Any exposed under bonnet filter is not going to get much cool air. On my system with the throttle bodies the air temperature sensor is in the back plate of the filter. With the logging software I can monitor the intake air temperature. Even on cool days it rises to over 40°C and on hot days to over 50°C. Given that it is drawing at least a percentage of its air from the louvres and that the rest is passing the radiator it is clear that there is little benefit to be gained without an enclosed air intake or perhaps a bonnet scoop.

Peter

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