Question About Cat Back & Axle Back Exhaust Systems

[SamSS]

- Is the resonator removed in cat back exhaust systems?
- Are mufflers the only parts that are changed in axle back systems? Nothing happens to the resonator in the axle back systems, right?

[mikeSS]

well i am not 100% sure on this..... i think on axle back system you mainly just are changing the muffler, but you do replace piping that goes beyond the muffler.

the cat back i believe you replace all of the piping that goes all the way to the front bumper...

i really dont know much but that my guess..... sorry ...lol

[SamSS]

Originally Posted by mikeSS

well i am not 100% sure on this..... i think on axle back system you mainly just are changing the muffler, but you do replace piping that goes beyond the muffler.

the cat back i believe you replace all of the piping that goes all the way to the front bumper...

i really dont know much but that my guess..... sorry ...lol

I was pretty sure that you change the mufflers basically on axle backs.

I think on the cat back systems, you change everything after the catalytic converter.
Now what's the difference between the complete cat back systems and the custom cat back systems? What happens to the resonators?

Here's a pic of the stock exhaust system (I think, not sure if it's completely stock)...



And here's what I think...

[mikeSS]

check this out./....... this guy is putting on a axle

[2010SSRS]

yes....cat back replaces EVERYTHING from cats back. axle backs replace mufflers to tips.

[SS 376]

SamSS described it pretty good. I think some aftermarket cat-back systems still have a resonator. I seem to remember maybe Corsa having resonators. Mine doesn't.

[SamSS]

Originally Posted by Queens Blvd

SamSS described it pretty good. I think some aftermarket cat-back systems still have a resonator. I seem to remember maybe Corsa having resonators. Mine doesn't.

No, I was talking to an exhaust shop owner today and he said cat backs don't have resonators.

[Don O]

Originally Posted by SamSS

I was pretty sure that you change the mufflers basically on axle backs.

I think on the cat back systems, you change everything after the catalytic converter.
Now what's the difference between the complete cat back systems and the custom cat back systems? What happens to the resonators?

Here's a pic of the stock exhaust system (I think, not sure if it's completely stock)...



And here's what I think...

That's sure a lot different looking than my stock L99 system (September car).

Don O

[BLK2SS]

Originally Posted by Don O

That's sure a lot different looking than my stock L99 system (September car).

Don O

That is a stock LS3 system.

[Avalnch]

Whao, whao, whao, wait a minute here.

I thought all the SS exhaust systems were the same! Now these pics really make me question the need for a cat back system on an LS3!

The posted pics from samSS show no main resonator under the heat shield and practically straight pipes to the stock mufflers. The H pipe looks completely wrong from a flow characteristics point of view, an X pipe would work better. I guess the real sound killer are the mufflers. Anyone know what the smaller resonators look like on the inside?

Are the exhaust systems different between the two models?? Having seen this side by side comparison makes me think that all that is needed for the LS3 to roar is to delete/replace the mufflers. Am I wrong, or is buying a $1000+ cat back system for the LS3 a waste of money??

Tom

[Johnny1]

Thats what the LS3 exhaust looks like I've seen under a 2## LS3. I'm putting an axle back (Borla Stinger) on my 2SS LS3 when it comes in. But I prefer to keep the H pipe. But I would sure like to know what those resonators look like inside also. So I can decide whether or not to have them cut out (don't mind some drone if I do). I"ve seen a post of what they look like on the L99 from a post on here. Would someone replacing there exhaust on a LS3 PLEASE cut one of the resonators off and post a picture of what it looks like through it as far as flow and sound adsorbance. Thanks

[BabyHauler]

Originally Posted by Avalnch

The H pipe looks completely wrong from a flow characteristics point of view, an X pipe would work better.

I belive the H pipe in the center is more about equalizing pressure for the two exhaust banks (which in turn should help flow) and less about flow across the H pipe itself.

[BabyHauler]

Originally Posted by Avalnch

Am I wrong, or is buying a $1000+ cat back system for the LS3 a waste of money??

I watched the youtube video and flowmaster claimed 8hp and 9ft.lbs from just a axle back system, on the corsa website for the cat-back system they claim like 6 or 7hp.

I dont think this is because flowmaster is better then corsa I think it is because at around stock HP levels the stock LS3 piping from the cats to the rear mufflers flows just as well as the aftermarket cat backs.

I belive the best way to go unless you wanted to pump out some serious HP would be just to get an axle back (if you have a M6). The sucky thing is corsa doesnt offer just a axle back.

All this is of course based on the 2 pics that were posted above. If they are not the standard M6 and A6 exhaust then just forget everything I just said.

[firengnred]

Okay... A cat back system replaces everything from the cats back to the tips eliminating the resonator and replacing it with either a true X-Pipe or a muffler with a X-Pipe inside of it. Some makers such as Magnaflow offer two set ups. The above described called the street series or, one called the competition series which is the same but with no mufflers before the tips. The axle backs replace the pipe from basically the axles back to the tips. Again, some with mufflers and some without.

