Exhaust questions. Performance and sound

[The maro]

Hey guys. New member, just got a 2015 l99 SS a few weeks ago. Love the car but I can't stand how damn quiet the thing is. I've done a ton of research and have an idea of what I want to do to the exhaust but still have a few questions.

I'm debating on what my first mod should be. Deciding between high flow cats, replacing the resonator with a non resonated h/x pipe, or just a muffler delete.

I want an exhaust that's low and choppy. From what I've been seeing the stock mufflers are pretty much straight through. They honestly sound decent at times.

My questions are this- what would make the most noticeable difference right off the bat in terms of both performance and sound? Resonator delete and h/x pipe or cats? Are the stock mufflers relatively loud when the other exhaust components are allowed to breathe a little better?

[Synyster]

Headers for performance. Cats would provide a few ponies, but I'm pretty sure you need a tune anyway. So, headers.

Cat back won't give any power, but if you want deep then the SW Retro is good. If you want headers later though, be warned that's a loud ass combo.

I've not personally heard the stock exhaust with headers or anything, but the guys here that do it seem to like it. Just seems a little too high pitched for me though.

[mmcdonald1179]

High flow cats for more sound and performance

[Red2014SS]

I've been on the same quest since last year. I'll pass along my experience and maybe it will save you some money and time.. Here is what I have learned....

Muffler delete - My first change. Nice improvement. $100 - Deeper sound, a little louder. Quite racey at higher rpms..Nice, neighborhood friendly mod.

Headers and high flow cats - Second change - A lot deeper, not really louder. Not loud enough. Sounds great at wide open throttle. Sounds stock at idle..not as much difference as I expected.

Third change - Removed stock resonator and replaced with Jeg's X-pipe....(so, at this point, I have headers and basically straight pipe out the back tips)..

LOUD enough to wake the dead. Insanely loud on a cold start up. It sounds like a stock car. It actually sounds great... I had no idea the resonator was doing that much work.

...but I gotta tone it down now. I think that if a cop got behind me, I'd probably get a fix it ticket...so, I have a GMPP axle back being delivered tomorrow. Hopefully, this will be perfect. I did learn that the stock resonator does about 70% of the sound reduction on these cars (L99). The stock cats do about 15% and the stock mufflers are about 15%. YMMV.

Performance? Headers and a tune. Hands down, best money spent. Different car. Night and day. It will spin the tires when it shifts to third gear if I want.

Good luck with it.

[poorboy10]

I'll put in my 2 cents, I'm on my 3rd exhaust setup(magnaflow resonated xpipe and muffler delete with j pipes). By far this is the best sounding outside the car and is almost stock quiet cruising down the road. When i was stock the other 2 setups i had sounded decent, but once i added the long tubes and cam it was a different story. Me and my boss have the same exact mods except he left his catback stock until recently. He added the solo axle back with j-pipes to the stock catback and it sounds awesome. That is how i ended up where I am.

[The maro]

Originally Posted by poorboy10

I'll put in my 2 cents, I'm on my 3rd exhaust setup(magnaflow resonated xpipe and muffler delete with j pipes). By far this is the best sounding outside the car and is almost stock quiet cruising down the road. When i was stock the other 2 setups i had sounded decent, but once i added the long tubes and cam it was a different story. Me and my boss have the same exact mods except he left his catback stock until recently. He added the solo axle back with j-pipes to the stock catback and it sounds awesome. That is how i ended up where I am.

Probably going to start out with the x pipe and remove the resonators and see how that is and then if it isn't how I like it I'll go with a muffler delete. Appreciate the input. This is probably cheapest and most effective until I can afford some high flow cats and headers.

[The maro]

Thanks for the input guys. Probably starting out with what I said above. Resonator delete, x pipe, and a possible muffler delete.
Cats and headers will come later

[Apex Motorsports]

Bone stock SS with Stainless Works Retro Chambered cat back.




And here is the same car with the addition of a set of Stainless Works 1 7/8 headers and high flow cats.

[myold88]

Since you have the L99 I would go with the Solo J-Pipe Axle Backs which deletes the mufflers
but also controls the L99 drone. Without J-pipes, you may not be a happy camper. I've had
mine for 5 years now, great deep sound with no drone.

[Pro Stock John]

I've had a few different exhaust combos.

The path you take depends on whether you plan to ever go catless.

This combo for example sounded like a race car and was too much for me:



Removed Spiral Flows, swapped in Maxflows: (very little drone)

[The maro]

Originally Posted by Pro Stock John

I've had a few different exhaust combos.

The path you take depends on whether you plan to ever go catless.

That actually brings up another question. I'd love to go catless, but don't want a CEL. Is there any way around this without a tune? Foulers or a test pipe that doesn't cause it.
And most my work would be done in Dallas. What are the odds I could even get cats removed unless I go to a small shop in the middle of nowhere?

[Pro Stock John]

Catless, you would need a tune.


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[The maro]

Originally Posted by Pro Stock John

Catless, you would need a tune.

That's what I thought. Thanks man. Might have to hold off on that for a while.

Gonna go talk to a shop soon and see what all these options are gonna cost and go from there.

[Pro Stock John]

You could just do JBA hi flow catted mid pipes


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