If it's true that the airflow hits the firewall and then forms a high pressure area under the bonnet then that high pressure could be an advantage for the engine air intake if you can pick it up in a reasonably cool area.
That's true, sort of free turbo charging - however - the reason for my concern on this topic is that a couple of years ago we drove down in to France via the channel tunnel. When we arrived at the tunnel there was a bit of a queue so we went from 70mph to stationary in quite a short distance. Unbeknown to me the fan relay had decided it wanted a day off and shortly after we stopped the engine overheated and most of the contents of the cooling system blew out. The header is just in front of the passenger side windscreen and whilst alarming it didn't cause any injury however if we had been travelling at motorway speeds it could have blown back in my wifes face and she wouldn't like that. This is why I'm keen to control the temperature whilst moving.
Last edited by Guten; 03/01/1908:28 AM.
Simon 2002 4/4 1936 Austin 12 light 4 Ascot saloon 2023 AMG Mercedes C300e estate 2021 Audi A1 sport
