Compressor Surge w/ Blitz DD Bov

[jdm_s14_zenki]

EDIT: PROBLEM SOLVED!!!
If anyone has a similar problem with your blitz bov or you get alot of chatter (compressor surge) or your bov is leaking vacuum or boost, this is what you do to get rid of the chatter(if its because of your bov not functioning properly) and to make it bullet proof against boost and vacuum leaks:

Heres my story:
Ok, so I bought this bov 2 days ago from some guy that had it on his WRX. Looks very clean, so i bought it. When i first installed it, i noticed that the adjustment screw was all the way loose. So i left it alone then drove around. I get major compressor surge. Cant even hear the bov at all at any rpm. all i hear is fluttering, SO i tightened the spring, and of course the same thing! then i backed off the spring a few turns. same thing. Im just curious to see if anyone had this problem with this bov. Its not leaking boost or vacuum at all!! so thats not the problem, and yes its correctly hooked up.

Heres the solutions/maintenance:

If you loosened the adjustment screw all the way and you still chatter that means either your piston is stuck closed, or your spring tension is too tight. In my case, the spring tension was too tight

If you piston is stuck simply take the bov apart from the top (4 allen bolts) and slowly and carefully open it up. the spring might pop out at you like it did me :[
Next just take everything thats inside the bov (piston, spring, inner wall of the bov, ect,) and clean it with some carb cleaner or something. Make sure that the piston is nice and smooth and it smoothly plunges inside the bov with no resistance. if needed, take some fine grit sand paper and sand the inside defects until the piston moves freely. do not screw with the rubber part of the piston.
Next you will need some kind of lubricant. I used air compressor oil cus thats all i had laying around. oil up the piston and the inner cylinder of the bov.

Next, you will need some gasket sealer. I prefer the high temp, oil resistant (black stuff in a black tube from autozone) gasket sealer. anywhere where theres a paper gasket, or metal to metal parts that you have taken apart (top cap of bov, between bov and flange, ect.) apply a neat and thin layer to it. if the layer is too thick, when you tighten the bolts down, the gunk will squeeze into the cylinder/piston area, hindering the free movement of the piston.

Put everything back together. Apply the gasket sealer or teflon tape if you have any to any screws that go into the bov. for instance, the adjustment screw needs to be sealed off good or else you might leak boost/vacuum. Also, do the same with the vacuum hose fitting that goes into the bov. both blitz bovs i had leaked vacuum from there. Check for cracks in that fitting area as well. mine was over torqued and it cracked so i had to use gasket sealer to seal it up temporarily. then use jb weld if you dont plan on messing with that fitting ever again.

All this work will pay off. There is NOWHERE for the BOV to leak as long as you use the gasket sealer in the right places!

To reduce spring tension, simply cut the spring shorter. I cut about a 1/4 of the total length of the spring. i had the standard 18psi spring. Dont cut the spring too much or you will be adding a crap load of washers under the spring to make up for the loss in tension.

After this is all done, you need to tune your BOV. Heres how to do it.

Replace the adjustment screw back into the top of the bov. when you tighten down that screw, you will notice tension all of a sudden. thats when the adjustment screw starts tightening the spring. at that point, turn the screw about 1/2 - 1 turn, then use the lock nut to hold it in place.

Try driving around and see how you like it. The chatter should be gone at this setting no matter what rpm or vacuum/boost level you are at. If you like it, leave it. If the car starts bucking, you are loosing boost, or vacuum, thats because the spring is opening under vacuum. Its too loose, so start tightening that screw aanother 1-2 turns, then try again. repeat these steps till you get it dialed in.

I have mine adjusted to where if i let off the throttle in very low rpm (the point between vacuum and boost on your boost guage) there will be a little tiny bit of chatter. but you can barely hear it. at about 1-3 psi boost, you should not hear the chatter at all and only hear your bov woooshing. especially at high boost, you should only hear the bov. no chatter.

This stuff worked for me. It will work for you, dont waste your money buying another bov. Just fix it and dont worry about it for a longg time!


So ya, its 1am right now and i gotta work at 8 am, im really tired so if i miss-spelled anything or i dont make sense, just let me know and i'll fix it. Hope this helps you guys out, cus ive been dealing with this damn problem for over a year now and i FINALLY FIXED IT!

[Rogue240sx]

as I said in the other post making a spring shorter is going to increase the spring rate. It's like trying to bend a 2foot long aluminum rod opposed to a 1 foot long aluminum rod of the same diameter. the longer one is alot easier to bend.

[jdm_s14_zenki]

PROBLEM SOLVED!!!
check out the first post on this thread for the solution for blitz bov leaks and chatter!!!

btw, can we archive this thread? Ive seen alot of posts of people going nuts on blitz bovs cus they tend to leak, and or the spring tension is too tight from factory.

