What is loudest?

I'm talking loudest outside the car and inside the car interior between these setups?

2 High Flow cats "completely gutted" with h pipe and Flowmaster 44's, stock headers

OR

2 High flow cats "not gutted" h pipe SLP Loudmouth 1's stock headers

NicK C...stock set up does not have headers...has exhaust manifolds. I would guess #1 would be loudest?
I'll tell you what is loud. My wife is loud. You should have heard how loud she was when I came home from work covered in glitter. That is freaking loud my man!

I have flow master outlaws but have lontubes and off road H. But with the lethal off road X different OTAs and the Flowmaster outlaws its LOUD! people say its retarded loud but I like it.

raustin0017 said:

I'll tell you what is loud. My wife is loud. You should have heard how loud she was when I came home from work covered in glitter. That is freaking loud my man!

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LOL. That is funny, I don't care where your from.
And I under stand completely.

Nick C said:

I'm talking loudest outside the car and inside the car interior between these setups?

2 High Flow cats "completely gutted" with h pipe and Flowmaster 44's, stock headers

OR

2 High flow cats "not gutted" h pipe SLP Loudmouth 1's stock headers

Click to expand...

The answer depends on RPM and engine load.

At cruising speeds, low load, the gutted cat setup will be the loudest and allow for the most resonance even with a chambered muffler setup.

Under load, the high-flow cat and SLP LM1s will be louder in my opinion. It'll sound liked a pissed off elephant trumpeting when it hits the resonant frequencies around 2.5k-3.5k rpm. It's the higher frequencies that will make it ear-piercing with straight-thru mufflers/resonators. The '44s will be loud, but it'll be lower frequency. Noise is a funny thing- two different frequencies at the same dB will "sound" like they are at different levels because our ears are "designed" for frequencies along the normal range of vocal frequencies. The in-cabin resonance is what will be horrendous with the gutted cat setup, which you actually "hear" through the vibrations in your body.

I've run catted, straight pipes, multiple muffler combinations on multiple cars. High flow cats are the way to go for a street car in my opinion- you can still get that ear-melting volume when you want it, but it quiets down nicely even with straight-thru mufflers/resonators.

S197s have far better sound insulation than SN95s, but still... After driving my '00 GT with straight pipes (shorties, O/R X, SLP LM1s) for a year, I probably have hearing damage. That's why I went for the catted H on my '14.