i notice that most people who run a scoop of some kind (1x4 or 2x4) have the opening faceing the front?...any particuliar reason for this?...i would think that it would cause a drag cause of the air hitting the inside back of the scoop?...does it run this way, affect the A/F ratio as far as different sz jets in the primaries or idle air screws?...i personally run a V-stack with a flame arrestor in the top, giving me 360* of air
I wondered the same thing, but look at the 1/4 mile dragsters (Car) they all dont seem to have any problems with their set ups and i know that there are quite a few guys that run damn near the same types of engines that they do. Power to power that is.
I dont have any idea if your 360 deg. velocity stack is or is not more efficient rather the scoop designs?
I suspect that my scoop my be limiting my power, however, I also think my windshield is creating a vacuum which happens to be directly in front of my scoop. I havent tried running it without the scoop since I put it on, but I might have to take the windshield off and run my flame arrestor only to see what kind of difference it makes...I doubt that the scoop actually creates much drag...
Ask yourself why cowl induction works....high pressure area at base of windshield.
Pressure always wants to go from high to low.
To be effective, a functional scoop opening must be located at/in a high-pressure area.
Best to allow the amount of air entering to be regulated by the pressure in the bowls and the motor's needs rather than to allow forced air to regulate the air to the motor/carb.
Carbs theoretically work better in a calm air environment, ie. an air box.
I have heard is that you actually will loose HP with the scoop facing forwards caused by turbulence and eddies disrupting the airflow and mixtures.
Anyone got an engine dyno and wind tunnel combo? If not then all this is moot.
Aerodynamics may cause the air to miss the forward facing scoop entirely.
This is subject to the specifics of the boat and placement of the scoop.
Velocity stacks at high speeds could create a low pressure area over the opening because of the air flowing across them. This can create a rich mixture condition, i.e. the "Bernoulli effect."
Turn that scoop around! What have you got to lose, less dirt & road stuff getting into it, less chance of rain or someones roost getting in there
One bonus I have had from my scoop is once when I was beached I had some monster wake from a big cabin cruiser wash right over my transom and flood the hell out of my boat. They were crashing right over the engine, and my scoop kept the water from going right down the carb.
However, I'm missing a couple hundred RPM and I suspect the scoop. Like I say, I think my windshield is creating a vacuum right at the opening of it, so it's very bad placement...