kevboost7

Just wanted to update everyone. I finally got around to working on the car this year and I did a boost leak test. It seems like i was hooking up the 3 port mac-valve correctly, but there is a massive leak on the rear turbo's wastegate actuator. Where the seam comes together.

Doing it this weekend. For sure this time. Thank you forum gods. And im running map sensor now with the haltech. Still have the AFMs attached to the mushroom dome shaped air filter things

Revisiting this thread again x2... 1 year later. This car has been an ongoing project between life. But, I never removed the re-circ pipe. I know, shame on me. But since then, i took it to get tuned and only making about 280hp (lame) and i'm chasing a boost issue where the car wont boost past 7-8psi. Mac valve installed. Haltech Platinum pro with the map sensor. This is the first time i've tackled the turbo side of things, but i have that side somewhat taken apart to chase the waste gate vacuum lines. And noticed this stupid pipe again. I'm peicing together the puzzle and @GTSBoy mentioned that it was a big vaccuum chamber and said a bunch of car math stuff that I couldn't quite follow the car math (im trying). You guys think this would be the culprit? between rotting vacuum hoses? i'm making a DIY boost leak tester this weekend.

What is PR2?

Did you run the power cables for the mac valve to the other side of the car near the fusebox? Utilizing the stock boost controller cables? or did you run new ones?

@Milhouse Sorry to hear that brother. I never got to the bottom of mine, although i didn't have a large amount of oil like you described. I just wipe it up as best as i can everytime i'm under the car and if i ever have to remove the engine, then i'd find the root cause of this leak. It sucks that you just had your engine out though.

If i did that, how would i run the 2 electrical wires across the other side cleanly? Is that what you guys did?

Some advice, i realized that the cable broke, because there is a big ass washer on the seatbelt thing and it was squeezing the cable causing it to have extra tension. Make sure that big washer isn't sandwiching the cable.

I replaced this cable recently. I purchased it from concept Z performance. And it was a R34 one. Can confirm it works. https://conceptzperformance.com/nissan-infiniti-nissan-oem-trunk-lid-gas-filler-opener-cable-nissan-skyline-r34-gt-r-gtt-84650-aa100_p_56279.php

Is it possible that there is a leak somewhere? or if my turbos are gone? or if my wastegates are stuck?

Not sure why everyone thinks i hooked it up wrong, but Josh is spot on with my vacuum line set-up. The picture of my MAC valve shows the 2 red vacuum lines going to the water/coolant combo pipe and the black vacuum line is going to the last nipple under the plenum. (See below) Josh i have a few questions: 1. You might need to use an air compressor or just blow through the hoses. When it's off it should connect port 3 to port - Can i blow air with my mouth? 2. Put 14 psi into port 1 vacuum line and verify you can hear it venting into the intake piping before the turbos. It shouldn't hold pressure substantially. - Why 14 PSI? I have a compressor, but im not sure if i can get it to those tolerances.

Hey guys, sorry i just got back from my trip to greece. I was able to take a video of everything. See the link. Dont judge me for the spaghetti wiring/hose mess right now lol

1. I thought this turbo pressure line comes from the plenum? Is there a way to get the turbo pressure line near the turbos? 2. How do i plumb in the selonoid in its internal gate so it goes only 1 way?

im about to just drive this car off a cliff I swear i hooked up everything exactly like the diagram. could it be a boost leak?

yessir, haltech platinum is in. I did multiple runs and my manifold pressure (boost pressure) never exceeds 8psi. All the settings are correct. Open boost with 33 hz. No matter what duty cycle % i put, it dosent change boost pressure.

I found it in my glovebox. Looks like whoever owned it before had did some snipping. No clue what it is for. Any ideas?

Alright, i connected everything properly, but my car isn't boosting past 7-8psi. Any ideas? 3 Port Solenoid is working, i hear it clicking.

im talking about a generic diagram. Like this one:

Interesting. Those turbocharged engine diagrams usually has all the boost go straight into the intake valve lol. So i thought they were the same thing.

Does the factory boost gauge pressure = turbo pressure? Couldn't i just T into that line by the firewall? I mean its too late, i already shredded all the skin on my hands, but man.. https://www.gtrusablog.com/2019/06/where-do-i-tap-my-rb26-for-boost-sensor.html

Thanks man. Im in the garage now. Dear god, that last hose is so far back. I forgot how much of a pain in the ass it was to work under the plenum.

Can someone explain what the blue line is then? Green is waste gate. What is the blue? And why is the plenum "turbo pressure"?

@GTSBoy @joshuaho96 Thank you guys, and especially thank you josh for that diagram you made. It is clear for me now. Why does the 3 Port only come with 2 of the barb fittings? I will have to buy another barb fitting now. @r32-25t There are no professionals near me. I am learning, which is important to me and one of the reasons i got this car. And the one professional i took it too was my tuner, who told me to get rid of all the 30 year old hoses and just run new hoses from the wastegates. I felt like there was a better way to do it. Thats why im on here.

Okay thats what i thought you were trying to say. I will give that a shot tomorrow. It just did not seem right, because every diagram i see on the internet has 1 port on the 3MAC Valve with the cap that vents to atmosphere. I'm still confused, on this diagram below with the twins. I thought that the "turbo pressure" line was the blue line. In the RB26, where is the turbo pressure line?

thats literally what i did!