When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
"Better" is somewhat subjective. Are you asking in terms of power gain? Sound? Initial cost? Ease of installation? How it looks in the engine bay? You need to be more specific in order to get a specific answer. If you try an advanced search using "CAI", you'll get lots and lots of returns. This question has been asked quite a bit.
ps. I have the AEM CAI. It was a good price, gives a bit of extra punch, sounds real nice. However, it required some cutting of the car for the install and leaves a gigantic "hole" in the engine bay where the stock box used to be.
1. Cost
2. Ease of installation (cutting involved or hood modification required?)
3. Gains and more importantly, WHERE in the RPM band.
4. Asthetics
5. Will it allow room for your own STB (if applicable)?
6. Sound
7. Do you want to retain the OEM box?
Using any or all of these conditions would either rule out or include any of the following:
IDI "Spoon" intake
Spoon yellow CF intake
Mugen CF intake
Comptech intake w/ CF topped cover
K&N
Injen
AEM
Weapon R
PRM Jet Stream (my choice)
DC Sports
I'm sure there are others I've left out but they essentially fall into four categories, those that utilize the stock OEM air box, those that locate the filter near the front right wheel well opening and those that place the filter in the upper regions of the engine compartment but enclose or encase the filter, protecting it from the vast majority of heat coming from the block. The Mugen goes one step further than the latter by not only placing the filter above but routing a gorgeous carbon fiber air duct down below. It's also about $1500.
All I can do is tell you why I opted for my PRM Jet Stream intake. I did alot of research on intakes and could not find one single owner of this system that was displeased with it. A few guys in the Toronto owners forum (see clubs) have it (the company is located in Ontario) so once I confirmed their thumbs-up, I called Gerry at PRM and (according to him) became the first S2000 owner in the states to purchase his latest unit for the S2K. I've fiddled with it and done a few alterations but after two months of trying to make his mouse trap better, I have found that it works best left unaltered and installed the way it comes delivered. The horn (as I discovered) actually plays a very important part in the air delivery process as it "funnels" the path of the air into the K&N filter (which is enclosed inside the black casing). When I removed the horn section, my accelerometer tests revealed a LESS effective intake. When I put it back in place, my times showed a consistent improvement so I know this "vortex" type of approach to intakes (and filter construction) works. I have run my car very aggressively in temps above 85 degrees, pulled the car over at three bars, opened up the hood to be blasted by the underhood temps but when I put my fingers inside the intake opening, it was CONSIDERABLY cooler than what was happening on the outside. I've fiddled with wrapping the aluminum piping with insulation wrap but simply haven't gotten around to ordering the wrap which encloses around that section. I did apply some Rubatex rubber insulation over the black casing and that seems to have made the interior even cooler but in truth, that casing does a fantastic job of protecting the filter from the engine temps. When you turn the car on and open the hood, while idling, you can put your hand inside the horn section and feel the air being funneled in...it's kinda neat actually. There isn't much of that intake "whistle" you hear with open filters though and the PRM doesn't deliver that intake "honk" that oftentimes will completely mask over a nice exhaust note...it just sort of growls alongside it. There is no cutting involved and while I haven't dyno'd the unit yet (I will later in October), my accelerometer testing (done so judiciously the details would put you to sleep) did reveal a solid 8-9hp gain in my HP tests but bare in mind, accelerometers measure drag as well so the "actual" numbered improvement at high speeds might be a shade higher. The logbook of info I have done on my meter runs pages long. I'm not really moved by dyno plots on intakes though. You won't really get a true and accurate indication of their effectiveness unless you're moving thru the air...in my case, above 50mph. The PRM is designed to maximize high RPM power so it's not the kind of intake to buy if you're looking for gains down low. I figured if I was after power, it was because I was in VTEC land anyway so that's where I wanted the biggest gains. I'm not a butt dyno guy, but have owned enough sportscars over my 41 years on the planet to know when a mod is either doing harm or good (and sometimes, neither). Most of these intakes are all within the same parameters of performance....that being within 2-4hp of each other. The ones to avoid are the ones which place the filter directly adjacent to the engine without some sort of protection. Those are simply very poorly designed and you really don't see anyone carrying those earlier offerings anymore. Call 'em the "hot air intakes."
It comes down for most of us to "power, asthetics and cost." Use your own guidelines but for most of the units described above, cost and looks are the biggest differences, not results.
I took the AEM CAI and have no regrets. I have their products on other cars and the results have been nothing but positive. They are a reputable company producing quality parts.
I did the install myself. I was fairly straight forward. I took about three hours at a novice level. That included a pizza break and two quick breaks. The most time consuming part was trimming the splash pan as cleanly as possible. If you just cut a big gapping hole in it you'll be screaming in VTEC in under two hours. However, I chose the "professional look" route.
I have the PRM also and feel a very definite improvement throughout the rpm range. Before vtec it sounds very much like stock with a low subtle growl. At vtec it adds a raspy note to the stock sound - not unpleasant. There is plenty of cool air available coming both from the wheel well area and to the left of the radiator. Costs about $295 including shipping.
From my personal experience, I believe S2000 intakes have less to do with adding straight-line power and more with sound and less bogging in hot weather.
I had the AEM:
1) Did not like the sound from 6K-9K as it makes the car sound like any other car with an AEM CAI (farty and given our stratospheric redline, even fartier than the others).
2) Totally by feel, but the rev range characteristics changed for the negative as I felt a noticeable fade from 8K and up
3) Does not look all that great in the engine bay
4) Did add a bit of power in the mid-ranage (again, by feel)
I personally love the sound of the stock box with an aftermarket exhaust. However, if I ever do buy an aftermarket intake again, I'd go for one that's on the quieter side. And fighting over 1 or 2 hp differences between intakes is splitting hairs and that includes the well designed stock box.
