ok, ok, I know some may think it's sacrilege, but given that my D2 is rapidly becoming worth 2/5 of 3/4 of bugger all, I'm feeling more comfortable with doing similar 'customising' to it as I did with my D1. I had a GU scoop on my D1 directing air over the turbo region at speed and allowing hot air to escape during low speed work. I have no idea whether this really achieves much but am thinking about putting a scoop on the D2 and was seeking opinions (apart from not at all) on whether to locate it in the middle to direct air onto the motor or off to the side over the manifold/turbo region? Other options to remove some heat from what is a very crowded engine bay is to jack up the bonnet supports at the rear slightly or to put in some D3-air intakes on the sides of the vehicle... Maybe I've just had too much to drink...

best position for GU bonnet scoop on D2
Smartar$e answer is of course on a GU.
Seriously, if you want it to help cool engine bay, face it backwards, when moving forward the air motion over the bonnet and scoop will create a vacuum behind the opening of the scoop and will draw air in, also when stationary the engine fan will blow hot air out, fair dinkum, Regards Frank.

Also if you have the opening facing forwards consider a couple of vents in the guards to let the hot air get pushed out. If you fit SS vents watch out cause they do get hot.

I'd do as Tank said and mount it backwards (would it be benificial to remove the top section of the turbo heat sheald and try and seal the sides withe the bonnet) How would having a bonnet scoop effect your deep wading ability?

Dobbo I would think it would allow the engine bay to fill with water more easily.

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I was thinking of a GU scoop on my d1 but now you have mentioned the problem with water crossing's i'm abit unshore because you want beable to create an air buble inder the bonnet if there's a scoop

TIM.

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TIM.

How does the scoop affect the vehicles that do run them?

And the bonnet creates an air tight seal? Seriously don't think the scoop would make much of difference would just let water in that was running over bonnet.

Could always make a flap that you could close when crossing rivers/creeks, or just jam a towel or something in the hole till you get across, Regards Frank.

Feral disco I am part way through engine bay ventilation upgrade to my V8 D1 so maybe my humble opinions can provide some guidance for you.

First things to remember is get this wrong and you can make things far worse under the bonnet and for air to move it needs a pressure differential. This subject has nothing do with the car movement.

The stock Disco relies on the pressure difference across the core of the radiator caused by the higher outside pressure and lower pressure inside the engine bay being maintained by pressure escaping through openings at bottom of engine bay.

I don't have any measuring equipment to prove this but I am hoping my solid steering guard protector helps to reduce the pressure build up in the engine bay. My thinking is the guard is reducing a pressure build up from turbulence particular in the area just behind the radiator.

The next target is to get more pressure out of the engine bay. There are only two places to do this. The bonnet and the two sides/guards.

A Bonnet Vent needs to be letting pressure out of the engine bay not raising the pressure by forcing air into it!!!!

I am guessing the pressure above my bonnet is lowest at the front and highest at the rear or near windscreen. That is why air conditioning air vents are located at bottom of screens where outside pressure is at its highest. Under the bonnet I also think the pressure will increase from front to back, particularly if my steering guard is doing its cooling job.

That says to me the pressure differential between above and below the bonnet increases towards the front of the bonnet. Put a vent anywhere near the rear or windsceen or where outside pressure is at its highest, particularly a rear mounted reverse facing vent, then there is real danger of the flow going in not out of the engine bay. That increase in engine bay pressure could suddenly do horrible things to radiator efficiency.

I am currently in the process sourcing an appropriate reverse facing vent and locating on the bonnet centreline as far forward as I can or may even test out a GU style forward facing number. I have a blacked out bonnet so what ever the outcome should look OK.

That done I might then turn my attention to side vents to further improve flow out of the engine bay.

Hope this helps or at least widens the debate.