Igot mine from GT Racing. I stuck a fishtank thermometer before and after, did a few before and after runs and saw about a 15 degree difference BTW

I am setup to test this. stay tuned :)

Be good to see some actual figures Shawn.

Shawn, do you need a stock panel to test with?

Shawn, you could just tape the opening on the header panel but you need to re-install the stock air duck between the bumper opening and the intercooler.
IMHO, this is where I see a limit with two openings. The stock opening with the stock air duct allow a good and clean air flow. As soon as you create a second opening, without air duct and with a lower pressure on the higher one, you will create turbulences and the air flow will not be optimal. I prefer a good and clean air flow with a good extraction behind the intercooler.

Let us know where your temp probe(s) are located.

Actually, Porsche's wind tunnel plot shows this in a high pressure zone. The plot scales are inverted with higher pressure below the abcissa.

Do you have more info and pictures about this?
Is it with the Turbo bumper?

I am just surprised that Porsche use this same area for extraction on any GT2 or GT3.

Nice photo.
Do you know if internal ducting is needed to accomplish that, or is the pressure differential enough?

Yes and actually you need both.

Well it's obvious you need the ducting since the air has to exit the radiator and make a 90 degree turn up to do so (in the case of the 911 GT3/Turbo).

But it's the not ducting that makes it work.

It's the difference between the pressures that allow for the air to flow through the heat exchanger, from the front of the car and exit through the hood.

That said... the 951 creates a low pressure area directly above the bumper, specifically because the front of the bumper is a vertical flat surface that is at a perpendicular angle to the direction of air flow, and the next surface above that (the hood) is at a very shallow angle relative to the bumper.

That leaves a low pressure area (relative to the pressure directly in front of the bumper). And it's right where people cut in vents.

Now the potential situation exists where the pressure in the engine compartment, is probably greater than the pressure entering the vents that people cut in, in the nose panel.

That's the issue.

Somewhere I have old wind tunnel testing data, and it shows a clear lower pressure between the area of the nose panel and the bumper relative to the pressure in front of the front bumper. But the problem is that it's not quantified. And therefore not specific.

Nevertheless, there is quite a difference in pressure between these two areas.


TonyG

https://cimg1.ibsrv.net/gimg/rennlis...98819e00a7.jpg


Porsche 944

I am not sure if this is the diagram people are referring to but if it is accurate it might be helpful. The trick when reading it is to realise the graph underneath doesn't directly relate to the diagram but to the plotted points on the diagram, which start at 1 next to the wheelarch then go forward around the bumper and then onto the car. It seems just before point 10 to point 17 are all low pressure. By the look of the diagram this is for a 944 not a 951.

Will be very interested to see the results of any testing.

Looks more 924 Glen. Testing will be the way forward, agreed.

You are right Patrick, never even thought of that option!

Not really, if you look at point 10 on the graph and where point 10 is on the car you will see that it is a low pressure area. Point 10 is about where everyone drills their holes.