Vaughany Posted September 4, 2004 Share Posted September 4, 2004 I have recently fitted a restrictor ring to my car to keep the boost under control as I have recently had the first cat removed. The restrictor is holding the boost at about 1 bar now, without the restrictor the boost was peaking at 1.4bar. Rather than get a new slightly larger diameter restrictor made. Can I just file down this restrictor a bit to enlarge the hole so more boost can be reached. The current restrictor is about 2" diameter and without the restrictor fitted the diameter was 2 1/2" as this is the size of my first cat pipe. I was thinking that if I increased the diameter of the restrictor ring from 2" to 2 1/4" this would hopefully raise and hold the boost at 1.2bar ( Desired level for my J-SPEC on stock twins) What do you think does this sound about right? I would appreciate if this dilema could be answered asap as I was going to give it a go tomorrow morning. Quote Link to comment Share on other sites More sharing options...
Homer Posted September 4, 2004 Share Posted September 4, 2004 I have the Chris Wilson restrictor ring in which I think is 2inch dia. In summer weather the max boost I see is 1.05 bar, but when the temperatures are lower (say around 10degreesC) the boost hits 1.2 bar easy. If you were to cut the ring down you'll see some big increases in boost when winter comes, if those increases mean you reach 1.4+ bar then you could be in the danger zone for turbo problems. Quote Link to comment Share on other sites More sharing options...
Vaughany Posted September 4, 2004 Author Share Posted September 4, 2004 Hi Homer Yeh I know what you are saying but at present my boost is making only 1 bar with the 2". I want to increase the diameter only a bit to try increase the boost to ideally 1.1 - 1.2bar. I am aware that come the colder weather I may experience 1.3bar or higher but will I have to control my peddle to keep the boost out of the danger level. I was also thinking that come the colder weather I tend not to drive as hard due to the weather and road conditions. Maybe I will only increas the diameter from 2" to 2.2" and see what effect this has. Thanks for your opinion, worse comes to worse I will have to buy a new restrictor if when I alter this diameter the boost raises to high. Quote Link to comment Share on other sites More sharing options...
Homer Posted September 4, 2004 Share Posted September 4, 2004 I'll be interested to see your results with a 'slightly' increased restrictor ring diameter Wish someone would come up with a restrictor ring that accounts for seasonal temperature variations!! Technically impossible I know but proper boost controllers cost an arm and a leg to set up! Quote Link to comment Share on other sites More sharing options...
Vaughany Posted September 5, 2004 Author Share Posted September 5, 2004 Homer I will post up the results and size diameter that I went for. I am looking at approx 55mm to hopefully achieve 1.15bar. I'll let you know how I get on. Quote Link to comment Share on other sites More sharing options...
merckx Posted September 5, 2004 Share Posted September 5, 2004 I've also got a CW restrictor ring fitted to the full decat which I did a couple of weeks ago, at first it was boosting to just under 1.2 bar. Went out for a drive the other night which was a little cooler and the boost had risen to 1.3 bar. I'm sure during the cold winter weather it will go up even more. I'll definately have to fit a new restrictor ring with a smaller hole! Quote Link to comment Share on other sites More sharing options...
Vaughany Posted September 5, 2004 Author Share Posted September 5, 2004 Well i have just increased the size diameter from 2" (when measured in mm it was actually 52mm). At this diameter the car was making 1bar. I have increased the diameter to 56mm and have just too the supra for a spin. The car is now making 1.2bar, I know that this might creep above this when the weather is cooler but I am not worried as I tend to drive calmer when the weather is cold as the road conditions usually are bad at this time aswell. Also I am hoping with the CW SMIC, uprated fuel pump and water injection I will be a little bit safer so if it does creep up to 1.3 bar I should still be safe. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 6, 2004 Share Posted September 6, 2004 Small ID increases make a big difference to boost, as you have found out! Quote Link to comment Share on other sites More sharing options...
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