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I am an arms deala!
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Hey guys,

I just got back from the track last night where I posted my new fastest time of 12.7 @ 114. This run was on 18.8 psi. I decided I wanted to up my boost to 20 psi and see if I couldn't get a 12.6 or 12.5 run in. After I raised it my car got slower, not by much, 12.8 and 12.9 runs all night. On the last run of the night I decided I wouldn't try to pay closer attention to the boost controller. When the car went into third gear boost progressed slowly to 19.8, I then heard a boost leak and pressure immediately dropped to 17.5 psi. I've checked all the intercooler lines and vacuum lines for leaks and couldn't find any. So I believe the stock BOV was leaking. I can hear my blow off because of the blitz intake. Have any of you had similar problems with the stock BOV and if so, what can you do? I don't have the money for an SAFC or VPC and an aftermarket BOV. I could buy an aftermaket BOV, but I don't want the car to stall after coming of a WOT run. Anyone know if HKS as fabricated a recirc kit for the Supra's yet. I know they have for the Eclipses's. Any help would be appreciated.

Thank in advance,

Jesse
 
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Before jumping to any conclusions, make sure that the BOV really is the problem. Attach a 20 psi compressed air source to one side connector, and make sure that it doesn't leak. Then, use a vacuum pump on the top connector and make sure that it opens.

Unlike most aftermarket BOV's, the stock BOV only opens when vacuum is present in the intake manifold. If you look at the BOV, you will see that it would be very difficult to make it leak unless something is broken.

If your BOV is leaking after all, replace it with another stock BOV or possibly 2 BOV's in parallel. Leave the aftermarket BOV's for the single turbo guys who really need them.
 
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Leak

I know when I was working on my DSM, I would rig a simple device to replace the intake filter. All it has was an air fitting on it so I could supply compressed air to the intake system. I could slowly raise the pressure of the source until I was satisfied with how much air it was holding. I would know as soon as any hoses were loose on the intercooler, etc. It may be a vacuum line is leaking instead of the BOV. I would expect that the BOV, being metal, wouldn't leak unless the spring is simply giving out at that point. I know with the first generation DSM BOV's, which are metal also, you can crush it just a bit to make it hold a bit more boost pressure if you got an abnormally low leak point on your BOV.
 

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Do you see any oil around the hoses attached to the BOV or on the heat shield beneath it? If so, then boost is leaking from loose hoses. I replaced the BOV hoses, got them from jeff at jay marks toyota. I also replaced the stock clamps with worm type and tightend them up really good. I haven't seen any oil since then and I'm able to hold boost within .02 kg/cm2 to redline. Another area is the EGR. Many have had leaks around the EGR and the plate has stopped them. Hope this helps.
 

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Yeah I tested my BOV to over 25 psi and it didn't leak.

Oolan, do you know if they make aftermarket BOVs for singles that are like our stocker? I had always heard people talk about ajusting springs, compressor surge, leaking, and whatnot and didn't know what they were talking about until I realized our stock BOV was designed differently.
 

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There's a stock mounting location kit for the HKS SSBOV but I think it still vents to ATM? Not sure though.
 

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I am an arms deala!
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Discussion Starter #7
Well i know that it's coming from the passenger side of the vehicle. I have done the egr mod, but haven't installed the plate. It has done this before I did the egr mod though, so I don't think that this is the problem. I'll go over all the hoses again and make sure nothings leaking.
 

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I was talking about the EGR plate block off. I guess many have had leaks around the EGR where it mounts to the manifold. Get the block off plate as well.
 
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Grant said:
Yeah I tested my BOV to over 25 psi and it didn't leak.

Oolan, do you know if they make aftermarket BOVs for singles that are like our stocker? I had always heard people talk about ajusting springs, compressor surge, leaking, and whatnot and didn't know what they were talking about until I realized our stock BOV was designed differently.
I've heard that the HKS Racing Type II BOV might actually be like this, but I'm not sure. And, at $500, it would be an expensive mistake if it isn't. I'm looking for a good BOV so I can install my T66 kit.

I've even thought about 4 or 5 stock BOV's in parallel... :D
 
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