NOOB at exhaust questions.

SpawnGT · March 12, 2007

Current setup is a FLOW ceramic coated UPpipe, and a Crucial SHorty DOwnpipe, and its all stock until the axel back where i have straight pipes that i bought from a user, now i used to have an electrical exhuast cutout but i dont want it on the car anymore, i wanna have performence but no harsh noise coming from the passanger seat(i had it installed on the second part of the downpipe right before the 3rd cat.

Am i correct that

After the shorty DP is where the 3rd cat is?

and after that on the midpipe is the resonater, ?

Im currently running a Stg2 TDC protune for a catless system becuase it was made ideally for thre cutout....so here my dilemma is there a way to remove that cat after the downpipe and the resonator on the midpipe and install soemthing there that does not increase the noise of the exhuast? becuase its as loud as i want it to go right now (id prefer just alitttle quiter actully). I saw a memebr or two that have straightpipes going from the turbo and it was extremly loud.

can i remove the 3rd cat, and remove the resonater and install a more flowing 3rd cat and more flowing resonator and keep the volume the same or make it quieter? also i need to pass inspection so is there anyway to pass inspection with aftermarket 3rd high flow cat and a aftermarket resonator?

please help out if you can....include what kind of set up you have as well. THank you for your help guys.

**TRS** · March 12, 2007

My understanding is that the 3rd cat (after your shorty DP) isn't that restrictive and the resonator (after the 3rd cat) not really at all, so there's not much to gain there. There is the Crucial high flow 3rd cat but you'll likely get more noise over the stock 3rd cat. There's also a replacement mid pipe and Y pipe combo available from either Perrin and AVO but since these have a smaller resonator than stock, again you'll probably get more noise.

The Y is supposed to be a restriction because of it's "pinched" design so I'd focus there first. AFAIK, there' isn't just a bolt in replacement Y pipe.

Passing inspection depends on your state's method. Some just plug into the OBDII port and look for codes, while others do a visual check.

So, to meet your goal to free up flow without any increased noise (plus possibly having to have a stock looking cat on the car) I'd leave the stock 3rd cat and resonator in place and have someone weld in a more open Y pipe.

My exhaust:

Flow shorty DP

Crucial high flow cat

AutoSpeed cat back

**itsme** · March 12, 2007

Spawn I PM'd you back. But I will post the pictures for you again. I have a '05 LGT 5mt wagon w/ typhoon intake, coated PDE up, Crucial coated shorty DP and a TDC stage 2 map for that setup. It was a nice inprovment over stage 1 and was fine with it. Then I got a deal on a custom TBE. I went 3" stainless steel mendrel bent pipe to a 2.25" Y. I had a flange made and added a 3" hi flow cat then ran a 3" Borla XR1 muffler as a resanator then after the Y dual 2.25" Magnaflow muffler all SS. Now it has a nice rumble and no droning on highway.