I am probably missing something here but I suspect you don't need to go wider than turbo inlet...
Throwing out a few chunks of info, questions and ideas, not 100% sure all is correct but I love knowing the maths behind things. Please tell me what you know, this is what I 'think' I know...
Density = kg/m^3 (d)
Mass per unit area = kg/m^2 (ma)
Volume of air = m^3/s (vol)
Cross sectional area = m^2 (xsec)
Velocity = m/s (s)
Air flow formula through pipe with normal air pressure,
vol / xsec = s
Diameter of turbo inlet is fixed and Garrett will tell you what their turbos can achieve. So they know what boost etc can be achieved through this hole...
Xsec is fixed so vol is proportional to s. The maf you buy will have a voltage range 0-5V. If I'm not mistaken maf actually measures s and calculates mass based on other known parameters of system, I.e. Ecu knows the size of pipe that maf sensor sits in.
Let's say maf tops out at 10m/s and reads 5V in 2" pipe... putting same sensor in 3" pipe and pulling same air volume would reduce s and thus lower voltage. V proportional to s.
I suspect taking the sensor out of our standard maf and putting it in bigger pipe would be compatible with programmable ecu, if you can somehow tell ecu what you've done, I need to watch someone programme an ecu to understand this...?
What bhp can Z32, 350z, R34, R35 cars achieve with maf in their standard housing? They all have a fixed xsec which I assume ecu must know to get related V?
Is any of my chat sensible?
the turbo is sucking in air into its inlet , so it must create a vacuum to do this ,and this vacuum must take energy to do so - which is better a long thin pipe or a short fat pipe ?
the maf is a fairly dumb thing , it just heats a wire and it measures the amount of electricity needed to heat it -air passing over it cools the wire and more electricity is needed to warm it up again -this difference is the mass of air fowing over it -thats it other than it knows the temp of the air as a factor in calcs -not that smart
Shaping the air passing through the pipes to the turbo has a benefit but is hard to achieve as the pipes bend and the speed of the air is not constant , you need fast moving air in order to ¨"shape it" and you only get this at high turbo speeds