This is kind of a continuation of the 100 mpg thread, but since I'm taking it in a different direction, and that ones kinda long, starting a new one. We've all heard of it, some of us have probably tried it, or know someone who has. Make a sandwich, with 2 carb to intake gaskets as the bread, and 1 or more layers of SS screen as the meat.Some say to use 2 layers of screen, and run the strands of 1 at a 45 degree angle to the other.Others say to make it so the screen is at an angle to the direction of flow, and to explain why, say this; "Take an aerosol can of wd40 or similar product, and a piece of screen. Hold 1 in each hand, so that you can view the edge of the screen, as you spray thru it. Start spraying with the can parrallel to the screen, and gradually tilt the screen.When you get to the 'right' angle, the spray turns into a cloud or fine mist."Some have put the screen between 2 intake manifold gaskets. And then, theres Don Kendalls Intake manifold scrolls. (See the Yahoo group of that name for details).Basically, he uses Galv. screen, (in case any pieces come loose and are sucked into the combustion chamber, less likely to cause damage). He rolls the screen up, and works it into the intake manifold, so its laying in the main runner, and going up the legs, ALMOST to the intake valves.All claim similar results;better milege, smoother running, more low end torque.All things which are somewhat subjective, without thorough before and after testing.
I had always figured the way they work is similar; droplets of gas are caught in the screen, and smaller droplets are sucked off the 'backside'.Then I read the patent for the "Webster-Hieste Valve".The inventor puts forth a theory to explain how his invention works, that he calls "Sonic shock vaporisation".Never heard of it anywhere else.
First, some background. Webster was the patent lawyer, Hieste the inventor.Hieste had been experimenting for several years with variable venturi carburetors. (Or, as I prefer to call them, Constant Vacuum carbs, as opposed to Variable Vacuum carbs.)His invention is composed of 3 main elements; The 1st is the valve.It mounts at the bottom of the variable vacuum (typical american style) carb, centered under the venturi. At least in terms of its effect on vacuum, it converts a variable vacuum carb to a constant vacuum carb, insuring that you'll have similar vacuum at all throttle positions.The 2nd part is a fuel air mix diverter. Also centered under the venturi, its a cone shaped piece, with its flat botton resting on the bottom of the intake manifold, and concave sides.Its purpose is to turn the fuel air mix from vertical direction to horizontal direction.The final part is the screen; 2 layers of screen, 1 course, (50 strands per inch) and 1 fine, (120 strands per inch), layed right up against each other, and formed into a cup shape, and then into a flange that can go into the sandwich (looks like a sink strainer).His theory, or explanation is this; The droplets of atomised gasoline are traveling down out the bottom of the venturi at greater than the speed of sound .They are turned 90 degrees, and firstly cross a slower moving stream of droplet free air, coming down the outside of the venturi. Then they encounter the screen, which causes a sudden decelleration.This sudden deceleration causes 'sonic shock', which causes the droplets to vaporise. For analogy, I think of it this way; Imagine you had "Bewitched" kind of power. A fighter plane is traveling at Mach 1+. You twitch your nose, causing it within 50 feet, to slow to,...say 100 m.p.h.Even tho it didn't hit anything, such rapid deceleration would cause it to,...well vaporise.
The claim in his patent is for improved mileage. He apperently DID demonstrate it for the big 3, in the early 80's, and had a 'successful' demonstration.
