Can't hold +8psi [SOLVED]

[Legnooms]

So I am new to working with turbo-chargers, I have some experience from the turbo diesel however never with anything performance oriented.
My legnum (1998) has a MBC and boost gauge, at lowest settings MBC im getting about 7psi at 3500RPM 4th gear and it won't go any higher.
At max MBC I can sometimes squeeze out an 8psi.. I've dialed everything back to min. because I feel like there must be a leak somewhere that won't hold more than 7psi and when it hits 8psi its probably producing a shit load of work but can only hold 8, is that a reasonable deduction?

Anyway,
I'm going to replace the BOV and hopefully that will fix it, i've replaced vac lines from wastegate->MBC->Inlet because they were a bit dodgy but no effect.
Any suggestions on where I should look for other culprits for the low boost?
Also recommendations for what BOV I should replace with it?
Thank ya

SOLUTION:
Blow off valve pressure line was blocked, boost not assisting to keep the B.o.v closed so it would simply act as a wastegate at the BOV spring pressure.
Solved by bypassing hardlines/unblocking them with wire/cable

 

[pretzil]

Replace with a metal evo 7,8,9,10 bov. It fits exactly and will hold all the boost you want to run.

How did you fit the MBC? I've seen more than enough where people have only fitted it to 1 turbo

 

[Legnooms]

From intake->MBC>vac line in depths of hell.

I was thinking about putting a dual port bov.

 

[pretzil]

Okay, at least the mbc is fitted correctly by the looks.

Any bov should work better than factory but the cheapest and best performing one is the OEM evo ones, it's up to you if you want to spend 3 times as much for adjustable phshhhhhhhh noises.

 

[Legnooms]

Yes its plumbed between the intake and both wastegates.
Eh dualport sounded like fun, never had a turbo to go pshhhh with then I can just switch it back to recirc.
I've had a few people try to convince me that atmos vent can give better spool up. From reading forums here though I was thinking an evo 8 bov.

 

[NuffNuff]

In my experience it's almost always the hot side cooler pipe. Undo the clamp and reseat it and tighten again. Worth a shot

 

[Legnooms]

Hmm, well I found this on the bottom of the intercooler, some kind of plastic moulding shit which does NOT inspire confidence... On **driver. Side (hot side?)

 

[NuffNuff]

hahahahaha

is that JB Weld?

 

[Legnooms]

yeeeeeeep oh lawdy. Ah well at least I don't have to feel guilty for $pending on a new intercooler as well its classed as a repair not an upgrade/mod now

 

[NuffNuff]

HDI GT2 time buddy, thats hilarious

 

[naughtika]

you can see their finger print in there too.. maybe do some forensic investigation to see if who put it there

 

[pretzil]

Good excuse to upgrade to a tube fin intercooler. Is it PFL or FL?

 

[Legnooms]

Its FL, seems the HDI GT2 is where its at anyway

 

[Gav]

Its FL, seems the HDI GT2 is where its at anyway

It's a good upgrade. Will handle any power you throw at it

 

[Legnooms]

I am feeling quite overwhelmed by the whole selection and processes behind this haha
Im guessing this is a knock off of the HDI?
Or is This what i'd be after? :S

 

[Gav]

I am feeling quite overwhelmed by the whole selection and processes behind this haha
Im guessing this is a knock off of the HDI?
Or is This what i'd be after? :S

Similar. Will still be a huge improvement over what you have now.
Ivan used to sell a heap of parts for legnum's like intercoolers and silicone hoses.
I believe I few members are running this cooler

 

[NuffNuff]

http://www.ebay.com.au/itm/232477533192

And a set of Chinese eBay hot side cooler pipe will suffice

Prices have gone up heaps I remember paying 450

 

[Legnooms]

Okay, got back from rwc just bulbs, inner rack and a CV boot

I was thinking about the IC and how its probably leaking all the boost and made me wonder if it would cause the car to run mildly rich and at poor economy (got 13L/100 with gentle driving mostly 100+ boost @5-6psi)
If the boost can go over 8psi its because at those pressures its like a reverse vac leak so I'm losing metered air?? Even at lowest set MBC I imagine its loosing air. Thoughts?
Will def. Document after IC and BOV replace

 

[Gav]

13L isn't that bad here is my fuel log

 

[Legnooms]

Well I guess that's not too bad then, just expected less on 5psi with very gentle driving all highway kms.
What app/product do you use to track this Gav?

Tim