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hi guys i installed a mechanical boost gauge yesterday so i could install a boost controller,

i was hoping that i could run a duel setup so i can run the standard boost then with the flick of a switch i could run 10psi, but after installing the gauge i took the car for a run and noticed its boosting at a constant 11psi !!!! not the standard 5psi.

so i opened the bonnet and looked every were to see if i could find a manual boost controller but there is none, my question is how could my car be running more boost without a boost controller, could it be modify ed or is there something possibly wrong ?

when i purchased the car they said it was stock but the turbo may have been a factory upgrade because the spool up sound is different to any they have had in ?

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ive got a turbosmart dual stage boost controller for sale if you need it. 120 and its yours.

i never knew standard r34's to run 5 psi lol

isnt the reading in kpa?

so .5 kpa is 7psi... as i think 1 pound is 14 psi?

0.5KPA relative is 0.072PSi relative.

they run 5 psi up to 4500 then 7 psi to redline . it might have a r32 actuator on it . or most likely it had had the restrictor removed or drilled out . it the solenoid still plumbed in and wired in?

hi i had a look at the exhaust and i have 3" from the cat back and the cat and back pipe looks like its 2-2.5" ?? this is the best photo i could get with the bulky camera i have .

thanks again for your help people , sorry to start a debate about the standard psi im new to turbos and was told they run about 5psi standard! sorry my bad i was miss informed.

post-70954-1268557529_thumb.jpg

As someone said above, they run 5psi and switch to 7psi higher in the rev range.

That's the standard OP6 turbine housing you have there - compressor housing looks a little bit shiny but could just be nice and clean stock variant. I'd say your actuator has been fiddled with, or you have a leak in the vacuum line running to the actuator.

hey, sorry don't want to steal your thread mate but isn't the stock boost in an r34 gtt up round 11-12 psi? mine is running with no mods and the in car gauge is up there...

from what i have read on other posts its only ment to be 5psi then 7psi ???

unless thats for the r33? so im comfused as well because alot of people will tell you at 12psi your pushing your turbo to its limits and it may fail.

you maybe like me and posibly something has been done to it in japan by a previous owner.

I've seen 2/3 stock R34s on dynos around here and they all ran near 11psi with just exhaust - I don't recall even seeing any sign of dual boost levels, like the R33s have.... though its been a while. I do remember the ~11psi part (with no boost control) vividly though.

ok so should i replace the line ? how can i tell it it has a leak ? would it be louder at spool up ?

No harm in replacing it, it's only vacuum hose - very cheap stuff and easy to replace. You can use leak detector spray?

Yes you can hear a vacuum leak sometimes, which you may mistake for a spooling sound...however it is more than likely louder because you are running 11psi instead of 7psi. Now that people are mentioning it, perhaps R34 do run 11psi standard? They have about 20kw more than the R33 RB25 but I always put that down to the variable valve timing.

Yup mine boosts to between 0.6-0.7 on the standard guage. On a dyno it shows a constant 9psi without any boost control mods at all.

do you have any exhaust mods? that might be the difference? just guessing tho

34's dont run the solenoid like 33's AFAIK

The 34's I have driven have only ever boosted to about .6 max - with no sign of a switch from 5-7psi...

They definitely have a solenoid; You can both see on the gauge and feel the power change on my R34 at 4500rpm (in the wet, I've had it cause the rear end to slide out as the boost increased at 4500rpm).

With a 3" turbo-back exhaust and k&n panel filter, mine will do 0.5bar (7psi) up till 4500rpm, then 0.6bar (8.7psi) to redline according to the MFD.

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