Interestingly, he says nothing in his patent about needing to heat the intake manifold.I know my 262 has a heated carb spacer, below the carb, to prevent carb icing.When gasoline vaporises, it gets cold.Maybe thats only when vacuum is used for vaporising, and doesn't happen during 'Sonic shock vaporising".I don't know if its possible/practical to get totally vaporised gasoline into the combustion chamber, or whether the compression stroke would cause it to change back into a liquid.I don't know if adding heat would help to keep it vaporised. I don't know how much (if you could do it) it would improve mileage, or if 'lean burn' would be a problem.It does seem to me that a constant vacuum carb is a logical first step. I don't know whether Hieste came up with his valve cause he figured he'd never sell Detroit on those 'Europeen" carbs, or whether the valve is what made his invetion unique, and therefore patentable.I am gonna experiment with this, and to make it easy on myself, I'm starting off with a Predator Varible Venturi Carburetor.You can't "over-carb" with a variable venturi, and they list them as 300-930c.f.m. I'm bolting it to a Clifford intake, needing min. of 390 c.f.m., so I shoud be o.k. there.No need for the valve, so gonna put a bar, (triangular in cross section, with concave sides and a flat bottom)centered with the 'point' directly under the air doors, to turn the flow from vertical to horizontal.And then make a 'sink strainer' with 2 layers, (1 coarse, 1 fine, strands 45 degrees to each other).Anyway, wifes home with 'honey-do's, sorry for the long post, hope this generates some discussion. Jim
I had always figured the way they work is similar; droplets of gas are caught in the screen, and smaller droplets are sucked off the 'backside'.Then I read the patent for the "Webster-Hieste Valve".The inventor puts forth a theory to explain how his invention works, that he calls "Sonic shock vaporisation".Never heard of it anywhere else.
First, some background. Webster was the patent lawyer, Hieste the inventor.Hieste had been experimenting for several years with variable venturi carburetors. (Or, as I prefer to call them, Constant Vacuum carbs, as opposed to Variable Vacuum carbs.)His invention is composed of 3 main elements; The 1st is the valve.It mounts at the bottom of the variable vacuum (typical american style) carb, centered under the venturi. At least in terms of its effect on vacuum, it converts a variable vacuum carb to a constant vacuum carb, insuring that you'll have similar vacuum at all throttle positions.The 2nd part is a fuel air mix diverter. Also centered under the venturi, its a cone shaped piece, with its flat botton resting on the bottom of the intake manifold, and concave sides.Its purpose is to turn the fuel air mix from vertical direction to horizontal direction.The final part is the screen; 2 layers of screen, 1 course, (50 strands per inch) and 1 fine, (120 strands per inch), layed right up against each other, and formed into a cup shape, and then into a flange that can go into the sandwich (looks like a sink strainer).His theory, or explanation is this; The droplets of atomised gasoline are traveling down out the bottom of the venturi at greater than the speed of sound .They are turned 90 degrees, and firstly cross a slower moving stream of droplet free air, coming down the outside of the venturi. Then they encounter the screen, which causes a sudden decelleration.This sudden deceleration causes 'sonic shock', which causes the droplets to vaporise. For analogy, I think of it this way; Imagine you had "Bewitched" kind of power. A fighter plane is traveling at Mach 1+. You twitch your nose, causing it within 50 feet, to slow to,...say 100 m.p.h.Even tho it didn't hit anything, such rapid deceleration would cause it to,...well vaporise.
The claim in his patent is for improved mileage. He apperently DID demonstrate it for the big 3, in the early 80's, and had a 'successful' demonstration.
Interestingly, he says nothing in his patent about needing to heat the intake manifold.I know my 262 has a heated carb spacer, below the carb, to prevent carb icing.When gasoline vaporises, it gets cold.Maybe thats only when vacuum is used for vaporising, and doesn't happen during 'Sonic shock vaporising".I don't know if its possible/practical to get totally vaporised gasoline into the combustion chamber, or whether the compression stroke would cause it to change back into a liquid.I don't know if adding heat would help to keep it vaporised. I don't know how much (if you could do it) it would improve mileage, or if 'lean burn' would be a problem.It does seem to me that a constant vacuum carb is a logical first step. I don't know whether Hieste came up with his valve cause he figured he'd never sell Detroit on those 'Europeen" carbs, or whether the valve is what made his invetion unique, and therefore patentable.I am gonna experiment with this, and to make it easy on myself, I'm starting off with a Predator Varible Venturi Carburetor.You can't "over-carb" with a variable venturi, and they list them as 300-930c.f.m. I'm bolting it to a Clifford intake, needing min. of 390 c.f.m., so I shoud be o.k. there.No need for the valve, so gonna put a bar, (triangular in cross section, with concave sides and a flat bottom)centered with the 'point' directly under the air doors, to turn the flow from vertical to horizontal.And then make a 'sink strainer' with 2 layers, (1 coarse, 1 fine, strands 45 degrees to each other).Anyway, wifes home with 'honey-do's, sorry for the long post, hope this generates some discussion. Jim
