Custom CAI under-car scoop project

[whitenoyz]

I think the point is to prevent water from getting sucked up into the intake, but AEM makes a bypass valve that prevents that, and it looks a little cooler. But hey, DIY always feels good

[UnDeR_FLiP]

Originally Posted by whitenoyz

Negative, the top of the car is curved more than the bottom, just like an airplane wing. bernoulli's principle states that air moving over the car will be moving faster, which is why cars at high speeds need spoilers to produce downforce, because around 150 mph, planes take off, and so will cars unless they're being pushed down. An air intake at the top of the car will get air that is moving faster. Whether that will translate into performance gains, most likely.

word, I'm gonna have to check my sources..lol. I think I heard on some Discovery Channel show (where they were showing the performance aspects of an F1 car, or something) that the air moving underneath the car moves faster than the air over the surface, thus sucking the car onto the pavement at high speeds.

Guess I may have gotten things mixed up. haha.

[whitenoyz]

Well the massive wing on the front and the back of the F1 car slows the air moving on top, but the air moving under keeps going. The air pushes the spoilers down, so they car ends up weighing thousands of lbs. more than when it's standing still. It can actually drive upside down in a tunnel at around 140mph, or maybe faster, not sure the exact speed.

[BrokenJohnny]

what's a point for doing this? more power? or keeping the dust away? cuz i don't see either happenign
goos job tho that's quete a bit of work

The point of this is to duct fresh air directly towards the filter, without any of it being wasted by going into the rest of the engine bay.

Will it give me any more gains than a standard cold air intake? I have no idea. Will it give me less gains? I doubt it. Do I care either way? A little bit. Did I have fun doing it? Hell yeah!

As for dust,I guess your filter will always be picking up dust. That's it's job. With this set-up, my filter will not get splashed with muddy road water, like it would when it was sticking out from beneath the bottom of my car. The filter is now about 7 or 8 inches higher up than it was before, and covered by the metal shroud. I figure now that I've drilled a few holes in the bottom of the accordion pipe, most of the water collected during rainy driving will just drain through the bottom part. Also, with this set-up, during mid speeds, my intake will have less effort sucking in fresh air, because it will have a constant supply being directly channeled into it.

I think the point is to prevent water from getting sucked up into the intake, but AEM makes a bypass valve that prevents that, and it looks a little cooler. But hey, DIY always feels good

The bypass valve is more to prevent your engine from sucking up huge amounts of water. If you took your intake pipe and stuck it in a bucket, it would suck up massive amounts of water and be destroyed. With the bypass valve, it would only suck water into the first few inches on the tube, and then air through the bypass valve.

But aside from all that, I don't think a bypass valve would prevent tiny droplets of water being sucked towards your filter, especially during heavy rain. I'm imagine that any tiny fragments of water would be instantly vaporized when they reach the hot intake manifold. But again, unless your filter has holes in it, no water should ever reach the combustion chamber.

But that's just my personal speculation. If I'm wrong, please let me know.

[Turk]

A few tiny droplets of water would cool things down nicely . Its like having a free water/meth injection . just no meth

[88626gt]

Bump...

This thread gave me some ideas to fix my own cold air intake, so I thought I'd just bump it to add what I ended up with.

I just got around to checking the air filter on my newly acquired mx6 to find that only the flange was left. I guess it was sitting too low and was accidentally ripped off at some point by the previous owner. The first thing I did was adjust the pipes and cut off 3.5" from the bottom to get the new filter to sit like this:


Then the splash guard was in the way and wouldn't be protecting the filter once it was trimmed, so I thought I'd make a new guard. All your talk about pressure zones made me want to take advantage of the one just in front of the radiator, so I bent up a new splash guard that would protect the filter as well as channel some left over high pressure air to the filter. I ended up with this:


It completely replaces the plastic guard in front of the filter, and extends into the bumper:


There's about 1" of space between the shield and the bottom of the radiator/sub frame.


