Changing MAF Diameter - z32 N62

[amreboot]

Hi All

I have a tune for my z31 that uses a z32 maf and 1000cc injectors.
The tune was done a draw-through setup with the stock z32 MAF housing (3") diameter.

I have recently changed my setup to a blow-through setup and purchased a solid z32 maf housing at 2.75" diameter. I chose the 2.75" diameter so that it directly matches my throttle body.

I understand that there could be a need now to adjust some values to accommodate the smaller diameter.
Going from 71.5mm (2.8") ID to 63.5mm (2.5") ID was a 11.1% change.

Can anyone comment on this setup or give some advice on what I may need to do?



Here are pics of the setup





Here is a pic of the z32 N62 MAF housing

A link to the manufactures website: http://mrpmachineshop.com/2013/01/26/an ... inity-j30/



Thank you!
Alex

[Matt]

You would need to readjust all 64 points of the VQ map and resize the K constant accordingly.

One method is pick a starting load point on the VQ map and then adjust K until that runs right and then adjust all the other points. Do acheive this you need to monitor the AFRs and get them to about where they were previously. It will take a bit of time to recalibrate the curve to a new MAF size becuase the curve characteristics are now changed and there are 64 points on there

[amreboot]

Yeah, that seems to be too much unneeded work.
I will contact the manufacture and exchange it for a 3".
The tune was done professionally and was nearly $650. I'd rather keep it how it is.

Thanks for the feedback Matt!