Porsche Enthusiasts Club Forum

Thought I would post up some pictures of some vents I have had pressed into the bonnet to try to aid heat extraction and flow through the intercooler.The D9 louvre panels do not have enough of an upstand for my liking and the 968 intercooler duct does not work on the 944 bonnet and looks wrong. Mark kindly supplied a cheap spare bonnet that I had blasted and zinc primed before approaching a local coach builder to get these louvres pressed in. The two outside rows are above the strut top areas apparently low pressure points and the rows at the front as close as we could manage to get the press to where the intercooler is. For the moment I am running the intercooler duct but have an open front panel to try.
Not cheap to have done but am pleased with how they turned out . Hopefully they don't look like I should be off to a cruise round the McDonalds car park !

Cool. Will be interested to see it painted and on the car. Ihave a Trumpf nibbler with some louvre tooling. Was thinking of trying something similar.

I may have to have my bonnet painted, how much were the vents and who did them ?

Looks much cleaner then stick on type. I think the side ones at a slight angle 30 degree would look quite nice. Not sure if this would effect there function. Be good to get some data on the matter. Temp logs with stock bonnet and yours

Thanks for the replys. I agree that just having the two rows to the rear of the bonnet would look pleasing but, function before form and this is on a track focussed car, I wanted to see if the louvres at the front of the bonnet will aid airflow from the intercooler . I will try and get some tempature readings before having the bonnet painted and swapping them over.
Pauly they were done by Mouland and Yates in Ower, Romsey . If you were to just have the upper rows done it would be sensible money, the expense was getting the larger 10" louvres done in the front of the bonnet.

Nice work. I think any form of hood venting should provide an improvement over stock. The D9 versions were the 1st I put in and while I used to see a pretty obvious heat haze after coming into the pits I doubt they were actually providing positive extraction as such. Ideally the best or most efficient vents can look a little extreme on a road car as they need to be very steep and sharp in cross section. I would like to modify our D9's and even the louvres on the front wheel guards to be as steep as the central hood vent shown in profile.

For a fast road car that might see some trackdays, I reckon yours look very well done!

Thanks Patrick, your comments are much appreciated. For 'steepness of attack' you must admire the italians for purity of the function on this Group B lancia Delta S4 , 90 degree angle pop riveted to the bonnet !

that would certainly create a big vortex of air over that vent, like to see how it worked in a wind tunnel, be interesting to see the effect of angles on that.

your vents look so much better than my stick on jobs, i would prefer proper metal on my next bonnet, how much would just 2 outer vents cost. mines not a turbo, so not as much under bonnet heat.

Hi Stuart, it would be best to contact Mouland and Yates (they have a website) to get a price. There work is first rate as you can see by the maserati race car and aston martin dbr they are building for customers hand forming all the aluminium panels by hand. They can punch these louvres in or can hand form any size louvre you require, even make a new bonnet in aluminium but at a price. I would imagine the price for the two rows you mention would be around £200,mine cost alot more because the central ones are much more difficult to press as there is a curvature to the bonnet. Hope this helps.