icsamerica

Has anyone modified the hood and air box to allow fresh air to enter at the base of the windshield as shown below. Many modern cars seem to have air vents or intakes at the base of the windshield. I though this was a high pressure area when at speed. I'm thinking even a small scoop would be out of the line of sight and have a ram air effect. I'd really like top use the real-estate the intake tubes presently occupy for chassis / spring tower bracing which is badly needed on the 928. The existing stamped tabs are not enough and in the wrong place. The biggest obstacle I can see is water ingestion from rain and splashing. Looking for ideas.

Mongo

Mark Kibort I believe did this a long time ago. The area in front of the windshield is a high pressure area and ideal for cowl induction

linderpat

do you plan to track the car? Not necessary for DD, but could be useful in the high performance arena.

Jerry Feather

First of all, the area right at the bottom of the WS is not a high pressure area but rather a dead air space. That means that the air there is simply atmospheric pressure. I know this empirically from my flying days. Then it you move forward a bit, as shown by your drawing, you are only going to get a tiny bit to ram air, nowhere near what you are already getting thru the front openings of the 928. You need to get a better study of the airflow around the 928 in order to see where the pressures really are; and I suspect you are not going to find a better place than you already have.

Bulvot

icsamerica

Thanks, that's good info. The primary reason for considering this is that the intake tubes are in the way of some chassis bracing I'd like to do so since the air at the base is at 1 to 1.2 ATM its worth some further consideration.

gazfish

Curious why you think additional bracing is badly needed?

FredR

Is it my imagination or is the highest pressure point where the stock system takes its air from?

Have not seen that diagram for a long time but what I seem to remember is that the high pressure point at the bottom of the windscreen is a very narrow band presumably caused by the velocity of the car smacking into the wind blast killing velocity head and thus converting the energy into pressure as per Mr Bernoulli's theorum. The faster the car is travelling the more the effect one presumes.

I did actually try a modification someone proposed using a spare air filter top housing wherein I cut slats on the back of it to expose the top of the filter element and then left the firewall rubber seal off. Not too surprisingly I could not really tell positively if it made any difference or not but "the mind" suggested there was a slight improvement- probably "placebo effect".

icsamerica

Have a look at this picture, in compression you can see the hood is far out of alignment. At rest the hood lines up perfectly. That's chassis flex on full display and it might be eating up a full degree of camber, possibly more.