scott, how does yours sound with the X pipe? __________________ 2010 Camaro Black with White Stripes, Jannetty Racing Roto-Fab CAI, VMAX Ported Throttle Body, Long Tube Headers, GMPP Axel Back, Emblem Pros Custom "VOODOO" Under hood Bow tie, Chrome Gill Inserts, HUD plate, Sparks Performance White SS front and rear Plate MPD-1 Spoiler

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04-19-2011, 02:44 PM	#3
JeffStein Drives: 2011 camaro 2SS Join Date: Apr 2011 Location: Ohio Posts: 14	Does it sound pretty good? A lot better then stock?

04-19-2011, 02:53 PM	#4
Scott@Bjorn3D Drives: Kami, 2013 2SS LS3 Luvin Join Date: Oct 2008 Location: Eufaula, Alabama Posts: 6,427	Much deeper sounding. Car sounds pretty mean with mine. Then if you want to get meaner you can cut the big freaking resonator out and put a X-Pipe in like I did

04-19-2011, 04:10 PM	#5
butch32 Drives: 2012 Zl1 and 2011 ss camaro Join Date: Jan 2011 Location: MI Posts: 28	What GM part # did you guys use for the L99? Also did you get more drone when the afm kicks in?

04-19-2011, 05:52 PM	#6
Switchback700 Drives: 2010 2SS IBM L99 Join Date: Apr 2010 Location: Livonia, Mi Posts: 274	The reason GM does not offer the exhaust for the L99 is probably because when the AFM kicks in the drone is terrible. On the highway it would vibrate the whole dash, mirror, console... you get the idea. My AFM was tuned off pretty quick...... along with my warranty. I have the road version GMPP axle back.

04-20-2011, 03:41 PM	#10
Switchback700 Drives: 2010 2SS IBM L99 Join Date: Apr 2010 Location: Livonia, Mi Posts: 274	Not sure of the part number but my GMPP's are not the offroad version, they are the quieter version (supposedly same as Borla Touring). When I got mine they were listed for the L99...... I don't think there's a difference, it's just that GM does not want them advertised for the L99 because of the AFM noise problems.

04-20-2011, 04:44 PM	#11
JeffStein Drives: 2011 camaro 2SS Join Date: Apr 2011 Location: Ohio Posts: 14	Does the road version of gmpp exhaust sound much different than stock?

04-20-2011, 05:24 PM	#13
nancygrl 雪の玉 Drives: '22 Z71 RST Silverado Join Date: Feb 2011 Location: South Posts: 3,415	The Borla touring is a lot of fun in a manual, it has an even nicer sound after I installed my rotofab cai. Sucks you have to deal with AFM, couldn't imagine how awful that must sound.

04-20-2011, 05:31 PM	#14
Switchback700 Drives: 2010 2SS IBM L99 Join Date: Apr 2010 Location: Livonia, Mi Posts: 274	I will have a Diablosport Predator for sale in a couple weeks after I get my Dyno Tune. Easy to turn off AFM and install stock tune back if needed. It was much more enjoyable to drive without AFM after modifying the exhaust.