293 replies to this topic

[WillC]

OT a bit but, can someone let us know what the applications of silicon can be? I know I cannot be used for radiator hosing because of the stuff being porous but what about boost and vaccum lines ? is it because the pressure is low enough to not make a difference?

Also I know you want to figure out the problem yourself but man have you mechanic spend some good time under your bonnet and find out the problem.

[Mbooma]

Well a small update

I still hav boost but its not working correctly an i spoke to my boss as he has a twin turbo rx7 told him about the issue an he said he had a similar issue an i told him about how i think it may be sumtin wrong in the pandora box an he laughed an called it a rats nest long story short he knew that because his car has one aswell an he had to change 3 solindoids to fixed it an now runs great so i will go through on green plugs while they are clicking an clean them out with UEC an go from there but as my first thought of it having to be eletric it seems to be the most reasonable reason.if its a solinoid ... so ill give that a go and keep u all updated

[Mbooma]

Also just quickly wen my 2nd turbo starts spuling its REALLY LOUD is that nornal?

[migoreng]

Dunno. I dont even think my turbochargers can be heard..(thats compared to the typical skyline/silvia)...

maybe youve got a boost leak?

[Zac]

I can almost always hear both my turbos spooling...

[TSG]

I can hear my secondary on occasion when it activates. There is also a light whine off throttle on the freeway, but it might be unrelated.

 

I've heard mine make a chattery whine under load, but not since the airflow issue.

 

Record and post the noise if its audible, someone might know what it is.

[Jimbo]

I reckon it might be the intercooler valve being sticky. Primary boost is just pissing back through the secondary... hence no boost. Which may mean the vacuum tank is having dramas.

[Tim.]

I reckon it might be the intercooler valve being sticky. Primary boost is just pissing back through the secondary... hence no boost. Which may mean the vacuum tank is having dramas.

 

Although the valve usually has a constant feed of oil from the "intercooler catch can". Because of this, I find that mine's always silky smooth

[migoreng]

Regarding boost/ping problems, has anyone tried using Octane booster from Nulon and other brands? Wynns, etc? It claims to increase octane by about 2.5 numbers. I always use BP Ultimate 98 fuel.
 
What about Subaru injector cleaner? I have never used it since I bought my car a year ago (25,000km ago)
 
Upper engine cleaner doesn't smoke much at all...Just a 1 metre puff for 2 seconds so apparently my intake manifold is clean...i'm not sure if I should even use it every 10,000km..maybe stretch to every 20,000km?

[WillC]

what type of access do you have to tools and what type of downtime are you able to deal with? I mean you can try take things apart and inspect them yourself. exhaust turbos intake, intercooler, sensors are all doable.
For sensors eg. o2 and crank/cam angle maybe you can borrow one off a working subaru for testing then put it back. 1 part at a time. It will take time but you will get there. If all sensors are good them you will definitely know it will be heads or internal.

[Tim.]

Without a video clip or some hard facts/numbers not just "doesn't boost" or "now boosts but makes a noise", it will be incredibly difficult to diagnose. Heck they are hard enough to troubleshoot when they are in front of you let alone across the internet.

[Robbks]

it's not a sensor or engine issue.
it's vacuum/ solenoid/ changeover related.

Step0
Refer to step 10

step1
remove intercooler and check the pipes and connections are in good order and that the ICV works
Check your BOV is not leaking/ block it up temporarily
While TMIC is off, inspect the intake pipe for cracks/ leaks and ensure all breather pipework is in the right spot and good order and the PCV is operating correctly

Step2
remove each and every vacuum line between the BBoD and other components one by one and clean/ check/ replace them as necessary. making sure you replace any restrictor pills

Step3
remove the BBoD and clean all the solenoids, their vents and lines one by one. 

