I’m currently using a drop-in K&N but I want to get rid of the airbox altogether. I’d like to get everyone’s opinion of the different options out there.
Warm-air vs. Cold-Air? Is the extra expense and hassles (install, rattles, rain, etc.) of CAI worth it? Foam vs. gauze? Any brands you like or avoid?
Thanks
I have found that Good Foam filters offer much better flow then paper and cotton. I tested many on street and race cars both on and off the dyno and there is a significant difference in flow. Foam is the most difficult to maitain (it needs cleaning more often).
From an all out performance perspective on a naturally asperated engine (generally speaking), CAI with foam filters would offer the greatest hp/torque gains.
I would NEVER recoment a CAI, especially on the street, with out a bypass valve. During the big rain storm this summer we had 3 customers, at my shop alone, that hydrolocked and destroyed there engines ( two were not cheap honda JDM engines) due to CAI’s w/o bypass valves. Also last winter we had a customer that blow up his engine due to his CAI filter getting so packed with snow it would not breath and was also taking in moisture. Look for independent dyno tests on your make and model for gains with CAI vs. WAI as if there is not much of a gain on you particular application CAI is not worth the potential hassles.
Not to scare you but only consider a CAI with a Bypass valve and ensure that you maintain it from not only dirt but also snow packing. If you do this you’ll be fine.
On naturally asperated engines the issue of size of the intake and length is also critical. Companies like Comptech, Injen and AEM usually pay particular attention to the “tuned length” of the intake and in some applications find that a shorter properly tuned intake length offers greater gains then a longer CAI system. They may, or may not, openly disclose this that is why it is advisable to look for independent dyno tests on various products, preferable compared on the same dyno with the same car. This is the only way to get a accurate measure for what system will suit your application. But generally the bigger companies are more expensive because of this attention to detail, making them the better bet. Again, generally, shorter intakes develop less torque and better high rpm response, longer ones develop more torque and less high rpm response.
I could list off dozens of differnet examples and combinations that we found worked best on different cars and set-ups but it would not be accurate to assume they would work best for you. I look for dyno #'s on particular systems and consider how diligent you will be in maintaining the setup to make the best informed decision.
Hope that offers some help, at least in terms of performance. Feel free to call me or cory at the shop if you need anything else.
best of luck! Neil
Thanks Neil!
A gold mine of info and guidance for a noob like me 
I’ve had a hard time finding info for my car because it is an older sedan and not made by “the H-word”. No independant dyno comparisons for NA 1G Altimas. Is it OK to look at NA 240SX tests since they both use the KA24DE? Or does the higher compression make comparisons inaccurate?
The only big name products I found (specifically for 1G Altimas) were drop-in replacements by HKS (foam) and K&N (cotton), or cotton pop chargers from JWT and Stillen. Hot Shot has a CAI for it but I don’t think I will go that route. I’ll probably pick either the HKS drop-in foam panel or the Stillen WAI cotton cone.
BTW, I’m still interested in your price for installing a high-flow cat and relocating my O2 sensor. Thanks again for the advice,
Archie
hks foam mushroom and drop ins …or else blitz all metal
Thanks for the tip on all metal filters. I had no idea such things were available! Here’s what I found on their website:
“The BLITZ® SUS Power air cleaners are made from top quality T-304 stainless steel. Totally unique, the entire filtration element is made from a fine stainless steel T-304 mesh (200 micron mesh and 150 micron crown). This mesh means the filter will never wear out, and have substantially less restriction than any other filter. Another feature is the super fine pattern of the mesh. This straightens the airflow and dramatically reduces aerodynamic tumble (restrictive turbulence).”
Does that mean that anything smaller than 150 microns will pass through the filter? Human hairs range from about 20 microns to 200 microns. Lots of dust particles are smaller than 150 microns! I must be missing something . . . but what :?: . . . maybe I’ll go with the HKS foam.
Edit: Maybe they mean that the mesh is 200 microns thick? Obviously the thing must work, just curious how they do it without using oil to trap the dust. Can the steel mesh really be made fine enough to trap 10 micron particles?
Archie, I think that the 240sx would probably be the closest comparison to the altima. For most purposes i think that this comparison would suffice since your vehicle is hard to get dyno stats on. I 'll try and get back to ya today on a price for that other work. If you get a chance call me this afternoon as we may get busy. 447-3282.
Neil.
Neil, I got your message. Thanks to you and Scott for your advice. I’ll see you at your shop.
I just changed my HKS foam mushroom yesterday to the stock airbox with HKS drop in square filter becuase I checked and the whole cone over the first 2-3 days of slushy winter has become brown and slightly damp which is no good …
HKS foam does not repel any water such as K&N filters that are oiled and have a slight advantage but if enough water was sucked some would still come in no doubt which is a bad thing …
HKS foam is good in dry conditions but is useless in snow/rain conditions in my opinion
Yikes! So it just soaks up water like a sponge? :shock: Where was your mushroom installed? Do you think I will run into the same problem if I install one in the stock airbox location?