K and N Dyno for 2018 Tacoma

Why does the dyno not cover the power below 2500 rpm?

https://www.knfilters.com/dynocharts/63-9039_dyno.pdf

 

Probably a loss of torque, I don't buy the so called gains in that chart either.

 

nah, I think it's something about the dyno process. I can't find one that shows from idle upwards...

 

here I F'd around and did my own research for once

These readers feel that at least on a streetable combination, knowing how the engine performs at low rpm is nearly as important as the peak torque and power numbers. Rest assured this is not an arbitrary decision on our part; there are several practical, real-world reasons why we don’t routinely conduct engine dyno tests from such a low rpm.

First and foremost is the limitations of the test equipment itself. An engine dynamometer’s power-absorber unit is kind of like an automatic transmission’s torque converter. Like a torque converter, the absorber has a vaned rotor and a stator, but the fluid running through it is water rather than the hydraulic fluid of an automatic trans. Just as torque converters have different stall speeds (and a high-stall converter can’t hold an engine down low), dyno absorbers have different load capacities. There is a certain rpm range the absorber can work in. For the most widely used engine dynos, this is typically about a 4,000-rpm effective operating range.

https://www.hotrod.com/articles/dyno-testing/