usually a plenum mod is done in addition to a pile of bigger mods for a car tuning in successive years so any change gets lost in the overall upgaded dyno session. I can tell you Greg stops a dyno session and puts a blower directly on the plenum when he declares the car heat soaked... this happens more frequently with chrome or powdercoated plenums and occasionally with thermal dispersion (a type of ceramic coat) coated and stock plenums. Not enough cars logging IATs on the dyno that I see, maybe next year I'll do a test with different plenums on my red zed for posterity... accepting plenum donations!
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