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New blow off valve

howhow82
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YBSLO4 Proficient

YBSLO4

Posted
Posted

The screw aloows you to adjust hte spring tension. When you are running more bosot pressure you might find it starts to leak in higher rev's so you want to tighten the srping up, however if you are not running as much boost you want to loosen it off to ensure the BOV will be able to open. However they more adjustable nowdays for rice factor to get different sounds.

YBSLO4 Proficient

YBSLO4

Posted
Posted

BOV"s are illegal for the reason being that they vent blow-by into the atmosphere... yes they can be noisey, yes they cause the car to run richer but its stated that they blow un-filtered air/oil into the atmosphere... stupid really, cos last time i checked the exhaust vented to atmo aswell?? But thats all good its only carbon monoxides and what have you, alot worse than the 'ocassional' mist of oil comin from a BOV.

P.s. Don't forget BOV's if they aren't a good design will cause crappy throttle response, and having a atmo BOV means you must re-spool that released amount of air. They have their pluses and minuses.

Steve Grand Master

Steve

Posted
Posted

As YBSLO4 mentioned BOVs are illegal if they vent to atmo, because cranck case gasses must exit the car via the exhaust, Road Traffic Act 1962 (from memory) in SA. These traffic laws are now pretty much consistant australia wide. So they MUST plumb back to be legal - like the stock one.

As for adjusting BOV, tighter will mean it takes more (boost) pressure for the valve to lift. Yes it will make less noise, but the fluttering noise you hear is air reversing through the compressor, slowing the turbo down (increasing lag) and putting strain on the turbine - this isnt too good for obvious reasons.

I adjusted mine by winding it back until the fluttering sound was almost gone. Almost, because if you wind it back too far, you may have the car stall at idle as it doesnt seal properly. Something to have a play with until you are happy.

Steve Grand Master

Steve

Posted
Posted

The only noise testing I know of that a car needs to be roadworthy has to do with the exhaust, this is done with the car at revs, and the EXHAUST is not to exceed 89dBs. This is conducted with the car at specific revs, not changing gear - so I am not sure how any copper gets away with defecting cars for excessive intake noise (how could it exceed 89dB?) or noisey BOV which wouldnt be measured if a car was being tested for compliance with noise regulations - only for atmo BOV or pod that doesnt comply with ADRs.

I have heard of people claiming to be defected for this, and I would love to know exactly what regutation/act it is that they would be in breach of?

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