cold air intake - how to create one

[Tonglebeak]

My car is in my sig.

Unfortunately, K&N doesn't make a cold air intake for my car, and neither does anyone else from what I can tell, so I'll have to make my own. Just consider me the average at-home mechanic for right now. What steps/tools/anything, do I need to do in order to make this work? Does CAI really make much of a difference anyways?

Thanks.

[curtis73]

It doesn't make much of a difference depending on how much restriction is imposed by the factory intake. But its a heck of a rewarding project and the sound is pretty awesome

I had plenty of room under my hood so I just did it with some 3" PVC tubing and an elbow along with some rubber drain pipe joints from Home Depot. For a while I used a chrome big-bore exhaust tip for the tubing but I couldn't get it to seal to the PVC well enough.

If you have a tight engine bay you can get a little more creative. You can maybe find some of that bendable exhaust pipe repair stuff and bend it how you want it, then take it to an exhaust shop and have them bend a piece of applicable exhaust tubing to that shape. You can also buy some pre-made bends of exhaust tubing and weld up your own.

Get creative. You can't go too big so when in doubt go one size bigger than any stock diameters you find.

For the most part you want your intake sensors in about the same location, but don't get anal about it. Within a couple inches should be fine.

[Tonglebeak]

Thanks a lot for the reply. I'm curious to three things now:

1) Do you have a picture of your intake (so I can use it as a general reference)?

2) Where should the intake opening be located at? As far away and as low from the engine as possible, or does it need to be somewhere else?

3) What about air filtration? Can I simply use the stock air filter housing, or do I need to create my own?

I don't have any torches or whatnot to do any welding (don't have any welding experience to begin with), so if PVC piping works, then I'll love that a lot more

Again thanks.

[beef_bourito]

as for desired placement, you want someplace where it'll be cold, so far from the engine. common places are in the front fenders, in a place that gets alot of fresh air, i don't know, do you have a picture of your engine compartment that we could have a look at? you COULD use your stock filter and whatnot but you'd probably be better off with a K&N filter or another performance filter, it'll perform better and give you better gas mileage 9although it probably won't be very noticeable)

[curtis73]

You can hit up Ebay for a K&N cone filter or use your stock box. If there are sensors in your air box or in the intake tract, its just common sense placement when you put them in your own plumbing.

I don't have a photo of it and right now I have an aftermarket CAI (moved to california so I needed a "legal" one) But I'll see what I can find. Mine is a RWD V8 with the TB right up front so it might not help you at all anyway.

You want to source the air from somewhere cold. Most places under the hood are going to be hot, except the front while you're moving. I put mine behind the headlight assembly where the stock box was. I just put the K&N in place of the stock box. temperature sensors showed cool ambient air temps when moving, but warmer when your sitting still. Of course, when you're sitting still, you don't need extra power anyway

I like to keep the filters high. Some aftermarket intakes have a "snorkel" that goes down and gets air from below the front bumper but I've heard horror stories about puddles. You can basically kiss your engine goodbye if you ingest too much water. Don't worry about rain water or water splashed up from a car in front of you, but if you hit a puddle with a low snorkel like that it might ingest enough water to do some damage.

[GreyGoose006]

like if the road floods, and you try to drive out.
that kind of water.

[SaabJohan]

Originally Posted by Tonglebeak

2) Where should the intake opening be located at? As far away and as low from the engine as possible, or does it need to be somewhere else?

The placement is important. Not so much to get cold air, but in order to get air with a high pressure. This means that the air should be taken at a high pressure zone. This of course dependant on the shape of the car but in general we have two high pressure zones we can use. The first one is around the front bumper in the middle of the car, the intake to the radiator is placed here because of just that reason. The second place is on the hood just before the windshield, that's why air to the coupe so often is taken here.

A simple way to do it is to take the air the same place the radiator do, just place a duct over or on the sides of the radiator. Something like this is often used on racing cars but then the "whole package" tends to be redesigned. Meaning that the radiator type and placement is changed, so are the intakes and all ducting to and from these components.

[KiwiBacon]

Originally Posted by SaabJohan

The placement is important. Not so much to get cold air, but in order to get air with a high pressure. This means that the air should be taken at a high pressure zone. This of course dependant on the shape of the car but in general we have two high pressure zones we can use. The first one is around the front bumper in the middle of the car, the intake to the radiator is placed here because of just that reason. The second place is on the hood just before the windshield, that's why air to the coupe so often is taken here.

A simple way to do it is to take the air the same place the radiator do, just place a duct over or on the sides of the radiator. Something like this is often used on racing cars but then the "whole package" tends to be redesigned. Meaning that the radiator type and placement is changed, so are the intakes and all ducting to and from these components.

Work out the pressure gain from trying to use "ram air" at legal speeds.

It's not worth the headache. Plus you'll suck up a lot of insects.

[curtis73]

Agreed. Ram air or placement in a high pressure area has only been shown to account for a very few HP and only at very high rates of speed.

[Chiquae07]

he could piece one together from autozone, those spectre brand with the bends and things. they have some mock up kit that you could basically get for free with a rebate or so. thats basically what i did with my sentra. i removed the airbox, relocated the battery, and put the intake basically right where the battery was. put a K&N filter on the end and called it a day. cost me maybe 50,60 bucks tops. drilled a hole for the maf, and w/e other sensor comes before the maf right into the filter itself. its a ton louder, more throttle response, more power, and gas milage. its not too hard.

[doberman_52]

We like to use vent tubing for our CAI, easy to use and is cheap, anouther place you could put it is in the fender in front of the tire, but you would want a deal up on top to let air in there if the filter gets submerged in water, you could also have one made by a shop for ya too, it would cost me about $50 - $80 and i have a similar car to yours, the grill wouldnt be a bad spot either,