Hell_Spawn

Sup all, I have a question about what causes a bov to open while cruising around 65-75 mph or WOT. I read a post here a couple of years old a person having the same issues I now have. Here is the problem. I have a 2003 Evo 8 and was recently tune on e85. Car has 351 HP at 25psi using Evo 9 turbo. But my dam bov keeps opening at full wot and I can't even pass 15 psi (or 4000 rpm)and its driving me crazy. The only way it would go pass this is you have to play with the gas pedal until the bov controls itself then u can go pass 15 psi. Also if you are driving around 65-70 mph and u need to pass a car you step on the gas pedal normally and bov goes crazy.. I have to let go of the gas pedal then hit it again slowly. First I thought It could be turbo sending too much air than what the engine could handle. So my tunner fix my ROM so car would just build up speed while charging turbo more slowly and guess what? Same problem, my GFB bov stills opens no matter what. I have fix all boost leaks including new seals on throttle body. I also put a wider wider vaccum line on bov and same issue. Should I just throw this bov in the garbage? Lol

EvoTurboTurk

What type of GFB bov is it?


I have the tms respons & only problem I had was the top part where you turn to open/shut the recirc & venting, it becomes tight turning due to heat. I need to apply grease on it...


http://www.gfb.com.au/tech/troubleshooting/20-blow-off-valve-leaks-boost

^ try that if you havent

Hell_Spawn

I have the one that replaces stock.. You can have it recirculating or vent to atmosphere.

EvoTurboTurk

Is it the replacement parts? Replacing stock? Could you post a link from GFB which one it is..

Hell_Spawn

This is the one I have
http://www.gfb.com.au/products/blow-off-and-diverter-valves/respons-tms/respons-tms-t9033-adjustable-bias-venting-diverter-valve-bov-by-gfb

EvoTurboTurk

Thats the one I have, have you contacted them about your issue? Otherwise best to try & fix or replace with something else..

Hell_Spawn

Yeah I did, they try to blame it on the tune.. telling me the turbo was sending more air than what the engine can handle. That's why I asked my tuner to detune a bit to see if this was the problem but is not. BOV keeps opening during boost no matter what, do you have any issues with it?

ak47po

iTrader: (3)

Different bov same problem, ended up being an exhaust leak around my 02 housing, all bolts where loose causing the leak. Snugged all the bolts up and problem went away.

Hell_Spawn

Really an exhaust leak???? How can this be even possible? I'm not doubting you I just wanna learn more of this. In fact I replaced my stock downpipe and catalyst with a 3" apexi downpipe with a non brand 3"test pipe.. So my exhaust is going from a 3'0 straight to a 2.5 and has a massive air leak you can hear it as soon as you turn on the engine. I never tough this would be related to bov.

EvoTurboTurk

Actually that happen to me also, exhaust leak. Check all bolts & gaskets.

ak47po

iTrader: (3)

I had to address my exhaust leak because the car sounded like a freight train, just so happens it fixed my bov problem...coincidence maybe. I can't explain it.

EvoTurboTurk

Honestly GFB Brett in Australia was helpful, he wrote essays explaining everything.... I suppose there can be failure in any part, its all luck. I would say check your exhaust system properly or take it to an exhaust place..

Hell_Spawn

Yes I do have an exhaust leak because of my test pipe, I have not taken the car to a muffler shop yet because I have not time. I basically installed megan o2 housing, apexi downpipe with a testpipe on the same day.. then took the car to a friend to fix the throttle body and do the egr delete. I should have some free time so I'll keep you guys posted if I was able to fix the problem. I was able to get in contact with GFB but they told me first it was a tune problem and not the bov. Told me the turbo was sending to much air and engine could not handle it. So my friend made the turbo boost slower but bov stills open at any given time. Does not matter weather im going WOT or not. Then told me it could be the intercooler, but is not because its a new ETS with a 3.5 core and second I have a friend with same setup and he is runing fine. Thanks everyone for all your help.

This is my current setup:
muse intercooler piping kit
ETS intercooler 3.5 core
HKS 272 cams
HKS cam gears
Evo 9 turbo
Megan o2 housing
Apexi downpipe 3"
3" test pipe
GM solenoid
Running E85 on TephraMod V7

This is the log from VirtualDyno

ArturEVO8

Hi, i've got the EXACT same issue with an similar setup on an Evo 8
Did you find the issue ?

Evo2372

iTrader: (1)

I had the same issue bro and saw this on their site Check the vacuum connection. The valve relies on the manifold connection to provide boost pressure to keep the piston shut under boost. If there is a leak or kink in the hose, the pressure will be uneven on the top and bottom of the piston, causing it to open.
My line was split under the nipple coming off the inlet manifold.
just my2 cnts though, how can the tune effect the BOV. love to know.