Fined for airfilter

Ford_Crazy · 24-02-2007, 06:49 PM

Boys,

My cousin drives a nissan skyline (lame i know) the other day he was fined for having a k&n airfilter (unboxed) and a blow off valve. Is this right? He wasn't defected but just fined, what's the go with the law regarding these items? We are in Sydney so any advice would help.

Thanks

King Nothing · 24-02-2007, 06:53 PM

It's illegal to have an exposed filter, and unless it has air blowing directly onto it its a waste of time due to heat in the engine bay (skyline drivers, but anyway).

Not sure on the BOV but if he has fined him it must be illegal

blueline · 24-02-2007, 07:00 PM

ay ay ay depends on what skyline it is. most r33 drivers i know can be stupid at times but dont put us all in the same basket. us r31 drivers have a bit more of a clue. anyway the air filter has to be 'boxed' or separated from the engine bay or it is a defect. plus you can have a blowoff valve but it cant be vented to atmosphere. thats means it cant go 'woooo-chhh'(lame blowoff impression i know) it has to be plumbed back into the engine.

King Nothing · 24-02-2007, 07:06 PM

: ok fair enough, didnt realise it wasnt an r33. r31/32 drivers can be ok :nutsycuck

blueline · 24-02-2007, 07:08 PM

i was more aiming at the all out 'bag the skyline drivers' thing. i was just assuming it was a r33. am i right ford crazy?

Outbackjack · 24-02-2007, 07:13 PM

Next thing you know, you will be able to be fined for having a ugly girlfreind!!

*rayman* · 24-02-2007, 07:17 PM

They should put that law in place Outbackjack....

**GasoLane** · 24-02-2007, 07:19 PM

Way back when cars had carbys I used to reverse (turn upside down) the 'lid' of the air filter on my 351. This exposed the air filter element (and more air went into the engine.) Back then I was told by a very friendly HP officer that they used to do that to their HP cars but if the engine backfired they caught fire.

This could be the reason for banning exposed air filters?

EL XR8 · 24-02-2007, 07:28 PM

I think the exposed air filter rule, is because, if the motor was to backfire, fuel can travel down and exit via the filter, or blow the filter off, and spray fuel in the engine bay.
Thats what i've heard anyway. Don't know how much truth there is to that though.

Harro · 24-02-2007, 07:32 PM

Exposed Air Filter - Illegal

Blow Of Valve - illegal As it Vents Pure Exhaust Gasses into the atmosphere

Ford_Crazy · 24-02-2007, 07:40 PM

Thanks for the info guys, im not sure what engine the skyline has, it is a 01-02 model i think? So no bof and no exposed airfilter, bloody hell, there isnt much freedom when it comes to modifying cars these days is there?

**GasoLane** · 24-02-2007, 07:44 PM

Quote:

Originally Posted by Ford_Crazy

My cousin drives a nissan skyline (lame i know) the other day he was fined for having a k&n airfilter (unboxed) and a blow off valve. Is this right? He wasn't defected but just fined, what's the go with the law regarding these items? We are in Sydney so any advice would help.

Thanks

Of course we should ask what cousin was doing to attract the attention of Mr Plod that caused the under bonnet inspection.

xagsjoe · 24-02-2007, 07:54 PM

Quote:

Originally Posted by Harro

Exposed Air Filter - Illegal

Blow Of Valve - illegal As it Vents Pure Exhaust Gasses into the atmosphere

Dunno bout your second point there Harro its the INTAKE charge under pressure not the exhaust.

And as for the exposed filter dont tell my local RTA inspection centre as twice they have passed cars for me with exposed filters! One was my XY and the other my old XD

T_Terror · 24-02-2007, 07:57 PM

Thats pretty unlucky.

I dont know in NSW but in Vic you are allwoed to have 1 intake mod so its either a pod filter or an intercooler but not both.

Tell your cousin to look into it cause heaps of people drive around with pod filters and while it may be a defect i dont think its a fineable offence.

Harro · 24-02-2007, 10:03 PM

Quote:

Originally Posted by xyfmtjoe

Dunno bout your second point there Harro its the INTAKE charge under pressure not the exhaust.

