Dash Rendar Posted March 5, 2005 Share Posted March 5, 2005 Hi guys and gals I'm sure this has probably been asked before, but it's quite tricky filtering out the irrelevent info... And I don't know much about engines!! I have a Neuspec Type R exhaust (I'm told this is a full cat-back); only a single decat. I've also got a bleeder valve which seems to confuse the hell out of the garage I've traditionally used. (I'm not sure they have enough experience to deal with a TT Supra.) Currently, I'm getting about 0.6 - 0.7 bar with both turbos online. This seems a little low. However, when my garage were fiddling with the bleeder valve, they connected it differently and it boosted up to 1.1 bar (while the valve was still fully closed). I was worried this was too high, so I had them put it back the way it was. So... My questions are these: 1) How much boost should I get from the sequential TT system with my setup? 2) How much boost is safe with a single cat still in place and no boost controller? I wish I knew what was going on under the hood!! Quote Link to comment Share on other sites More sharing options...
Scoboblio Posted March 5, 2005 Share Posted March 5, 2005 0.6 - 0.7 seems low considering you've taken one cat out (which one is it BTW? apparantly the one nearest the engine is the more restrictive). I get about 0.8 - 0.9 with a nurspec cat back and both cats in place but this is on a cold day. I think about 1.0 - 1.1 bar of boost is not uncommon with a single decat and a decent exhaust, and 1.2bar is the generally accepted safe limit for J-Spec turbos So maybe the alternative way of putting in the bleed valve was the correct way? Quote Link to comment Share on other sites More sharing options...
Stu_Fraser Posted March 6, 2005 Share Posted March 6, 2005 Most cars seem to respond differently to decating...... ive just removed the first cat (nearest the turbos) and im getting about 1.2 bar without a restrictor ring. Quote Link to comment Share on other sites More sharing options...
JohnK Posted March 6, 2005 Share Posted March 6, 2005 Dont forget if you havent had the fuel cut removed you'll be hitting that at approx 1 bar (need to hold it above 1 bar for a couple of secs). You say you have got 1.1 so it might have been done if this was sustained boost Which cat do you have removed? If you dont have the first cat removed Id either get it removed or get an EGT gauge and make sure things arent getting too hot. Also Jspec cars dont usually require a bleed valve if you remove the cats and usually boost too high and need a restrictor ring Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted March 6, 2005 Author Share Posted March 6, 2005 TBH, I don't know which cat was removed. When I had the car serviced, I asked the garage to tell me how many cats it had and they told me there was only one. I should have asked which one was missing. D'oh! I would remove the bleeder valve, but I don't really know what I'm doing and I'm worried about buggering up the whole thing. Too many hoses... Actually, I do have an EGT gauge... At least I have the dial, but it doesn't seem to have been connected. That's next on my list of things to get done. Quote Link to comment Share on other sites More sharing options...
JohnK Posted March 6, 2005 Share Posted March 6, 2005 Are you sure the garage know what to look for when looking at your cat(s) the 1st cat is more or less your down pipe and sits almost vertically in the engine bay, they may have only spoted the 2nd cat on the bottom of the car. Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted March 6, 2005 Author Share Posted March 6, 2005 No, I'm not sure!!! I need to find a decent local garage! Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted March 19, 2005 Author Share Posted March 19, 2005 ... And I found one! I took the car to Paul at Miami-GT. It turns out that the turbos had some dubious plumbing. (The previous owner had made some attempts at converting to a 'true-twin' setup, but didn't quite get it right.) Paul replumbed and now I'm running at 0.9 bar. Excellent. And I've ripped out the bleeder valve. Quote Link to comment Share on other sites More sharing options...
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