BOV went quiet after Boost Controller Install

[Onnipotente]

After I installed a manual boost controller(ebay) my blow off valve(greddy type-s) barely makes any sound at all... even at full boost. I have both the boost controller and boost guage tapped into the vacuum hose that goes from the blow off valve to the throttle body. Did the sound of the BOV get affected because I added two T fittings to the vacuum hose or is it because of the boost controller?

 

[ProjectTalon130]

Honestly, I tapped mine off the Turbo itself, its more accurate and probably would have avoided the noise loss, though I don't see that as the culpret. try switching the source for the MBC. Good Luck.

 

[tylerk]

Getting pressure from the turbo compressor housing is NOT more accurate. Refer to "Proper MBC Install" in the Tech Articles section.
http://www.dsmtuners.com/forums/showthread.php?t=105573

 

[Sic95gst]

Getting pressure from the turbo compressor housing is NOT more accurate. Refer to "Proper MBC Install" in the Tech Articles section.
http://www.dsmtuners.com/forums/showthread.php?t=105573

I have a Turbosmart Gated MBC and the instructions from them say that you should not have any T's in the line the pressure source from the turbo goes directly into the MBC then comes out and runs directly to the wastegate. This is how i have set mine up and it works perfect.

 

[Jehu]

Getting pressure from the turbo compressor housing is NOT more accurate. Refer to "Proper MBC Install" in the Tech Articles section.
http://www.dsmtuners.com/forums/showthread.php?t=105573

Why not? Just because the article said so? A boost source is a boost source. At the intake the pressure is naturally damped due to intervening pipe length/IC etc. At the compressor housing the pressure reading is more accurate in the sense that it's what the compressor is seeing at that instant, but because of the lack of damping it will by nature fluctuate more. Technically speaking, the compressor housing is where you want to have the boost source because the feedback is more immediate. This is why most OEM turbos have the boost sourced from the compressor housing. With some MBC's, a damped boost source sometimes helps alleviate boost spiking.

Teeing off a boost/vacumn source too many times is not a good idea. You really want the BOV line to be exclusive. Having an MBC teed into the line, could potentially lead to a slower response at the BOV, especially if the MBC isn't completely sealed.

 

[tylerk]

Why not? Just because the article said so? A boost source is a boost source.

Because you want your boost controller to regulate pressure at the manifold, not at the compressor, not at the intercooler piping, etc.

 

[ProjectTalon130]

no, that is wrong...you are thinking of for a source...that would be correct if we were talking about boost guages..not controllers.

 

[terrible]

Wich is more important, compressor pressure or manifold pressure? I could see either being a good source for diffrent reasons.

 

[4geze63]

after installing my buschur j-pipe I had to tee the line of the bov hose, it made the sound of my bov more fluttery, I like it though

 

[justin_5585]

Because you want your boost controller to regulate pressure at the manifold, not at the compressor, not at the intercooler piping, etc.

Doesn't matter, because you set your boost controler using your boost gauge. So it might be adjusted a few turns less or more in the different respective places, but you still adjust it to x psi based on your guage, and still receive the same results.

-justin

 

[Jehu]

Because you want your boost controller to regulate pressure at the manifold, not at the compressor, not at the intercooler piping, etc.

Think about what you are actually controlling. You're confusing the end with the means. You are controlling the turbo wastegate, you want the wastegate to respond immediately to what the compressor is doing. If you're driving, wouldn't you want your brake to work immediately rather than have a 0.5second lag? You would then set the boost controller to achieve the targeted manifold pressure. This way the wastegate will be able to respond more quickly to transient conditions...

 

[tylerk]

Doesn't matter, because you set your boost controler using your boost gauge. So it might be adjusted a few turns less or more in the different respective places, but you still adjust it to x psi based on your guage, and still receive the same results.

-justin

This assumes a constant linear relationship between pressure at the turbo and pressure at the intake manifold regardless of conditions.

 

[justin_5585]

This assumes a constant linear relationship between pressure at the turbo and pressure at the intake manifold regardless of conditions.

Naturally, but what would alter this? Assuming you have a 1 psi drop from your intercooler, you should see 1 psi less at the manifold than at the compressor outlet throughout the different rpm ranges (slightly less drop at lower boost I believe). I don't know about your tt, but mine doesn't have notches on it for x psi, you simply tighten it to increase boost by increasing the spring rate, and vice versa to reduce boost. My boost guage reads boost pressures at the manifold (atleast off of a very close vacuum line), so
i utilize those readings to determine whether i need to tighten or loosen my mbc. I understand your logic, but given the way a mbc works, providing your boost guage is hooked up correctly, there is no reason to measure manifold pressure as opposed to the compressor outlet when you can adjust your mbc to compensate without any problems, and there is no delay from waiting for pressure to reach the manifold, therefor reducing boost spike. Remember, the factory setup goes from the compressor outlet to the boost control solenoid, and then back to the wastegate actuator. If it was too terribly unreliable they would have run the line from the manifold.

-justin

 

[Onnipotente]

Instead of intalling the boost controller somewhere else, i was thinking about tapping the boost guage to the fuel pressure solenoid. This way there is only one t-fitting (for the boost controller) on the vacuum hose going to the throttle body and hopefully it will sound the same way it did before when just the boost guage was hooked up. Does that sound about right?

Im a little confused with the dispute with the boost controller... instead of teeing into the intake manifold, I should tee into the compressor outlet?

Thanks.

 

[justin_5585]

To set up a mbc, simply take one piece of vacuum line from the compressor outlet (there is a nipple on the elbow where the factory line connected) and connect it to the mbc's inlet. Then take another piece of vacuum line and connect it from the mbc outlet to the wastegate actuator. That's it, as simple and straight forward install as they come, short hoses from the source to the destination = less delay, so therefore less boostspike. As for the boost guage, installation into the vaccum line at the fuel pressure solenoid is the most accurate reading, and to do that, you simply cut the line and insert a t, and then attach the vaccum line for your guage to the t. Hope this helps,

-justin

 

[Onnipotente]

To set up a mbc, simply take one piece of vacuum line from the compressor outlet (there is a nipple on the elbow where the factory line connected) and connect it to the mbc's inlet. Then take another piece of vacuum line and connect it from the mbc outlet to the wastegate actuator. That's it, as simple and straight forward install as they come, short hoses from the source to the destination = less delay, so therefore less boostspike. As for the boost guage, installation into the vaccum line at the fuel pressure solenoid is the most accurate reading, and to do that, you simply cut the line and insert a t, and then attach the vaccum line for your guage to the t. Hope this helps,

-justin

yea thats what im going to do... the instructions that came with the mbc are a little different but i will try hooking it up the way you described along with plugging the vacuum line that goes back to the intake and see what happens. thanks