Catted or Catless Down Pipe?

[justin303films]

looking into getting a downpipe for my 2007 lgt 5MT. is there a huge difference in power and is there a difference in loudness. i have to drive an hour and a half to school and im not looking forward to a loud exhaust highway drone noise.

I currently have a invidia q300 catback, cobb sf intake, acessport, lightwieght pulley.

[ras06LGT]

There is not a major difference in power and/or noise. Catless is theoretically going to be slightly louder, but variations in the rest of the exhaust system make this essentially null.

 

Main differences are price, smell (albeit I run catless and it's really not that bad), and emissions compliance if you are required to have your car checked.

[justin303films]

I would be running the Cobb accessport so wouldn't that shut the check engine light of either way?

[FJuan]

You'll also will need to get a tune, since there will be less back pressure post turbo. Contact Cobb or find an Opensource tuner to make the adjustments.

[ras06LGT]

I would be running the Cobb accessport so wouldn't that shut the check engine light of either way?

 

No CEL should show up from a new DP. You will fail visual inspection and maybe a smog check if your state requires that. If they ONLY check for CEL then you might be okay.

 

But yes, you will require a tune for a new DP.

[justin303films]

I live in Rhode island not sure what the testing is here and i was going to get tuning alliance to make a custom map for my accessport.

[FPerron]

I strongly recommend Tuning Alliance. Mike set me up with a performance 93 octane map for the street and a more aggressive 100 octane map for the track. Won my road racing class championship with it.

[amp583]

I went with a Cobb catted and glad i did – though I wouldn't know the difference since I never ran catless.

 

Catless runs a little cheaper, will give you very marginal gains, like under 5HP and will stink up the interior like shit.

 

I had the money and i didn't want my interior stinking like shit especially in winter when the windows are closed. I also bought an old generation AccessPort from the forums and flashed to the 3.01 Stage 2 map. Though its not as dope as a custom or e-tune, it works for me for now. When i throw more hardware on, I'll get an e-tune or take it to a shop. I will say, before i even threw parts on, I checked my AF and numbers using a tactrix.

[bigleben]

No real difference in power however you will see a noticeable increase in volume with both a Catted and cattless DP as you already have a catback.

 

IMO a catted DP + catback sound way better than a catless DP (too raspy)

[starionesir]

I prefer catless. One less thing to eventually fail as all cats do. My car has a very slight raspy sound when cold but goes away when warmed up. Nothing a resonator couldn't fix but it doesn't really bother me. As for smell I've ran many cars without cats and never had any increase in smell much less inside the car. If you've got a exhaust smell in your car you've got a leak somewhere.