Originally Posted by
turbotrev
Interesting.
Maybe just see what temps I'm getting with the bonnet sat normally then go from there then
Cheers Paul
Originally Posted by
Caddyshack
It COULD also allow the air out the back of the bonnet and aid cooling. I can certainly see hot air (waves) at the rear of my bonnet so I know heat is getting out and my car doesn't overheat like it used to but that was more down to the header design that has now changed.
It all depends on the application. Car manufacturers have the ability to amend the design at that stage until it works, a manufacturer is unlikely to resort to lifting the back of a bonnet. Just because they work to their model it doesn't mean it wouldn't work but I can also see that it MAY cause issues on some cars.
The abarth 500 had the boot open the whole time for cooling and some 911's had different "boot" lid arrangements for aero and cooling.
Heat will definitely exit the bay with the bonnet raised, but what makes a car overheat is not engine bay temps, it's coolant temps... raising the bonnet can disrupt the flow of air through the radiator and this is of course what keeps the engine cool and your temperature gauge where it should be.
But you're totally correct when you say it may work on some cars and not others, I've witnessed a CAD simulation using a BMW E30 and then later tested in a wind tunnel and it made it worse but that's not to say it does for every car.... Just something to bare in mind.
Oh and I've had RST's with raised bonnets (including my own briefly) where both coolant and intake air temps where very high compared to it being fully closed.