Samurai 20V Posted March 29, 2011 Share Posted March 29, 2011 Chaps, Got my restrictor rings cut out today, went for 2inch, 2.2inch and 2.5inch... My wife picked them up as I was busy, measured them, they gave me 2inch, 1.6inch & 1.2 inch....Idiots..Gonna go back to them tomorrow to sort it out. Just to confirm, I am fitting a 3inch double decat, my car has Kakimoto 3.5inch exhaust. Is 2, 2.2 & 2.5inch a good start to limit to about 0.9bar? I understand that this is trial and error, just want to confirm that I am on the right track.. Thks.. Quote Link to comment Share on other sites More sharing options...
Tyson Posted March 29, 2011 Share Posted March 29, 2011 I think for standard boost level it is 2.5 inch but I would start with the smallest one and check your boost gauge for any boost spikes. Quote Link to comment Share on other sites More sharing options...
Branners Posted March 29, 2011 Share Posted March 29, 2011 It is far from an exact science, try the ones you have, do a 3rd or 4th gear pull up a hill and see what boost you hit. Max boost is based on engine load, so you need to be about 50mph and floor it and see what boost it hits. Quote Link to comment Share on other sites More sharing options...
Homer Posted March 29, 2011 Share Posted March 29, 2011 As JB says there's no exact size, it varies depending on the car (exhaust model, decat size, engine health, IC health, etc. all play a factor). Best practice would be to get the smallest size (2inch), fit during winter and then drill it out until you reach the desired boost during a hard 4th gear pull (normally you'd aim for 1.2 bar). This finds the base maximum boost. It *will* drop when the weather gets warmer, so if you want to get 1.2bar during summer you'll need a boost controller. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 30, 2011 Author Share Posted March 30, 2011 Okay, that makes sense. Gonna send the 1.2inch back to be cut out to around 2.2inch, then try those sizes.. I want to aim around 1 bar, then use the boost controller to pick up to 1.2bar..It is winter in Japan atm. I will keep the 1.6inch incase I need some other size made up.. Thanks guys. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted September 11, 2011 Author Share Posted September 11, 2011 Ok, to add a result to this, I have finally fitted the Restrictor onto the car although setup has changed slightly. 1st Decat is 3inch, 2nd decat is 3.2inch, cat-back is 3.5inch... I fitted the 2inch restrictor between the 2nd decat and the cat-back. The car is holding 0.85bar on a 4th or 5th gear WOT uphill pull.. AFRS are reading around 10.2 on these runs... It seems to be holding without spiking, I could not get a full gear run, ran out of road. Current temperature is Japan is hot, above 28deg... I would say that this is an acceptable setup, in winter should see around 1bar or so? Opinions? Thks. Quote Link to comment Share on other sites More sharing options...
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