ccssupra Posted November 1, 2013 Share Posted November 1, 2013 Hi Guys, So I want more power out of my Supra, its a 1994 Jspec TT totally OEM. First thing im thinking is getting rid of that restrictive exhaust system, but I want to do it right. I have never had a twin turbo car before so I am unsure of the exhaust layout, I understand there are two cats in the system, obviously if I get a cat back they are still there. Is it a single decat pipe I need? I assume there are gains to be had with cat removal, but I also read something about needing a restrictive plate! Help me out guys Quote Link to comment Share on other sites More sharing options...
mattdavies Posted November 1, 2013 Share Posted November 1, 2013 If you take one cat out (2nd is easiest) and leave the other in no restrictor ring is needed, but if you take both out which is fairly easily done then a 1bar restrictor ring is needed. Will prob need a FCD due to on a cold evening you may creep over 1bar and then hit fuel cut. Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 1, 2013 Author Share Posted November 1, 2013 If you take one cat out (2nd is easiest) and leave the other in no restrictor ring is needed, but if you take both out which is fairly easily done then a 1bar restrictor ring is needed. Will prob need a FCD due to on a cold evening you may creep over 1bar and then hit fuel cut. Thanks. Is it all on one pipe then? For example, if I got this EBAY LINK that would get rid of both cats? Also, can you point me into the right direction for getting a restrictor ring? Quote Link to comment Share on other sites More sharing options...
mattdavies Posted November 1, 2013 Share Posted November 1, 2013 If you fitted that with a cat back you would still have your first cat and not need a RR. This is the setup I had on my car when I bought it and on a cold night sometimes hit fuel cut. First and second decats are generally seperate pipes But you can get a combined pipe, have seen one come up here once Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 1, 2013 Author Share Posted November 1, 2013 Well that maybe sounds ideal then, restricts it as much as a restriction plate but lower emissions for MOT time? So if I got a Blitr Nur Spec, that decat pipe and a fuel cut defender I would be playing it safe? Quote Link to comment Share on other sites More sharing options...
mattdavies Posted November 1, 2013 Share Posted November 1, 2013 Yeh that would be fine, exactly what I had and was good. FCD will only be there to stop it jolting and warning lights coming up if it creeps over 1bar Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 1, 2013 Author Share Posted November 1, 2013 Thanks for the help mate. Will get it all orderd then! Quote Link to comment Share on other sites More sharing options...
Jord Posted November 1, 2013 Share Posted November 1, 2013 Will a UK SPEC still need an FCD? I couldn't find a definite answer on that anywhere. Quote Link to comment Share on other sites More sharing options...
mattdavies Posted November 1, 2013 Share Posted November 1, 2013 I'm not sure, fit all the exhaust if over a bar the car cuts and the warning lights come on then yes you do ! But I think UK have a MAF not MAP so not sure if they work the same way Plus with double decat a UK only boosts to 0.8bar ish, so you would need a boost controller to raise the boost, Quote Link to comment Share on other sites More sharing options...
Jord Posted November 1, 2013 Share Posted November 1, 2013 Yeh wasn't sure if it worked the same with a MAF. I plan on going BPU to 1.2 bar with blitz nur spec r and probably double decat. Just pricing everything up. Quote Link to comment Share on other sites More sharing options...
Scott Posted November 1, 2013 Share Posted November 1, 2013 BPU Quote Link to comment Share on other sites More sharing options...
Jord Posted November 1, 2013 Share Posted November 1, 2013 I've read that a few times Scott, the FCD pages too. Doesn't confirm whether UK spec cars require an FCD. I've read threads that suggest due to it running MAF instead of MAP and having bigger injectors it might not require one. Just looking for some confirmation as I'm working on the assumption I'll need one for now and don't want to buy something I won't need. Quote Link to comment Share on other sites More sharing options...
Scott Posted November 1, 2013 Share Posted November 1, 2013 I've read that a few times Scott, the FCD pages too. Doesn't confirm whether UK spec cars require an FCD. I've read threads that suggest due to it running MAF instead of MAP and having bigger injectors it might not require one. Just looking for some confirmation as I'm working on the assumption I'll need one for now and don't want to buy something I won't need. Meant for the op, has a lot of reading ahead of him as most of this stuff has been covered 1000s of times..... so will end up with lot of eyes rolling with "here we go again" Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 1, 2013 Author Share Posted November 1, 2013 Meant for the op, has a lot of reading ahead of him as most of this stuff has been covered 1000s of times..... so will end up with lot of eyes rolling with "here we go again" I have read that a fair few times though. My main query was the exhaust system layout which isn't covered, and the use of decat pipes. Quote Link to comment Share on other sites More sharing options...
