charlieboo Posted June 5, 2008 Share Posted June 5, 2008 My supe is BPU but I've just had to put 1st CAT back on for MOT purposes. On the way to the station, I noticed an incredible difference in acceleration. The sudden surge of power at around 4000 revs is quite frightening compared to before. I thought this was supposed to be the other way around!!! My boost guage/controller is buggered and I am waiting for a new one to be delivered, but I've taken the buggered one out and my guess would be that I would still gain power/torque from taking off the CAT's when running standard boost? Any help appriciated. Oh, and I've switched between the two configurations a few times to ensure that it's only the de-cat that's causing this effect. Quote Link to comment Share on other sites More sharing options...
charlieboo Posted June 6, 2008 Author Share Posted June 6, 2008 Okay then, second question... What is the purpose of the sensor that goes into the CAT (one nearest the engine)? I have read that it is only a temp sensor, but I am wondering if this could be the cause of my power loss? I doubt it makes much different, but my Supe is a '96 Facelift TT 6 speed. Quote Link to comment Share on other sites More sharing options...
R Black Posted June 6, 2008 Share Posted June 6, 2008 Okay then, second question... What is the purpose of the sensor that goes into the CAT (one nearest the engine)? I have read that it is only a temp sensor, but I am wondering if this could be the cause of my power loss? I doubt it makes much different, but my Supe is a '96 Facelift TT 6 speed. Its a cat temperature sensor, i dont think it will affect the running of the car, as most people with decats take them off, so i doubt the ECU uses it. I don't understand how your car can go better with a cat than without, are you sure its not just your perception of speed is erm faulty? Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted June 6, 2008 Share Posted June 6, 2008 I run mine like this....only problem is slightly higher EGT's which is never good imo Quote Link to comment Share on other sites More sharing options...
charlieboo Posted June 6, 2008 Author Share Posted June 6, 2008 To be honest, the speed isn't the issue. In either configuration she is damn quick. My concern is the kick in the back you get at approx 4000 revs. All reports I have read on here state that with a double decat, you really feel the 2nd turbo come online, yet with mine, you feel it more (a lot more) with the CAT installed. It's not a problem as such but I'm concerend that things are seemingly different for me than everyone else. Quote Link to comment Share on other sites More sharing options...
bodilx6 Posted June 10, 2008 Share Posted June 10, 2008 Sounds weird mate. I had mine running with the 1st cat in and 2nd was decat and a free flow 3" cat-back. I made 354bhp flywheel with a hardly noticable skip in torque around the 4000rmp on the dyno sheet. Then I got a hold punched through the 1st cat (to imitate a RR) and started hitting up to 1.2 bars in higher gears. At this point the car makes 390bph flywheel with a very noticable jump in torque when the 2nd turbo steps in. This is also much more raw and violent than with the 1st cat in. Just as you expected. I cant explain why you see the opposite. I can provide you with my dyno sheets if you want to compare them your self. Quote Link to comment Share on other sites More sharing options...
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