Steve W2 Posted December 3, 2003 Share Posted December 3, 2003 I need the help of all you technical peeps on here to educate me in the ways of the Supra. I have done a search in this and found out some info. but dont think that it has answered my question. At present I have a GZ TT with only a Nur Spec fitted in terms of performace mods. I want to run higher boost levels and Know of the two options available. My qustion is - if i install a boost contoller now will I have to remove the CAT(S) to make it work properly. As i understand the controller can only up boost, not decrease it. Since I want the option of running on stock levels when required (gei I know) can I leave both my cats in without any problems, excess heat etc.? Your help in this matter would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Gaz Walker Posted December 3, 2003 Share Posted December 3, 2003 Lose the moggys first, then fit the boost controller if the levels aren't enough for you (they will!) Gaz. Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 3, 2003 Author Share Posted December 3, 2003 Gaz, If i take the cats out though I wont be able to run at stock levels though as my boost will go up to 1.5 Bar (ish). If I fit a restrictor ring to bring it down isn't this the same as having the cats as the restriction? Forgive me if I am being totally gei:stupid: Quote Link to comment Share on other sites More sharing options...
B1SEP Posted December 3, 2003 Share Posted December 3, 2003 If you want to be able to run stock boost levels, best way IMHO is to fit a boost controller...Blitz DSBC Type S works fine, SBCi-D if your feeling rich Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 3, 2003 Author Share Posted December 3, 2003 B1SEP - I may have confused you guys, I understand that feature of the boost controller is that you can have 3 (or so) user programmable boost levels that you can switch between easily. I want to be able to run low boost driving in to work in the morning but jack it up to 1.2Bar when I'm feeling fruity!! I was looking at the Blitz DSBC and Power meter. Justin - I sent you a PM on this yesterday. Cheers for you replies guys;) Quote Link to comment Share on other sites More sharing options...
B1SEP Posted December 3, 2003 Share Posted December 3, 2003 Yes I got your PM but couldn't reply as your box is full. Call me on 01233 636222 if you want a chat. With both controllers you get 4 programmes, each you use for different levels of boost. You can also turn the controller off, allowing stock boost. Quote Link to comment Share on other sites More sharing options...
Adam W Posted December 3, 2003 Share Posted December 3, 2003 Steve - your lowest boost level available will be with the controller switched off, you can then increase it above that point. As you say, with cats removed your lowest available boost level with jump from stock boost (10psi?) to about 16-18psi. You may need to fit a restrictor ring just to keep it down to 18psi. I couldn't comment on how much of an issue heat buildup will be with cats/restrictor ring fitted. Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 3, 2003 Author Share Posted December 3, 2003 Thanks for help guys. I will clear my PM box. So I think I can keep the cats, get a boost controller, and run normal boost (10 psi or whatevcer it is) with the controller swithced off and then turn it on to run higher pressures. I hope thats right!! Quote Link to comment Share on other sites More sharing options...
dandan Posted December 3, 2003 Share Posted December 3, 2003 Hi Steve how's it going mate? I've got the lower cat removed with an HKS pipe and top cat is still in. With the dsbc switched off I can make 0.7bar, no more. Then obviously got it set up for higher boost when needed. However, after going on dyno, it highlighted the fact that boost was tailing off (i think from 4500 onwards) when running higher pressures. The cat is the prime suspect and will be departing very very soon and replaced with cw pipe and restrictor. As far as I know the cats trap an awful lot of heat in the engine bay and also the extra backpressure means a fair bit of burnt gas is left in combustion chamber after the exhaust valve shuts. So this dilutes fresh cool air/fuel coming in. Can lead to detonation at higher boost and at best reduced power output. I don't think the restrictor traps anything like as much heat and once setup is a good option. Could size it for say 1.05bar and then use dsbc to up it to 1.2 when needed. Personally i believe that at high boost levels the cats should be omitted anyway for reliability reasons(heat/detonation etc). Dan Quote Link to comment Share on other sites More sharing options...
Willson Posted December 3, 2003 Share Posted December 3, 2003 Yeah, removing the lower cat seems to be the approved way if you have a boost controller. I intend on removing the other cat too when I get my new exhaust (one day......) for sound effect and a slight reduction in temps. As you say, the ring may then be required but it will still sound better. With one cat in and an Apexi exhaust, though lovely at WOT, it is too quiet (!) at idle. A few times I have had people cross the road in front of my car as they obviously didn't hear me coming ! I think I am gonna go for the Nur spec, so I can put the baffle in if it gets too loud, when warming the car in winter. Quote Link to comment Share on other sites More sharing options...
dude Posted December 4, 2003 Share Posted December 4, 2003 Cats out . Restrictor ring . Boost controller Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 4, 2003 Author Share Posted December 4, 2003 Cheers for your help guys. Once again you all proved to be a fountain of knowledge:) Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted December 5, 2003 Share Posted December 5, 2003 Personal view - I run cat one out, cat 2 in, Blitz Dual SBC and a Nür exhaust. Cat one out lets heat get away OK. I can run from 0.8 bar to 1.2 bar quite happily. I don't think the car is practical with cat 2 out as well - power delivery is too savage. But then I drive in the wet without TC! Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 8, 2003 Author Share Posted December 8, 2003 Cheers John. Did you say savage? I like it!! I will temporarily be running with both cats in until I can afford to buy a decat pipe and fit it. Am paying to do my stereo as well a t the minute along with all thos eChristams pressies, its just all too much. Plus I am looking at getting some Denso plugs and Blitx powermeter form Gaz probably before christmas too if he has them in stock. Quote Link to comment Share on other sites More sharing options...
SimonB Posted December 8, 2003 Share Posted December 8, 2003 160 quid from CW plus a few quid fitting, you know it makes sense! Quote Link to comment Share on other sites More sharing options...
Steve W2 Posted December 9, 2003 Author Share Posted December 9, 2003 Originally posted by SimonB 160 quid from CW plus a few quid fitting, you know it makes sense! Stop it Simon! I dont want to spend more money........oh ok then:D Quote Link to comment Share on other sites More sharing options...
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