Rep Power: 511

OKKKAAYYY now... i think i'm gonna start saving up for a k20 swap now.. lol.. or at least go with a "custom" kit just using the SF intercooler and a turbo assebly from dezod...

onto the problem..

I got a golden eagle vacuum manifold to organize all my vacuum tubes so i dont have a gajillion tees for everything I need/may need in the future. I drilled 2 holes that I was gonna use (for now) for my boost gauge and BOV. I get it all hooked up nice and perdy and tapped the brake booster line that many have suggested on here as well as the instructions that came with the mani (simply because it was a 3/8" line). I start up the car and I see no problems. I, however, didn't take it for a test drive because I was hella low on gas and I didn't feel like driving around.. lol. Anyways, this morning, I leave to go fill up my tank and wash my car. On the way to the gas station, I notice that my boost gauge was not being consistent with what my VAFC-II read for pressure. Also, I noticed that when I pushed in the clutch, the gauge read went from 20" Hg to 5-10" Hg.

Here are some pics to help you see what I did, and please, PLEASE tell me what I fooked up..

Here's where I tapped the line


Here's the connection to the vacuum mani with 2 lines tapped


The whole setup


Car idle, neutral, no clutch


Car idle, neutral, clutch in

 
Rep Power: 256

i was thinking my map sensor was f'ed because my vafc2 was showing low vacuum. the vafc2 reads the voltage from the map sensor to get a pressure reading. your boost guage is reading actual vacuum. the 2 readings arent going to be exact. your boost guage will be more accurate. hook up a vacuum guage to the intake mani and see what it says.

 
Rep Power: 511

well, Before I installed the vacuum manifold, I had the boost gauge hooked up to the vacuum line that taps into the intake manifold just above the brake booster line and it read fine. At idle, the VAFC-II would indicate -84 KPa (~25" Hg) while the boost gauge indicated about 25-30" Hg.

On my way back from getting gas (after I had noticed the problem), I went full throttle to indicate a positive pressure (+2 KPa indicated) on the VAFC-II, and my boost gauge still indicated 20" Hg until I either braked (where the boost gauge "spiked" up momentarily to ~7" Hg) or pushed in the clutch (where the boost gauge would read a constant ~7-10" Hg).

 
Rep Power: 256

clutch shouldnt affect the reading. something isnt right. i would double check all lines and whatnot. im not sure why the clutch is changing the reading.

 
Rep Power: 511

Yea.. that part confused the crap outta me.. hence why i supplied pics

 
Rep Power: 424

You tapped the master vac on the wrong side of the check valve. The T needs to go on the IM side of the valve, which is under the white clip... feel around in the line, you'll find it.
Splice the line back together, cut the line on the other side and tap into it there.

 
Rep Power: 511

bah... I felt around but didn't feel anything so I figured the check valve was internal to the brake booster..

So.. how does that explain the whole clutch business?

p.s. I was hoping you would answer this question prior to me having to go anywhere.. lol.. +1 to you.. you're my hero.. hehe

edit: if I could.. boo.. lol

 
Rep Power: 511

So, I fixed the problem.. I pulled the tee fitting golden eagle supplied, installed a 3/8" brass fitting used for air hose repair, and tapped the brake booster line after it bends and goes downward. Well, it works like a muthafukin charm! Woo!! lol.. The clutch still causes a momentary spike in the boost gauge pressure and still continues to boggle my mind, but as long as it doesn't hurt anything, it's no big deal. If anyone can give me insight on why the clutch does that, let me know.. Otherwise, this thread can be locked if you uber mod types wish

Oh, and apparently I missed the check valve by just about an inch.. lol.. when I pulled the tee off, I was able to see the blue color of the check valve.. lolo..