BOV Vacuum Source

[SlickPyro]

Couldnt get at the C clip so I decided to take the j pipe off. I went to lowes and got the npt tap and tap holder. then i went to autozone and got the vacuum nipple. I googled what drill bit to use with a 1/8 npt tap and i came up with 11/32. so i will have to grab one from my toolbox tomorrow at work. I also ran the bov vacuum line right to the intake manifold.

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Due to the replies I decided to do it the right way. Why half ass one little thing when I have put my whole heart and soul and alot of money into my laser already. Thanks everyone. I'll post a pic of my completed J pipe nipple.

 

[cjridert1]

Except the consistency will be similar. The only way this would make a difference is if you were measuring your boost before the intercooler. A MBC is a dumb tool, it doesn't care what it gets, it's going to do what it does.

Are you disagreeing by making the same point or am I reading wrong?

 

[SlickPyro]

Yesterday I drilled and Tapped the J pipe. I found online a machinists guide and it said for a 1/8 npt tap to use a Q drill bit I so happen to have the harbor freight giant drill bit set that came with lettered bits. So I drilled an A size hole to start and then drilled it out to a Q.

I then tapped the pipe. I checked many times the fit of the brass vacuum nipple. I tapped until I could screw it in a few threads. I mixed up some JB weld and slapped it on the threads of the nipple and then screwed it in as far as it would go by hand and then cranked it the rest of the way down until it stopped using a ratchet and socket.

I let it sit overnight to let the JB weld harden. Then I installed it tonight.
Here is a pic up close and then with it installed.

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I guess this answers the question of to T or not to T. And it seems that the answer is not to T. Thanks for all the help everyone.

 

[gofer]

... nice clean install and NEVER "T" into the bov, wastegate/boost controller, or fpr vacuum lines to use as vacuum sources.

 

[92AWDHX40]

I founds some aluminum tubing and had it welded, 25 bucks for the job.

 

[dsmvenge]

I assume its bad I have my mbc wg and bov all t'ed to together from the manifold I bought it like that and just put it back like it was

 

[Boosted98gsx]

... nice clean install and NEVER "T" into the bov, wastegate/boost controller, or fpr vacuum lines to use as vacuum sources.

Works for me

 

[SlickPyro]

I had mine T'd all last summer with no problems just a little bov flutter. and i thought it was cool to T the FPR vacuum line for the boost gauge? right?

 

[Boosted98gsx]

I had mine T'd all last summer with no problems just a little bov flutter. and i thought it was cool to T the FPR vacuum line for the boost gauge? right?

Yes, those are both "non-bleed" devices. The reason you don't want the T in the BOV is because of the potential for the boost controller to bleed off vacuum that would otherwise open the valve.

 

[romeen]

Yes, those are both "non-bleed" devices. The reason you don't want the T in the BOV is because of the potential for the boost controller to bleed off vacuum that would otherwise open the valve.

I wonder if this is truly accurate. It seems like the IM and all of it's associated vacuum lines should, in essence, all be part of one continuous vacuum source. So if you bleed vacuum/pressure from one portion of it then it should bleed vacuum/pressure from the entire system and not just the pressure inside of one particular vacuum hose.

I could be wrong, it just seems that way to me.

 

[Boosted98gsx]

I wonder if this is truly accurate. It seems like the IM and all of it's associated vacuum lines should, in essence, all be part of one continuous vacuum source. So if you bleed vacuum/pressure from one portion of it then it should bleed vacuum/pressure from the entire system and not just the pressure inside of one particular vacuum hose.

I could be wrong, it just seems that way to me.

It's accurate.

The smaller the diameter of the "manifold" (in this case, the tube), the more susceptible to leaks the devices connected to it will be. F = Pressure / area. The smaller the area, the larger the pressure required to exert a force. Also means, that a tiny pressure differential makes a big difference.

 

[romeen]

It's accurate.

The smaller the diameter of the "manifold" (in this case, the tube), the more susceptible to leaks the devices connected to it will be. F = Pressure / area. The smaller the area, the larger the pressure required to exert a force. Also means, that a tiny pressure differential makes a big difference.

I understand what you're saying but is it accurate to describe the vacuum hose as a separate space or "manifold" from the IM that it is attached to? In other words, if there isn't a valve or something else separating the vacuum line from the IM shouldn't the entire intake tract and all associated vacuum lines be considered part of a single vacuum/pressure source? Not arguing, just discussing.

OP, FWIW I have a single, dedicated vacuum/pressure line from IM to BOV as generally recommended.

 

[Boosted98gsx]

I understand what you're saying but is it accurate to describe the vacuum hose as a separate space or "manifold" from the IM that it is attached to? In other words, if there isn't a valve or something else separating the vacuum line from the IM shouldn't the entire intake tract and all associated vacuum lines be considered part of a single vacuum/pressure source? Not arguing, just discussing.

OP, FWIW I have a single, dedicated vacuum/pressure line from IM to BOV as widely recommended.

You have viscous forces taking effect in a vacuum line, so yes, it would be safe to assume a vacuum line as being it's own "manifold" as it would take much longer to fill the mass void brought about by a leak.

 

[romeen]

I would think that equalization of pressure in the system would be fast enough to not cause any adverse affects on BOV function but apparently it can (although I don't know how much). But I think I do understand what you're saying Andrew.