Catted Vs Catless Downpipe?

I prefer catless. If you already have or plan on getting Ecutek, emission will not be a problem.

 

In GA metro counties, we don't do sniffer test. As long as you have Engine Management which can clear CEL, you will be fine with emission test. It's your choice about being catted or catless. However, I do recommend going with catted if you have funds available. Power difference depends on your whole set up, but for me it wasn't worth it. That's why I spent little more money and got 3" Stromung HF cat. It still flows pretty good, and it's quieter as well. PLUS i'm saving trees as well. haha But i bet that I'm still producing pollution equal to 1000 civic hybrids.

 

Thats hilarious.

 

Catted is definitely more expensive. Although, the Helix catted I have seen is about the cheapiest you can go for high flow. Most people say its like a 5hp difference between the two. It also depends on what catback your running for how loud the exhaust will be. If you are running blitz nur or hks, it will be pretty loud. Although I am running the Perrin dp with a HKS hi-power and its quiet at idle. It doesn't start to bark until 4k rpms.

 

This is one topic I'm interested in as well. I need to choose which DP and exhaust I want, now that I've decided those are the parts I want to mod. What would be cool is a website that has sound bites of different UP/DP/exhaust combinations and what they sound like. I know it's not anything like the real thing, but I donno how else to experience what the sound will be prior to purchase.
Oh also, CAIs usually add sound too right? can anyone perhaps rate or rank different CAIs according to sound lvl? i.e. Apex>4 (1-5 scale with 5 being loudest), brandB>3, etc.

 

I think the AEM vortex CAI thingy is the loudest, or at least thats what they advertise. I use the AEM short ram and its pretty loud. You can definitely hear the sucking from the turbo.

The sound of the exhaust has everything to do with the catback and not really the dp. The catback's resonator or lack of is what gives the most defined exhaust note. Someobody posted a link of exhaust sounds not too long ago, but I dont remember the thread (probably in power section). You tell us what kind of exhaust sound you want, and we could probably give you good suggestions of how to attain it.

The Invidia V3, I felt was over priced. Its probably just as good as any other dp on the market. As long as the pipe is 3" and has some sort of bellmouth or divorced wastegate pipe you should be fine and make similar power. If you want catted, I thought the Helix was the cheapiest, but I could be wrong.

 

I like my Helix High flow catted DP plus I dont get that lovely exhaust smell. I doubt you would really notice any really difference powerwise using a catted vs catless DP.

 

279 is a pretty good price for most any full size dp. Just don't get the HKS.

 

Here's the site with a pretty good collection of exhaust sounds.

http://www.clubwrx.net/forums/showthread.php?t=58111&highlight=erz

Here's one with a ton of pics if your interested (sound link no longer works).

http://www47.homepage.villanova.edu/joseph.bozzuto/wrx_exhausts.htm

 

I actually spooled almost 500 rpm lower when going from a high flow to no cat. No soot, no nasty smells, just better response sooner...I have the TSX DP with race pipe, 3" mid and 2.5 axle back. Standard TSX Turbo back. I like it, not too loud, but you hear it still.

 

thanks for the sound bite info!!!
i'm sold on the Cobb. it's soft and fuzzy on the outside and bitchy when you get into it. merry christmas to me.

 

Go catted and help the environment.

 

In regards to downpipes, Ive been hearing bad things about DPs with divorced wastegate housings. Ive heard that at partial wastegate opening the exhaust gas is directed straight at the divider causing excessive turbulence.

Just something to keep in mind...

Oh and Superdude, definitely get the Cobb catback!! Ill be very envious...

 

Actually there is new information that has been found in a EPA study that shows that cats actually produce more no2 and that No2 is 300x worse than other gasses that were produced before cats on the greenhouse effect. I say just kill al the cows....they produce methane...terrible for the environment!

 

We can use that methane to power stuff too...

I might retain my stock 3rd cat because i'm getting a shorty DP and too cheap to buy a midpipe. I'm not loosing more then a couple HP anyways.

 

Got a link?

edit: Found it, it's n2o (nitrous oxide), not no2 that is increased. Interesting read; shows that there's no free lunch yet again. Though the reduction in nitrogen oxides, carbon monoxide and hydrocarbons help the environment, wonder how much of that is offset by the increase in greenhouse gas emissions.

 

Oops that is what I meant. Thought it was funny we were producing nitrous. Supposedly GM and others are now working on a new cat, but wh knows what they will produce this time and how much worse it might be.

 

I guess it depends on how your ecu deals with it, lol. It might just be a temporary thing. My advice would be to pull the neg terminal on the battery and reset the ECU. If it still comes back with more boost after that, then go with it, lol.

 

I say go catted. I make PLENTY of power with mine. Helix catted if you can find one.http://www.iwsti.com/forums/showthread.php?t=69718

Check this one out. Pretty dang close to the Helix...

 

^^^ i rode in his car and now my setup is going to be very similar to his

 

Milo, How are you coming with putting your set up together? You will love it without a doubt!

 

most of the stuff is here... waiting to buy injectors and fuel pump... all should go in by mid-feb
http://www.wrxatlanta.com/forums/showthread.php?p=130722&postcount=93

 

What injectors are you looking at? The Deatschwerks 740's are great for the money...if you are going the meth route. Mine have been flawless. Scott really liked them too. I'm going to have to come up for a ride when you get it all together.:naughty: