Banks Performance Claims That Measuring CFM Is Wrong

[FlyboyS4]

I came across the video (infomercial?) below from Banks Performance and thought the company is doing a real disservice to consumers that are interested in the subject of flow benches.

Briefly, they assert that flow benches that report CFM have been obsolete for decades, attributing this to the widespread use of forced induction, that reporting CFM is a flawed premise, and that benches that still report CFM are no longer relevant.

Their claim is that mass airflow is what matters, and they show how with the help of a product they are selling you can bring your flow bench up to date to report mass airflow.

I believe this type of misinformation is damaging because people unfamiliar with the subject will take away from the video that benches that report CFM are flawed.

https://youtu.be/VUCo3REGrLE

[Brucepts]

Watched this "advertisement" video a few weeks back and all they were doing in my opinion was advertising their gauges. Turned their SF flowbench into a big air-mover for a mass airflow style flowbench.

Same calculations can be done with some extra readings from some sensors . . . then you can output all those readings and read what ever you would like.

Could it all be done with an Arduino?

Might be a team working behind the scenes on a project just like that, keep watching the forum

[FlyboyS4]

I do quite a bit of product comparison tests and sellers of products that don't flow as well as their advertising implies have downplayed flow tests. That's what brought my attention to the video, a vendor claiming that CFM measurements don't mean very much, and they referenced the Banks Power video as evidence.

I didn't know anything about Banks Power, but I was aware of the brand, after seeing the video I'm disappointed with them due to the misleading information they gave.

[Tony]

CFM corrected to "standard sea level pressure and temperature" is the same as measuring mass flow in every respect.

Raw CFM numbers only become irrelevant if the conditions under which they are measured are not defined.
It should be pretty obvious that measured exhaust flow in raw uncorrected CFM will be a lot higher than induction flow, because of the heating and expansion involved.
But allowing for the small added mass of added fuel, mass flow out should be the same as mass flow in, or very close in a real engine.

If the orifice plate in your ratiometric flow bench has been calibrated to read correctly at standard seal level temperature and pressure, so will your CFM readings be corrected. Because the exact same air flows through what you are testing and the calibrated orifice, your readings will also be corrected.
If this were not so, it would not be possible to get any consistency of readings as ambient conditions changed.

Mr Banks is both right and wrong, and it would appear he might have a not so subtle motive.

[MaxRaceSoftware]

I came across the video (infomercial?) below from Banks Performance

definetly an Infomercial

CFM corrected to "standard sea level pressure and temperature" is the same as measuring mass flow in every respect.

your exactly 100.0 percent correct !

Flowbench CFM , if you wanted to, can always be converted to SCFM
then SCFM can always be converted to Mass or Grams/Second Flowbench Flow

basically that Banks video is all "Smoke and Mirrors" ... just keep relying on or using plain old Flowbench CFM numbers

Mr Banks is both right and wrong, and it would appear he might have a not so subtle motive.

i was thinking the same thing !

[bob]

I did watch the banks youtube take on maf sensors in flowbenches, appears to make sense if one is predominantly working or testing components used in forced induction motors and blasting air through them.Is a maf sensor and a banks Idash all thats needed to accurately ascertain cfm in a flowbench? Seems like a very reasonably priced option if it were true.

Bob

[FlyboyS4]

I don't see where there is a benefit to measuring resistance to airflow by comparing mass flow rates versus volumetric flow rates.

Testing parts for a forced induction system with the flow bench isn't being done at the air density a turbocharger or supercharger discharges, so whether the mass or volume is being measured, neither is accounting for changes in the pressure drop caused by the increased air density from the compressor. Even if it were at the "operating" density, I would assume both test subjects would be exposed to the same operating pressure, which would eliminate the density as a contributing factor.

To me it just looks like measuring mass airflow is an alternative method for arriving at the same conclusion.