And as for the exposed filter dont tell my local RTA inspection centre as twice they have passed cars for me with exposed filters! One was my XY and the other my old XD

Good point on the word exhaust. My understanding is they are illegal due to whatever it is that they vent. could be wrong tho

NC1183 · 24-02-2007, 10:10 PM

Externally venting blow-off valves, on some cars, cause those cars to run rich and not return to idle properly as the MAF has already registered the amount of air going in and told the computer how much fuel to add but when the blow-off vents there's no air to mix with that fuel.

And yeah, HARRO, the blow-off only vents intake air, they are designed to stop compressor stall

brendo83 · 25-02-2007, 01:21 AM

Quote:

Originally Posted by nc006

Externally venting blow-off valves, on some cars, cause those cars to run rich and not return to idle properly as the MAF has already registered the amount of air going in and told the computer how much fuel to add but when the blow-off vents there's no air to mix with that fuel.

And yeah, HARRO, the blow-off only vents intake air, they are designed to stop compressor stall

Externally venting BOV's are total rice anyway, in fact there are big debates over whether BOV's really do anything, theres no evidence to support that they extend the life of the turbo. 300 bucks worth of noise.

xr6donut · 25-02-2007, 01:31 AM

hey guys,info,pics etc on fitting trans oil cooler to my ba mk2 xr6 auto.also looking for a xr8 hood in perth,thanks

atec77 · 25-02-2007, 02:01 AM

Quote:

Originally Posted by Ford_Crazy

Boys,

My cousin drives a nissan skyline (lame i know) the other day he was fined for having a k&n airfilter (unboxed) and a blow off valve. Is this right? He wasn't defected but just fined, what's the go with the law regarding these items? We are in Sydney so any advice would help.

Thanks

Unboxed filters are illegal and a time waste , pop offs which vent to air are illegal , cop it .

Piotr · 25-02-2007, 02:24 AM

Guys to clear the air only oiled exposed filters are illegal. As long as the filter isn't oiled its legal.
Air venting blow off valves are illegal.

You get defected because the cop thinks your car doesn't pass certain ADR's not because it 100% doesn't comply.

Wally · 25-02-2007, 10:50 AM

Quote:

Originally Posted by Harro

Good point on the word exhaust. My understanding is they are illegal due to whatever it is that they vent. could be wrong tho

Atmospheric BOVs have three undesirable effects:

1: Noise
2: Fueling problems on MAF cars (should probably use speed density on turbo engines anyway)
3: Crankcase vent gases are expelled to atmosphere, instead of being burnt

**GasoLane** · 25-02-2007, 11:07 AM

Could someone explain to a simple Truck driver just why a 'Blow off valve' is necessary.

I've been driving Trucks, all with turbo's, for over 30yrs in all engine sizes and HP ranges and have never heard of any engine that is fitted with one of these.

But if these things are as noisy as you guys reckon I'd hate to think of the noise that a 14litre (850 cu in) 600hp diesel engine would make

Wally · 25-02-2007, 11:30 AM

On an engine without a bypass valve, there can be an undesirable lag between during gearchanges and the like. If the compressor is spooling in the high revs when the throttle snaps shut, the boundary layers on the compressor impellor will collapse, flow on the low pressure side of the impellor blade seperates from the blade contour and the impellor free wheels.The stall flutter you sometimes hear from rice mobiles is buffetting of the impellor blade tips from localised high pressure regions:- pod filters allow the noise breakout.

If you fit a bypass valve (BOV) the flow is sustained, even though the turbine is no longer motoring. It prevents flow stall to a degree, so that the impellor can regain compression faster when the turbine starts working again (throttle opens).

The bypass is operated by manifold vacuum. i.e. when the manifold is in vacuum the bypass is open.

Interceptor · 25-02-2007, 11:41 AM

Quote:

Originally Posted by GasOLane

Could someone explain to a simple Truck driver just why a 'Blow off valve' is necessary.

I've been driving Trucks, all with turbo's, for over 30yrs in all engine sizes and HP ranges and have never heard of any engine that is fitted with one of these.

But if these things are as noisy as you guys reckon I'd hate to think of the noise that a 14litre (850 cu in) 600hp diesel engine would make

no throttle body on a diesel is there?

