Hopefully, I have a straight-forward question:

Running a Perrin BigMAF intake, how much air flow is the MAF seeing for a given voltage? There is a chart floating around these forums displaying this information for the MAF in the stock housing, and I was hoping something like this existed for the BigMAF.

Take the figures for the stock housing and multiply it by 1.16 (that is assuming the intake is 70mm while stock is 65).

Thanks, man. I appreciate the information.

Make sure you cought my edit, I did some math wrong. Its 1.16

While your math is (at least now) correct(I missed what you had before, but was it 1.08? I did that too), there's a different story as to what's happening in the engine. Due to the neck down immediately following the sensor, certain loads places on the engine will read incorrectly due to turbulence and tumbling in the air stream. So for a particular value in that table, amount of air read may quite possibly be different than the actual amount of air getting to the engine. That, however could be overcome. The real problem is that that seen amount of air, may be accurate under different circumstances while the ECU has no ability to distinguish between the two...

hmm... i've started to compare my BigMAF readings against the chart i mentioned, and i have to say, i'm disappointed with my airflow numbers...

I'm only nipping 4.5v on my BigMAF with a SZ55 (non-fatboy) which, according to the math, is the same airflow as ~4.7v on the stock MAF. i used to hit 4.7-4.8v on the stock MAF running a TD06H/20G :(

Due to the neck down immediately following the sensor, certain loads places on the engine will read incorrectly due to turbulence and tumbling in the air stream. So for a particular value in that table, amount of air read may quite possibly be different than the actual amount of air getting to the engine.

I see what you are saying, but that isn't always the case. If it was a hard bend to change the diameter yea it could make some erroneous readings but I don't think its drastic enough to really toss it into confusion. Also, if he is reading peak values on a SZ55 I'm not worried about turbulance with a 5mm diameter change that is sloped. Its sucking in so much air the sheer velocity won't allow for much turbulence, IMHO. I'm no airflow engineer but I just don't see it happening.

Well, usually it's not at high rpm or max torque. It usually occurs worst low in the rev range when velocity is low. So I wouldn't say it's terribly dangerous, but it certainly doesn't feel right and looks ugly on a dyno...