Guest WJX808 Posted May 24, 2007 Share Posted May 24, 2007 Im driving an auto stock supra. (J spec) I have recenty changed my turbos to the UK spec supra as my original ones were leaking. I have also changed my exhaust system using a 3 inch stainless steel piping. The extractor is original though. When i boost the car...i get some overboosting problem. The boost went as high as 1.2 bar and it cuts off...luckily my boost cut is still functioning ...So now i could not floor the car all the way when im into top gear (ie. above 200 kph) as the boost will definitely climb to 1.2 bar if i floored it. Can installing a boost controller fix the problem? at least i could set the boost at the level i want to. And how much boost can a stock UK spec turbo takes? Appreciate your help and advice guys. Cheers Quote Link to comment Share on other sites More sharing options...
Daston Posted May 24, 2007 Share Posted May 24, 2007 A boost controler will only let you increase the boost, you will need to increase your fuel cut threashold if you want more pressure. I think the UK spec can take up to 1.3-1.4bar Quote Link to comment Share on other sites More sharing options...
Guest WJX808 Posted May 24, 2007 Share Posted May 24, 2007 but say with a boost controoler...can i fix the boost at 1 bar for example? And it will not increase even if i floor the throttle at high speeds? Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 24, 2007 Share Posted May 24, 2007 1.2 bar is fine... and yes a boost controller can only raise the boost level above what it would reach naturally. Quote Link to comment Share on other sites More sharing options...
wkdtime Posted May 24, 2007 Share Posted May 24, 2007 1.2 bar is fine... and yes a boost controller can only raise the boost level above what it would reach naturally. Assuming he's decat and other precautions. Quote Link to comment Share on other sites More sharing options...
Guest WJX808 Posted May 24, 2007 Share Posted May 24, 2007 Yeah...i understand that...but can it definitely fix my boost at a certain level say 1.0 bar or 1.1 bar...so that i will not reach 1.2 bar. I hate the feeling of not beien able to floor the throttle Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 24, 2007 Share Posted May 24, 2007 Yeah...i understand that...but can it definitely fix my boost at a certain level say 1.0 bar or 1.1 bar...so that i will not reach 1.2 bar. I hate the feeling of not beien able to floor the throttle No. If your car is hitting 1.2 bar without any form of boost controller at the moment then fitting a boost controller will not let you lower that. Quote Link to comment Share on other sites More sharing options...
Guest WJX808 Posted May 24, 2007 Share Posted May 24, 2007 No. If your car is hitting 1.2 bar without any form of boost controller at the moment then fitting a boost controller will not let you lower that. Jesus.. then what can i do to fix this prob? Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 24, 2007 Share Posted May 24, 2007 Jesus.. then what can i do to fix this prob? What problem? 1.2 bar is fine. If you really want to lower it then either get a restrictor ring or refit one of the cats. Quote Link to comment Share on other sites More sharing options...
jamesmark Posted May 24, 2007 Share Posted May 24, 2007 Ok in simple terms as this thread has went round in circles. Fit a FCD to raise the fuel cut to 1.2 bar as the stock ECU cuts fuel @ 1.0 bar. Get a 1bar restrictor ring this will then limit the boost (still may get boost spikes iirc) then get a boost controller to then raise the boost to 1.2bar. Quote Link to comment Share on other sites More sharing options...
Rich Posted May 24, 2007 Share Posted May 24, 2007 Ok in simple terms as this thread has went round in circles. Fit a FCD to raise the fuel cut to 1.2 bar as the stock ECU cuts fuel @ 1.0 bar. Get a 1bar restrictor ring this will then limit the boost (still may get boost spikes iirc) then get a boost controller to then raise the boost to 1.2bar. Quote Link to comment Share on other sites More sharing options...
Guest WJX808 Posted May 24, 2007 Share Posted May 24, 2007 What problem? 1.2 bar is fine. If you really want to lower it then either get a restrictor ring or refit one of the cats. The problem is now when i full throttled the car...it will reach 1.2 bar and the boost cut kicks in...hate that feeling when the boost cut kicks in...so what can i do to fix this problem? Should i change to a smaller inch exhaust piping? (im currently using 3 inch) Cheers Quote Link to comment Share on other sites More sharing options...
Steve Posted May 24, 2007 Share Posted May 24, 2007 Fit a FCD to raise the boost cut limit. The Thor one is a good one Edit: As said above in post 10 Quote Link to comment Share on other sites More sharing options...
wkdtime Posted May 24, 2007 Share Posted May 24, 2007 The problem is now when i full throttled the car...it will reach 1.2 bar and the boost cut kicks in...hate that feeling when the boost cut kicks in...so what can i do to fix this problem? Should i change to a smaller inch exhaust piping? (im currently using 3 inch) Cheers See post # 10..Nuff said. Quote Link to comment Share on other sites More sharing options...
Guest Geneb Posted May 24, 2007 Share Posted May 24, 2007 just put the front cat in bud ,easier and cheaper Quote Link to comment Share on other sites More sharing options...
jamesmark Posted May 24, 2007 Share Posted May 24, 2007 I must have the only invisible post(s) on the forum! Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 24, 2007 Share Posted May 24, 2007 I must have the only invisible post(s) on the forum! Did someone say something? Quote Link to comment Share on other sites More sharing options...
wkdtime Posted May 24, 2007 Share Posted May 24, 2007 Did someone say something? Don't think so.. Quote Link to comment Share on other sites More sharing options...
Nic Posted May 24, 2007 Share Posted May 24, 2007 What I can't understand is why your UK turbos are overboosting. Even with both cats removed and a straight through exhaust, the wastegate should limit boost to around 0.9-1bar. Can we just establish the following as this thread has got a bit confusing. 1. Do you have a Fuel Cut Defender already fitted? If so, are you saying the fuel cut level on the FCD is raised to 1.2bar? 2. Do you have a boost gauge fitted? I presume so if you say you are hitting 1.2bar, but just thought I better check. If your UK turbos are hitting a raised 1.2bar fuel cut level, then I'd suspect that the wastegate isn't opening, which could mean one of the small vac hoses is off or leaking. Check all the hoses to see if you can see anything. Quote Link to comment Share on other sites More sharing options...
Rico2006 Posted May 24, 2007 Share Posted May 24, 2007 Fit a FCD to raise the boost cut limit. The Thor one is a good one Edit: As said above in post 10 Thor no longer do their FCD... which is a shame - they are now recomedning the Greddy unit. Quote Link to comment Share on other sites More sharing options...
Rico2006 Posted May 24, 2007 Share Posted May 24, 2007 What I can't understand is why your UK turbos are overboosting. Even with both cats removed and a straight through exhaust, the wastegate should limit boost to around 0.9-1bar. Can we just establish the following as this thread has got a bit confusing. 1. Do you have a Fuel Cut Defender already fitted? If so, are you saying the fuel cut level on the FCD is raised to 1.2bar? 2. Do you have a boost gauge fitted? I presume so if you say you are hitting 1.2bar, but just thought I better check. If your UK turbos are hitting a raised 1.2bar fuel cut level, then I'd suspect that the wastegate isn't opening, which could mean one of the small vac hoses is off or leaking. Check all the hoses to see if you can see anything. I had this with BigH's car. Someone had fitted a bleed valve, and removed a boost controller before he picked the car up.. The pipework wasnt put back properly , and there was nothing controlling boost. Both the VSV and the actuator pipework were capped off and boost was creeping upto 1.34 bar. putting the pipework back to standard soon sorted this out, but it took me ages to realise it was wrong. Quote Link to comment Share on other sites More sharing options...
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