Heat dispersion from under the bonnet

[CJ]

Dude recently posted re his latest bonnet design and one of the comments was that he should have been looking to get rid of the heat from under there rather than let more air in (at least that is the way I read it ). That being the case, how would people suggest the heat is either a) Dispersed efficiently or b) Reduced from forming?

 

I am especially interested in comments relating to my own car (yeah, selfish I know ) which runs a single turbo conversion.

[Guest Terry S]

Both

[CJ]

Both

 

I know we should be looking at both but was wondering how?

[Guest Terry S]

Look at the bonnet on the purple car, I drove around for weeks with heat tape on the underside of the bonnet in Various points to established where the venting was needed, then had louvres punched there. Turbo Blankets & exhaust wrap help greatly too.

[CJ]

Thanks Terry.

 

Is there an effective way of actively trying to duct the hot air away from the area or is that done naturally anyway?

[Guest Terry S]

The cold air flowing over the bonnet will pull the warmer air outwards. The wing vents help too, as there are holes in the inner wing already.

[CJ]

Nice one Tel.

 

As I already have a turbo blanket, I will have a look around at prices for the exhaust wrap.

[Alex]

Properly ducting the forward faces FMIC and the radiator will help the intake of cooling air.

 

Then it's a case if using the air rushing over the bonnet and wings to create a low pressure area under the bonnet and suck the air out into the air stream....do this too far back and it won't work as the windscreen creates a high pressure area that forces air into the engine bay (hence the location of the passenger compartment vents). The Veilside and Top Sectret bonnets are on the face of it the best for dragging the hot air that's just passed through the rad, out of the engine bay. The Top Secret bonnet is a copy of the JGTC one...I'm guessing it's quite good at heat rejection But it's not too practical in the wet.

 

If you have additional oil coolers they should be ducted too, and the air should be vented as soon as possible. The Jun front bumper and some others have a vent(s) on the side of the bumpers for this very purpose.

[foodfreak]

on cold days you can clearly see the hot air flowing from the vents on mine,

 

specially the vent over the Turbo.....unreal

[Terminator]

The undertray is important too, as it helps reduce pressure and draw out heat under the car