McDowell Performance Tunin Posted March 4, 2010 Share Posted March 4, 2010 Just curious if there is a significant gain in power, with a tune of course, deleting the last cat in my stock downpipe. I have and sti up and already deleted my first cat. I kept the last cat because I wasn't sure how Utah emissions testing was done. Turns out the just plug into the obd-II port and check for CEL's. So, basically I'm asking if it's worth crawling back under the car and gutting another damn cat . Input is greatly appreciated. P.S. I open source tune my own car, so monitoring the chages is not a problem. www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
km580 Posted March 4, 2010 Share Posted March 4, 2010 Are you talking about the cat in the mid-pipe? I removed mine and didn't really notice any difference. Slightly louder exhaust noise but no performance gains. I'm at stage 2 with PDX tune. Fat people are hard to kidnap!!! Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 4, 2010 Author Share Posted March 4, 2010 I think that's a resonator...correct me me if I'm wrong. www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 4, 2010 Author Share Posted March 4, 2010 sadly I don't remember if the entire stock DP has two cats in it, it was a while ago when I took out the first. But I think the second is in that same pipe. www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
F-WDC Spec B Posted March 4, 2010 Share Posted March 4, 2010 Stock DP has 2 cats the mid is a resonator. The first cat is the most restrictive. You can also get a cheep used catless for better performance. Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 4, 2010 Author Share Posted March 4, 2010 I already took the first DP cat out, talking about the second www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
F-WDC Spec B Posted March 4, 2010 Share Posted March 4, 2010 I know i was just stating. you can do it if you want. Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 4, 2010 Author Share Posted March 4, 2010 Are you talking about the cat in the mid-pipe? I removed mine and didn't really notice any difference. Slightly louder exhaust noise but no performance gains. I'm at stage 2 with PDX tune. Yes, sorry, I forgot the stock DP has the two sections . Yeah my question is about deleting the third cat. I think it's after the rear O2 sensor www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 4, 2010 Author Share Posted March 4, 2010 Are you talking about the cat in the mid-pipe? I removed mine and didn't really notice any difference. Slightly louder exhaust noise but no performance gains. I'm at stage 2 with PDX tune. Did you re-tune your car after taking this cat out? www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
coldradio1 Posted March 4, 2010 Share Posted March 4, 2010 You may also want to check to see if they do visual checks as well. Every place I've ever been to puts a mirror under the car. Link to comment Share on other sites More sharing options...
km580 Posted March 4, 2010 Share Posted March 4, 2010 Did you re-tune your car after taking this cat out? No, I didn't thik I would need one. I didn't get any CELs when I did it. Fat people are hard to kidnap!!! Link to comment Share on other sites More sharing options...
doctorbrody Posted March 4, 2010 Share Posted March 4, 2010 Go with a catted bellmouth downpipe, and you'll make a lot more power than with a gutted stocker. The air's polluted enough without people deleting cats for no reason. Link to comment Share on other sites More sharing options...
captainhook Posted March 4, 2010 Share Posted March 4, 2010 Go with a catted bellmouth downpipe, and you'll make a lot more power than with a gutted stocker. The air's polluted enough without people deleting cats for no reason. A while back infamous1 dyno'd the difference between a gutted stock dp and an aftermarket one with a bellmouth and 3" piping I believe and the difference was like 4 or 5 whp. I wouldn't call that a lot. Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 5, 2010 Author Share Posted March 5, 2010 You may also want to check to see if they do visual checks as well. Every place I've ever been to puts a mirror under the car. I just had my inspection done. In Utah they just plug into your OBD-II port to check for CEL's. No visuals or anything else. Back on topic....has anyone gutted all three cats? I know I can get more power from a bellmouth, or another aftermarket set up. I can gut my cat for free . Just wondering if it's worth crawling under the car again to do this mod... www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
McDowell Performance Tunin Posted March 5, 2010 Author Share Posted March 5, 2010 right now, I'm about 240HP and 260-270TQ, according to airboy's spreadsheet. If I can get 10-15 more HP/TQ then I'll jump back under the beast. www.facebook.com/mcdowelltuning [sIGPIC][/sIGPIC] Click Here for Stage1, Stage2 and Stage3 Tuning and eTuning Info Link to comment Share on other sites More sharing options...
Boostin1657615274 Posted March 5, 2010 Share Posted March 5, 2010 Go with a catted bellmouth downpipe, and you'll make a lot more power than with a gutted stocker. The air's polluted enough without people deleting cats for no reason. don't worry, you are still increasing pollution by switching from having only the OEM rear cat to a downpipe with the typical metallic substrate aftermarket cat. Part of the reason why they are so cheap compared to a new OEM cat is that they have hardly any catalyst precious metals in them compared to stock. But they do control the smell under idle and low load driving. On the search for a new DD... Link to comment Share on other sites More sharing options...
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