[NemeGuero]

I don't think this is a good idea either. Try cleaning your BOV instead to fix the locked piston.

Don't cut the spring.

[jdm_s14_zenki]

you dont HAVE to cut the spring. i cut mine because my spring tension was way too tight (i probably had the stiffer spring which is optional on blitz bovs, i bought it used so...ya..). like i said, when i loosened the spring all the way, i would still get 100% compressor surge do to the fact that the piston wasnt opening, because of the spring tension. then, i cut the spring, and fixed the problem. my problem was not because of a stuck piston, or dirty piston. im meerly offering a solution for those who DO have a stuck piston.

[smithers584]

[QUOTE]as I said in the other post making a spring shorter is going to increase the spring rate.[QUOTE]

cutting the springs raises the spring rate?

ok well if cutting a spring makes it stiffer, then we all should cut the factory springs (suspension) on our cars to make them lower and handle better! Why do you think when you see a car with cut springs they bounce all over the place, not because they made the spring stiffer i will tell you that much. maybe i am just completely confused.

[Nostradamus]

Cutting does increase spring rate. A 10kg spring with 10 turns should gain 1kg if you cut off 1 full turn with a linear spring. Spring rate is proportional to the number of coils in the spring. This is not true for progressive springs.

[Rogue240sx]

cutting your stock springs excessively leads to poor drivability and harsh ride, not to mention that stock struts aren't made to handle the increased spring rate . What cutting your spring in the BOV might do is it might lower the preload a little bit if not completly eliminate is depending on how much you cut. I haven't taking apart a blitz unit so I can't say for certain but I know for a fact that cutting a spring makes it stiffer.


edit: in your case the preload was too much. preload and spring rate are 2 different animals. I'm not here to argue i'm here to inform.

[jdm_s14_zenki]

i dunno, but if you cut the damn bov spring. it reduces the spring tension! period! dont argue with me...im the one that DID it!

[NemeGuero]

Originally Posted by jdm_s14_zenki

i dunno, but if you cut the damn bov spring. it reduces the spring tension! period! dont argue with me...im the one that DID it!

Without actually understanding properly WHY it worked..
Good job.

[jdm_s14_zenki]

Originally Posted by NemeGuero

Without actually understanding properly WHY it worked..
Good job.

uhm, i know exactly why it worked. thats why i did it and thats why it worked. and it seems to me that you are the one that doesnt "properly" know why it worked. thats why you make these ignorant comments. :] im not being sarcastic here. im being honest.

The point is.
If you're spring is too stiff, and you're too cheap to get a different one..like me, and your piston isnt opening with the amount of boost youre using, then cut the damn spring. Its real simple and it works. if your piston is stuck and the springs not too tight then clean out your bov and lube it up.

And if your bov is leaking, do what i said and use gasket sealer on all the parts of the bov that have that stock paper gasket, use it on the fitting that goes into your bov (from the vacuum hose) and use it on the adjustment screw. these are the only places that your bov would leak from. If your bov is cracked in the area where your fitting goes in (like both of my blitz bovs had) then you gotta use jb weld to seal it, or you can temporarily fix it by applying some of that gasket sealer on it and on the threading of the fitting.

[jdm_s14_zenki]

i never said anything about "spring rate" i said "spring tension" and besides..i cut the spring about 1/4 or the full length. and now the spring is much easier to "push" the piston in. Which can only mean that the spring has "less tension" in it, which makes it easier for the "pressure" comming from the turbo (when the throttle closes) to open the piston. BTW, i was just kidding about the arguing thing..i was being sarcastic.

This makes perfect sense to me. It should make perfect sense to you as well. I mean think about it..Like i said, its one thing to say something works, and its another thing to actually try it and then say it works.

[Rogue240sx]

Originally Posted by jdm_s14_zenki

i never said anything about "spring rate" i said "spring tension" and besides..i cut the spring about 1/4 or the full length. and now the spring is much easier to "push" the piston in. Which can only mean that the spring has "less tension" in it, which makes it easier for the "pressure" comming from the turbo (when the throttle closes) to open the piston. BTW, i was just kidding about the arguing thing..i was being sarcastic.

This makes perfect sense to me. It should make perfect sense to you as well. I mean think about it..Like i said, its one thing to say something works, and its another thing to actually try it and then say it works.

All I'm trying to say is that cutting the spring makes the spring physically stiffer but here's the deal. you took a 1/4 of the total length off of the spring so now the spring isn't compressed as much as it was before since it takes up less space, in other words you've dropped the pre load of the spring(other wise the initial force that the spring pushes down on the piston with is now less). I know bottom line it worked for you and that's what matters, but I feel if you have a better understanding on why what you did worked it'll help you out in future situations.

That whole knowledge is power thing isn't just some stupid sang people told you when you were young, it's absolutely correct.

[driftpolice]

I know its an old thread, but thanks guys this thread was a huge help.