ghostbuster Posted February 14, 2014 Share Posted February 14, 2014 I've read many great and helpful bits of info on this forum, so here's something someone else might be interested in from me:innocent:. I made a video recording of the exhaust note on my jap spec 1994 TT, it's got an after market intercooler (the original went all flakey and I believe was leaking), it also has a catback exhaust. Well now I've removed the #1 cat to see what the difference is, here are a few points that may be of interest. I didn't have the greatest of luck removing the cat as the three studs up to the manifold extension were stuffed:(, two screwed out of the manifold and brought the threads with them the final one broke off (after heating all with oxy/cet), it was the most difficult one to get at (naturally) and had to be drilled out and new treads tapped all round. I would not recommend this unless you have the use of a ramp etc. The decat pipe was about 30mm shorter than the cat so the rest of the exhaust was dragged forwards (no real prob but maybe the rubber exhaust hanging rings may not last their full life due to the extra bit of strain). Anyway, I shot a bit of video before the cat removal and a bit after. I was most interested to see what difference it made to the amount of exhaust noise, well to be honest very little, mine is not a loud car anyway (probably due to the efficient cooling of exhaust gasses in the cat back pipe). It has made a little difference to the overall sound, it's a bit more growl ish but hardly and louder at all. I only finished this yesterday afternoon so I've not done much testing (and I'm not 100% sure I trust the boost dial, it's got a Fast & Furious sticker on it:jester:) I noticed right away when driving it that it has a noticeable increase in 'bottom end', the boost seems to come in a bit earlier. I'm not sure if there is more boost though, I'm going to get another gauge, just to be sure. Here's the link to YouTube http://youtu.be/2zgajz8Kbtc (I hope ) I was wondering? The #1 cat has a sensor probe, this I presume is supplying info to the engine management system, now it's not connected what is NOT happening? anyone know? Regards, Mike. Quote Link to comment Share on other sites More sharing options...
shaky Posted February 14, 2014 Share Posted February 14, 2014 It's a cat temp sensor, most cut them off or use a tie back and shove it out the way. Quote Link to comment Share on other sites More sharing options...
ghostbuster Posted February 14, 2014 Author Share Posted February 14, 2014 Yes I know, but my thoughts are other than indicate to the dash a 'Hot Cat' does it's reading mean anything to the ECU? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted February 14, 2014 Share Posted February 14, 2014 In a word, no. There are de cats out there that have a probe boss fitted, I bought one on eBay. Quote Link to comment Share on other sites More sharing options...
Marcus GTE Posted February 14, 2014 Share Posted February 14, 2014 (edited) I've read people recomending to tie the sensor back rather than cut it as I think you might get warning lights if you do. The 3 bolts at the start of the first cat are a bit of a pain, mine came of ok one day and then one desided to round off under a week later. Less restriction in the exhaust system by removing the cats that cause back pressure will increase throttle response by allowing the turbos to spool a bit quicker. So that will explain the feeling you're describing. Hope you enjoy the change Edited February 14, 2014 by Marcus GTE (see edit history) Quote Link to comment Share on other sites More sharing options...
mellonman Posted February 14, 2014 Share Posted February 14, 2014 i just unplugged mine and pulled the wiring out from under the seat and put a grommit in place of the hole Quote Link to comment Share on other sites More sharing options...
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