Air box mods

[nissannewby]

Well most of my intake has arrived , need to go to see a guy about the best [most efficient] way to go.
1. 76mm all the way reduced at the turbo to 50mm
2. 76 again and gradually size it down to 63 then 50mm at the turbo
3. is to run 63mm all the way and reduce at the turbo to 50 mm.
Must admit polished stainless looks awesome , plus most of the t bolt hose clamps
arrived too and some special size silicon hose

Option 1 everyday of the week. Keep the pipe as big as you can right up to the turbo.

[nissannewby]

can anyone tell me about the catch can line that goes into the intake hose after the MAF.
is this just recycling fumes from the catch can
the other line goes to the rocker cover
Can it be eliminated and use a tee from catch can to rocker?

You can eliminate and just vent the hose that went into the pipe just after the maf to atmosphere. It is a pollution device though so it should return to a low pressure area.

[threedogs]

Thanks Matt I was going to cap it at the catch can,
Was just down talking to Andrew at On Track, he thinks the theory is right
but what gains I get may be minimal, I do need to buy a Hump hose which I did.
I think in the end Id be happy with a small boost gain,to keep EGT down, plus it looks neater lol
Minimal gains but more efficiency I'll take that

[nissannewby]

You cant cap it at the catch can. The vent line from your rocker cover needs to able to breathe. If you cap the catch can then thw crankcase will pressurise and cause all sorts of dramas.

So what you can do is have your hose from the rocker cover go into your catch can then on the outlet of your catch can just run a length of hose into your chassis rail leaving it open on the end.

[threedogs]

Cool thanks again , now to source some larger IC boost pipes.
they increase in Diam at the IC, they could also be wrapped to keep temps down too
this will replace my OE IC piping

http://www.ebay.com.au/itm/90-degree...item35d53dc5c9
For anyone up sizing the pipes they will need 60mm

[threedogs]

You can eliminate and just vent the hose that went into the pipe just after the maf to atmosphere. It is a pollution device though so it should return to a low pressure area.

had a bit of a think and want it to look the part so
Im going to tig weld a fitting into one of the Stainless elbows
I have some AN 10 braided hose to pretty it up with the right terminals

[Paule]

Hmm, I think it does have to be very similar sized piping, remember your stock maf housing slightly reduces in size where the MAF sit inside the piping to speed up the air flow over the maf sensor, the HPD actually is slightly larger in that same area where the MAF sensor sits in the piping(it is honed out slightly where the MAF sensor sits, allowing more air past the maf sensor and slowing the air going past as well), if anything the HPD maf housing could do with being just a little smaller in that area, it is not 30% bigger BUT allows up to 30% more airflow past the MAF sensor tricking it..

Ideally imo the HPD maf housing could do with only allowing 15%-20% or so more airflow past the maf sensor but if you have a chip it can be used to allow more fuel and get a good air fuel mix going and achieve what your aiming for.

Taking this into account I removed my maf housing and measured it up yesterday, the ID has a 2.5mm tapper in it with it being larger on the in going side. So I chucked it in the lathe and removed the taper. To try and slow the airspeed over the maf as I could only get 14psi, with moderate spool up, before getting limp mode. First thing I noticed was how much smoother it is at idle.(my passenger side airbag used to vibrate). I have uped my boost to 16psi now and have had limp mode once since. I'm gunner take another .5mm out on Monday and see how it go's. Is the hpd housing I'd straight through or tapered?

[Dinger]

Taking this into account I removed my maf housing and measured it up yesterday, the ID has a 2.5mm tapper in it with it being larger on the in going side. So I chucked it in the lathe and removed the taper. To try and slow the airspeed over the maf as I could only get 14psi, with moderate spool up, before getting limp mode. First thing I noticed was how much smoother it is at idle.(my passenger side airbag used to vibrate). I have uped my boost to 16psi now and have had limp mode once since. I'm gunner take another .5mm out on Monday and see how it go's. Is the hpd housing I'd straight through or tapered?

From looking at mine I think it was straight through the taper is on the outside. The area where the MAF is located is thicker. I can check mine on Friday if you need exact.
I am running 17psi now with no issues.
How did the stainless end up?

[SG1]

Taking this into account I removed my maf housing and measured it up yesterday, the ID has a 2.5mm tapper in it with it being larger on the in going side. So I chucked it in the lathe and removed the taper. To try and slow the airspeed over the maf as I could only get 14psi, with moderate spool up, before getting limp mode. First thing I noticed was how much smoother it is at idle.(my passenger side airbag used to vibrate). I have uped my boost to 16psi now and have had limp mode once since. I'm gunner take another .5mm out on Monday and see how it go's. Is the hpd housing I'd straight through or tapered?

Good work, basically that's all the HPD Maf housing is, BUT has slightly larger where the MAF sits, if I was to do it again I would do exactly as your doing and just hone the original MAF housing ever so slightly, not as much as the HPD, but admit since installing the HPD maf housing and air box lid have not had limp mode once but needed a chip to put more fuel in, on a side note I have tried several different psi rating from 14 which was all I could get max before mods to 20 psi and have found that by my gauge 16.5 psi is perfect and has really good smooth power gains with egts in the low 300's at 100k's now, much better than before.

[Dinger]

I have had the same results as SG1.
Zero incidents of limp mode both towing and not.
As I said earlier max boost is 17psi, 10 psi at 100 km/H and EGTs 250c