So my ap1 came with a gutted oem air box, k&n filter and snorkel going to the oem box. I was thinking of building my own cai using 3.5 tubing, velocity stack and air filter. I would plum it to place the air filter in the bumper cover somewhere. After pulling the air box there is no way to put the air intake without going in back of the radiator. I am wondering if the stock air box may have some value, because the air goes over the radiator to get to the box. I also like the look of the oem airbox.

I have done lots of research on this and there is almost too much info. What about building half a cai, by using 3.5" tubing with a velocity stack and filter going into the oem air box? Then just use the snorkel to feed the box. Is there any value using the stock air box this way, or should I ditch the whole thing?

 

You'll probably get many different opinions, don't take my word as gospel but here's my two cents.

Using a long intake pipe of constant diameter will give you a nice resonance in the power band, the longer the better. But you will likely be switching to a material that absorbs heat quickly (metal) and depending on the location of the filter you could risk hdydrolock in deep water / heavy rain conditions - depending on how you plumb it. This would be the best performing system because of the resonance created by a long pipe and the cold air source, if you are able to get the filter into a cold air space and you don't mind the added risk from water.

The OEM air box is thick plastic which gives some protection against engine heat, and it is a relatively low restriction system. The main downfall of the oem system is where it sucks air from, as the oem air box mouth is right near the radiator.

The OEM intake arm has very little restriction, and the OEM air filter has a built in velocity stack, you wouldn't gain much by replacing either of those two items IMO. The OEM air filter flows well and filters well.

A pretty middle of the road system would be the oem air box, oem intake arm, stock air filter, and a snorkel feeding into the top of the air box from a front bumper source - much like the J's Racing snorkel or others. A significant benefit comes from being able to suck in cold ambient outside air rather than hot underhood air with perhaps a bit of ram air effect, though the ram air probably doesn't have much effect until you get really high vehicle speeds. This system is very safe against water issues.

 

The OEM box pulls air from above and in front of the radiator; the OEM air guide directs air above the radiator support and to the box for colder air. Take a peek down at the guide and you'll see how it differs from driverside to passenger side.

The cooling plates which people install aren't really helping anything. The guide already does that, all the plate does is trap the air which was directed upwards to the intake.

 

Thanks, lots of info here. Ok can we separate the performance factors here? My understanding:

Airflow

Heat management

Resonance


So we are saying the oem system is good when it comes to airflow? Is the velocity stack key, because I have a k&n with no stack.

As far as heat management, the oem system maybe is good? I have a snorkel going over the radiator. Would that be better or worse then something like the aem v2 or similar design?

I know nothing about intake resonance tuning. Is this a key factor? Where can the power be gained?


So I have access to materials for very cheap. It won't cost me much to make and try new designs. Or should I just stay with the oem box?

 

stock airbox gutted is your best bet. when I bought my s, I gutted the box of the baffle. then installed a k&n filter. gutting the stock box and installing said filter gives you 7 to 8 hp gain. how do I know this, cause I did this on a dyno. the stock box makes a perfect cai. even more so if your using a snorkel like you mentioned. and its piece of mind as far as water getting sucked up. cai's using the filter in the bumper are notorious for that. your present setup is perfect. wouldn't change a thing.

 

some K&N replacement filters don't have a built in velocity stack, but some do. I am not sure of the model numbers that do or don't, I always liked the oem filter anyhow.

I think if you are using the oem air box with an existing snorkel, you are probably doing quite well in terms of performance, and reliability.

I think the resonance gain from a constant diameter long intake pipe usually occurs in the midrange around vtec, shows up as a bump in the power curve.

 

Well my k&n is beat up, has a tear in the screen. What would be a good replacement with a velocity stack?

 

I put a gauge on the intake arm to see when to change the air filter and found that with a almost new air filter(8000 miles) it registered a vacuum of 8" H2o.


https://www.s2ki.com/s2000/topic/921...#entry21319421

ROD

 

I don't know if that is good or bad, but at what point do you think it will need replacing ?

 

You have 8" off vacuum in the intake tube at idle? How much with zero air filter?

Does anyone know where I can get a reasonably priced air filter with a velocity stack?