Exhaust or hf cats

[Vert2SS]

I have a 2011 SS conv l99.....I am looking at doing a sound improvement only mod. What would give me a more aggressive sound without being too loud...solo hf cats with stock exhaust or solo Mac XC catback ? I have a feeling doing both would be too loud for what I am looking for.

[daveagogo1]

Be aware Dean. That anything you do to the cats with stock exhaust without a tune to remove AFM will only greatly enhance the sound of the AFM kicking in and out.

The Solo Mach XL with J pipes has had good results on taming the AFM. And let's face it. Anything will increase the sound over the stock setup.

[Xedes]

I thought the Solo HF cats didn't require a tune.

[daveagogo1]

Originally Posted by Xedes

I thought the Solo HF cats didn't require a tune.

They don't but without a tune to remove AFM that will only get louder even with the stock catback. He wants more sound but, i doubt the louder sound of AFM kicking in and out is what he is after.

[IndeedSS1]

Taking AFM out of the mix, the SOLO cats will give you the most sound and performance. imo the Mach-X isn't that loud nor could I tell a performance increase. I do feel that the two of them combined is great though.

AFM - I don't have a L99 so I have no idea what that is like with aftermarket exhaust, other than no one likes it.

[newmoon]

Originally Posted by IndeedSS1

Taking AFM out of the mix, the SOLO cats will give you the most sound and performance. imo the Mach-X isn't that loud nor could I tell a performance increase. I do feel that the two of them combined is great though.

AFM - I don't have a L99 so I have no idea what that is like with aftermarket exhaust, other than no one likes it.

Agree 100%, the Solo H/F Cats are a great mod. They will add hp and tq and also up the sound of the factory exhaust. When I had my car running the Solos I did have the GM Perf Exhaust and the car sounded great.