from what I understand (by the way that hood looks so amazing) the front air dam will direct air away from under the car and also up towards the radiator. Seems that some people who do the higher speed open road races run into problems with not getting enough air going through the radiator. Someone posted that really interesting article not too long ago about measuring pressure gradients across the car. I'll look through the posts and see if I can find it.
Nascar guys don't have that problem and they have really small openings but they do have state of the art radiators, coolers and ducting
All you need to do is place a cheap magnahelic gauge or manometer in the cabin and measure pressures at the front in various placements.. and then in the bay to compare. Simple math will tell you where you're at and give relation to actual atmospheric.. and whether you need to be monkeying around with funneling additional airflow through the radiator. Just remember that more air out.. allows more air in.. and it's doubtful that such a large opening in the front of a less than aerodynamic car like these will need to have air funneled into it even more than it already receives at 140mph. Look at the minimalistic front venting in todays higher horsepower cars and you can see that huge dominating radiator openings just aren't needed as badly as some will think they are. And I agree.. that hood is certainly nice. Just not really enough sq/in of louver to do much for evacuating the thousands of cubic feet per second that are getting smashed into the engine bay at higher speeds. I just quick google searched to see if there was anything to help avoid me writing a thousand words and this seems to be a decent one with clear explanation of what's needed from a cooling standpoint. David Vizard did some testing(engine bay.. aero.. and even ram air optimization) many years ago and the results were surprising. Which is what lead me to using that trick myself. Works well on testing exhaust back pressure at various locations too. The added bonus to maximizing your cooling efficiency through proper venting is that the trapped air doesn't get shoved under the car which ultimately causes lift and variations in traction as we go bouncing down the road at 140. http://autospeed.com/cms/title_Undertrays-Spoilers-Bonnet-Vents-Part-1/A_2159/article.html PS. once you see how much air is being trapped in that old Fords bay?.. swap in about 15 fender washers per hole with longer bolts to hold that hood in place above the hinge. You'll be very surprised at the results and is exactly why many used to do that on the old cars. Cheap.. easy.. and it actually works.
Aerodynamics is a very deep subject and really misunderstood by a lot of people. There are many ways to increase airflow and reduce drag on a standard car. Sometime if you have the chance go to Bonneville Speed Week in August/Sept and walk the tech lines with the stock bodied cars. In no particular order, a belly pan with using the driveline tunnel as a funnel will actually draw air from the engine bay kind of acting like a vortex generator (take a look at the underside of NASCAR or some of the 200mph GT1 cars. The pan does not have to completey enclose the underside, just enough to smooth it out. Another is to inclose the rear wheel well, this really disrupts airflow around the car. Another is to put a complete wheel cover over the wheel, or at a minimum of taping over the lug nuts................at 100+ they disrupt air more than would think. Putting vortex generators along the very top of the rear window will actually distrupt the air and cause the vacuum on the rear window (which equates to pressure) allowing smoother airflow. As for the spoiler in the front, if you were to make a type of splitter like they use in NASCAR or on the Shelby Super Snake I don't think you will have any problem with air getting to the radiator and this could be easily bolted on and taken off. One point the Mercedes came up with a lot of years ago when designing the Gull Wing cars is that the optimum road clearance is 2.7" from the road to the bottom of the car...................this decrease aerodynamic drag by some 3%. I could go on for sometime about making your car more stable and slippery over 100mph but there are a couple of websites I will try and find that do a really good job of explaining how to make a regular car more aerodynamic with less drag. I certainly can't say I am an expert, but having been involved with road racing for a number of years and being at Bonneville has really opened up my eyes.
To add with what olerodder said...remove side mirrors...duct tape between windshield post and rain gutter will improve aerodynamics.
you simply pull the original bolts.. swap in the spacers(I like fender washers because they provide a larger footprint between the hood and hinge to help avoid wobble) and compensate for the added thickness with longer bolts. This will effectively raise the rear of the hood to vent air more efficiently up and over the car.. and even has a slight effect of reducing the high pressure area at the rear of the hood/base of the windshield. What I plan on doing to mine when it becomes a much more aggressive build a few years down the road(after enjoying the lightly modified chassis with the kids for a while) is to use a well designed multi angle approach of aero tricks. This will include front spoilers with splitters leading up around the wheel well.. elongating the rear end(these cars are near horrible in that regard.. fastback or not.. and even moreso when you jack them up with shackles to look cool).. deleted mirrors.. tucking exhasust up tighter while using a custom belly pan.. a lighter than usual rake.. along with stiff'ish suspension to avoid excessive jounce/rebound at high speed. IMO.. all you need do to ready that car for some constant 140mph blasts down the striaghts is to add the cool looking chin spoiler(don't forget to reinforce the hold down areas by using washers for a larger fastener contact patch).. shim up the rear of the hood by about 1 to 1.5 inches.. adjust your front springs to a slightly lower angle of attack than the rear.. and then go have fun.
Read thru these articles again. Raising the rear of the hood should not release underhood pressure as its a higher pressure zone. Think about how the cowl works to get fresh air into the cabin and how the cowl induction hoods work. If it were a low pressure zone as suggested then it would create a vacuum in the cabin and draw air away from the engine intake for those fancy hoods. http://autospeed.com/cms/title_Under...9/article.html My front spoiler added high speed stability to the car at hwy driving speeds. It no longer feels like it is floating when pushing 80+mph. I plan to add a splitter under it that will continue to the back side of the radiator support. This will close off the area between the gravel pan and the rad support. This area allows air to bypass the radiator. The other purpose is to create a low pressure area just past the radiator. This will draw air out from the engine bay after it has already passed thru the rad. Another area to aid in cooling would be to vent the hood in the front 1/3. I have not tested but this should be a low pressure zone as well. Think late model shelby hood. They have a vent in the center of the hood about a 1/3 the way back.
Great advice so far thanks everyone. Here are some cool pics of other cars from the silver state and their aerodynamic modifications:
Wow, wonder what kind of speed they were working on with that 63 Galaxie? Chris, I hadn't thought about it that way before. So would side vents with a channel behind the shock towers out to them be a good way to create a vacuum and move trapped air out from the engine compartment?
I wonder what percentage difference there is with/without their " aerodynamic modifications"? that '63 front end would be like pushing a 4'X8' sheet of plywood down the road...
