A flap that when in one position seals off the path from the cowl to the carb, but opens the path from the engine bay to the cowl. And in the other position, opens the path to the carb and seals off the engine bay to cowl path. That wouldn’t be hard at all, aside from the fact that the control for it would need to be flexible enough to not get messed up when I open and close the hood. I’m thinking like a bicycle brake cable, or motorcycle choke cable, etc. Actually there are already those three cables controlled by the heater control sliders… what does the longest one do, the one that runs all the way across the passenger side of the dash? I could totally pillage that and use it to control the cowl flap.
And then with it manually selectable, I would be able to do some testing to see if I could tell even the slightest difference in performance with it set each way. Since I have no dyno access, that could be some really fun testing.
Oh and there were at least one or two cars that had cowl vents that would open or close following engine vacuum, I believe. But there’s no way I’d go that route. My thinking is to connect as few things to manifold vac as I can get away with, not add extra ones.
Correcto!! With the taller 351W in my car sporting an Eddy Performer RPM intake (short hi-rise) and a 1" carb spacer… a 4" thick K&N filter on a drop base still clears the scoop… abeit JUST barely.
The key to making any of these designs is having a really well sealed air box that keeps under hood air outside of the air. Adding a scoop on top, without sealing the air box to the underside of the hood will result in more air coming out of the scoop than going in.
No worries Bill, a good solid seal is absolutely a priority for me. The whole thing that got me started on this path in the first place was me wanting to feed my engine cool air, not the very hot air from inside the engine bay.
I’ve already been thinking about how best to implement the manually selectable flap for the cowl which I have decided will be called the “T3 system”. If it doesn’t have a really solid seal, then there’s no way it’s going to work as intended.
I’ve been to three cruise nights in the past week, and at all of them I have been aiming a keen eye towards any cars with cowl induction or ram air setups that I can find, to study how they’re implemented.
Most airplanes use a manual flex-type cable to actuate the cowl flaps, tho there are some that use electric type actuators. That 70SS system is what I was thinking. … Now, to make BOTH your systems work, you could put two of those back to back, one facing forward, the other to the rear, and have it shut one when the other opens, etc…???
I’ve always liked that Air Grabber scoop. A buddy of mine had one on his car, I forget if it was a Satellite or a GTX. It was vacuum operated by throttle response or a switch on the dashboard. I can agree about the “little tacky” though it’s kind of got the wow factor compared to some of todays car styling.
Steven
I may have just had a really cool idea (no pun intended). Running with the idea of the cowl having a flap that is either in position 1, providing cowl air for the intake, or position 2, opening to vent the heat out of the engine bay-- what about using an electric motor to do it, and have that electric motor take its trigger from the switch for the brake lights? So when pressing the brake, it vents, and when not pressing the brake, it seals the engine bay and feeds the carb? Maybe use a duration-based trigger (like bob’s ELFI kit does, right?) to only vent the bay when the brake has been held for at least three seconds, something like that, so it doesn’t switch modes every time I make any sort of reduction in speed. And I could put a 3-position toggle under the dash to have it forced to position 1, forced to position 2, or follow the brake pedal trigger.
I really like this idea, I’m wondering what sort of motor would work though, would have to be something small, strong, have adjustable stops for both positions, and be heat resistant enough to be happy living under the hood right above the engine.
Why a motor to the flap door? Why not use the naturall G-force. Flap door with hinge/bearing on the middle.
Accelerating the flap door falls back, braking it falls forward, maybee with a little over weight to the front of flap door so the engine compartment vents when idling.
I think you over kill the problem. Move the battery to the trunk, usa a vent hose from the stock air filter snorkel, build a air box where the battery was.
Drill holes to the inner fender, or go on with the hose through inner fender down under cooler frame if you wish.
Cold air is enough good.
This is about naturally aspirated motors, right? You cant force air into this type of motor, it sucks (vacuum) the air/fuel mixture that it need and is given through the carb.
This type of motor has been around for some time, a 100 years or so, and i think the most ideas alredy been worked out not working.
Otherwise car of today would have them.
Ram (forced air) and front valance induction were both found on Pontiac performance cars in the 70’s. I’ve actually seen a couple Trans Ams in the past few weeks that have both a shaker hood as well as front valance forced air scoops. I was disappointed to see that my idea of combining both wasn’t that original, but also it was good to see that it was done on a car as cool as a Trans Am.
I think pretty much everyone is in agreement that it’s best to bring colder air into the intake rather than hotter air. From data I’ve seen, moving the battery or anything else to put an air box under the hood is okay but not as good as pulling actually cool air from outside the engine bay. Pulling air from the engine side of the radiator really makes no sense if you think about it. This is just my opinion, but I’d be willing to bet the reason cars were designed that way for so long is because it was convenient, not because it was ideal.
Scott I just wanted to point out that an Air Box introduces air from outside the engine compartment. The Air Box is closed or sealed under the hood. With the air box you have a access cover in the engine compartment for air filter maintenance. The company Air Raid improves most of today’s factory “air Box” systems with straighter less restrictive plastic plumbing and ram air type of inlets.
Steven
“They” said it would never work. “They” being Internet keyboard commandos, “it” being using garden-store leaf blowers to supercharge an engine for more power. We, however, have proven that you can make more power on the dyno by cramming extra air and fuel into an engine with gas-powered leaf blowers; we did it on our “Vette Hack” car in the Nov. ’10 issue. What we didn’t know was if the power gains would add up to speed on a real track. In a recent episode of our Roadkill show, we found out the fun way.
I realize some cowl induction systems are supposed to exploit a high pressure area in front of the windshield but I’d be worried that using the actual cowl vent area might lead to the odd situation where you actually get a vacuum to the intake instead of neutral flow or positive pressure.
I suppose if you were racing and closed off the inlet to the heater/AC ducts it’d be less dicey but if you want heat and AC who knows what might happen?
The quick and dirty method for seeing if it will help or not is to just affix some string in the area you’re looking to draw from. If the string gets sucked up off of the surface then it’s not where you want to draw air from.
Scanning back through this thread I saw reference to the 82-85 Mustang 5.0L dual snorkel intake setup. That actually has plastic tubes inside the fenders pointing down towards the back of the air-dam. The point being they don’t just open into the fender back there and hope for the best, they actually had some direction behind the scenes. The 86+ Mustangs basically just stuck the end of a tube into the fender to draw in cooler air, no attempt at picking it up from anywhere other than the outside of the inner fender.
As someone else mentioned, most of the time these scoops are more of a cold air induction than an actual ram-air system – especially towards the middle of the hood where the pressure is a negative rather than the base of the windshield or leading edge of the hood where it will be more positive.
Exactly right. And the use of cold air on all newer vehicles follows the same methods - not for horsepower, but for fuel efficiency. Cooler air is denser, allowing more oxygen into the engine for more efficient operation to meet CAFE requirements.
I have to laugh at the idea of cowl induction interfering with air conditioning or heat. Cowl air induction might be worth 2 - 3 horsepower at 190 MPH on the superspeedway. On a street car it’s just for the look. Air conditioning would add enough weight to negate the gains made at high speed. But the car would never reach the speed needed for it to be useful. So it’s just for the look if we are talking about a street driven car.
… Now, to make BOTH your systems work, you could put two of those back to back, one facing forward, the other to the rear, and have it shut one when the other opens, etc…???
