I have been pondering about setting up good air flow for 2k. The one that came to my mind is a K & N type of filter. In the past, I had one installed in my '87 MR2 but found that it's not good for the engine. My guess is that this type of air filter is just letting too much dirt into the engine. What are your expereinces with your 2k and have you experienced premature engine wear at 40k, i.e lower engine compression?

 

[QUOTE]Originally posted by Grazhoppa
I have been pondering about setting up good air flow for 2k.

 

Works fine on mine.

 

this has been discussed before. If you do a search you can find more specific info. My understanding is, in short, yes the k&n lets a bit more dirt in due to increased airflow and over time it is possible that this dirt can possibly cause wear inside the block. Notice I said "possibly". I don't recall any empirical testing shown. I *think* changing oil frequently (every 3000-3500 for me) will help to keep things clean, since any garbage inside the engine is going to end up in the oil, that is probably where it will build up.

Just my thoughts, I may be mistaken about some of this it's my own personal voodoo.....

EDIT- any "performance" intake will act the same as a KN, there is no magic, just more air

 

We did some lab testing and found that all gauze filters let in dirt, and the touted foam filters also did at about the same rate. Paper filters actually filter poorly initially, until the large holes get filled in,and then the better ones (including most Japanese OEM) filter quite well. Ingested dirt is the number 1 cause of premature wear.

Gauze filters were intially attractive to racers because they could continue to let air in even when very dirty, so they did not choke off power under race conditions.

I am not totally convinced that this translates into a benefit on the street considering the rather poor filtering. I know all about K&N's specs, but our measurements using "Test Dirt" (there actually is such a thing) showed that K&N's claim of an "oil curtain" is exagerrated, and that after they are cleaned, they often do not have the whiskers to catch small debris. When I used gauze filters, I used them till they were dirty and then discarded them, "Million Mile Warranty" and all that aside.

Plus, there have the been the "gauze wars" - Accel says its cotton gauze is domestic and better than K&N's "foreign" cotton. Who knows?

The point is this for the S2000: an engine does not benefit (and at best we are talkling a few HP at the top of the RPM band anyway) from increased airflow filter unless there is not enough air getting to the engine in the first place. The S2K airbox and filter are very large for a 2.0 liter engine, and I doubt it would get starved for air unless any of the filters was so dirty as to be ignored.

I have heard some people claim that SC'ers and turbos spool up faster with a gauze filter, and that throttle response is better. I have not noticed it, and there is likely a strong placebo effect going on here, as with many mods (I once designed a PROM that retarded mid-RPM torque in a Corvette 350, and my friend thought the car was faster with the "hyperchip" installed.)

On the Cobra Forums, we have shown that a 6" conical gauze filter makes huge HP, and has plenty of airflow to spare - much more than the engine can use. But "Bigger is Better" counts a lot in Website Folklore, so guys are jamming 9" filters into the Snakes. It is kind of funny - like "mine's bigger".

Finally, there is the real issue of oil from the gauze and foam filters migrating on mAF sensors and othger downstream components - this can either temporarily or permanently damage these components, cause aberrant idle, and affect idle mixtures.

I personally do not see where the benefit outweighs the risk. If you use a gauze filter, change the oil - a lot.

 

[QUOTE]Originally posted by Road Rage
We did some lab testing and found that all gauze filters let in dirt, and the touted foam filters also did at about the same rate. Paper filters actually filter poorly initially, until the large holes get filled in,and then the better ones (including most Japanese OEM) filter quite well. Ingested dirt is the number 1 cause of premature wear.

Gauze filters were intially attractive to racers because they could continue to let air in even when very dirty, so they did not choke off power under race conditions.

 

Road Rage,
what do you think about sponge filters like the comptech?
Grazhopper, CAI is a great mod but the best ones have the hazzard of hydrolock (i.e. AEM/Injen/4IG). Something that helps is a snorkel type intake (allows you to keep the stock set up and is easily removable or the comptech syle with the faux vent in the bumper dremmeled out.

 

I had high hopes for these foam filters, and tested an Amsoil one - we found it did flow well, but not better than K&N types, but also found it filtered no better than the gauze filters, which is not so hot. So if you want a few HP at the expense of higher wear or more frequent oil changes, use a gauze/foam filter. I personally have decided after many years of fooling with these aftermarket filters that the OEM one works well, and does not restrict airflow, since the S2K system has more far more air flow capability than it can use anyway - the airbox is huge!

 

I have been told that dirty K&N filters filter better than clean ones because the dirt adds to the filtration material. This seems feasible so it is stored in the back of the brain along with all the other info that seems feasible but is as yet unconfirmed.

However, Toyota came out with a warning some years ago about the oil in filters like the K&N forming an oily mist (even when properly oiled) which can change the temperature change and therefore the resistance of the hot wire in a hot wire airflow sensor. S2k's use speed density instead so that won't be a problem (no airflow sensor at all means of course that you can't damage a car's airflow sensor.)

 

There must be an echo in here....I could have sworn I posted on the issue of oil migration risks. Oh , well.