Quote:
Originally Posted by 86TOYO2k17
If you pour a 1 cubic inch stream of water into a 4 inch diameter pipe, and then increase the pipe to 5 inch diameter, the volume of water and rate of flow will not increase as the restriction isn't the pipe size but the amount of water. its not like pouring too quickly in a funnel and the funnel slowly "fills" up and either spills over or you stop pouring.
The engine can only draw so much air, the TB size is already greater than the amount of air the engine can draw on it's own it is not a restriction hindering flow so going larger will have no effect on maximum power (unless FI) it will only change the throttle mapping up until maximum power because you will have greater airflow going through the butterfly valve of the larger TB at any given throttle position unless remapped to account for this.
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Sorry but in real world practice with a +2mm over-bored OEM TB or 72mm TB
AND port matching IM I saw a 2-3% increase in MAFv usage. If there is a bottle neck the pressure will just be dropped at the next neck down in line. There's an entire flange after the TB which no one every takes into account. I should add I have an extrude honed IM that neckes down to ~70mm before the plenum. Grams TB uses a reducer plate to go from 72mm down to the OEM 66.5/67mm opening. Yeah it obviously wont make a different as the IM port size hasn't changed.
Your example isn't applicable to an engine for many reasons the main one being the lack of a pressure differential before and after the "funnel" and the manner in which air flows in an intake system.