[firengnred]

I was looking to get the Magnaflow comp. Series cat back when i had a brainstorm which i will share. The Comp. Series cat back runs $1200 from Magnaflow. This setup replaces the resonator with a X-Pipe muffler and eliminates the mufflers. Well, the stock system is already mandrel bent stainless steel tubing. So... I purchased an X-Pipe muffler to replace the resonator and the Comp. Series axle back from Magnaflow. Essentially creating a Comp. Series cat back for $450... $600 installed. That's a savings of over $600. That will buy a CAI or a tune or both! :-)

[Avalnch]

Originally Posted by firengnred

I was looking to get the Magnaflow comp. Series cat back when i had a brainstorm which i will share. The Comp. Series cat back runs $1200 from Magnaflow. This setup replaces the resonator with a X-Pipe muffler and eliminates the mufflers. Well, the stock system is already mandrel bent stainless steel tubing. So... I purchased an X-Pipe muffler to replace the resonator and the Comp. Series axle back from Magnaflow. Essentially creating a Comp. Series cat back for $450... $600 installed. That's a savings of over $600. That will buy a CAI or a tune or both! :-)

Yes, indeed, that would buy you the CAI and more.

I thought the Magnaflow Comp Series (muffler delete) includes a large dual-in-out resonator where the LS3 H-pipe would be. If you simply installed an X-pipe in place, then you basically have a completely mufflerless exhaust system. Any drone or popping or excessive loudness?

[SamSS]

Originally Posted by Avalnch

Yes, indeed, that would buy you the CAI and more.

I thought the Magnaflow Comp Series (muffler delete) includes a large dual-in-out resonator where the LS3 H-pipe would be. If you simply installed an X-pipe in place, then you basically have a completely mufflerless exhaust system. Any drone or popping or excessive loudness?

I have the resonator removed on my SS (L99), but not the mufflers. So are you saying if I remove the mufflers and put an x-pipe there, I'll have a custom cat back similar to that of Magnaflows?

And out of curiosity, what does the true x-pipe do?

[Avalnch]

Ahh, you still have the stock mufflers (I did not know that). I think if you deleted your mufflers at this point, you may get lots of popping (from what I've read on this forum). This may be why the Magnaflow system includes a dual-in-out resonator.

All things being equal, there are two main factors in considering an exhaust system, volume and velocity of the exhaust gases. Larger pipes will give you volume which is needed for high horse power engines because they create more exhaust gases. A higher exhaust gas velocity inside the pipes help the gases escape faster, thus reducing back pressure and helping the motor "breathe". For a given range of motor HPs and sizes, the exhaust system needs to be carefully considered.

A "True X-pipe" is designed to add velocity to the exhaust gases leaving your engine. A higher velocity will help stock exhausts cause it will get rid of the gases quicker and allow the motor to breathe better. The 'X' shape helps scavenge the exhaust between right and left banks as each cylinder pushes out it spent gases. A regular 'H' pipe helps equalize the pressure between the left and right sides which is suppose to aid in exhaust flow, but nowhere as well as the 'X' pipe can. That's why aftermarket exhaust companies offer the X pipe.

[1969to2010]

the x pipe is supposed to increase mid range torque ,
im intrigued by the post about the X pipe muffler did you use a magnaflow x pipe muffler ? I want to go with the Axle back SLP 2 but I also want to benefit of an x pipe but the pricces of an X pipe made or our cars is insane, so this might work for me.

[1969to2010]

Im actually wondering if a universal x pipe can be made to work with not too much fabrication, also the stock L99 pipes are 2.5 right ?

[SamSS]

Originally Posted by 1969to2010

Im actually wondering if a universal x pipe can be made to work with not too much fabrication, also the stock L99 pipes are 2.5 right ?

Yes. Both LS3 and L99 pipes are 2.5.

[1969to2010]

Originally Posted by SamSS

Yes. Both LS3 and L99 pipes are 2.5.

thats what I thought, So I think I have finally made a decision
magnaflow x pipe after cutting the resonators out then SLP loud mouth Axle back done deal!
Sam your thread def helped me out,,

[Danny Thomas]

Have the Magnaflow x pipe with resinator and muffler delete...it is an awesome setup for $300 parts and labor. There is still some AFM drone but nothing that can't be lived with. No matter what you use to get a louder system...there will be some type of drone. This a nice way to go when not doing a full blow header / exhaust system

[firengnred]

The reason I went with the X-Pipe muffler rather than a true X-Pipe is to tone down the volume slightly and deepen the exhaust note. Remember i'm putting on the Comp. Series axle back which has no mufflers. Yes this is basically building a custom cat back system for half the cost.

[firengnred]

If you get a tune you can disable the AFM which will eliminate the drone.