asupracar Posted November 8, 2004 Share Posted November 8, 2004 From my previous post- I wanted to know what people think about raising the boost with the cats in!. Cash flow low at moment so no chance of a exhaust and decat for me! YET Is it OK to raise boost to 0.95 bar (3RD) approx with bleeder as I like the extra power. Just got the car so don’t want is to F88K UP What’s your thoughts? Link to comment Share on other sites More sharing options...
stt Posted November 8, 2004 Share Posted November 8, 2004 Mine ran 0.9 bar when I got it,It did have a 5zigen exhaust with both cats in at the time,Im now running 1.2 bar with one cat,cant see that it will do any harm but I will no doubt be shouted down if im wrong! Link to comment Share on other sites More sharing options...
Suprash Posted November 8, 2004 Share Posted November 8, 2004 It just depends how much more heat it will generate for your cats, but to raise it to .9 from stock which is .8 I think, I would have thought it would be ok, you may throw a cat sensor light though. If your short on cash have you thought about just gutting your cats out....... Link to comment Share on other sites More sharing options...
asupracar Posted November 8, 2004 Author Share Posted November 8, 2004 Gutting sounds interesting but I don’t want to damage them for MOT time. What’s this cat heat thing? I suppose it gives you a warning when cat temps become to high. Just thinking would it be really necessary, as I don’t thrash the car. Just the odd Power Run now and then So far the thoughts are that its OK_ as long as I don’t thrash the car so the cats heat up Link to comment Share on other sites More sharing options...
Suprash Posted November 8, 2004 Share Posted November 8, 2004 Gutting your cars means slicing them open and ripping out the honey comb shite inside that reduces emmisions, its this honey comb inside that stops yuor exhaust from flowing freely. But yes this will completely knacker them for MOT time, but if your short on cash the best thing to do would be by two stock cats (and I saw some for sell in the for sale section, I cant imagine someone charging a lot for cats, as most people cant wait to rip them out), anyway buy them get them gutted, and stick them in, then come MOT time stick your originals back on. But if your uping your boost .9 then the cats will be ok, if they get too hot you will see a cat light come on. But decatting will allow your turbos to spool quicker, anywhere up to 1.1/1.2....... Link to comment Share on other sites More sharing options...
LeeT Posted November 8, 2004 Share Posted November 8, 2004 as ashley says but just gut/replace the 1st cat. its the most restrictive cat and the car will still pass emissions with just the 2nd cat in place. Link to comment Share on other sites More sharing options...
asupracar Posted November 8, 2004 Author Share Posted November 8, 2004 Hi- ye the cat gutting idea sound good if I have a spare set- So now ill be searching,. which light will aluminate when the cats get hot? Link to comment Share on other sites More sharing options...
Suprash Posted November 8, 2004 Share Posted November 8, 2004 Originally posted by asupracar Hi- ye the cat gutting idea sound good if I have a spare set- So now ill be searching,. which light will aluminate when the cats get hot? Its a little symbol that looks like a cat, and not the pussy kind..... Link to comment Share on other sites More sharing options...
asupracar Posted November 8, 2004 Author Share Posted November 8, 2004 I think I am being thick! I can't see a cat light. Just checked the manual and the car no cat light? Its a UK spec if that got any thing to do with it Link to comment Share on other sites More sharing options...
paul mac Posted November 8, 2004 Share Posted November 8, 2004 I have a mate with a 300 zx who gutted his cats and the car did'nt sound right at all, and it did'nt do much for the performance either, the car made a wierd burbling noise, we came to the conclusion that as the gas flowed down the exhaust it expanded into the now defunct cat chamber and then had to compress itself back into the normal size exhaust possibly causing turbulence in the system (bad), he soughted it by welding tubes into the cat the same size as the exhaust, this may not apply to the supe but i think it is worth considering Link to comment Share on other sites More sharing options...
suprarob Posted November 9, 2004 Share Posted November 9, 2004 Hi asupracar I,ve been running my uk supra at 1.1 bar for over a year with both cats in. Like you I don,t drive around constantly at full boost. I,ve had no problems I also know of a uk which is running 1.2 bar with both cats he has no problems either But when I have some spare cash after xmas the 1st cat is coming out, I,m told it helps the turbo,s spool up quicker hope this puts your mind at rest Link to comment Share on other sites More sharing options...
Scooter Posted November 9, 2004 Share Posted November 9, 2004 Isn't the issue of high(er) EGT's more important than high cat temp per se? Poor IC, high boost and restrictive exhaust system could give high egt's couldn't they? Its been a while since someone melted a piston/spark plug but it does happen............. I know people run around with non stock boost for long periods with no problems but just to play devils advocate, if something untoward does happen it will be big £'s Link to comment Share on other sites More sharing options...
Wez Posted November 9, 2004 Share Posted November 9, 2004 I use to run .9bar with first cat in and it does generare alot more heat, we also found that it didn`t like going much past that as there was too much back pressure. With no cats the difference is noticable. Link to comment Share on other sites More sharing options...
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