Step4

put all that crap back together

Step5
remove the boost control lines at the Prmary Turbo and plug them up (temporary)

Step6
fit a piece of vac hose between the compressor outlet nipple and wastegate actuator to give you wastegate pressure boost control (7/9 psi)

Step7
Reset ECU and test the system

If you still have issues then move down the list here
Step8
Block up the Secondary BPV. Really it's 99% useless anyway
test

Step9
Check operation and adjustment of ECV. It may not be tight enough causing exhaust gas to divert into the secondary at all times. 
you'll eventually get some boost at around 5000rpm if this is stuck open

Step 10
Convert to single turbo.  
IF you like pain and poor performance, go back to step 1

[Mbooma]

Look id love to do single turbo but i dont hav the time or knowledge nore the funds to do it an i understand how hard it is to know wat im blubbering about here apose to being in front of it but needless to say ill be at the next harrys meet so if any of u are there feel free to come shove ur head under the bonnet untill then ill start by replacing all vaccum lines and cleaning out pandora an go from there

[Robbks]

There are a few other mods you can to do simplify the system.

the ECV has two ports. A top port and a bottom port. you can effectively remove the two solenoids and vacuum lines going to the top-port. and plumb it in here near the secondary BPV
it works 99.99% the same, but removes a whole heap of garbage from the BBoD and engine bay

The ECV Duty Solenoid, the line feeding it and the restrictor pill has a tendency to clog up and it blows the ECV open early, resluting in dodgy boosting
It is still pulled and held open by vacuum from the tank, when the ECU tells it to changeover

 

 topport.JPG   90.87KB   22 downloads

Essentially, everything marked in red can be disconnected from the vacuum system. (solenoids need to be connected to ECU or bypassed with resistors)

 

 TP2.JPG   164.11KB   4 downloads


SO now with all that junk bypassed.
and the top port plumbed into the line that feeds the DPS (this line ONLY sees boost once the ECV is open and the Secondary BPV closes)

Here's your new simplified system

 

 TP3.jpg   142.84KB   3 downloads


 

[Robbks]

See the top photo. there's a BIG vac line running from the top port of the ECV (big round silver thing mid left of the photo)
that loops back to the right and TEES into a smaller line.

that 1ft piece of hose replaces two troublesome solenoids.

there's a heap of these writeups on RSLC from Myself (username Rob) Billsy and TassieTT.

What you also need to do is adjust the ECV rod length properly so it opens soon enough, but not too early

 ECV.JPG   29.2KB   10 downloads

if you look at the rod going from the ECV actuator to the ECV itself (in the Secondary up-pipe) it has two 10mm lock nuts above a LONG flat-sided section.

​-loosen off the lock nuts

-you need to warm up the car and have it idling.
-you then need to turn the adjuster part (flat sided bit) to lengthen the rod (which opens the ECV) until you hear it rattling,
-then tighten it again about 2 full turns.
-do up teh lock nuts and test
this will put enough pre-load on the actuator so that it's held closed, but once the system gets sufficient exhaust flow it will start to creep open slightly and allow the "pre-spool" to begin on the secondary (the whole bypass above is bypassing the pre-spool system which does bugger all)

if it's too loose, it will blow open too early and you'll get erratic boost, too late and it won;t open soon enough, making the VoD worse.
Mine was set perfect after a little tuning that it would give an almost seamless transition.
 

[Tim.]

So no boost spikes once you remove the ECV duty solenoid? The system uses the ECV as a wastegate of sorts to manage boost. That would be the only downside to this mod that I can see.

But hey any solenoids and vac lines that you can remove without causing other issues sounds like a good mod.

[Mbooma]

Yea its all good an yea would be amazing stuff if i knew wat uz were talking about hahaha remember im a mass noob wen comes to this systwm haha an there is so much reading to do lol in saying that id love to o this mod but dont inderstand wat u said is there a link to a diy for that bypass thing hahahaha

[Jimbo]

Rob, i was actually going to suggest your trick. Just before i sold my GT-B the BBOD chucked a hissy fit. Got on the blower to Rob for this sneaky trick and had zero problems. Infact after this mod it felt alot better..