Cincy05LGT Posted November 9, 2009 Share Posted November 9, 2009 I have been searching for a thread on testing for boost leaks, and so far I have come up with very little. Should I plug the intake right after the airbox and pump it up with a bike pump/shrader valve? Or should the test be performed after the turbo? Once again, this is a completely stock setup. Any help would be appreciated! I am thinking of doing this today after work if I can get any feedback. Link to comment Share on other sites More sharing options...
Balrock Posted November 9, 2009 Share Posted November 9, 2009 Generally you do it right after tge MAF. You need a cap or something to plug up the system with and a valve stem or something coming out and then inflate. I recently had mine done and it held to 30 some PSI, I think it was. Link to comment Share on other sites More sharing options...
schwinn Posted November 10, 2009 Share Posted November 10, 2009 I thought someone had a nice procedure written up, but I found this quickly with a search: http://www.legacygt.com/forums/showpost.php?p=770654&postcount=12 Don't use too much pressure, though - I'd probably go around 10psi... 30psi might be a bit much, but should still hold. I'd rather not risk it on my car... Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 11, 2009 Author Share Posted November 11, 2009 Ok, so having popped the hood tonight, this is looking alot harder than it sounds. Taking the intake off of the turbo inlet seems difficult to reach and hard to put back on, (not that I'm scared to try), I would just need a whole day with nowhere to go is all. Just getting to the turbo inlet seems nearly impossible Underneath part of the intake manifold. I can access the hose clamp to remove the rubberized thing that fits around the turbo inlet, but how do you get it back on in that tight area? Remove intake manifold? Sorry for being such a noob in advance. Edit: Also, I was wondering if just pressurizing the tube in which the MAF is located along with the rest of the intake manifold is not recommended. Seems like an easy way around messing with the turbo inlet, but I figured there's a reason nobody suggests it. Link to comment Share on other sites More sharing options...
05lgt5spd Posted November 11, 2009 Share Posted November 11, 2009 its easy, read my post in here http://www.legacygt.com/forums/showthread.php?t=124064 Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 11, 2009 Author Share Posted November 11, 2009 So I take it it is safe to pressurize the intake tube pre-turbo? I was just wondering since it does not normally see any boost pressure. Link to comment Share on other sites More sharing options...
05lgt5spd Posted November 11, 2009 Share Posted November 11, 2009 I have done it and so have others, I have done up to 25psi, just do it to a couple lbs higher than what your car runs Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 11, 2009 Author Share Posted November 11, 2009 Thanks for the help! I'll def be doing this tomorrow. Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 14, 2009 Author Share Posted November 14, 2009 OK... so I assembled my intake plug and pressure tested the intake using a bike pump with a built in air gauge. After each pump I could hear air leaking from a small solenoid looking unit mounted to the right end tank of the intercooler. I sprayed soapy water to look for bubbles and saw a few at the flange. However, it only blew bubbles when I put a little pressure on the flange. Is this unit a diverter valve, what the heck is it? Could it be leaking inside the valve? The car runs fine, but will not hold pressure during my leak test. Any answers? Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 15, 2009 Author Share Posted November 15, 2009 So I have found out this is the Bypass Valve that is leaking. I can't tell whether the valve is leaking internally or if it is leaking from the flange. Any way to test it? Link to comment Share on other sites More sharing options...
schwinn Posted November 15, 2009 Share Posted November 15, 2009 Sounds like the stock blowoff valve (BOV). Here is a company/picture of an aftermarket one: http://www.turbosmartonline.com/index.php?id=188 Is that the item you're talking about (stock one is black plastic, not shiny like this one). If it's leaking at the flange, then you could check the oring under it, to make sure it's not bad... otherwise it could be the valve itself, leaking by. I believe the stockers will leak under stage2 levels, so they are pretty weak and don't always seal well... Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 16, 2009 Author Share Posted November 16, 2009 Yes that would be it. That looks prettttyyyyy..... Maybe I'll go the aftermarket route rather than having to explain to Subaru how I "found" a boost leak to get it fixed under warranty. Plus I'll have the nice pssshhhhhhh!!! after each shift! I'll search around for other reviews on aftermarket BOV's (Unless someone wants to throw their opinion at me). Link to comment Share on other sites More sharing options...
