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Loosing Boost Pressure

nemo

By nemo,
in Engines & Forced Induction

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nemo Contributor

nemo

Posted
Posted

I recently had the turbos changed on my 32gtr to garrett bb turbos and now when driving at around 80-100kph i can hear a noise as if the bov are opening and closing slightly but i had new ones put in with tighter springs and it still seems to do it and when its happening if i put my foot down its like i got no boost pressure and its like driving a n/a car, has any one had the same issues that could help me out.

cheers

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Blue_GTR Enthusiast

Blue_GTR

Posted
Posted

Had a similar problem recently

Check for boost leaks, you must be losing pressure somewhere try checking the following

-Intercooler piping / clamps

-Intake piping leading to turbos / check AFM's aren't loose

-Check there is no vaccum hoses loose.

Make sure all clamps are tight etc. And no loose vacuum hoses

nemo Contributor

nemo

Posted
  • Author
Posted

i pulled my air flow meters off to get more room to check few vacuum hoses and noticed that one of them was missing a o ring on the side they bolt to the air filters would this possibly be the problem? ive ordered a few but wont get them for couple days, are they really needed?

nemo Contributor

nemo

Posted
  • Author
Posted

Ive just replaced the o rings on the air flow meters and tightened all the hose clamps and vac clamps i could reach and still the car seems to do it, do you have any others ideas of what this could be?

could it maybe be the dump pipes not flowing enough? or may be the acuators set too loose and not coping with the extra pressure, cos there the ones off my old turbos which were only the old bush bearing type

Brocaine Community Regular

Brocaine

Posted
Posted

Anything pre-turbo is not going to have this effect, so it's probably not going to be your afm's or the o-rings on them.

If you've still got factory rubber intercooler piping, check over that. You may have a leak there somewhere.

Failing that, block off the BOV's and see if it makes a difference. I blocked mine off with cut up bits of coke can. Hooray for improvisation.

anagtrfix6.jpg

nemo Contributor

nemo

Posted
  • Author
Posted

but wouldn`t blocking of the BOV`s cause unwanted pressure to be forced backwards into the turbo causing the compresser wheel to spin backwards? but when i changed my BOV`s we put race spec springs in them which were almost double the strength of the original ones and didnt change a thing.

MBS206 Grand Master

MBS206

Posted
Posted
but wouldn`t blocking of the BOV`s cause unwanted pressure to be forced backwards into the turbo causing the compresser wheel to spin backwards? but when i changed my BOV`s we put race spec springs in them which were almost double the strength of the original ones and didnt change a thing.

NO!

The air going backwards CAN'T spin the turbo backwards due to the design of the compressor.

The air going backwards applies ZERO force on spinning them backwards.

No BOV DOES NOT force blades to go "backwards"

What boost controller are you running?

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