simbasupra Posted August 16, 2012 Share Posted August 16, 2012 Hi guys I've had a look at other threads and couldn't find an answer, so decided to post a new thread. I have seen threads regarding jspec decat diameters but not UK spec. From what I understand it doesn't matter what diameter decats you fit to a jspec as you have to fit a restrictor ring anyway. I have a UK spec and was wondering if 2.5" or 3.0" decats made any difference. Would there be performance differences? Boost differences? Reliability differences? Thanks Quote Link to comment Share on other sites More sharing options...
sideexitsupra Posted August 16, 2012 Share Posted August 16, 2012 3.0" will flow better than a 2.5" obviously. I actually went from a 3.0" to 2.5" when I changed my exhaust and had to play with the boost controller to get it back up to 1.2 bar due to the decreased flow. At BPU I don't think you would see much difference. Over BPU and it may effect exhaust temps I guess? Quote Link to comment Share on other sites More sharing options...
SteveC Posted August 16, 2012 Share Posted August 16, 2012 Some will say that 2.5" is sufficient for BPU, but I went for 3" decats and an 80mm system - just over 3". The more free-flowing the system the better (if you don't need a restrictor ring - as on a UK model), but obviously there does come a point with increased diameter where all you get is a loss in ground clearance. Quote Link to comment Share on other sites More sharing options...
simbasupra Posted August 16, 2012 Author Share Posted August 16, 2012 Some will say that 2.5" is sufficient for BPU, but I went for 3" decats and an 80mm system - just over 3". The more free-flowing the system the better (if you don't need a restrictor ring - as on a UK model), but obviously there does come a point with increased diameter where all you get is a loss in ground clearance. in another thread i noticed you said your decats were from whiftbitz, but i can only find 2.5" decats from them. where can you get 3" decats for a uk from? Quote Link to comment Share on other sites More sharing options...
SteveC Posted August 16, 2012 Share Posted August 16, 2012 in another thread i noticed you said your decats were from whiftbitz, but i can only find 2.5" decats from them. where can you get 3" decats for a uk from? From Whifbitz. They're made up to order as opposed to being listed on the website. PM or phone Paul Whiffin for a price. Quote Link to comment Share on other sites More sharing options...
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