I thought about boxing in the filter so the only air inlet was this new one, but I'm too lazy for that right now.

No idea how much of a difference it made because at the same time I changed the oil finally, cleaned the intake pipes/couplers/throttle body, and reset the base timing and idle. It's running a lot stronger now, so it could've helped If it did or didn't, I'm satisfied with the splash guard protection at least, and it only took an hour or two and under $10 worth of materials.

[outlaws318]

Originally Posted by whitenoyz

Negative, the top of the car is curved more than the bottom, just like an airplane wing. bernoulli's principle states that air moving over the car will be moving faster, which is why cars at high speeds need spoilers to produce downforce, because around 150 mph, planes take off, and so will cars unless they're being pushed down. An air intake at the top of the car will get air that is moving faster. Whether that will translate into performance gains, most likely.

I love stuff like that "bernoulli's principle"

In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's gravitational potential energy. Bernoulli's principle is named after the inventor Daniel Bernoulli.

Bernoulli's principle can be applied to various types of fluid flow, resulting in what is loosely denoted as Bernoulli's equation. But in fact there are different forms of the Bernoulli equation for different types of flow. The simple form of Bernoulli's principle is valid for incompressible flows (e.g. most liquid flows) and also for compressible flows (e.g. gases) moving at low Mach numbers. More advanced forms may in some cases be applied to compressible flows at higher Mach numbers (see the derivations of the Bernoulli equation).

Bernoulli's principle is equivalent to the principle of conservation of energy. This states that in a steady flow the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. If the fluid is flowing out of a reservoir the sum of all forms of energy is the same on all streamlines because in a reservoir the energy per unit mass (the sum of pressure and gravitational potential ρgh) is the same everywhere. [2]

Fluid particles are subject only to pressure and their own weight. If a fluid is flowing horizontally and along a section of a streamline, where the speed increases it can only be because the fluid on that section has moved from a region of higher pressure to a region of lower pressure; and if its speed decreases, it can only be because it has moved from a region of lower pressure to a region of higher pressure. Consequently, within a fluid flowing horizontally, the highest speed occurs where the pressure is lowest, and the lowest speed occurs where the pressure is highest.

[vandejm]

i just relocated the battery (9lb race battery) and put the intake into the fender behind the splash guard...was pretty easy to do...

[cf_z]

you shoulda seen the 'cai' that (the now banned..) evil_demon rigged up with his hole in his hood. He had the thing like snorkeled out the hole. it looked sick. he said it worked really well too haha.

[BrokenJohnny]

Originally Posted by cf_z

you shoulda seen the 'cai' that (the now banned..) evil_demon rigged up with his hole in his hood. He had the thing like snorkeled out the hole. it looked sick. he said it worked really well too haha.

Any chance you can dig up the thread? I'd like to see it.

[cf_z]

there never was a thread. He did it after he got banned.

He pulled up in my ally one day and i was like "what the [fizzle] is that...".haha.

if you ever saw any pictures of his car with the big hole in his hood, just picture a flexable pipe hanging out with a metal screen and some cloth ish stuff. I bet it worked like he said too.

[FS-ZE Freak]

^^ is there any way you could snag a pic of his 'CAI'..I'd love to see something sticking out of some one's hood.

[cf_z]

... he also texted me and told me he blew his engine. If i ever go up to his house again i will be sure to bring my camera.

[Stealth]

old thread, I just woulda made a splash guard though. I got dirt and [shizzle] all over my filter and I didnt even drive it in bad weather or gravel roads... Its just the fact that the filter is under the car its going to get dirty.

Also no matter how dirty your filter is, when you take it off to wash it in the sink look inside its like brand new Thats why you shouldnt have to worry about dust. With this style of intake I would be more worried about it scooping up water, whereas if its not enclosed in these 2 cones with a downwars snorkel theoretically the bottom half of the filter can be submerged and you will still suck in air from the top half.