Dalee1104 Posted January 2, 2019 Share Posted January 2, 2019 So I'm looking into buying a new downpipe so I can get the spec b to stage 2. Right now the car has a 3inch stainless steel catback exhaust which is mated to the stock downpipe. I was curious what kind of downpipe you guys use? I want to go with a catted downpipe and I'm looking for a 3 inch size. Dont want to break the bank so I'm always happy with a bargain but also dont want to buy crap parts. My buddy sent me a pic of a rev9 3 inch catted downpipe for 200 bucks. What do you guys recommend? Any good and bad experiences with different brands? Best fitting downpipe and such? Link to comment Share on other sites More sharing options...
Dalee1104 Posted January 2, 2019 Author Share Posted January 2, 2019 Oh also what would be best, bell mouth? Divorced Wastegate? Not sure what's really out there. Never replaced a downpipe Link to comment Share on other sites More sharing options...
compsurge Posted January 2, 2019 Share Posted January 2, 2019 Grimmspeed makes a really nice downpipe. You won't get a legitimate catalytic converter unless you buy an EPA-legal GESI OBDII (Vibrant 7530) and weld it in. Link to comment Share on other sites More sharing options...
relative4 Posted January 2, 2019 Share Posted January 2, 2019 Rev9 works. Cobb and GrimmSpeed have better cats, but GrimmSpeed has the lower O2 sensor bung upstream of the cat, which is asinine. The Cobb for auto trans also has that, but I think Spec Bs are all manual? Link to comment Share on other sites More sharing options...
relative4 Posted January 2, 2019 Share Posted January 2, 2019 Grimmspeed makes a really nice downpipe. If you don't want your lower O2 sensor to work. Link to comment Share on other sites More sharing options...
compsurge Posted January 2, 2019 Share Posted January 2, 2019 If you don't want your lower O2 sensor to work. The one I bought had it post cat. It doesn't matter as the only cat that is legal is the GESI. The downstream sensor isn't used for anything as most tuners will disable the emissions code. Link to comment Share on other sites More sharing options...
shralp Posted January 2, 2019 Share Posted January 2, 2019 Always had great luck with the Cobb catted units, have them on both my track car and daily driver. Great build quality and longevity Link to comment Share on other sites More sharing options...
Notorious Posted January 2, 2019 Share Posted January 2, 2019 Don’t have to worry about where my rear O2 bung is if I’m catless LOL. I’m using a CNT catless with no issue for over 40k miles. I would definitely recommend getting a cat though. The Rev9 unit will work like they said but depending on your state regulations it won’t pass smog. I live in California so I have to reuse the stock down pipe every two years. Link to comment Share on other sites More sharing options...
cryo Posted January 2, 2019 Share Posted January 2, 2019 Dalee1104 - I would suggest a catted from a higher quality company like cobb, most cheaper downpipes are going to have cheap cats that dont really do anything. Let us know if you plan for a custom etune and we can get you all squared away! Dave [sIGPIC][/sIGPIC] Providing unmatched customer service and a Premium level of Dyno/E-tuning to the Community cryotuneperformance@yahoo.com facebook.com/cryotuneperformance. Link to comment Share on other sites More sharing options...
Dalee1104 Posted January 4, 2019 Author Share Posted January 4, 2019 Yes all spec b have the 6 speed manual. So the car has 3 cats currently, 2 in the downpipe and 1 farther down that the downpipe bolts to. Up pipe is catless in the 08 but I need to upgrade the downpipe for stage 2. I live in Washington so dont have any emissions of any sort but also just dont want to go catless for various personal preferences. That being said only 1 cat in the downpipe should be okay considering I have the other one in the midpipe. As for the AFR sensor and 02 bungs and such the AFR will always be upstream of all cats so I shouldn't have to worry about that right? And 02 position is behind the stock cat in midpipe so that shouldn't be affected by the downpipe at all. Being that I dont have emissions I'm balancing the rev9 or the cobb, one is far cheaper than the other and one is higher quality Basically with this car I want a little more power and still want to daily the car reliably so stage 2 is what a lot of people recommended but an e-tune from what I've heard is far superior so depending on cost I might actually go that route Link to comment Share on other sites More sharing options...
Dalee1104 Posted January 4, 2019 Author Share Posted January 4, 2019 Any info on which kind of housing I guess is what you'd call it? I see some bragging divided or bellmouth and such. What's the pros and cons to those and which should I aim for? Link to comment Share on other sites More sharing options...
compsurge Posted January 4, 2019 Share Posted January 4, 2019 I'm not sure there is a cat in the exhaust midpipe - isn't it a resonator? Have you considered stage 1? It's the best bang-for-buck. Link to comment Share on other sites More sharing options...
relative4 Posted January 4, 2019 Share Posted January 4, 2019 Any info on which kind of housing I guess is what you'd call it? I see some bragging divided or bellmouth and such. What's the pros and cons to those and which should I aim for?Makes absolutely no difference. Link to comment Share on other sites More sharing options...
relative4 Posted January 4, 2019 Share Posted January 4, 2019 I'm not sure there is a cat in the exhaust midpipe - isn't it a resonator? Correct. Link to comment Share on other sites More sharing options...
chato Posted January 4, 2019 Share Posted January 4, 2019 bellmouth supposedly creates more turbulence at the back side of the turbo, and many people doing high horsepower builds go with an external wastegate. only practical difference is that bellmouth can make tightening/removing one of the lower mounting bolt a pain, but usually ok if you use an anti-sieze on it. location of additional O2 sensor bungs can be important if you plan on doing a custom tune, cobb’s is ideally located for that. Link to comment Share on other sites More sharing options...
KartRacerBoy Posted January 4, 2019 Share Posted January 4, 2019 I had a catted downpipe from Cobb for my 4th gen mated to a 3 inch exhaust. Made enough noise to make my daughter grumble. Link to comment Share on other sites More sharing options...
Dalee1104 Posted January 4, 2019 Author Share Posted January 4, 2019 Well I know theres a resonator in the mid pipe as I've deleted that as well but where the downpipe bolts to the rest of the exhaust there is a cat. I'm not sure if the car has had the exhaust replaced before so maybe that's why? As for the tune I do plan on stage 1 as soon as my accessport gets here but I also want more so I wanna work up to stage 2 and probably stop there Link to comment Share on other sites More sharing options...
VespaGTS Posted January 5, 2019 Share Posted January 5, 2019 I have a Catted CNT that I bought here on LGT. Sweet deal and fit was perfect. It is a lot louder (drone) than it used to be so I will be installing a resonator very soon. It’s damn annoying. Also using GS adaptor as well. Link to comment Share on other sites More sharing options...
compsurge Posted January 5, 2019 Share Posted January 5, 2019 Well I know theres a resonator in the mid pipe as I've deleted that as well but where the downpipe bolts to the rest of the exhaust there is a cat. I'm not sure if the car has had the exhaust replaced before so maybe that's why? As for the tune I do plan on stage 1 as soon as my accessport gets here but I also want more so I wanna work up to stage 2 and probably stop there Correct. There are two cats in the downpipe between the turbo and the flange that mates to the midpipe. Link to comment Share on other sites More sharing options...
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