Compressor surge issue.
 

Okay, so I'm sure this question has been answered plenty of times, but I would just like a better understanding of whats going on. I recently just turboed my 1985 AE86 Corolla 16 valve. I installed a 16G turbo with iwg, and running around 7 psi. I am getting compressor surge. I'm not even sure if the BOV is opening up. Now before you tell me its a bad BOV, I will tell you that I have tried 3 different BOVs. When I rev up to about 6k RPMs I hear a wa cha cha cha sound(lol), if I shift anywhere from 2k to 5k nothing happens really. I have the BOV hooked up to a good vac source, I have tried modifying one on the BOVs by removing one of two springs inside so its super soft, still no luck. I am kinda stumped. If anyone can help me with this issue, I would definitely appreciate it. Let me know if there is anymore information needed.
Thanks
Here is a picture of my set up for reference.
http://photos-f.ak.fbcdn.net/hphotos...2_373314_n.jpg
And another from a few weeks ago, when I just finished the install.(Sorry about the dirty engine bay.)
http://hphotos-snc3.fbcdn.net/hs371...._3415699_n.jpg

I had a similar problem on my Honda and it was because I put the vacuum line to too weak of a vacuum source ( I put mine on the intake side of the turbo and that didn't work, moved it to the intake manifold and it's all good). I would run the vacuum line for the BOV as close as you can to you intake manifold as you can, if not right on it. Hope that helps.

Okay, so the vac line thats going to it goes a little like this.
Attachment 6480
It comes from a nipple on one of the pipes on the intake manifold side. Should I change that way it routed? The hose is kinda long, should I cut it down as much as I can?

Put the Blow off vac line to a intake mani vac source

Would you recommend running a line from one of the nipples here, to the bov?
Attachment 6479

if it's before the throttle body, the vacuum line will have pressure on it and not let the bov open, after the throttle body you'll get vacuum and it will allow the bov to open.

It looks like those lines are after the throttle body and should work, and keep the vacuum line to the bov as short as possible.

Thanks for the input. I will try a few things tomorrow and post back.

Okay, so I tried running the line from two different places, and still the same results. I tried running the line from one of the nipples by the TB, and even the breather thats right on the intake mini.
Here and here.
Attachment 6476

Any other suggestions?

Hummmm..... must work that way..


Check if the vacuum line isnt blocked with some kind of trash, oil or something

check the vacuum lines on the throttle body to make sure theres enough vacuum coming from them. best way would be a vacuum gauge but if you start the engine and pull a line off you should be able to here and feel a good vacuum source. find out how much vacuum it takes to open the bov. you want to adjust the bov to a setting just over the vacuum signal from the engine at idle. for example: if your engine produces 20 inhg at idle then adjust your blow off valve to open at 22-25 inhg.

How I determine how much vacuum it takes to open the bov?

go to pepboys, advanced auto parts, or any auto parts store and in the tool isle you will find a vacuum pump/gauge. its 10.00 or less. you use the tool apply vacuum to the bov and see what amount of vacuum it takes to open. put it in place of a hose on the throttle body and it will tell you how much vacuum your engine is producing at idle.

all the vacuum line does is puts equal pressure on the opposite side of the valve when the throttle plate is open, the spring creates a bit more pressure to keep it closed under vacuum or boost, you want that as loose as possible w/out it allowing air to leak. As stated above, when the throttle plate snaps shut, there is vacuum in the manifold and in the vacuum line, allowing the valve to open. If you haven't made a pressure tester for your system, now would be a good time to do it. Using the tester, pressurize the system (don't forget to regulate the air going in to your max psi you want) and make sure the BOV is not leaking, or any other leaks for that matter. Unplug the vacuum line from the BOV and it should open. That's how I would check for proper operation. Good luck!

Also You might want to take that BOV apart. Those knock offs aren't known for good quality diaphragms.. or anything else for that matter. Check for tears and smooth operation. It look's like you have little spring pressure judging by the pic. I would dedicate a nipple to the BOV (don't tee it). It's always good to use one from the plenum. Or tee off the Brake booster if necessary.

I think you got a weird problem, try to put your BOV and vac line into another turboed car to see what happens

Yeah, this is becoming a real PITA. I can't even test it anymore, for some reason the car wont even start now. I drove it, parked it, and now it wont even crank. I bought a new battery(needed it anyway) and I have power everywhere except to my distributor and starter it seems. The injectors turns on, fuel pump turns on, all interior lights, radio, etc. turns on. I'm assuming its a bad ground somewhere. Its just one thing after another lol. Thanks for all the help though trying to diagnose this problem!