Air box mods

[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.