Toyota EFI L-jet type air flow meter


At 52*50mm size, it gives about 130mbar pressure drop at 232hp. Pressure drop on the intake side of the turbo is much worse than on the pressurized side. Turbos give a pressure ratio, not a set output pressure. That means that to get 1.1 bar boost (2.1 bar absolute) with -0.13 bar intake pressure (0.87 bar absolute) needs a 2.1/0.87=2.41 pressure ratio! That's as bad as a 310mbar pressure drop after the turbo. Adjusting the spring tension does not give quite linear enrichment/leaning. So I do not think it is worthy, and plan to get rid of the damned thing ASAP.

There are two sizes of Air Flow meters, 80mm od and 70mm od inlet, flap size is about 52*50mm or 58*56mmm.


Karman-Vortex type air flow meter

Used at least on 7M-GTE and 1UZ-FE.
Hot-wire air mass meter is one quite common one but Toyota does not use them. Also, there are no Toyota mechanical fuel injection systems (thankfully!!!).

Many TCCS systems don't have an air flow meter at all, but use a combination of MAP (Manifold Absolute Pressure) and a more accurate throttle position sensor. This gives the smallest intake restriction.


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