K&N and cone filters are used to straighten the airflow and promote better combustion. That is where the stillen intake fits it, good but sucks in hot air.
For the CAI has the benifit of cooler air but if you suck in air and straighten in (PRCAI) and then bend the pipe before the intake manafold are you mixing up the air again?
In the OCAI the air is brought in to the car and then straightned and send directly to the intake.
Ideal woule be for the Stillen/POP intake with a cover to get cold air, (I'm working on that)

 

I think a few people have suggested sticking some sort of piping in front of their underhood style intakes... Sounds like a good idea to me....

 

Oscai isn't better than the CAI, and actually the CAI helps straighten the airflow in that pipe as well as the MAF screen, unlike the stock box. lol

 

OSCAI 2.0, with ram air, may be better than CAI though. We'll see next week at Maxus.

 

Russ ... how about MY setup??

http://members.home.net/empz/MAXIMA/OSCAISIDE2.jpg
http://members.home.net/empz/MAXIMA/OSCAIBIG.jpg

Clicky Clicky!

 

The key to increasing horsepower is to give your engine more cold air, faster. Both CAI and oscai add an additional source of cold air, one from fender, one from bottom of engine. Advantage: nil. CAI uses a cone filter which allows more air than a panel filter. Advantage: CAI. The OSCAI uses all stock tuning, with accordian bends and very non-straight airflow while the CAI uses a straightened piping to conduct the air quickly to the TB. Advantage: CAI. Score: CAI 2, OSCAI 0.

Now, we know that the CAI will give you more HP, but you will see a loss of torque down low because of the air speed (faster air gives less torque in low rpms). Now, for many auto's this would cripple them in performance (because we can't control engine speed as well as sticks). The oscai will give you less overall torque and HP than the CAI but it will keep more torque down low. What each individual wants from his or her car should decide which is best for them.

Wow, that was a ramble...

 

I ask that when i first got my car. Does adding a CAI reduce low end torque?

 

No it does not, CAI gives you more power through the power band, it does not take away. Only the cone intakes take away low end grunt.

 

I agree the routing of the tube work on the CAI is smoother and less turbulent.

How about ram air though?

OSCAI 2.0 ram air 1
CAI not ram air 0

So the advantage is not as great. CAI=2 vs. OSCAI 2.0=1

Plus the intangibles

PR CAI $200+ (installation cost or above average installation job)

OSCAI $50 (free installation)

PR CAI cut hole in inner fender
PR CAI you may throw the check engine light. I've seen it on many cars.

 

You've got it backwards half way. The PRCAI, by nature of is larger than stock diameter, slows down the intake air velocity at low RPM. This is what decreases power because it effects cylinder filling, and therefore volumetric efficiency.

You want to maintain maximum charge velocity all the time. Unfortunately, with a fixed intake system, there are trade offs.

Also, all this talk about turbulent versus laminar flow in the intake is really pointless. The flow is very turbulent no mater how smooth the pipe is by the time it reaches the intake valve.

 

You are right that the larger diameter piping and whatnot does slow air speed, but it is faster because of the straightened piping. The accordian style stock piping slows down velocity because of the pockets the air can get stuck in. I think a combination of straight pipe and oscai could possibly give you the best of both worlds.

And as to the ram air, don't expect too much. Even true ram air setups only add 1-2hp at very high speeds (like 90+mph). And I don't really know your setup, but it would need to be completely sealed and not have that many 90 degree bends for it to work at that efficiency. I'm not saying you won't get more cold air, but I would't expect much of a ram air effect.

And yes the cone filter will decrease torque drastically down low, so will the CAI, just not as much. Each option has strengths and weaknesses.

 

Okay my 2 cents.

Air velocity is what you want for low end grunt. Faster the velocity, the better the throttle response. The larger CAI piping may decrease this or not.

Cones don't necessarily decrease low end grunt. It may if it's sucking hot air but that could be fixed by fashioning an airbox around it.

The main difference I see for the CAI vs oscai is that the CAI's filter is stuck on the end of the piping and the oscai's filter is much nearer the maf sensor. Since the cone is shown to give more top end power(due to less tubing friction length), I would give the nod to the oscai. The 2nd most important fact might be tube diameter. I don't think the shape of the tubing is affecting things THAT much.

I would think a airbox built around the cone would be the most ideal. But the oscai is much,much cheaper to do.

 

This was my orginal point. I suspect that the "Best" filter would be a stillen intake (cone with venturi) that has a box to draw outside air like the CAI (With the addition of PRCAI parts behind the MAF)...My idea for this box around the cone filter is using a plastic gallon container (i.e. gatorade) and cutting a hole out of the bottom for the filter and attaching a hose to the opening for cold air??

 

Hmm that might work. But I was thinking that the top would not need to be sealed. The hood would do that. How about encasing the cone w/ aluminum sheets(or plastic etc..) and then cut a large hole in the sheet. Then attach a long HVAC tube from the hole down to where ever you want the air to source fron. Use some foam strips on the top edges of the sheets to seal the top(hood) portion. This is ala SCC article.

 

I am a little confused about these 2 cold air packages. Does anyone have links or pictures of them?

Thanks
Ray

 

http://paulwendy.com/maxima/svcai.htm is an example of OSCAI.

 

How about MY Setup??

There are NO Accordian Bends ... its a Damn Straight Smooth Pipe!!

 

That is quite impressive, that must be the latest vesion of OSCAI. You must be one of the engineers for Ooglie.

 

I was confused on which intake system I would go with, but I ended up going with K/N with OSCAI.

I think there is a guy (Alex) in the Phoenix are who has the same car as me (00' 5spd) except he has a Stillen Cold air intake, and I actually had a higher mph in the 1/4! I really don't see any reason to have to put up with that loud sucking sound.