The last BOV question

[Skerd]

My blow off valve started working out of the blue a few weeks ago. I guess it was just stiff and tight after maybe sitting on a shelf for who knows how long. Now with the Moto-Concept chip installed (Sanj did it in 48 hours) tonight I just increased it it all the way counterclockwise to maximum 30psi. The BOV adjustment instructions say "overzealous adjustment could lead to irrepairable turbo damage".

My question is even at the maximum setting, how exactly does that hurt the turbo? The BOV doesn't make the turbo make more boost. What am I missing?

I increased it the last three turns because it was making the ppphhhtttt
noise way before I intended to shift. Should I shift when the noise is being made (and turbo backpressure alleviated) or should it make the noise BECAUSE I am shifting?

[cnh1990]

It should make the noise when you let up on the throttle when the throttle plates shut on the intake.
Adjust the valve so this should occur. You do not have to shift only suddenly let up on the throttle to vent the bov.

[GUY JOHNSON]

When you hit 6000 rpm and the engine is at full boost and shift that is when you should hear it. If you hear it while boosting it is set to low.

[Skerd]

Thanks. I will keep adjusting.

[cnh1990]

At the low setting it is set to 12-14psi open it up and try one turn at a time and drive. I revolution equals about 2 psi. You may test it by gettin the boost to come up slamming the throttle plates shut after acceration. The BOV should not work during low level boost. I have mine set to work above 5K.

[Skerd]

This weekend I will fine tune it. Just to make sure, when you lean over the engine while sitting in the boot to adjust it, turning it clockwise will decrease the psi setting, right?

[cnh1990]

Well that depends on the way it is mounted. i have seen it mounted two way. So I will answer in a safe way. As you look at the BOV adjustment valve where the small hose hooks up you turn it counter clockwise to increase the boost trigger and clockwise in to lessen the boost trigger. If you are not sure turn the valve full clockwise to set it to the lowest setting then turn it 1-2 complete revolutions to set it to about 12-14.7 psi trigger. DO NOT WRENCH IT TIGHT OR YOU WILL BREAK IT. THE SLIGHTEST BIT OF RESISTANCE AND IT IS TIGHT. Before making any adjustments remove the c clip under the valve and replace it after the adjustment. After several days use you may have to re adjust (counter clockwise) due to run in of the valve that loosens it a bit.
Calvin

[Skerd]

Copy that, over. If with the new chip it makes 14.7 @ 1.25 = 18.375 boost, does that mean the correct amount of revolutions to adjust it should be 3.1875? This would be a 12psi starting point + 6.375 still needed, divided by 2.0 per each full rotation?

[cnh1990]

Well that is correct but you may want to start venting before max boost. The BOV is not supposed to open to partial throttle conditions only when the boost is on the higher side. When the trigger is activated then the BOV will blow open. The trigger will come from the small hose on the adjustment valve and the action to trigger will be sudden lift of off the throttle inducing vaccum. there will be a significant psi difference between either side of the throttle plates when it slams shut prior or during a shift. The BOV will then correct for the imbalance by venting and make a small pachew type noise. Also the 2 lbs.psi is an approximate so it maybe more or less revolutions but is a good starting point.
Calvin

[Skerd]

Thanks. Tomorrow I will adjust it.