3 plug 4 plug trivia L Series mpfi

steptoe · Post by **steptoe** » Wed Mar 03, 2010 10:38 pm

LTurbo Thomas and I discovered a little bit of trivia when we met up to test my spare 4 plug hot wire air flow meter on his car. The three plug Karman vortex style flapper afm has threaded flange holes to bolt air filter box to it whereas the 4 plug hot wire afm has just holes to bolt the afm to captive nuts on the air filter box. One has a part number ending in 40, the other - 50. Told you it was trivia

Gannon · Post by **Gannon** » Thu Mar 04, 2010 5:16 am

Another bit of trivia,.. the flapper air flow meter and a karman vortex air flow meter are completely different bits of equipment.

We all know how a flap or vane style AFM works

But a A Kármán vortex sensor works by sensing turbulence. The air stream is disrupted and his causes a wake in the air stream and subsequently the wake will collapse repeatedly and cause Kármán vortexes. The frequency of the resulting oscillation is proportional to the air velocity.

steptoe · Post by **steptoe** » Thu Mar 04, 2010 1:22 pm

reminds of the days when i thort constant velocity joint was a technical term for a uni joint in tailshaft ! thanks for the input