Air Flow / under bonnet temperature
Turbo Mini Forums

Hey, i have been doing some thinking about under bonnet temperature since its always a issue with our turboed minis.

As many i also have raised my bonnet at the rear - mostly because it was prepared like that from the pre-owner. But it seems so work in some way. After driving the bonnet and the sheetmetal under the windscreen is warm but not hot. Only after standing for a while it gets hot enought to burn your fingers in this region.

So i did my reading and there are many different opinions around. The one are sure that its a high pressure area and air is getting blown in, the other sy it works perfectly fine that the air gets sucked out.

I dont really have a problem with my current setup, but i was simply curious and since a CAD-Model of a mini fell in my hand i did a little simulation:

Pressure around the car:


Velocity around the car:


according to this the truth lies somewhere in the middle. There is almost no pressure (40Pa) at the rear of the bonnet. Assuming you have a higher pressure in the engine bay from the inflow at the front its most likely that the air simply gets blown out.

Thought i share with your guys

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=8799

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Oh would you look at that!

Thanks Robert for the link, i did not know this thread.

According to the simulation there is no pressure there at all, but maybe the flow inside can be explaned by the vortex in this area flowing against the driving direction.