Quote:

Originally Posted by brendo83

Externally venting BOV's are total rice anyway, in fact there are big debates over whether BOV's really do anything, theres no evidence to support that they extend the life of the turbo. 300 bucks worth of noise.

blow-off valves are intended to release excess air pressure between the turbo and the throttle body when the throttle closes during gearshifts. When it closes, the air pressure spikes from the turbo still doing its job, the turbo will get to a point where it cant force any more air in, and stalls, dropping the turbine spee below what is required to make boost. A Blow-off valve vents this excess air pressure either to the intake tract between the turbo and the MAF, or to the atmosphere, thereby preventing the turbo from stalling, and reducing the time for boost to build up to working levels.

brendo83: with some of the older turbo's having ceramic compressor wheels, a BOV will prevent spikes in intake charge pressure from shattering the ceramic fins on the compressor wheel.....

Wally · 25-02-2007, 11:48 AM

Interceptor, you ever carried out a test on how the impellor speed varies between an engine with a BOV and one without? You are aware that work drops with reduction in flow?

brendo83 · 25-02-2007, 12:50 PM

Quote:

Originally Posted by Wally

Interceptor, you ever carried out a test on how the impellor speed varies between an engine with a BOV and one without? You are aware that work drops with reduction in flow?

As I was saying, I am not aware of any extensive research that attributes compressor wheel damage to excess boost pressure during closed throttle.
Theres a lot of theory and heresay, but I'm yet to see conclusive evidence.

theres a huge debate on the ausrotary forums

http://www.ausrotary.com/viewtopic.p...d2cab68e3da295

Read it and then tell me how not having a BOV will cause turbo failure, in fact a faulty BOV can cause turbo failure.

Piotr · 25-02-2007, 01:25 PM

A BOV is fitted for one reason and one reason only onto standard car. To reduce noise, becuase without own you get flutter noise.

F1 Cars never had BOV's
Indy Cars - No BOV
Le Mans petrol - No BOV

Wally · 25-02-2007, 05:59 PM

Quote:

Originally Posted by brendo83

As I was saying, I am not aware of any extensive research that attributes compressor wheel damage to excess boost pressure during closed throttle.
Theres a lot of theory and heresay, but I'm yet to see conclusive evidence.

theres a huge debate on the ausrotary forums

http://www.ausrotary.com/viewtopic.p...d2cab68e3da295

Read it and then tell me how not having a BOV will cause turbo failure, in fact a faulty BOV can cause turbo failure.

Dead link. I don't need to read an argument, because I've been around centrifugal/mixed flow compressors for three decades and done a reasonable amount of testing on turbochargers. I can't tell you that the absence of a BOV will cause failure, just as I can't tell you the presence of one will. Personally I don't fit BOVs on the engines I build, but then I tend to select the right size unit in the first place.

The recirculating bypass valve was something Porsche came up with to get the racing edge. Ask anyone with a BOV, pod filter, etc and they will tell you how they have prodigious amounts of power, even though the real gains are probably imperceptible.

When the compressor hits the surge region, the tip speed is still fairly high and there will be turbulant air between the blade and the diffuser plate/volute. It's those pockets, flow seperation and the collapsing boundary layers which cause some stress on the blades, which translates to aggravation on the shaft, piston and bearings. Floating bearings will tend to cope well with the peturbations.

If a turbocharger is fitted with a BOV, it will continue pumping so long as the rotational speed is adequate. Because it is pumping it is doing work. When the throttle snaps open there will be a rapid increase in effort from the turbine which can translate into high torsional loads on the shaft, because the compressor has been pumping, but decelerating in the process. Without a BOV the compressor will not be pumping and the impellor may even speed up slightly so that when the turbine starts working it does not have a noticeble inertial load from the impelllor to cope with.

Wally · 25-02-2007, 06:02 PM

Quote:

Originally Posted by Piotr

A BOV is fitted for one reason and one reason only onto standard car. To reduce noise, becuase without own you get flutter noise.

F1 Cars never had BOV's
Indy Cars - No BOV
Le Mans petrol - No BOV

If you are comfortable with that, then power to you.

**GasoLane** · 25-02-2007, 06:22 PM

Quote:

Originally Posted by Piotr

A BOV is fitted for one reason and one reason only onto standard car. To reduce noise, becuase without own you get flutter noise.

F1 Cars never had BOV's
Indy Cars - No BOV
Le Mans petrol - No BOV

F1 cars dont have turbos so they probably dont need a BOV

As a matter of interest do cars, like Ford, Holden, Saab, have these things (BOV's) factory fitted.?