hadyn Posted March 11, 2005 Share Posted March 11, 2005 I want to decat soon and ideally i would be going for a full decat, but im currently on a budget so one decat will have to do. What I want to know is what will produce the biggest power and response gain?Removing the 1st (frontpipe from turbo elbow)cat or the 2nd Cat (cat which joins on to cat back exhaust systems) ? Im presuming removing the first cat will have the better gains? Will I also need to fit a restrictor ring even with one cat in? My car boosts to 0.9 bar now with both cats in, so would i need a ring on top of the other cat to keep the boost below 1.2 bar? Link to comment Share on other sites More sharing options...
Scoboblio Posted March 11, 2005 Share Posted March 11, 2005 Not sure about the restrictor ring (can't hurt tho ), but the first cat at the front is the most restrictive. Link to comment Share on other sites More sharing options...
Timwildman Posted March 11, 2005 Share Posted March 11, 2005 I've got just the 1st cat out, i'm not sure about the power gain but you will notice the first turbo spool up quicker. I have no problems with out a restrictor ring. Link to comment Share on other sites More sharing options...
hadyn Posted March 11, 2005 Author Share Posted March 11, 2005 its the spool up time i want to make faster as it seems to take ages to spool to positive pressure (well it seems like ages compared to my old S14 which used to come on boost when i blipped the throttle ) Okay so if you havent been able to prove a power increase on the rollers, does the car feel more responsive and revvy with the 1st cat removed? Link to comment Share on other sites More sharing options...
Timwildman Posted March 11, 2005 Share Posted March 11, 2005 Okay so if you havent been able to prove a power increase on the rollers, does the car feel more responsive and revvy with the 1st cat removed? It feels more responsive, yes. Link to comment Share on other sites More sharing options...
Samurai446 Posted March 11, 2005 Share Posted March 11, 2005 Has anyone got any rough ideas to how much it would cost to remove both cats on a 95 twin turbo? Link to comment Share on other sites More sharing options...
Clarkey Posted March 11, 2005 Share Posted March 11, 2005 £300 for the 2 decat pipes. £100 for a Walbro fuel pump £40 - £60 for decent plugs. Do a search. I use Denso IK22's - they're £60 for 6. Other people use NGK's. UK car ? Then it's £150-£200 for a boost controller Jspec ? £17 for restrictor ring. Link to comment Share on other sites More sharing options...
JohnK Posted March 11, 2005 Share Posted March 11, 2005 Remove the first cat first. The heat reduction in the engine bay alone justifys this. Link to comment Share on other sites More sharing options...
hadyn Posted March 11, 2005 Author Share Posted March 11, 2005 what do you usually boost to with the first cat removed?? 1 bar??? Link to comment Share on other sites More sharing options...
Chase Posted March 11, 2005 Share Posted March 11, 2005 1.1 - 1.2 on mine - Got an RSR as well though... Link to comment Share on other sites More sharing options...
JohnK Posted March 11, 2005 Share Posted March 11, 2005 I have a UK spec so I cant answer the boost question. Link to comment Share on other sites More sharing options...
hadyn Posted March 11, 2005 Author Share Posted March 11, 2005 so if im 0.9 bar now with a dragger cat back - ill be on 1.1ish bar??? That means ill be hitting fuel cut all the time without an FCD? Link to comment Share on other sites More sharing options...
Clarkey Posted March 11, 2005 Share Posted March 11, 2005 You may get 1.1 or maybe 1.05. Get rid of both of the cats & get yourself a TRL VFCC from thor. It comes set by default to fuel cut at just over 1.25 Bar. This morning - when I had a play with the S14a .. Hit 1.25Bar on my peak-hold DEFI. Link to comment Share on other sites More sharing options...
Stu_Fraser Posted March 12, 2005 Share Posted March 12, 2005 Ive just removed the first cat on mine and im getting 1.2bar easily with no boost spikes..... Link to comment Share on other sites More sharing options...
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