dandan Posted August 12, 2003 Share Posted August 12, 2003 I am after people's opinions on the following exhaust configurations. I've got my 60,000 mile service approaching and am considering removing the first cat (as lower 2nd one is already gone) and replacingwith CW pipe and inevitably a restrictor ring. I've heard conflicting arguements for and against leaving the cat in. For: Slightly better fuel economy, lower exh gas temps, cooler running, faster spool up time and nice sound. Against: MOT inconvenience, poorer engine response. If i remember correctly Leon had advised someone against removing the 1st cat as this would slightly damage engine responsiveness and I know Nathan at TDI is not keen on removing them due to boost problems. I am not after a cheap way of increasing boost (less back pressure) as i already have a boost controller. I'd like a restrictor ring put in to keep boost at 1.0bar unless adjusted using controller. What i really want to know is, is there anything (performance/reliability wise) to be gained by replacing the cat with the CW pipe and a suitable ring to bring me down to 1.0bar. What do you think? Quote Link to comment Share on other sites More sharing options...
Thorin Posted August 12, 2003 Share Posted August 12, 2003 Real men have no cats! If you're going to remove it, only to then restrict it back down to 1.0 bar, then raise it to 1.2 bar or whatever when needed I don't really see the point and I'd probably just leave it in. It does sounds nice though Quote Link to comment Share on other sites More sharing options...
dandan Posted August 12, 2003 Author Share Posted August 12, 2003 Cheers Mike, So does everyone only remove them as a way to increase boost? Are there no other real advantages at all? Quote Link to comment Share on other sites More sharing options...
Thorin Posted August 12, 2003 Share Posted August 12, 2003 Originally posted by dandan Cheers Mike, So does everyone only remove them as a way to increase boost? Are there no other real advantages at all? Did I mention it sounds nice? Quote Link to comment Share on other sites More sharing options...
Patrick_Devlin Posted August 13, 2003 Share Posted August 13, 2003 Got CW to replace both mine last year and then Leon fitted a Hiper 6 months ago. Incredible difference... I have a restrictor ring in place to keep boost down to 1.1bar, it was peaking at 1.4 before... There has been a reduction in fuel economy but other than that I have had no problems. The plus sides are, big difference in response and overall power and a wonderful noise. Definitely recommend it. Quote Link to comment Share on other sites More sharing options...
SupraSapphire Posted August 13, 2003 Share Posted August 13, 2003 I've also got a CW full decat but haven't had any trouble with over boosting. Mine boosts to 0.9 bar and sounds ace Just out of interest, how much extra boost do people normally get from a full decat? I got around 0.2 bar extra. Quote Link to comment Share on other sites More sharing options...
Chase Posted August 13, 2003 Share Posted August 13, 2003 Hey Jon, how's it going? Where ya been? Quote Link to comment Share on other sites More sharing options...
tDR Posted August 13, 2003 Share Posted August 13, 2003 Originally posted by SupraSapphire I've also got a CW full decat but haven't had any trouble with over boosting. Mine boosts to 0.9 bar and sounds ace Just out of interest, how much extra boost do people normally get from a full decat? I got around 0.2 bar extra. Jon don't tell me you've got a full decat with the stock exhaust - That'll be why only 0.9 bar - the standard exhaust is a restriction in itself. Get some Veilside Titanium loving goin on Quote Link to comment Share on other sites More sharing options...
SupraSapphire Posted August 13, 2003 Share Posted August 13, 2003 Yeah, only just got around to getting my membership enabled. But I'm back now Originally posted by ThunDeR Jon don't tell me you've got a full decat with the stock exhaust - That'll be why only 0.9 bar - the standard exhaust is a restriction in itself. Get some Veilside Titanium loving goin on As it happens my new Blitz Nur Spec should arrive on Monday Then I'll get so real improvements :flame Dev How much do you reckon that'll raise it? Another 0.2bar or more? Quote Link to comment Share on other sites More sharing options...
tDR Posted August 13, 2003 Share Posted August 13, 2003 Another 0.2bar would be safe. Just keep an eye on it cos it could spike as far as 1.4+ bar with no restriction in the exhaust system. Could be a good excuse for a decent set of hybrids tho Quote Link to comment Share on other sites More sharing options...
tDR Posted August 13, 2003 Share Posted August 13, 2003 Nice choice of exhaust BTW, that was my all time favourite until I clapped eyes on the Veilside Ti. Quote Link to comment Share on other sites More sharing options...
SupraSapphire Posted August 13, 2003 Share Posted August 13, 2003 Thanks Mate. I'm looking forward to fitting it Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 13, 2003 Share Posted August 13, 2003 dan, the performance issue has never been really tested, but with 1 cat & boost controller i dont think there will b anything in it, except quieter sound compared to all cats out. u might not need a restrictor ring. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 13, 2003 Share Posted August 13, 2003 Originally posted by dandan I am after people's opinions on the following exhaust configurations. I've got my 60,000 mile service approaching and am considering removing the first cat (as lower 2nd one is already gone) and replacingwith CW pipe and inevitably a restrictor ring. I've heard conflicting arguements for and against leaving the cat in. For: Slightly better fuel economy, lower exh gas temps, cooler running, faster spool up time and nice sound. Against: MOT inconvenience, poorer engine response. If i remember correctly Leon had advised someone against removing the 1st cat as this would slightly damage engine responsiveness and I know Nathan at TDI is not keen on removing them due to boost problems. I am not after a cheap way of increasing boost (less back pressure) as i already have a boost controller. I'd like a restrictor ring put in to keep boost at 1.0bar unless adjusted using controller. What i really want to know is, is there anything (performance/reliability wise) to be gained by replacing the cat with the CW pipe and a suitable ring to bring me down to 1.0bar. What do you think? With a decent Intercooler and a set of colder plugs you'll be fine upto 1.3bar (with the Mines ECU) I had my restrictor ring sized for 1.1bar - worked a treat. Though after the de-cat my Boost Controller was mainly a passenger. I never got far enough down the list of mods to use it properly again. Quote Link to comment Share on other sites More sharing options...
