Crescent Fresh Posted January 25, 2008 Report Share Posted January 25, 2008 The guts of my cat broke apart and have now been removed (empty cat is still there). I am barely failing the emissions section of inspection. 1. Does a catalytic converter hurt performance and fuel economy? If so, will an unskilled driver notice the performance? 2. How important is the back pressure caused by the cat? 3. Any suggestions to what cat to buy and where to get it should I decide to get a new one? Thanks Quote Link to comment Share on other sites More sharing options...
Tony94S4 Posted January 25, 2008 Report Share Posted January 25, 2008 will notice little better turbo response and little louder with no cat here are couple universals on ebay I had great experience with magnaflow products in past, but they both look the same http://cgi.ebay.com/ebaymotors/ws/eBayISAP...A:IT&ih=005 http://cgi.ebay.com/ebaymotors/ws/eBayISAP...A:IT&ih=005 two welds, it shouldn't be more than $60 to put on Quote Link to comment Share on other sites More sharing options...
Crescent Fresh Posted January 25, 2008 Author Report Share Posted January 25, 2008 Tony, I'd rather stick with brands that I can research more. I like your idea of Magnaflow or Mandrel Bends. Anyone have more info on this topic? Quote Link to comment Share on other sites More sharing options...
Tony94S4 Posted January 25, 2008 Report Share Posted January 25, 2008 That's what I have 3'' down pipe with one 90 degree and one 45 mandrel bend pipes stainless with v band clamps Attached to 3'' magnaflow exhaust Quote Link to comment Share on other sites More sharing options...
CBrownstead Posted January 26, 2008 Report Share Posted January 26, 2008 (edited) a lot depends on your cam, I do not know lotus cam setup at all, but in the performance cars, and race cars, a really agressive cam can have a bit of overlap between the exhaust and the intake lobes, if you have no back pressure at all, you can actually lose fuel air mixture, doubt this happens in the 2.2 . . . but I have seen it happen on chevy V8's with major modifications . . including turbo. Have a callaway twin turbo vette from the 80's, saw the decrease on the dyno with super agressive camshaft . . . so cats are generally performance robbers . . . but a wide open exhaust on a car that was designed to have some backpressure can cause issues as well . . . having no cat at all can cause your O2 sensor to read too lean as well . . . because the exhaust gases get away too quickly . . . but with the turbo I doubt this happens at low RPM's either . . . Edited January 26, 2008 by CBrownstead Quote Link to comment Share on other sites More sharing options...
Tony94S4 Posted January 26, 2008 Report Share Posted January 26, 2008 with the size of lotus turbo exhaust housing and wheel u shouldn't have that problem at all Quote Link to comment Share on other sites More sharing options...
lotusessex80 Posted January 26, 2008 Report Share Posted January 26, 2008 On my STI, with the 2.5 liter with no cats, i shoot flames because the downpipe that connects from the turbo to the catback on the sti has no cats. so on sti's turbo spool depends on the downpipe and not the turbo cat back, however, without proper Engine Management, you get boost creeps. I dont know if that helps you or not but no cats = faster turbo spool. Where I live in Wisconsin, I know for sure my STI wouldnt pass emissions. I have 850cc injectors, blow off valve, no cats on any pipes, a free flowing headers, 250lp walboro fuel pump, Access Port II for my Engine Management system. gas burner..LOL. Ill gladly trade it for a v8 Esprit, anyone? Quote Link to comment Share on other sites More sharing options...
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