Hole in Hood (not head)

Interesting. Is it actuated based on temperature?

It's a manual change in the duct position. It is either bolted up or down.

The problem at this point is required airflow is a guess but I still needed to go forward with enough fabrication I could move to paint. The hood still needs a little finish work.

I have changed so many things the ratio of screen to vent could change after I get it going. I have to see what it does.

One goal I had was to close off all under car exits for the air through the radiator. No air goes out the bottom nor into the wheel wells. All air goes out this hood.

Added to the mix is a trans cooler where the air conditioner was and an oil cooler where the gas tank was. Both of these will help with temp control as well.

Gary, from what I have heard, the air flow at high speeds is enough to lift the entire hood a few inches. If you could somehow hinge that piece it would open itself at high enough speed.

That's a good idea. I could allow it to go out how far I wanted by cable. I would be ahead of myself building that right now though. I need to see if the airflow is right for the car first.

quote:

Gary, from what I have heard, the air flow at high speeds is enough to lift the entire hood a few inches. If you could somehow hinge that piece it would open itself at high enough speed.

That was my thought exactly. A couple of the PCNC guys have unlatched their front hoods when running through the desert at speed and report that the air pressure from underneath raises it 2-3 inches where it equalizes with the pressure on top and sits there. I found this to be the case one time when I forgot to latch my front hood (didn't notice it was unlatched sitting in the garage) and I got onto the freeway.

So just allow the louver/vent to be free swinging with a limited travel to avoid any damage, and allow the natural air pressure to open it when needed, then it will fall back to a closed position automatically as you slow sufficiently.

Good thoughts and approach here, I have a couple points to add.....

The shape of the front trunk foreward bulkhead is such to push air down and out the bottom of the car. Have you modified that area at all? If the air has nowhere to go will it cause resistive downforce on the front of the car?

The auto opening hood hatch is a good idea in principle, but I cannot see what advantages it offers over an always open area in the hood? Personally I'd be more inclined to cut the front trunk forward area and install a single reverse scooped hoop ala GT40 style. This would offer better air evacuation at all speeds and provide increasing downforce as speed increases.

Gary, I'd like to know more about your transaxle cooling system and how it is plumbed.

Julian

Garth, when we open doors on small airplanes the door opens about 2". You can push it to 3" but that is about all and you can't close it either. The low pressure holds it out and wind force keeps it from opening more.

I doubt I would do anything like that because I don't think I want to make it too complicated. The premise just being closed looks a WHOLE LOT BETTER and if I need it for say a track event in August I can open it....Or even remove it.

Joules, see here for the front trunk modifications:

http://www.rc-tech.net/pantera1/hood/hood.htm

I have not hooked the lines to the transaxle yet so I have not gotten that far with it. I did alter the old A/C mount to accommodate the cooler and I have a Tilson pump.