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South East Area Rep
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Discussion Starter #1 (Edited)
I was reading on here the other day about earthing to kill the second stage boost,when today i looked under the bonnet to have a play when i find no vacuum hoses attached to the solenoid!

What's happened here? now im not the most mechanically minded bloke in the world but i cant believe i didnt see this before.
But what worries me is there's no vacuum pipes going to that solenoid,it's bypassed completely and im sure someone said that could confuse the ecu?
How? and why?
Has anyone else found this before?
I've got no aftermarket electronics controlling anything yet.

Is this fine like this or is it gonna cause probs?:confused:
 

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South East Area Rep
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337 Posts
Discussion Starter #4
The actuator's standard.
Looks like whoever put the blue hose on did the bov too at a guess cos it's blue hose there too but got recipts etc for that being fitted by a well known skyline tuner.
So if they did do this too why not cover solenoid plugs or disconnect it?
 

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South East Area Rep
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Discussion Starter #5
Yeah manual boost controller would make sense,but there aint one if u look carefully it just looks like the small vacuum hoses have been bled into air intake hoses at different points.
 

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AKA RSP
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4,762 Posts
If that blue pipe is just going back into the intake it will run higher boost as it will be a constant bleed. Is there a restrictor in the pipe as well?

Richard
 

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South East Area Rep
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Discussion Starter #8 (Edited)
Yeah it looks like it does go back into the intake and i cant see any restrictors.
It pulls fine and seems smooth all the way round,when i floor it the factory boost guage goes about a needles width over the halfway line between 0 and +7 if that can help? is this too low/high? sorry im a novice.

My main concern is there chance that something could go wrong?
Heres a few more photo's hope they can shed a bit more light but hope you guys can help? cheers.
 

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boost

It sounds to me like you are not getting full boost. If you are right in saying that the needle on the boost guge is only reaching halfway between the 0 and +7. I have a secondary guage fitted to mine and looking at it while driving, when your guage reads the halfway marker you are only getting somewhere in the region of 0.4 - 0.5 boost.
 

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South East Area Rep
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337 Posts
Discussion Starter #11
Ok so are you getting the 0.7-0.8 over the 5000rpm mark?

Iv'e just taken the car out and it definately does'nt go past halfway between 0 and +7 with o/d on or off as its auto,and over or under 5000rpm does'nt make a difference.

My mate has a manual thats std and with a seperate boost guage his stays at the same mark and reads 0.4-0.5 bar too even over the 5000rpm mark so wheres the 0.7-0.8 bar come from?Just earthing the solenoid?

Do i reconnect the hoses and if i do which hose too which lug on the solenoid?I presume the blue hose off the t piece to solenoid then another hose off the solenoid back to the t piece?
 

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KRAKEN,
I took a look at my boost solenoid tonight after following the various boost threads & guess what! I've no hoses on it either.
The hose that went to the air intake side of the intercooler is still connected to the intercooler pipe but is blanked off with a screw & a tiewrap!!
The thicker hose from the +ve pressure side of the air intake goes straight to the actuator with no tee.
From reading a few of the other threads I'm assuming this is giving me single high stage boost. (This is also assuming the restrictor is still inside the pipe. You can't see it from outside)
I agree with skylinegts33t & think that you are only getting low boost, as you have a permanent bleed hose to the -ve pressure side of the air intake.

However I can't recall seeing my std boost guage reaching 7, so i may not have the restrictor in the pipe.
To be honest I've only had the car a month & been concentrating more on the road than the boost guage when flooring it. Plus my rev counter doesn't work so I can't tell at what revs the boost comes in exactly.

Perhaps someone more qualified can confrim this.
 

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there r two methods of getting a permanent 1 stage boost ,instead of 2 stage 1 method is to ground the boost solenoid another .the second is to by-pass the boost solenoid which looks like whats done 2 your car,hence no pipes on the boost solenoid,
i wouldnt really take the standard boost guage as gospel ,mine never goes anywhere near the +7 ur better off get an aftermarket guage,it ll give u a true reading off ur boost
 

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South East Area Rep
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337 Posts
Discussion Starter #15
Ok think im getting somewhere now?
Std fitment from what i gather is,Off top of boost solenoid,pipe goes down to intercooler pipework.
Off bottom of solenoid goes to T centre,left of T goes to top intercooler hardpipe,right of T goes to actuator(if looking from n/s wing).
There is a reducer in this part(mine is in the short piece on left between T and top hard pipe) i think this has to be between here and actuator?
But on closer inspection where the blue pipe has been bypassed from solenoid to centre of T it also has a reducer in it! now the thing is does that need to be there?is this taking on the part of the std boost contoller?and if it is,does this class it as a manual boost controller of some sort as it's got to have been put in when bypassing the solenoid.
Now if you change the diameter of the reducer in the blue pipe would that change the level of boost?Could this be why the guage only goes to halfway between0and+7?
The thing is when i changed it back to how it should be(blue pipe to top of solenoid bit of pipe off bottom to middle of T)the guage stayed just below the halfway mark until it reached 4500-5000 then moved up to halfway!Which would possibly mean thats 1st and 2nd stage boost?with the restrictor in the blue pipe still in situ.
So it looks like it's relying on a reducer in a bit of pipe coming up from that intercooler piping that seems to work, but im not sure on that!
Looks like im gonna have to get a secondary guage to be certain and a decent boost controller,take it somewhere to be checked and 100% happy.
Any suggestions/critisism on this would be great cos it's doin my head in!!!!:shakehead:
 

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This is the standard pipework for the solenoid.
You are correct in what your saying regarding the pipework although the restrictor should be in the pipe between the tee piece and the top intercooler pipe.There should only be 1 reducer in amongst all this pipework.
IE HERE
 

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Now if you just want to achieve the high boost to do away with the 2 stage boost.....
Find the black wire on the boost solenoid and scotchlock a connector and piece of wire to it.The other end of the wire you put to earth/negative (-)

Like in this picture.Its not the clearest but its the yellow wire thats been added.
Hope that makes sense to you.Sometimes its easier just to look at a pic to see how its done.!
 

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"The thing is when i changed it back to how it should be(blue pipe to top of solenoid bit of pipe off bottom to middle of T)the guage stayed just below the halfway mark until it reached 4500-5000 then moved up to halfway!Which would possibly mean thats 1st and 2nd stage boost?with the restrictor in the blue pipe still in situ.
So it looks like it's relying on a reducer in a bit of pipe coming up from that intercooler piping that seems to work, but im not sure on that!"





YUP thats the correst way and that would be running 2 stage boost correctly.
 

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South East Area Rep
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Discussion Starter #20
Iv'e got the restrictor in line (std black pipes)as circled above,so if i replace blue pipe with a piece that aint got another restrictor in it then connect it up as std it will have std 2stage boost.
So why would someone bybass the solenoid but then put a restictor in that pipe to get the lower boost constantly?pointless?!So it obviously needs a restrictor in it to make pressure to bleed into line.
I reckon that they had done this to get full boost all the time but,a,the restrictor may be too big?,b,it is working fine full boost constantly n my dash guage aint accurate enough?which i think is true,so until i put a secondary boost guage in il never know,so im gonna order one now and when iv'e fitted it il change things about and post results.
 
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