Quote:
Originally Posted by aardvarcus
Thank you for your comments Aerohead; I am sure you have realized that I am getting most of my ideas from you. Currently my fully open grill sizes are 230 in^2 lower and 100 in^2 upper. (Ignoring the side grills and reducing for the aluminum angles the grills mount to. These are “blocked” with 40% open mesh, resulting in net open area of 92 in^2 lower and 40 in^2 upper. Assuming a vena contracta of 0.64 for the sharp orifice, this nets effective grill area of 59 in^2 lower and 24 in^2 upper or roughly a 3/4ths block. In the winter I ran additional partial lexan blocks behind the grill mesh, resulting in net effective of 30 in^2 lower and 4 in^2 upper, or roughly a 7/8ths block.
I would like to use aluminum for anything I add to my grill. I have looked, but been unable to locate a trash can lid of the proper shape and size. I have also searched for pots, pans, vases, bowls, funnels, etcetera but have not located the proper shape and size. What I have found that are aluminum and the correct shape are velocity stacks for cold air intakes and carburetors. The carb ones are approximately 8.5” inlet and 5.13” outlet, and the cold air ones are a 7” bell with a 3” to 4” outlet. If I were to use the carburetor one, what figure would be best used to compare the amount of air it will flow to what I currently have? Calculating the area based on the inlet would produce 57 in^2, but using the outlet would be only 21 in^2.
I am assuming there is a flow advantage to using the streamlined intake shape as compared to the adjusted area of all the little holes I presently have, but I don’t think that fact is enough to make up for the further reduced area I will have unless I use multiple of the smaller intakes. The only other option I can think of is to make one, however I think I would end up with a wider rectangular type of shape with rounded edges, not an ideal 3d spherical form. I had also considered getting one of the smaller ones, cutting it in half, welding a curved top and bottom piece in that matched the profile, and turning it into a rounded rectangle of sorts, but that would be a lot of expense.
Aerohead, another question I have is do you have any sort of ducting directing your intake air to your radiator? If so is it streamlined? I presently don’t have a duct, but I did block off most of the areas I didn’t want the air to go.
Lastly I am presently working on making some tire spats fore and aft of each of the wheels. I am basing my design loosely off of what they did on the ford probe, except making it out of conveyor belt type material, hopefully in a way that will stand up to rough roads.
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Walter Korff of Lockheed Aircraft recommended using the dimensions of the radiator core as the basis for inlet design dimensions.
He advocated an opening which was as wide as the radiator,but only 1/6th as tall,into an airtight diverging duct which was as deep as the full height of the core.(All NASCAR teams use this inlet)
This would handle the full heat flux of the engine under full load.(Racing)
I choose my trashcan lid according to Korff's rule-of-thumb,but at Bonneville realized it was too large since I never actually got to full power,and was so indicated by the temp. gauge.
So I dumpster dived at the Dollar Store in Wendover for cardboard boxes and taped up half of the opening.
I'm at 1/12th radiator area and I'd driven on to Carson City,Nevada,and back home with the cardboard,registering the highest mpg to date.
Once home I duplicated the block with sheet aluminum.
It's on the truck right now and will remain.
I'd let your radiator be your guide.
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There are aluminum and plastic Jello molds that might have some diameters of interest.Architectural supply houses can provide aluminum waste receptacle lids of many sizes.(Love Field in Dallas has amazing jet-turbine inlet trashcan lids in all the restrooms).
Also,some commercial rooftop exhaust fans have an inner fairing concealed within the main housing which has an ideal leading edge inlet.
The aluminum Jello molds you'll most likely find in antique shops.Thrift stores will have the plastic.
Go by the outlet diameter,this is your critical dimension.
