peteyjr Posted February 9, 2009 Share Posted February 9, 2009 I think making a custom DP is not as cost effective and performance enhancing as well as a custom CBE. My exhaust guy took a good look at my Magnaflow CBE system and pointed out several design flaws. He said he could build a better one for cheaper than a new one. On the other hand he praised the Invidia DP saying it was well designed and executed with few bends. If you buy used (roughly going for $ 300) i'st hard to beat . Link to comment Share on other sites More sharing options...
ultimakf7 Posted February 9, 2009 Share Posted February 9, 2009 If you keep the stock CBE, the exhaust will stay quiet... with the tradeoff of having a more restrictive exhaust. Link to comment Share on other sites More sharing options...
Kylar Posted February 15, 2009 Share Posted February 15, 2009 Is the 05-09 Downpipe and catbacks compatable? Sorry for the newb question Link to comment Share on other sites More sharing options...
Guest LGT-NY Posted February 15, 2009 Share Posted February 15, 2009 So it looks like I'll be going with the Cobb catted DB! Yeah, Down Bipes are sweet. :lol; Link to comment Share on other sites More sharing options...
rtbrjason Posted February 15, 2009 Share Posted February 15, 2009 I did this tonight. Not sure where people are getting 20-30 mins from. It took about 20-30 mins just to get the heatshield off. From there, ran into only 1 major issue. One of the top bolts for the downpipe to turbo was factory cross threaded on. It required a torch to cut the nut off the bolt. That was about 30 more mins of screwing around. I only pulled the upper most section off and it really only took a few mins to gut it out. Everything went back together fairly smoothly aside from having to use a different nut/bolt in the one spot. All in all it took close to 2 hours, but it seems to be quite worth it. Link to comment Share on other sites More sharing options...
Blazin2000 Posted February 16, 2009 Share Posted February 16, 2009 for those that have gutted the first cat in the dp, have you tuned the car afterwards? I have an '08 and I want to do this and I am wondering if I need a tune after gutting the stock cat? Link to comment Share on other sites More sharing options...
05SilverScubie Posted February 23, 2009 Share Posted February 23, 2009 for those that have gutted the first cat in the dp, have you tuned the car afterwards? I have an '08 and I want to do this and I am wondering if I need a tune after gutting the stock cat? I have an 07 spec now and i was wondering the same Link to comment Share on other sites More sharing options...
executor485 Posted February 23, 2009 Share Posted February 23, 2009 for those that have gutted the first cat in the dp, have you tuned the car afterwards? I have an '08 and I want to do this and I am wondering if I need a tune after gutting the stock cat? I gutted the first cat and kept stage 1 base map but real time flashed to stage 2, then I had to clear the ECU one time and forgot to change the real time map, so it was still on stage 1 mapping, it didnt throw any codes for me, but there was a noticeable power decrease. Also, recently put an invidia DP on, MUCH better... But almost too much... It blew the end tank of my IC, so JB Weld to the rescue... If I pass you on the right, I'm flipping you off. Link to comment Share on other sites More sharing options...
wpmarky Posted February 23, 2009 Share Posted February 23, 2009 When you guys say "gut", what exactly are you removing? I don't see the walkthrough up anymore. From what i've gathered from other downpipe threads, you drill away at the stuff in your DP until they fall out, and then polish the inside after that. Is that all? Link to comment Share on other sites More sharing options...
executor485 Posted February 23, 2009 Share Posted February 23, 2009 Drilling... Not that I know of... Guess you could... Just use a breaker bar or screwdriver or something, you smash out all the catalitic converter stuff (wear a mask) and just make sure its all out.I didnt know what people were talking about until I actually took it off the car and saw it, once you see it, its VERY obvious as to what you remove. Just an FYI, the gutted DP is not as effective as a bellmouth DP, but it does help some if you just cant afford the DP. If I pass you on the right, I'm flipping you off. Link to comment Share on other sites More sharing options...
rtbrjason Posted February 24, 2009 Share Posted February 24, 2009 Mine was tuned (opensource) prior to gutting, and the tune was adjusted after. I'm still doing excessive amounts of data logging, but I can assure you the gutted oem dp makes a considerable difference from stage 1 levels. I suspect another 10ish whp could be had with an aftermarket downpipe, and maybe 15ish with a fully catless dp. It would be a noticeable mod without tuning as well, but you'll likely throw a cat efficiency code. You should really have a tune imo. As for the gutting, just smash out all of the catalyst material as mentioned above, no polishing will be required, it will all fall out. This part of the project only took a few mins for me. Link to comment Share on other sites More sharing options...
