Fiberglass hood mods... crazy?

IgotDUST said
Alrighty then,glad theres no confusion lol.

And your right,the only way to know for sure will be to do it and learn from it....But I have thought about it and I think its doomed to fail for atleast one reason.

And that reason is...

At high speed when you want to evacuate this air pressure the most.

You will be moving so fast that the external air pressure will be more then that of the internal engine bay air pressure....meaning that the pressure from wind due to the increasing speed will be putting so much force on your "flaps" that the engine bay air pressure will have to be greater than...in order to open the flaps to release the pressure.

With that in mind,you would have to have some type of system to aloow them to open reguardless of exterior pressure.

Rather that system be,before you race...you manually open your flaps before a race and lock them into a stationary position.

Or you make a design where the "flaps" you cut in the hood are connected to lets say a choke cable inside the interior of the car under the dash or something.

That way when your at the line you can lean down,pull the cable and pop them open.

But I do not think that they will open on there own from engine bay pressures alone.

Just something to think about.

You may have something, there. It may come to that...

Do you know what a boundary layer is?

In case you don't, a boundary layer is a dead area that envelops the hood to a height of, say two or three inches, and has basically, "Dead Air" forming a blanket of air that isn't really going anywhere.

I am no aerodynamics expert (obviously!), but I have read several articles on the construction of hood-mounted air scoops that mentioned this "boundary layer," and all those articles say it exists and is a problem, mainly because it's different for each vehicle.

Look at a '68 HEMI Dart or Barracuda; notice how tall that hood scoop is?

The reason, is, to get it above the boundary layer, where it can be effective.

I am thinking (hoping, actually) that the boundary layer on the part of the hood that has the flaps that are to open with air presure from underneath, will NOT be subjected to aerodynamic forces that would hold them closed; that the boundary layer will be sufficient to provide a favorable pressure differential that will raise the flaps, at least, some, and let some of that air beneath the hood out.

One thing for sure; I don't really know enough about aerodynamics to talk inteligently about it (and, I am aware of that), so I will just have to cut and try, and if it doesn't work, then, I'll probably try something else.

If there's not enough air pressure under these flaps to push them open, then, it's my feeling, that it's not worth doing. I don't really think a manually-opened flap would be necessary IF there's really a need for evacuation of that underhood air.

Have a good weekend!!!8)