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The responses above are fantastic! Thanks. Like one poster above, one thing I don't want to do (I'd rather driver her bone stock) is to mount an open air filter low in the engine bay using a comparatively long tube. I really don't want to get the thread off too far on the hydrolock subject, but just realize that I live in a location where "flash" thunderstorms produce "flash" street flooding with unexpected depths over 1', so as long as I live here, I will feel that this kind of CAI is out for me. If the PRM causes hot weather low RPM bog-down, it's lost it's luster for me. I didn't have noticeable low RPM bog driving here today bone stock, and we hit 107 degrees!
I am, however, intrigued by those who suggest running a SECOND intake source into the stock airbox from the hole in the pax side fender cavity, perhaps coupled with other mods to cool the air coming in from the stock inlet (such as xviper's radiator insulating mats). And, do you think we could develop a "spoon like" attachment for the stock air inlet horn that would not further restrict the opening because it would clamp OVER the stock horn?
I copied Russ's current intake, with the exception of using the new RS Akimoto Funnel Ram IV filter instead of the FR III.
Here are some pix of the tubing I have feeding this setup:
The black tubing is 4" that my NASA friend gave me. It has a very stiff encapsulated wire ribbing, and the black plastic itself is also very tough and rubbery. As jehman mentioned, there are obstructions behind the light, so the 4" stuff ends right above where you see it pointing up behind the light.
These next two pictures are the assembly that the 4" ducting attaches to. After taking the pix, I used 2 black screws to screw the aluminum piece to the remaining faux air duct. The aluminum piece is from Home Depot, and is some sort of rain gutter thing. You can see where I trimmed it a little.
Although there is no photo, the 4" stuff goes right around the aluminum piece. I used a heavy duty zip tie (1/4" wide, the kind A/C people use) to fasten the 4" tubing to the aluminum piece. I imagine a worm-type hose clamp would be fine also.
Looking down into the "fender hole" - depending on your pc monitor's brightness/contrast settings, you may be able to see the glistening convolutions of the 4" stuff down there. If I reach my hand down there it is right there.
All buttoned up. The gray tubing is a section of vacuum hose and runs around the radiator. There's a tab that protrudes from the back of the grill which keeps the hose from moving anywhere.
I will be replacing the Comptech/RS Akimoto intake with the full Comptech intake in the next week or two.
My main concern was avoiding any possibility of hydrolock. Secondly, I liked having the filter easily accessible. That ruled out the AEM/Injen types.
I was interested in the PRM, but they are in short supply.
I liked the Comptech, but only recently did I really understand and come to appreciate the design. The two sections of ducting I installed will feed the Comptech box pretty well.
A friend in Jacksonville just installed the PRM with a 1.5" diameter ducting in place of the 4" stuff I used, and it goes straight from the grille to the PRM horn. 1.5" makes it thru the tight confines behind the light with no modifications.
Another friend routed the same 1.5" ducting to a bulkhead fitting attached to the stock airbox. He now has the Comptech CAI that I had an opportunity to look at.
As far as DoleBludger's question...I don't know that I can prove a benefit, but more air can't hurt.
The primary resonance is going to be determined by the length of the tube from the throttle body to the end of that tube. So, if you have a tube that goes from the TB to a filter behind the headlight (ala Comptech), the resonant frequency is determined solely by that. Any tubing you bring up to the filter will not affect that resonant effect. If you were to seal up the tubing to the box (IOW, the box can only get its air from the extended tubing in the fenderwell), you might see a secondary resonance effect, but the biggest factor will still be the primary tube length.
Please forgive what may be a stupid question,, But I'm here to learn. In a case where additional air is pulled from the pax side fender cavity, do you mean that the distance to the filter is relevant in effect produced? I must applolgize, but it seems from this thread that there are many of us out there who feel the s2k isn't getting enough (cool) air to perform at it's best. Many of us aren't great auto techs. We just like to drive sports cars, so call us "drivers" or whatever. The "techs" that I've known before say "always start with the air intake" in making a car perform better. However, the ones I know are at a loss as to this car (which, after all, is somewhat limited production, at least around here). So, if we assume that at least part of that air is comming from that hole to that cavity, is it best to have the filter close to the cavity, or relatively far as in the stock air box?
It really depends on where you want power gains. There are three primary factors at play with an intake system on the S2000.
1. Air temperature - here the length of the tube really doesn't matter much. You just want the coolest air possible.
2. Overall restriction - The less restriction you have, the better. Compared to the stock airbox, systems which put a small snorkel on the front have more restriction. Aftermarket filters tend to have less restriction. The longer the pipe, the more restriction. The bigger (diameter) the pipe, the less restriction. A continuously tapered pipe will have less restriction than a straight walled pipe.
3. Resonant tuning - The length of the primary pipe (from TB to air filter) will determine what frequencies the pipe resonates at (you can look up formulas for this - resonant frequency, helmholz resonators, etc. should be good starts for the search terms). At the resonant peaks the intake will act like a mild supercharger, raising intake pressure in the intake manifold and increasing power at that point. In a straight walled pipe, these peaks tend to be somewhat narrow in rpm range and high in intensity. Systems like the AEM and Injen tend to have resonances in the mid 3000's and mid 6000's rpm wise. If you were to cut that pipe length in half, the resonances would move up (to about double the frequency).
Which is most important? Well, they all are. I'd say cool air comes first since the S2000 ECU is so sensitive to intake air temps. After that restriction and resonant frequency are kind of equal. You kind of trade one for another. Putting the resonant frequencies where you drive every day tends to mean a longer (more restrictive pipe). Less restrictive pipes don't give you the resonant frequencies lower down where you would like them. So, what do you want? Figure that out, then start looking at system design.
Originally posted by jehman
This may seem kinda silly because I typically hate infomercials, but has anyone tried that air flow gizmo that supposedly smooths out the airflow in the intake tube prior to the throttle body?
Jehman
Hey Chiung, shoot me your best price on your Akimoto IV if you want to sell it. I'm still waiting on the carbon fiber kit Tim was thinking of doing a group buy on but until then, I'm either going to try the BMC box or stick with the current set-up. Hmmm, come to think of it, are you going to use the RA filter with the Comptech kit?
07-14-2003, 03:51 PM
