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Rb26 Vacuum Lines

JU5T1N

By JU5T1N,
in General Maintenance

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Flash89 Mentor

Flash89

Posted
Posted (edited)

the small hose on the plenum, thats where the pressure comes from to open the waste gates, its also with the vaccumm lines that go to the factory solenoid

the way the factory solenoid works that it release the pressure from the waste gates by bleeding the air back into the intake pipes of one of the turbos

so if you are going to have a after market EBC get the pressure from that small hose at the back of the plenum then the line that goes to the wastegates use the the line that was on the standard solenoid. (make sure its the line that goes to the waste gates) the other line of the standard solenoid just goes back to the intake pipe so that doesnt need to be used anymore.

just make sure when take off the hose off the plenum to put the new hose on for the EBC solenoid, block the hose you took off the plenum soo you dont have pressure leak to the wastegates

another way to find out where the lines go to, is to blow air through them, if you have a air compressor

hope it helps

Edited by Flash89
  • 4 weeks later...
xfixiate Rising Star

xfixiate

Posted
Posted

After three degrease routines and poking around with a massive overhead light and a tube I traced all the lines.

News is still breathtakingly odd.

The line that goes from the back of the plenum, and is supposed to connect to the T metal tube line (under plenum) actually goes to a Y fork that has been installed in the std boost controller line at the front.

The line that is in the T metal tube (above) goes nowhere and has a bolt in the end.

The std boost controller lines are plumbed up OK (with the exception of the metal Y fork). So I think I will be getting some odd boost spikes - not a lot of pressure will make it down that tube.

Since I can barely see these tubes, let alone get my fat anglo paws inside the spaces, should I cheap-shot and just buy some tube connectors, or re-tube them all with the proper lines. I'd like to do the latter, but if i'ts going to be a sh!t of a job, I'd rather not start....

Godzilla32 Veteran

Godzilla32

Posted
Posted

Just put it back as it should be, people do things for strange reasons. More than likely at some stage someone has had a aftermarket boost controller attached and they required a direct feed of manifold pressure. Get a mirror to help you see with a torch to shine onto it.

Deren

xfixiate Rising Star

xfixiate

Posted
Posted
Just put it back as it should be, people do things for strange reasons. More than likely at some stage someone has had a aftermarket boost controller attached and they required a direct feed of manifold pressure. Get a mirror to help you see with a torch to shine onto it.

Deren

Couldn't get the hands in close enough to get at the ends under the plenum, so have used a straight connector and some snail clamps.

Changed oil and filter, just need to fit new battery and all ready for rego.

Oh and the obligatory after change degrease (oil filter relocator kit isn't bulletproof for not spilling oil :P )

  • 8 months later...
sshhh Contributor

sshhh

Posted
Posted

Hi I need help,

I have been researching and tinkering with my rb26 and am having trouble locating the rear vacuum line. My engine was transplanted so were kinda trying to figure things out.

I have found the old by pass line and transfered it to my blow off valve, (sard r2d2) which wont open.

Im running an AEM ECU with map, AIT, and boost control. I noticed that the shop that tuned the car used the fuel pressure vacuum to run the MAP, boost gauge, FPR, and used the charcoal canister vacuum to run the EBC.

now following this thread I tried to locate the old boost line behind the head and upon inspecting finding it It had no vacuum. I traced it further to the throttle side and also no vacuum. I think i need to pull down the throttle body to get a closer look but its a real big job and Im not to keen to do it.

How do I locate the rear vacuum line source or stock wastegate vacuum source?

thank you!

andy95'R33GTR Rising Star

andy95'R33GTR

Posted
Posted

ok..

http://www.skylinesaustralia.com/forums/post-a154051-

my problem is these two vaccum lines from the for the boost solenoid is not working, i mean no back pressure? what could be the problem? i just installed the old wastegate lines of the turbos, so i could get back the control of my boost, because im running full boost before....but i want my avcr back...

sshhh Contributor

sshhh

Posted
Posted
ok..

http://www.skylinesaustralia.com/forums/post-a154051-

my problem is these two vaccum lines from the for the boost solenoid is not working, i mean no back pressure? what could be the problem? i just installed the old wastegate lines of the turbos, so i could get back the control of my boost, because im running full boost before....but i want my avcr back...

i have the same problem, im working on the car now i cant seem to find an alternate vacuum source besides the BOV and FPR vacuum.

andy95'R33GTR Rising Star

andy95'R33GTR

Posted
Posted
i pulled out that hose which goes under the throttle body on the inner side near the firewall and its got no vacuum either. i dont understand it!

yes, we need to find another source of vaccum for the solenoid...could somebody here help us about the air chamber under the phelum>?

Godzilla32 Veteran

Godzilla32

Posted
Posted

There are 2 restrictors in 2 of the vacuum tubes on the plenum side of the engine. If left in they will restrict boost to as you say about .7 bar. One is in the short hose that runs from the metal vacuum gallery pipe to the bottom side at the rear of the plenum. It is located where there are 3 outlets hanging under the plenum at the rear. The other is in one of the lines going to the stock boost control solinoid. Note: all restrictors are located by a yellow band marked on the tubing.

Try removing the one near the control solinoid first and test for boost change. From there if there is no change then remove the other also.

Deren

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