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where do i hook up the vacuum line?

sillyme

Proven Member
151
0
Aug 3, 2005
seattle, Washington
i have a vacuum line that connects to the factory intercooler piping but with my upgraded front mount. there's no nipple there for the hose. where is a good place to put it? what would happen if i don't hook up that fitting and seal it off? thanks
 

oldman

DSM Wiseman
9,794
191
Jun 21, 2003
Dayton, New_Jersey
LOL Are you talking about the vacuum lines going in and out of the BCS/MBC?
 

MrBoxx

Moderator
3,727
119
Aug 19, 2005
Midland, Michigan
LOL Are you talking about the vacuum lines going in and out of the BCS/MBC?

I was thinking that, too. Looks like you'll have to drill and tap your intercooler pipes or weld a fitting on.

A picture would indeed help to see what kind of piping set-up you have.
 

sillyme

Proven Member
151
0
Aug 3, 2005
seattle, Washington
there's a pipe with a fitting on it attached to the turbo on the oem setup. on my setup. there's no nipple on my upgraded intercooler pipe. i followed the line and it hook up to the factory boost control solenoid. is there another way to do it without drilling and tapping? should i do two nipples if i do that route since i'm going to install a boost gauge? thanks for the help guys.
 

project_tsi

DSM Wiseman
DSM Wiseman
2,699
116
Sep 4, 2004
Eau Claire, Michigan
The other way to run the line your reffering to is to Tee it off the BOV's vacuum line. It's not as acurate, but many people use it and it works.

However, it is more acurate to have the pressure signal line as close to the turbo as possible, weather it be in the IC piping, or in the turbo's compressor cover itself. In my setup, I drilled and tapped the compressor cover and put the fitting there.
 

oldman

DSM Wiseman
9,794
191
Jun 21, 2003
Dayton, New_Jersey
project_tsi said:
The other way to run the line your reffering to is to Tee it off the BOV's vacuum line. It's not as acurate, but many people use it and it works.
Dan, there are many reasons why one shouldn't tap the BOV line and acuracy is only a small part, the biggest problem is proper functioning of the BOV. The mbc will end up bleeding pressure off the line causing the BOV to open under boost. The situation is made worse if the mbc is a bleeder type which is also a vacuum leak off boost causing the bov to react slower when letting off.
 

MrBoxx

Moderator
3,727
119
Aug 19, 2005
Midland, Michigan
sillyme said:
there's a pipe with a fitting on it attached to the turbo on the oem setup. on my setup. there's no nipple on my upgraded intercooler pipe. i followed the line and it hook up to the factory boost control solenoid. is there another way to do it without drilling and tapping? should i do two nipples if i do that route since i'm going to install a boost gauge? thanks for the help guys.


It'll take maybe half an hour to put a nipple in the intercooler pipe, and if you don't have the tools to do it, you can buy them for cheap and then you'll have those tools to use for any other projects in the future. Or you can borrow from a friend and have some company or an audience while you do the work.

For the second part, the place to tee a boost source for a boost gauge is on the vacuum line between the intake manifold and the fuel pressure regulator, not an intercooler pipe. Here is a little how-to with pictures, courtesy DGajre777. The only thing I would change differently from his is to use rubber vacuum line instead of white nylon line. It's easier to use and doesn't kink or crack. Use a brass barbed fitting on the back of the boost gauge and a regular NPT plastic tee for the line between the mani and FPR.
 

oldman

DSM Wiseman
9,794
191
Jun 21, 2003
Dayton, New_Jersey
sillyme said:
much appreciated. won't drilling and tapping a fitting in the intercooler piping cause a little restriction? just curious
Not if you do it right. Tap it near a flange so you can reach in and grind off the excess fitting thread with a dremel.
 

project_tsi

DSM Wiseman
DSM Wiseman
2,699
116
Sep 4, 2004
Eau Claire, Michigan
oldman said:
Dan, there are many reasons why one shouldn't tap the BOV line and acuracy is only a small part, the biggest problem is proper functioning of the BOV. The mbc will end up bleeding pressure off the line causing the BOV to open under boost. The situation is made worse if the mbc is a bleeder type which is also a vacuum leak off boost causing the bov to react slower when letting off.
Oh Bruce I know its not a good place. I was just letting the kid know his options, he did ask if there was any other way.
 

oldman

DSM Wiseman
9,794
191
Jun 21, 2003
Dayton, New_Jersey
project_tsi said:
Oh Bruce I know its not a good place. I was just letting the kid know his options, he did ask if there was any other way.
Sorry Dan :) , just making sure he understands what he could be getting into.
 
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