ok guys im thinking about upgradng my downpipe and have some questions. what kind of downpipe should i be going for i guess u can say i have a 01 gc8 with 05 swapped and am uncertain about which type and if anyone had one tat i could buy to thanks
05' swapped what? wrx 2.0 or sti 2.5? personally i would go with bellmouth, best overall. But a lot like divorced with ewg. little more spendy but better boost controll.
The COBB catted bellmouth unit is the best money can buy...but it's $700. It'll fit the WRX and STi (as will all downpipes I think). I personally run an Invidia bellmouth w/o cat. Works great. On downpipe design: The best downpipe is of the divorced-wastegate style. It keeps the wastegate and turbine exhaust separate to minimize turbulence, but if it isn't done right it's going to be less effective than a bellmouth design. The stock unit is of the blank plate design, which is a plate over the wastegate (think brick wall) and a pipe lined up behind the turbine. Horrible. HKS sells a unit like this. If you were to run a COBB Stage 2 map with this design you'd have horrific boosting issues because the wastegate couldn't move any exhaust.
ERZ up and down is what I have. fitment is great, but when you have your exhaust custom built from the dp back there is usually no fitment issues
then the bellmouth type downpipes will work for ya. there's a ton of options out there. pay attention to the design and construction of the rear flange, where it meets the catback pipe. You want something that is sturdy. (well constructed) Why? Some downpipes that can be purchased on ebay have cheap thin walled construction and it's not always straight. (Then you'll have a hard time creating a good seal and remaining leak-free. ) I've installed a number of Invidia down pipes and you can usually get them cheap if you shop around. The fitment is always spot on! Don't forget to wrap your pipe before installing it
What? Cast bellmouth, fantastic welding, O2 bung, tapered ending that uses the rock-solid donut gasket for the best seal, a great high-flow cat.... ...all of the above make it the best DP on the market. Money wise? Hell no, an Invidia will do 98% of what the COBB unit can for $450 less, but the COBB unit is the best you can buy in terms of quality. The koolaid is delicious
I guess it depends on the application. I wouldn't pay 450 dollars for a catylitic converter and a cast bellmouth. The Invidia's welds are just as top notch and it has an 02 bung so in terms of quality, I'd say they are even. So, in my opinion, the Cobb is NOT the best you could buy, since you could get the same quality of parts with no cats for 450 less.
I think we're agreeing, but using different words. The COBB unit is slllightly better not considering price. Objectively, not factoring in price, I can reasonably say it has the advantage due to R&D, materials uses, etc....but just barely. 1% barely. But when you factor in price, the Invidia slays it because it so much cheap and is (near as makes nearly no difference) good. You could argue that the extruded pipe design vs. cast design of the Invidia vs. COBB makes the former more likely to fail under duress (thinner material, less weld surface area), but who the hell is going to use an OTS DP and care about that? Yeah, I got the Invidia one for the same reason as everyone else: $450 isn't worth the 1% quality difference.