05SilverScubie Posted February 24, 2009 Share Posted February 24, 2009 Thanks for the info guys Link to comment Share on other sites More sharing options...
wpmarky Posted February 24, 2009 Share Posted February 24, 2009 i'm assuming that the gutted dp will throw codes unless you flash the ecu to stage 2? Link to comment Share on other sites More sharing options...
rtbrjason Posted February 24, 2009 Share Posted February 24, 2009 i'm assuming that the gutted dp will throw codes unless you flash the ecu to stage 2? I didn't run it long before getting the stage2 tune, but in the time that I ran stage 1 tuning with the gutted dp, I did not get any CELs. I assume I would have eventually. I see you have an 08 specb. There is an opensource stage 1 and 2 map available on romraider for your car. You would just need a laptop and tactrix cable to flash and log those maps. The stage 2 map, is specifically for a gutted OEM downpipe. Link to comment Share on other sites More sharing options...
wpmarky Posted February 24, 2009 Share Posted February 24, 2009 Yah, that's me posting on MickeyD's threads =p Have you tried it? At first I thought gutting your downpipe was just unplugging some wires, but if you have to smash the cats, it sounds like this mod is irreversable unless you buy another stock DP. I leaning towards waiting until after the 36k warranty to do this ezmode stage 2, and will probly just go with suspension mods for now. Link to comment Share on other sites More sharing options...
rtbrjason Posted February 24, 2009 Share Posted February 24, 2009 Yah, that's me posting on MickeyD's threads =p Have you tried it? At first I thought gutting your downpipe was just unplugging some wires, but if you have to smash the cats, it sounds like this mod is irreversable unless you buy another stock DP. I leaning towards waiting until after the 36k warranty to do this ezmode stage 2, and will probly just go with suspension mods for now. Yeah the stage 1 maps were developed by mickeyd with myself and havanahjoes cars used for logging. The stage 2 was developed and logged on my car after hollowing the first cat. Either map is a great choice. Once you remove the stuff from the downpipe, there is no way to put it back. You could always just buy someones used stock oem upper portion of the downpipe and gut that. Prob could be had for $50 or so. Link to comment Share on other sites More sharing options...
wpmarky Posted February 25, 2009 Share Posted February 25, 2009 Do i need to get some new DP gaskets before the gut? The car itself is still pretty new, so should they still be ok to reuse? Or are they the paper type gaskets... Link to comment Share on other sites More sharing options...
wpmarky Posted February 25, 2009 Share Posted February 25, 2009 One more thing, does anyone know what kind of gains can be expected from a gutted downpipe stage 2 tune? I've heard that stage 1 alone is a 20-30hp difference, would the gutted DP + stage 2 tune be +40-50hp over stock? Link to comment Share on other sites More sharing options...
rtbrjason Posted February 25, 2009 Share Posted February 25, 2009 Do i need to get some new DP gaskets before the gut? The car itself is still pretty new, so should they still be ok to reuse? Or are they the paper type gaskets... I bought new ones, but it was pretty clear that I could have re-used the old ones. Link to comment Share on other sites More sharing options...
rtbrjason Posted February 25, 2009 Share Posted February 25, 2009 One more thing, does anyone know what kind of gains can be expected from a gutted downpipe stage 2 tune? I've heard that stage 1 alone is a 20-30hp difference, would the gutted DP + stage 2 tune be +40-50hp over stock? It differs from car to car, and with environmental variations etc, but using airboys spreadsheet and my stock/tuned log files, I show a hp increase of 40hp and tq gains of around 50 or so depending on which log I use. Link to comment Share on other sites More sharing options...
wpmarky Posted February 25, 2009 Share Posted February 25, 2009 so that dyno is with your gutted dp and the stage 2 etune on romraider?? Link to comment Share on other sites More sharing options...
Guest Posted February 25, 2009 Share Posted February 25, 2009 Get a downpipe with a cat near the turbo. I think the best design is AVO. The metal variant has really huge cat (four times as big as Cobb, seriously) right in stock location which keeps noise in check, plus it's located where it does better job and it dos not hang low where it can be damaged or be a fire hazard to something on the ground. It's 3" all the way and comes with a removeable reducer to 2.5". Also, bellmouth can be switched to twinscroll. Link to comment Share on other sites More sharing options...
05SilverScubie Posted February 25, 2009 Share Posted February 25, 2009 Get a downpipe with a car near the turbo. Usually a good thing Link to comment Share on other sites More sharing options...
Kylar Posted February 25, 2009 Share Posted February 25, 2009 With the availability of cheap down pipes out there I'm confused why so many people are destroying their stock exhausts...not to mention the improved flow with pretty much any aftermarket DP will be much better the the restrictive stock dp, even with the cats gutted. Link to comment Share on other sites More sharing options...
rtbrjason Posted February 25, 2009 Share Posted February 25, 2009 With the availability of cheap down pipes out there I'm confused why so many people are destroying their stock exhausts...not to mention the improved flow with pretty much any aftermarket DP will be much better the the restrictive stock dp, even with the cats gutted. Probably because it costs $0 and remains stock looking. I actually had a cobb catted dp ready to install in my garage but sold it and then gutted my stock. True that an aftermarket piece will flow more, but not so much more as to make it all that cost effective. You free up most of the power by removing the cat right after the turbo. At that point you can spend $500 on a dp to realize 10-12 more whp if that makes sense. Link to comment Share on other sites More sharing options...
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