I've searched here (NAM) and youtube for sound clips/examples, etc. to no avail for what a stock exhaust manifold (header) would sound like if the pre-cat and cat has been removed. *The CAT pipe/section is still there but it has been gutted i.e., hollow.
Also, the post-cat section that connects to the rest of the cat-back has been bored/ported out from the stock 1.5" or whatever it is to 2.25 or 2.5".

I'm currently running the one-ball setup as far as the cat-back is concerned.

My question is, will this sound raspy or extremely loud? LOTS of drone?

I expect an increase in sound for sure but how much? Any ideas?

If it sounds like a rally/race car then that's fine. I just DO NOT want it to sound like a dinky honda, ricey fart-cannon, etc.

Also, any ideas of possible performance gain?

Thanks in advance.

 

We removed the upper cat on our in-house R53, but still have the larger cat in place. With a borla race exhaust with no resonator, sound did not change.

 

We've decated the precat many times, but don't take out the main cat. I don't suggest taking out both cats, it will be ALOT louder and illegal, and you'll get a check engine light.

 

when removing the upper cat did you guys remove that restriction before the pre-cat too, and no change in sound?

i have been pondering this when i get a wide band bung installed as a bit of cheap hp.

-Jonathan

 

I should have added that it has an 02 sim and it "looks" stock. Also, Kentucky doesn't smog test. The guy I got it from sound he never got a cel which was one of my concerns.

I'm still left wondering what sort of sound change will take place. If it ends up being "too" loud I can always switch back but I really would like to know what sort of tone I may get before I do it. I'd sure hate to sound like a rice-burner for those days/weeks before I could revert back to stock manifold.

If it is too loud, I'll just have my cat welded onto the modified manifold.

I take it no one hasn't an idea of what sort of "tone" I'll receive?

 

I did this a long time ago, didnt make my car louder at all, it was a pain getting that thing out of there-

 

That's strange - I expect it to be louder. Did it alter the tone at all? Did you like it? Anyway to describe it?

 

i have the alta header and catback, the insides of my cat actually blew out from the heat and now its really loud... still not ricey tho. Around town I dont mind the noice at all, pops a lot more, highway gets a bit droney though requires the radio to be turned up.
-Greg

 

Thankyou Greg.

 

Won't I lose power/torque with decat though? If that's the case, I may just have my cat welded onto the de-pre-cat'd manifold. Plus, I don't think I would want to be super loud all the time, atleast, not on a daily.

Besides, I plan on getting a full cat-back in the future. Either Invidia or Stratmosphere.