Thinking about removing the cat on my 05 s2k for a lil bit better flow, i only have a invidia q300 catback exhuast right now and im trying to figure out if there will be a gain with no CAT.

 

Q300 sounds like @ss with a test pipe. Pm sonic9 I helped him install it on his and it was too raspy. He ended up going back to a stock cat.

 

What year is your S and will you be getting a tune after? Personally, I would only swap it if I was also getting the car tuned since there's so much more to gain that way.

 

I would only swap it for a test pipe if you are getting tuned. If not the gains aren't with the sound or smell. I have a test pipe and am tuned so it was worth it to me.

 

Or just go with a High Flow Cat. 1-2 HP less (depending on tune) compared to test pipe.

 

Test pipe is a cheap way to get a few hp and can be maximized with a tune like mentioned above. I have a test pipe on my oem exhaust and it was worth the $100. The smell is not bad, but is noticeable at times. If you have the cash, just get a high flow cat.

 

For performance? A tp by itself will probably loose some hp, not gain it. As was mentioned, the only formula for easy gains in our cars is a tune, along with a tp or hi-flo cat.

Its not the our cats don't flow well, its that they have a resonant pattern that tp and hi performance cats don't. So allows tune to take full advantage.

So yeah, if you are going to get a tune, get a tp or cat. If not, don't be a ricer and get a tp and kill trees for nothing.

 

thanks i dont plan on getting a tune so im gonna stick to just the cat back.

 

Well if you care absolutely nothing about the ozone layer and want to gain a few hp/save a couple pounds.

Personally I think its an excellent mod

 

I was driving around with a testpipe for a while to repair my OEM cat.
Fujitsubo Legalis R exhaust.
No tune, no nothing, just remove cat, install testpipe.
Definitely noticed a bit more power between 6 and 9.
The sound was not that nice, not too loud just crappy.

The car smelled like the 70's.....

(on the outside....)