Jord Posted November 1, 2013 Share Posted November 1, 2013 Meant for the op, has a lot of reading ahead of him as most of this stuff has been covered 1000s of times..... so will end up with lot of eyes rolling with "here we go again" Ah no worries, I was expecting the "here we go again" with my question Quote Link to comment Share on other sites More sharing options...
Scott Posted November 1, 2013 Share Posted November 1, 2013 I have read that a fair few times though. My main query was the exhaust system layout which isn't covered, and the use of decat pipes. You're going to fit right in here. Did you try clicking on "Decat"? It's covered numerous times in both the BPU thread and the Decat thread..... I just took 29 seconds to check Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 2, 2013 Author Share Posted November 2, 2013 You're going to fit right in here. Did you try clicking on "Decat"? It's covered numerous times in both the BPU thread and the Decat thread..... I just took 29 seconds to check Apologies, I guess I just wanted confirmation really before spending a lot of money! Quote Link to comment Share on other sites More sharing options...
Scott Posted November 2, 2013 Share Posted November 2, 2013 Apologies, I guess I just wanted confirmation really before spending a lot of money! I wouldn't recommend buying new, be patient and pick the parts up 2nd hand. The mechanical difference from shiny to grubby is nil, but the price difference is HUGE Quote Link to comment Share on other sites More sharing options...
LOGIE Posted November 2, 2013 Share Posted November 2, 2013 I wouldn't recommend buying new, be patient and pick the parts up 2nd hand. The mechanical difference from shiny to grubby is nil, but the price difference is HUGE as above. if you pm SPG I think he has a as new whifbitz 1st decat going cheap Quote Link to comment Share on other sites More sharing options...
LOGIE Posted November 2, 2013 Share Posted November 2, 2013 1st item http://www.mkivsupra.net/vbb/showthread.php?295503-Parts-(Aftermarket-and-OEM)-update-08-09 I think there is a 2nd decat in there also but the res ring is too big for your needs Quote Link to comment Share on other sites More sharing options...
Big Supes Posted November 2, 2013 Share Posted November 2, 2013 Subbed... will need this thread soon. Quote Link to comment Share on other sites More sharing options...
Nic Posted November 2, 2013 Share Posted November 2, 2013 (edited) I have never had a twin turbo car before so I am unsure of the exhaust layout, I understand there are two cats in the system, obviously if I get a cat back they are still there. Is it a single decat pipe I need? I assume there are gains to be had with cat removal, but I also read something about needing a restrictive plate! Here are some pics of the standard exhaust system to help explain the layout. 1st and 2nd Catalytic Convertors - the smaller 1st cat - nearest the engine - on the right, the 2nd larger cat on the left. Pic of the stock 1st and 2nd cats next to a single decat pipe, this replaces both cats. The problem with a single decat pipe like this is that it makes it a lot harder to refit the cats come MOT time. Stock 1st and 2nd cats next to aftermarket 1st and 2nd decat pipes. Having 2 separate decat pipes makes it easier to bolt the 2nd cat back in place for the MOT. Pic of the stock cat back exhaust system. The 2nd cat bolts up to the mid pipe which on the stock exhaust system splits into 2 sections, these then bolt up to the rear back box. Most aftermarket cat back exhausts use a single mid pipe between the 2nd cat and back box, the quieter exhausts have a silencer on the mid pipe, other louder systems just have a straight through mid pipe. See here for pics of various cat back exhausts available http://www.garagewhifbitz.co.uk/index.php/toyota/supra/exhausts-decats.html Edited November 2, 2013 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
ccssupra Posted November 2, 2013 Author Share Posted November 2, 2013 Oh that is a massive help! Thanks for taking the time! I now know what I'm after for. Thanks again Quote Link to comment Share on other sites More sharing options...
Jord Posted November 2, 2013 Share Posted November 2, 2013 That's an awesome post Nic, really helped me understand decats too, cheers for that. Quote Link to comment Share on other sites More sharing options...
shaz2010 Posted November 2, 2013 Share Posted November 2, 2013 I'm not sure, fit all the exhaust if over a bar the car cuts and the warning lights come on then yes you do ! But I think UK have a MAF not MAP so not sure if they work the same way Plus with double decat a UK only boosts to 0.8bar ish, so you would need a boost controller to raise the boost, I have a double decat and cat back on my uk spec rest is stock and I hit 1bar and some times 1.1bar on the boost gauge! I have a boost controller and fcd but not yet fitted. I was getting a miss fire or I was hitting fuel cut so I changed to a cooler grade spark plug as you need to and it runs fine now. Quote Link to comment Share on other sites More sharing options...
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