Ok so during the winter I went to see Damien at Day Tuner to have my 97 919 blade setup as it's never run right. Had the first trackday on Friday and although now its great after about 10mins I believe the temps under the bonnet are getting high as 3&4th gear at 6-8k revs it coughs and sputters and is ok after. So for me its temp related because it's great at first.

So what are peoples experience with venting this area, side or top to create a venturi and keep the air flowing, I'm thinking top vents?

Cheera

vent from top or side but both are effective,

you can use naca ducts also like these and they look good to aswell as function

http://www.kitcardirect.co.uk/naca-air-intake-ducts-carbon.html

With the full screen, it's been found that there's a high pressure area just in front of the screen, where you'd normally think of putting a vent across the back of the bonnet. When people have done that they've seen rain spray going IN the vents. I'd go either for the sides or possibly one long vent each side on the top (running front to rear).

Issue could be carb' float bowls boiling I guess. Could you put a cold air feed to them?

I read these articles about vent placement a while ago. Makes you realise it is more than just cutting a few holes. Placement is key.

Part 1

Part 2

Part 3

Cheers guys I'll have a read and try sort it out.

Hi
we did this on both sides
& it worked fine, 70mm holes
with stainless grill stuck behind


Bonnet Vents both sides