Jim_1979 Posted July 23, 2006 Share Posted July 23, 2006 I have stock exhaust on a TT Auto. Curious what difference double de-catting it would make, while still keeping the stock exhaust?? ... I assume no restrictor ring etc would be required? Would it still boost more or is it more so the exhaust system that is the most restrictive part? Also what sound difference would this make to a stock exhaust if any?? Thanks for the comments !! (ps... I will be joining the forum as a paid member any day now!... great place!! ) Link to comment Share on other sites More sharing options...
ardasaliah Posted July 23, 2006 Share Posted July 23, 2006 I would also like to know if the exhaust is more retrictive then the cats_ sure someone will come along shortly Link to comment Share on other sites More sharing options...
MrAngry Posted July 23, 2006 Share Posted July 23, 2006 From the keyboard of the Oracle Here Link to comment Share on other sites More sharing options...
Feakins Posted July 23, 2006 Share Posted July 23, 2006 I'd be interested to know what this would sound like. Link to comment Share on other sites More sharing options...
MarkTheBoy Posted July 23, 2006 Share Posted July 23, 2006 From the keyboard of the Oracle Here Does this mean it definitely wont boost past 1.2bar then or is it worth fitting the restrictor ring anyway just to be on the safe side? Also what about FCD and a new fuel pump? I've been playing with the idea of just decatting my stock exhaust but then started adding up the extras of a FCD and an uprated fuel pump and it got expensive quickly. Will I definitely need a FCD and an uprated fuel pump or will I be able to get by for a little while with just the decats? Anybody know? Link to comment Share on other sites More sharing options...
Feakins Posted July 23, 2006 Share Posted July 23, 2006 I'm a bit of a rookie but I think....you will need to install the FCD as this kicks in at anything above 1 bar. Also the fuel pump to be honest is only optional but as most cars are around 10 years old most people do it for peace of mind. If I was you I would do things slowly and say jsut get the FCD and the fuel pump and then maybe do the rest next month?? As for the restrictor ring I think that just adds more restriction so make sure a fully decatted exhaust doesnt go above 1.2bar. So this would mean if you have the restriction of a standard back box then with the ring it will boost even lower, maybe below 1 bar. Do you have a boost gauge, I'd probably leave out the restrictor ring and I think it wont go above 1.2 bar. Link to comment Share on other sites More sharing options...
tDR Posted July 23, 2006 Share Posted July 23, 2006 Boost on mine has raised a little to about 0.9bar with 2nd online, running my just fitted 2.5" decats mated to stock cat back exhaust whilst waiting on my Blitz Nur Spec R arriving this week. It's still quieter than a church mouse too! You won't need FCD, walbro fuel pump or restrictor ring at this boost level. Cheers, Brian. Link to comment Share on other sites More sharing options...
Feakins Posted July 23, 2006 Share Posted July 23, 2006 Cool, is it jsut as quiet as with the standard system?? I might do this to keep it quiet then get a boost controller if I want to go above 0.9 bar. So you have 1st and 2nd decat? Standard back box? Or does the Nur Spec some with the 2nd decat? Link to comment Share on other sites More sharing options...
tDR Posted July 23, 2006 Share Posted July 23, 2006 Nur spec is cat back, I am currently fully decatted with stock exhaust mated to decat pipes. It sounds just as quiet to me but I'm a deaf bugger at the best of times so maybe it's very very very slightly louder. There are quiet aftermarket exaust systems which will flow a lot better than the stock item and keep exhaust temps down as these would be higher if you use a boost controller with the standard exhaust. Link to comment Share on other sites More sharing options...
Feakins Posted July 23, 2006 Share Posted July 23, 2006 Yeah I've seen a Kasimoto on ebay that looks like it still has 2 silencer boxes but i'm not sure if I like the tailpipe. If I can get a Nur Spec cheap I will see how that sounds with the 2nd CAT still in. Link to comment Share on other sites More sharing options...
Jim_1979 Posted July 23, 2006 Author Share Posted July 23, 2006 where's best to get decat pipes from? Link to comment Share on other sites More sharing options...
Feakins Posted July 23, 2006 Share Posted July 23, 2006 http://www.whifbitz.co.uk do them and I think Chris Wilson makes then and they are highly recommded. Got my first CAT off him for around 130. Link to comment Share on other sites More sharing options...
letmeshowyou Posted July 23, 2006 Share Posted July 23, 2006 It will be *slightly* louder than stock, but not alot. Personally I'd put the restrictor in at the same time just for peace of mind. Saves having to take it all apart to pput one in once the exhaust changes too. The big thing I noticed with cats out on the stock exhaust though is how much quicker the turbo's spooled. Def a worthwhile thing to do! Link to comment Share on other sites More sharing options...
Supradan Posted July 24, 2006 Share Posted July 24, 2006 What about the other way leaving the cats in but changing the cat back system to an hks ti would this have any affect on the boost levels?? Link to comment Share on other sites More sharing options...
letmeshowyou Posted July 24, 2006 Share Posted July 24, 2006 yes, you'd also see the boost rise a little from stock. Link to comment Share on other sites More sharing options...
MarkTheBoy Posted July 24, 2006 Share Posted July 24, 2006 Cheers guys, Thats settled it, gonna sort myself out with a pair of decat pipes tomorrow. Gonna fit the ring to be on the safe side too untill i get a boost gauge. Any one know somewhere I can get a good boost gauge for not too much money? Ive seen the ones on Whifbits site and they look cool. Any recomendations? Link to comment Share on other sites More sharing options...
Supradan Posted July 24, 2006 Share Posted July 24, 2006 yes, you'd also see the boost rise a little from stock. Would it be high enough to cause any problems?? Link to comment Share on other sites More sharing options...
MarkTheBoy Posted July 25, 2006 Share Posted July 25, 2006 Would it be high enough to cause any problems?? I'll let you know, Picked up the decats from Paul W today, they look really good. Nice bloke too, Gonna fit them at the weekend. Look out for the post entitled POP GOES THE GZ Gonna get a boost guage soon though to be extra sure but it shouldn't boost past 1.0 (ish) on a stock backbox............. Hopefully Link to comment Share on other sites More sharing options...
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