HarryN Posted November 16, 2009 Share Posted November 16, 2009 I am usually bias towards BoV that route back in. Not the ones that blow out to the atmosphere. Again, this is one of those "to each their own" things when it comes to blow off valves. Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 16, 2009 Author Share Posted November 16, 2009 I plan on autocrossing the car next year, and would like a little bit of the whoosh sound when shifting, however I probably wouldn't like to hear it while cruising around town, nor would my gf. I am thinking a sequential BOV would suit me well since it only makes noise under high boost levels. Link to comment Share on other sites More sharing options...
schwinn Posted November 16, 2009 Share Posted November 16, 2009 Venting the gas out means that metered-air is now "removed" from the system, so you will temporarily run rich. This, of course, also means you get the whoosh sound. Like HarryN, I prefer keeping the system operating properly, and would recommend a full-recirc BOV... but I guess it doesn't matter too much. Certainly do more searching on reviews and see what's what... I am no expert on BOVs. Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 16, 2009 Author Share Posted November 16, 2009 Well, after doing some research I think I will have the dealership fix the leaky OEM BPV since they just did a shortblock replacement under warranty in Sept. My 60k warranty will expire in May, and the shortblock warranty is good to next August. I think I'll be better off staying with stock components until then just in case anything goes wrong. Stay stock stay happy... for now. Thanks for all the opinions. Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted November 23, 2009 Share Posted November 23, 2009 If it's leaking at the line between the TMIC and BPV, why don't you just grab a 10mm socket and a socket wrench and take it off and put it back on with some attention to detail, and see if it still leaks. It's a big skinny rubber ring that makes the seal. Probably just not seated right. [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 23, 2009 Author Share Posted November 23, 2009 Sorry for not updating in a while... This weekend I pulled the PBV off and found NO GASKET whatsoever. I did my best to cut a gasket and popped it in there. My intake now holds atleast 16psi without leaking, I didn't want to test any higher than that. In the mean time Subaru is ordering an OEM gasket under warranty. I can't believe how much power and gas mileage I was missing out on. Datalogging+forum guys advice=happy subie Link to comment Share on other sites More sharing options...
mikeislord Posted November 23, 2009 Share Posted November 23, 2009 Good to hear it worked out for you. I also didn't have that gasket and simply made one using RTV. Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted November 23, 2009 Share Posted November 23, 2009 ^^^ man you guys had some rotten luck not getting that gasket. Good you had the willingness to cut or to lay on a temporary gasket. My hunch was it was just installed all wrong, like one bolt was loose and the other one too tight, but a missing gasket altogether? [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 23, 2009 Author Share Posted November 23, 2009 From what I understand a boost leak can make your engine run rich. Also, I have noticed a slight increase in gas mileage since the gasket install which leads me to believe I was running rich. I know rich is better than lean, but catalytic converters can be clogged with soot and such. Any chance I have any long-term damage due to running with a boost leak for 3-4k miles? Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted November 23, 2009 Share Posted November 23, 2009 From what I understand a boost leak can make your engine run rich. Also, I have noticed a slight increase in gas mileage since the gasket install which leads me to believe I was running rich. I know rich is better than lean, but catalytic converters can be clogged with soot and such. Any chance I have any long-term damage due to running with a boost leak for 3-4k miles? wouldn't worry about it. you probably were't super rich... [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
Cincy05LGT Posted November 23, 2009 Author Share Posted November 23, 2009 What I figured... Can't hurt to be cautious. Link to comment Share on other sites More sharing options...
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