need help with MAF tube question

[wwaveforms]

I've just about completed my turbo project but need alittle help with the maf. I previously had a turboed sbc in the car with a forward facing throttle body in just about the same spot as the current one, so its allready set up with 3 inch tubing. I have an 09 Avalanch maf and was thinking about taking the insert out of it and putting it in the 3 inch intercooler tube to avoid reducer coulping before and after or switching to 4 inch pipe. The maf has an ID of 86mm and the tube 72mm for a surface area difference of 20%. Would I just reduce the frequency grams per sec by 20% or should I just put the maf before the turbo and deal with the blow off, which in my case isn't very frequent?

[VTuner]

I've just about completed my turbo project but need alittle help with the maf. I previously had a turboed sbc in the car with a forward facing throttle body in just about the same spot as the current one, so its allready set up with 3 inch tubing. I have an 09 Avalanch maf and was thinking about taking the insert out of it and putting it in the 3 inch intercooler tube to avoid reducer coulping before and after or switching to 4 inch pipe. The maf has an ID of 86mm and the tube 72mm for a surface area difference of 20%. Would I just reduce the frequency grams per sec by 20% or should I just put the maf before the turbo and deal with the blow off, which in my case isn't very frequent?

Cross sectional area (A) is given by A = pir^2 = pi(D/2)^2
where D is the MAF housing diameter in mm. (e.g. 86mm, 72mm, etc.)
Your area difference is 30%, not 20%. I would install it before the turbo (suck through your MAF, don't blow through it). Make sure to have a straight section ~4" before the MAF with no transitions to minimize turbulence.