Cone or airbox? Why does cone cause problems?

[LHD_Kid]

I have put this in the general forum as I was just hoping for a general discussion and opinion session...

Standard 3B airbox gets removed and replaced with a decent quality Apexi dry filter cone, decent heatshielding and reasonable cold air intake sorted...
Why does the car suddenly keep cutting out with overboost protection?

(This is absolutely not heat soak related....)

Apexi cone removed and replaced with complete standard 3B setup again, works perfectly with no overboost protection cutting in....

Any ideas?

How do other people run cones, or other intake upgrades?

Chris

[porkkis]

In the original airbox there is a turbulence preventive cross plate. That enables the MAF to read correct values.

With the cone filter the air flow is not laminar and your MAF measures too much air because of turbulences. This makes your car run overly rich and also makes the ignition advance too low.
Usually the effect is the opposite: less air is measured and car is running lean and too much advance causing an obvious pinking risk.

So that's not overboost protection but a protection against boost leaks when too much air is measured in.

[LHD_Kid]

Hmmm, I noticed the cross plate,... so what is the answer then?
If you use a Dahlback (or similar U bend after the filter, would this "straighten out" the flow before reaching the MAF?
I can understand it if you bolt the filter straight to the MAF, but with a link pipe...?

[newsh]

This is really strange and interesting.. I guess it could be re-mapped.

[porkkis]

You can't guess or estimate how the flow goes. Manufacture some kind of a cross and try it. I bet it works a treat.

[LHD_Kid]

So, what about using the one that is part of the existing airbox? I guess this would mean that I cannot put it back again after I use it though, so would be a one way trip....
I think I will have a go at this, not just for my sake, but for others too.... Why am I the only person this has happened to?
Beats me... but I'll give it a go...!
(Although I read a post from Stevieyid - he also had problems with an Apexi)

[kwlw]

So, what about using the one that is part of the existing airbox? I guess this would mean that I cannot put it back again after I use it though, so would be a one way trip....
I think I will have a go at this, not just for my sake, but for others too.... Why am I the only person this has happened to?
Beats me... but I'll give it a go...!
(Although I read a post from Stevieyid - he also had problems with an Apexi)

Mmm, this may be the answer. I'm running Apex'i with pipe adapter which contains cross inside . It's from S4 original airbox. However I still think, that there can be leak in the intake somewhere...

I see no reason to butcher 3b airbox, maybe you can find something similar from another airbox in the scrapyard if you want to try.

Sau
P.S. Locally in the electronic shop we have such thingys:

http://www.evita.lt/det-938-product.html

I would take two sheets of alloy, make "rails" with smal saw, and push them inside. to try. Maybe your local shop has them. They are called audio systems breathers. BTW who made an Apex'i adapter for you ?

[porkkis]

The part can be taken out of a 3B air box without breaking anything. It may be tight, but it's still a separate part sealed by an o-ring.

[LHD_Kid]

ahaaaa...... thats the answer then carefully remove 3B box cross...
(I made my own adaptor from Aluminium...)
This has to be worth a go....

[ericd]

I'm still a wee bit confused by this sorry, but with reference to the cross plate, if the MAF still has the mesh on the Filter side , how is a cross plate or any other pipe work gonna influence the flow drastically when it has to pass thru the mesh last before it enters the Maf ?, or is the assumption that the mesh has no relevant influence on the flow entering the Maf ? Or maybe I'm confusing myself on this...

As far as I know a lot of people are running cone filter without a cross plate and without problems, usually the coupling hose length between filter and maf is an average 76mm , like the one in the pic below


tn_dscf0284.jpg


b.t.w.
On the aby box I think you can remove (pull out) the cross plate assembly, but the cross itself is moulded into the surrounding plastic cylinder

[Bibby]

I can't say I've experienced problems with the Dahlback u-bend and filter assembly.

[AAH!]

I can't say I've experienced problems with the Dahlback u-bend and filter assembly.

Same here.

[quattronutter]

i have had several s2,s with cones,none caused any problems apart from the hose splitting where its clamped to the turbo intake causing poor running, due to the weight of cone filter not being correctly supported..

[porkkis]

Great, you all are running on same chips as lhdkid. Great.

[kwlw]

Great, you all are running on same chips as lhdkid. Great.

I'm running stock. So it turns to be the same (as far I understand lhdkit hasn't made a repam yet). And I also have a mesh screens of MAF (which I think should deny turbulence effect).

Sau