SIMON LC Posted September 27, 2007 Share Posted September 27, 2007 Ok have I got this right?I gotta J-spec TT fully de-catted with restrictor ring in to hold her at 1.2 bar max.Obviously with the colder weather its starting to creep upto about 1.4.If I put a boost controller on it,it wont restrict the boost and drop it?I need to put a smaller restrictor ring in and then control the boost up off the boost controller,is this right? Link to comment Share on other sites More sharing options...
Nic Posted September 27, 2007 Share Posted September 27, 2007 Yes correct, a boost controller can only raise the boost above the base reading (ie. max boost reading with boost controller turned off). I would fit a restrictor ring to limit boost to 1 bar, then use the boost controller to raise boost as required. Link to comment Share on other sites More sharing options...
bodilx6 Posted September 28, 2007 Share Posted September 28, 2007 how about if you got the first cat in place and running 0,9 bar. Would it be sensible to use a boost controller to raise to 1,2? If exchanged, would there be any noticeable difference between the cat and a fx 1 bar RR? (e.g. spool?) Link to comment Share on other sites More sharing options...
Guest svarten Posted October 2, 2007 Share Posted October 2, 2007 Ok, im new to supras, but are the cats or restrictor rings the only thing that controls the boost on a supra? aren't there wastegates? and if there arent could it be installed? EDIT: How does it work more specifik? the cats decrease the flow of exhausts? Link to comment Share on other sites More sharing options...
Homer Posted October 2, 2007 Share Posted October 2, 2007 Ok, im new to supras, but are the cats or restrictor rings the only thing that controls the boost on a supra? aren't there wastegates? and if there arent could it be installed? EDIT: How does it work more specifik? the cats decrease the flow of exhausts? The problem is caused by the wastegate on the Jspec turbo's. Basically it's too small to manage the boost and once the restriction (created by the cats) is removed they will overboost massively. The wastegate is an internal type so cannot be changed without replacing the turbo. Therefore, the safest way to increase boost is to add some restriction back into the exhaust (restrictor ring), to acheive a base line boost in cold weather (say 1.2bar), then use a boost controller to adjust the boost to keep it at the level when air temps go up. The UK and VVTi cars have a larger wastegate so boost can be controlled with only a boost controller. Click here for more information and info on the recommended mods: BPU Link to comment Share on other sites More sharing options...
Guest svarten Posted October 2, 2007 Share Posted October 2, 2007 aha! thanks for the answer Link to comment Share on other sites More sharing options...
TurboBrett Posted October 2, 2007 Share Posted October 2, 2007 The problem is caused by the wastegate on the Jspec turbo's. Basically it's too small to manage the boost and once the restriction (created by the cats) is removed they will overboost massively. The wastegate is an internal type so cannot be changed without replacing the turbo. Therefore, the safest way to increase boost is to add some restriction back into the exhaust (restrictor ring), to acheive a base line boost in cold weather (say 1.2bar), then use a boost controller to adjust the boost to keep it at the level when air temps go up. The UK and VVTi cars have a larger wastegate so boost can be controlled with only a boost controller. Click here for more information and info on the recommended mods: BPU i have been figuring out why boost increases when a full decat system is used on j-specs i came to this conclution, but assumed the wastegate was external and so could be changed to a bigger one, obviousy that bit was wrong but i have heard of the wastegate being bored out on T3's because of boost creep (turned out to be a dud actuator:blink:), is this a possibility to do on the j-spec turbo's? or should i just forget about it untill it is needed (and probably stock turbo's removed anyway) anyways i supose if it works dont fix it EDIT: lol maybe thread hijack but i thought relavent Link to comment Share on other sites More sharing options...
TurboBrett Posted October 2, 2007 Share Posted October 2, 2007 dont realy know why i am thinking about all this anyway i wont be loosing the cats unless i can get mot'd without em Link to comment Share on other sites More sharing options...
Nic Posted October 2, 2007 Share Posted October 2, 2007 ii have heard of the wastegate being bored out on T3's because of boost creep (turned out to be a dud actuator:blink:), is this a possibility to do on the j-spec turbo's? or should i just forget about it untill it is needed (and probably stock turbo's removed anyway) There is not a lot of meat around the internal wastegate opening. Even with the stock wastegate diameter, I have seen quite a few turbos where the casting has cracked around the opening, increasing the diameter would only make it weaker. Link to comment Share on other sites More sharing options...
Homer Posted October 2, 2007 Share Posted October 2, 2007 i have been figuring out why boost increases when a full decat system is used on j-specs i came to this conclution, but assumed the wastegate was external and so could be changed to a bigger one, obviousy that bit was wrong but i have heard of the wastegate being bored out on T3's because of boost creep (turned out to be a dud actuator:blink:), is this a possibility to do on the j-spec turbo's? or should i just forget about it untill it is needed (and probably stock turbo's removed anyway) anyways i supose if it works dont fix it EDIT: lol maybe thread hijack but i thought relavent It would be a lot of tricky work and to be honest I'm not sure if it's even possible - I've certainly never heard of it being done before. The restrictor option does work, though is a workaround rather than a fix. I would seriously question whether the expense of modding the wastegate would be worth it, even if it's possible. It would probably be far easier to convert to UK/Euro/US spec turbo's (or hybrids) than try and mess around with the jspec ones. Link to comment Share on other sites More sharing options...
TurboBrett Posted October 5, 2007 Share Posted October 5, 2007 It would probably be far easier to convert to UK/Euro/US spec turbo's (or hybrids) than try and mess around with the jspec ones. lol the easy answer allways runs away when i look for it lol if it ever becomes a problem i think this could be the option to take but dont think i can afford engine mods for the first 2 years at least:D Link to comment Share on other sites More sharing options...
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