tDR Posted August 13, 2003 Share Posted August 13, 2003 Originally posted by SupraSapphire Thanks Mate. I'm looking forward to fitting it That reminds me.... remember to fit colder plugs with an appropriate gap Jon. Quote Link to comment Share on other sites More sharing options...
SupraSapphire Posted August 13, 2003 Share Posted August 13, 2003 Originally posted by ThunDeR That reminds me.... remember to fit colder plugs with an appropriate gap Jon. Got'em already. CW fitted them last service Sorry dandan, we kinda hijacked your thread for a minute there. Hope you didn't mind. We'll stop it now Quote Link to comment Share on other sites More sharing options...
dandan Posted August 14, 2003 Author Share Posted August 14, 2003 no problem chaps. Alex when you say a decent intercooler, are you implying a front mount? At the moment my insurance is a little "tender" and i'm not sure how a fmic would go down. However they're fine with a water injection system (and the cat out if i go for it) so that will probably be my next addition. That should push the detonation barrier a little further away don't you think? I thought the Mine's fuel map only went to 1.1bar, what would happen to the fuelling at over this, ie up to 1.3bar? Got my plugs today NGKBKR7E, going in tommorrow night. Thanks for help on those. Quote Link to comment Share on other sites More sharing options...
dandan Posted August 14, 2003 Author Share Posted August 14, 2003 So what is the general opinion on all cats out? As i said i don't "need" to do it to raise boost so is it worth it? Come on people, don't tell me you've taken your cats and and don't really know what difference it made?!? Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted August 14, 2003 Share Posted August 14, 2003 It feels like it sharpens the car up a bit and gets louder. I had 2nd cat out with a stock(ish) exhaust and was running about 12-14psi. I hit fuel cut once. Went full decat - JPS - (still stockish exhaust), hit fuel cut every time I moved. Fitted FDC and the stock plugs gave a 'soft cut' feel at about 15-16psi. Fitted BKR7E's and it went to 16-17psi. Fitted a 3" straight through - JPS own system. Went straight to 17-18psi. Crept up to 20psi during my first run at Woodbridge a few miles later. See my avatar and sig for the result.............................. Each time the car felt faster but I've no hard figures. Chris Wilson does a 'replacment' stock intercooler. Quote Link to comment Share on other sites More sharing options...
dandan Posted August 14, 2003 Author Share Posted August 14, 2003 ooooh nasty! i remember reading your posts about it steve, gutted. although at least you've got a nice fresh motor to play with now! if i do go ahead i'll get a restrictor put in to hold at about 1.05-1.1 and then adjust "as and when" with my boost controller, hopefully avoiding any high boost meltdowns with a max of perhaps 1.25bar (18.4psi). thanks for your opinions steve, much appreciated Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted August 14, 2003 Share Posted August 14, 2003 The most gutting part was paying the bills :eek: I've still got the get the car set up but then.... Stock (J spec) fueling, pump, turbos, intercooler (these are starting to get V crumbly on the earlier cars, search for recent thread) if all working properly should be safe at 18psi. Above that you are treading on thin ice. Last year there was a spate of disintegrated turbos due to overboost, this year seems to be melted internals. Probably best getting an EGT fitted, that should give you warning of the internals about to melt. I'm not being negative, but there are a few cars blowing up so it's better to be safe and know what the risks are. Quote Link to comment Share on other sites More sharing options...
Patrick_Devlin Posted August 15, 2003 Share Posted August 15, 2003 Havent checked out the IC on my 93 JSpec yet, although from what I've read I'm expecting it to be past its best. Now if I go for a CW SMIC will that cause the fuelling to become inefficient and cause the car to run lean? Will I have to upgrade the fuel pump at the same time to be safe. I'm running 1.1bar with restrictor ring, no cats and Hiper? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 15, 2003 Share Posted August 15, 2003 Originally posted by Patrick_Devlin Havent checked out the IC on my 93 JSpec yet, although from what I've read I'm expecting it to be past its best. Now if I go for a CW SMIC will that cause the fuelling to become inefficient and cause the car to run lean? Will I have to upgrade the fuel pump at the same time to be safe. I'm running 1.1bar with restrictor ring, no cats and Hiper? No mods to the rest of the engine are needed when fitting one of my upgraded SMIC's. Quote Link to comment Share on other sites More sharing options...
Patrick_Devlin Posted August 15, 2003 Share Posted August 15, 2003 Originally posted by Chris Wilson No mods to the rest of the engine are needed when fitting one of my upgraded SMIC's. OK, putting the question another way then Chris... Uprated fuel pump or your SMIC as the next mod? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 16, 2003 Share Posted August 16, 2003 Originally posted by Patrick_Devlin OK, putting the question another way then Chris... Uprated fuel pump or your SMIC as the next mod? Unless you have fuel pressure / flow problems why would you want to change the pump? Far more likely your stock I/C is well past its sell by date... Quote Link to comment Share on other sites More sharing options...
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