NefMoto

So I've got a 3" CAI on my K03s would it be wise to go for a 3" MAF or would this be no use and should i stick to the stock 1.8T sensor and housing on my setup.

I'm reverting my car back from alpha-n, BOV. To a more stock like setup with an original DV and MAF. I've got all the parts i need now except I'm not sure which MAF is preferable in my situation.

On a k03 you will be fine on a stick 1.8 maf.

You dont want to big of a maf for your application as you can run into range versus resolution issues...whivh translates to driveability. Granted me7 transfers are 512 pt and not 16 or 32 point so likely would never notoce a differance either way..

Its just good practice to keep effective range closest to your setup.

Thanks for the quick reply, i see. Wouldn't i run into any power decrease considering i now have a 3" intake without a MAF and pushing the K03s to around 1.35 bar?

No. Those power levels aren't even close to justifying a larger MAF housing. Not even close. Look at the compressor map. It really is that simple.

assuming you have M3.8.3 with Gen HFM2 (Limit 680 Kg/h -> 189 g/s),
other than revving the K03 to high with 1,35bar,
there is an measurable edge in reduced pressure drop above 150 g/s
by upgrading to VR MAF.
Just measure your mass flow

Check sensor voltage too if you want. and ko3s wont hold 20 psi @ redline maybe 1 bar ( and prolly out or bad range on compressor map anyway)

Thanks for the replies everyone!


So 3" intake and 3" MAF is useless on K03s altogether. What kind of power levels and turbo would i be looking at when these upgrades become worth it. K04 064 hybrid, GT2871R? I'm asking because I'm still considering a forged engine with a bigger turbo.

Stop thinking in terms of power levels. Look at the compressor map for the turbo you are considering. You should be doing that anyway.

That said, there also intake restriction factors to take into account (as others have pointed out) that are not part of the maf sensor/housing diameter question. That's a bit harder to answer without actual dyno data or a turbo inlet pressure sensor.

Thanks for all the advice!

I've fitted an OEM bosch MAF yesterday, and a proper DV setup and got rid of my forge 004 (as stated in s4wiki lol). (Along with a lot more maintenance)

Now I can finally have a go at mapping it myself. Also, the malfunction in circuit on the 1st lambda resolved itself after getting rid of the BOV which kinda makes sense.

Is it worth using the existing tune as some sort of guidance. For things such as LDRXN curve, KRKTE and KFMIOP for example. After multiple reads of the wiki i have an understanding of what these maps do, but optimizing and changing them is something else.

Sure, as long as each change makes sense to you.