Loosing Boost Pressure

[nemo]

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

[nemo]

does anyone know why this may be happening

[Blue_GTR]

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]

cheers dude ill check it all out, did you get urs fixed? what was the problem?

[Blue_GTR]

Yeah i fixed it. Loose clamp on intake pipe that joins to one of the AFM's

[nemo]

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?

[Blue_GTR]

Could be the problem. Another good way to see if it is an intake leak is to use a smoke machine. If you see smoke leaking from somewhere, there is your problem

[nemo]

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]

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.

[Blue_GTR]

Gotta love the backyard/bush mechanic look

[Brocaine]

It's aluminium too.

Thrifty AND lightweight.

Is there anything the Coca Cola can't do?

[nemo]

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.

[nemo]

ive also got full hks intercooler piping

[MBS206]

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?

[nemo]

am running a blitz duel sbc.

i thought running a turbo charged car with out bov`s can cause the turbos damage when ran at a decent boost level

[gtstee]

in any gear at any speed are the bov opening up on boost?

[Waldo_87]

i also had a problem on my R33, found a bad PCV valve on my charcoal canister it was bleeding air there and doing exactly what your describing

[nemo]

it mainly does it while just crusing along around 80-100kph when i notice it most but yeah mainly mostly just in 4th and 5th

[nemo]

i also had a problem on my R33, found a bad PCV valve on my charcoal canister it was bleeding air there and doing exactly what your describing

were abouts is this pvc valve on ur charcoal canister located?

[nemo]

Does anybody else have any ideas on what my little problem could be??