Cato
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- Birmingham, UK
They lag behind the main butterflies. The primaries open fully, the secondaries open 25% (ish, for example) then open to full gradually (still quickly it's all relative). Once both are open the secondaries don't exist as they're in line with the open primaries. The secondaries remain fully open as you roll off and if you open back up they're still open, but if you keep rolling off they stay open until the primaries are closed then the secondaries are back to the starting postition.Oh I get it, increase the airspeed at low rpm, must need to be open more than the main butterflies then?
Probably would have reduced emissions too.
They'll have an effect on emissions in so far as you don't have a rich running point if you go from low rpm to WOT.