Plumback BOV legality - to airbox or inlet pipe?

[Bananaman]

Evening all,

So, tomorrow i need to decide on where my plumback pipe goes to.. i've always assumed that it needed to be post filter (between filter and turbo inlet) - but it struck me as being a hell of alot easier to do it to the box itself. (And tidier / hidden).

Is the latter legal / engineerable? Keeping in mind that:
-Running MAP not AFM
-Airbox completely sealed, with the only inlet to it being from a CAI pipe from the front of the car
-tri spokes are the sexiest wheel invented

Anyone got experience with this? I'll call the RTA tech line tomorrow but not sure how helpful they'll be. With that in mind i'm talking about in NSW.

Cheers
Bardin

[gztwenty]

I'm pretty sure it must be post-filter. I'm not 100% on that, but at least you will know it's legal as that's how everyone else does it. If you find out, be sure to post it up

[YLD-16L]

I've run it both ways Bardin.

Just run it post filter.

The way it's viewed is that even if it's in an air box that air box is still just a box open to atmosphere with a filter in it (assuming it's a pod in a box?).

I don't know what sort of answer you'll get tomorrow as it's sort of a grey area that you're in.

I'm sure you can plumb it post filter neatly and anyway the trispokes will draw everyones attention away from the engine bay

[Bananaman]

yeah it'll just be a pod in a box. I'm not particularly going to like how it looks either way because its an extra pipe from one side of the bay to the other.. but thats life when you want things legal

lol. i'm so tempted to get myself some 16" trispokes that will clear my brakes so that i can rock up to the KE cruise of 2038 and shit you all off

[Cuzzo]

Where does you catch can vent to?

[oldcorollas]

post filter = a smidge quieter perhaps?
and if you are getting oil into the intake via the turbo, then it will make mess of filter pretty quick.

pre\post filter is only a could of inches of pipe difference?

[wilbo666]

-tri spokes are the sexiest wheel invented

Cheers
Bardin

Your logic does not compute!

Cheers
Wilbo

[Bananaman]

Where does you catch can vent to?

Catch can will plumb back into the inlet manifold or wherever the stock breather goes to? I'd have to look its been a while

post filter = a smidge quieter perhaps?
and if you are getting oil into the intake via the turbo, then it will make mess of filter pretty quick.

pre\post filter is only a could of inches of pipe difference?

ahh... didn't think of this. I figured it'd prob sound pretty similar, but oiling up the filter i didnt think of.. thats less than ideal. That said, surely the bov wouldn't be seeing that much oil? Guess enough to ruin a filter.

Yeah only a few inches, but easier to hide. If it went to the box then it could hug the radiator support panel and in theory have more chance of not sticking out like a sore thumb, that is all

[YLD-16L]

yeah it'll just be a pod in a box. I'm not particularly going to like how it looks either way because its an extra pipe from one side of the bay to the other.. but thats life when you want things legal

Ahhh a crossover pipe like I also ran in the past.

and if you are getting oil into the intake via the turbo, then it will make mess of filter pretty quick.

With my current setup the BOV doesn't leave any oily film but in the past it has left an ever so slight oil film in the area in vented to.

Seems to vary from car to car depending on turbo health.

FWIW my BOV was loudest outside the car when it was plumbed into the box, second loudest was plumbed into the intake pipe and the quietest outside the car was venting to atmosphere strangely enough.

[Bananaman]

I'm having it done to inlet pipe, just because its safer on both counts.. May find out whether its legal out of interest, but i won't be doing it. Picking up the car tomorrow

[MWP]

Youll find the law will say something to the effect of "all air/oil/etc flowing from the compressor side of the turbo must be burnt".
So that basically means the outlet of the BOV must to plumbed post airfilter, pre turbo inlet.

[wagonist]

Pretty much all factory cars run their BOV back to the inlet pipe, so IMHO, that would mean legal.

Most BOV's are simply plumbed in via a 90 degree T piece.
Don't know if it would make much difference, but I've thought about actually aiming it towards the compressor wheel or using a slighter angle such that the "vented" pressure is actually aimed towards the compressor helping it to spool back up again.

[Bananaman]

I've thought about actually aiming it towards the compressor wheel or using a slighter angle such that the "vented" pressure is actually aimed towards the compressor helping it to spool back up again.

Makes sense in theory, but i wonder if it'd make a difference in the real world?

[Bananaman]

Thought i'd might as well post up how it was done:



Could just use some silicon joins for it instead of the rubber thats there now.. not sure if that will be possible in that size

[The Real Roadrunner]

.Don't know if it would make much difference, but I've thought about actually aiming it towards the compressor wheel or using a slighter angle such that the "vented" pressure is actually aimed towards the compressor helping it to spool back up again.

Zero difference to spool and performance but massive difference if the car runs a hotwire AFM as the pulsations when not plumbed correctly will make the AFM send a funny signal to the ECU.

i plumb them in post filter that way it quietens it down and if the BOV leaks under vac conditions no foriegn objects will be sucked in.

cheers
linden