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Type R BOV Problem?

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crazyquik22023

10+ Year Contributor
641
6
Sep 14, 2008
Akron, Ohio
I've had a Greddy type-r bov on my car for about 2-3 years now. I have never noticed this problem before so I'm assuming it isn't supposed to do this and is indeed a problem. I started having a problem with my car not wanting to boost past 25-26 psi, so I pulled out the boost leak tester. Found a few small leaks and fixed them but the intake system would still not hold more than 20-21 psi during the test. I know very few dsm guys use the type r but it is designed the same way as the type s. It has 2 nipples, one on the "head" of the bov and one on the body. The nipple on the head gets attached to a vacuum/boost line after the throttle and the nipple on the body either gets left vented or gets connected to a boost source after the compressor and before the throttle. I've left the nipple on the body vented since I had the bov. When I do a boost leak test as soon as I build up about 10 psi in the system is starts to leak out of this nipple and obviously out of the entire system. If I cap the nipple or hook the nipple up how it is supposed hooked up to the nipple on my compressor cover, the bov starts to leak out of the "mouth" at anything past 10psi. With the nipple vented I can't boost past 25-26 psi with my MBC all the way in, and with it hooked up I can't boost past 16-17psi. I know I can reach 32 psi+ with my wastegate spring and boost controller b/c I have been at this level before with the same setup. My question is do you guys think the diaphragm is damaged or is something else with the bov damaged? I'm really not sure what the problem could be. Any input would help. Thanks
 
My Type-S would also leak out of the mouth if I used the bottom port. But it didn't leak out of the bottom nipple from the top.

I replaced the diaphragm with a NRG one (which is much higher in quality by the way) and it still did the same thing. I could find nothing wrong with it and assumed it was happening due to design.

I run a HKS now with no leaks.
 
I used to run twin greddy type s and I had a similar problem, I couldn't get the car to build more boost then 28 psi. Boost woukd just fluctuate around 28 psi and not go up any higher. I tightened up the screw on top of the bov and that fixed the problem but when I let off the gas after a pull I could hear my turbo surging, so I removed the bovs to see how much there were opening and found out that they were opening no more then an 1/8 of a inch, basically defeating the purpose of having a bov. I took them off and out a 50mm bov on and no problems since then.
 
Check the o-ring on the bov. Could be damaged/gone causing air to leak into the bov and out the vent/nipple.

Where is there an o-ring? I haven't had my bov apart in a while but I don't remember there being an o-ring inside.. If there is Ill check it out.

I used to run twin greddy type s and I had a similar problem, I couldn't get the car to build more boost then 28 psi. Boost woukd just fluctuate around 28 psi and not go up any higher. I tightened up the screw on top of the bov and that fixed the problem but when I let off the gas after a pull I could hear my turbo surging, so I removed the bovs to see how much there were opening and found out that they were opening no more then an 1/8 of a inch, basically defeating the purpose of having a bov. I took them off and out a 50mm bov on and no problems since then.

Ya I've been thinking about switching to a 50mm tial or something like that but I spend a lot of $ on my type-r back in the day and I actually like it as a bov..but I do need it to work properly haha
 
Take it apart and check the diaphragm. Unlike the type s the type r uses a snap ring to hold on the top hat. Should take no more then 5 minutes to disassemble as long as you have have some snap ring pliers.
 
Take it apart and check the diaphragm. Unlike the type s the type r uses a snap ring to hold on the top hat. Should take no more then 5 minutes to disassemble as long as you have have some snap ring pliers.

You are correct.. I've had it apart before..it's very simple actually.. But honestly I have to say I don't know what to look for as far as a bad diaphragm. Am I looking for tears,holes? What causes a diaphragm to be bad?
 
They go bad over time since there made from a rubber like material. Here is a picture of a bad diaphragm. This is not from a bov but it should give you an idea.
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