Aftermarket Air Filters Debunked

[mcoffey]

Something I have suspected to be true before - now there is proof. ISO tests on air filters - basically, the K&N does offer slightly better airflow but at the expense of letting more dirt into your engine. Even then the power gain is negligeble. Read for yourself:

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

[BEECEE]

i for one never beleived the amount of gain advertised , my reason for buying one of these type of filters would be their longer life and raspy sound if you got any bhp gains that would be a bonus . this can be said for numerous type of products , from hair and skin products to power tools .you get good base product and any gains after this will be marginal , the powert of advertising .

[mcoffey]

Yeah, the K&N does make a diference to the sound but I would worry more about it's filtering capabilities.

[crx92ie]

Not expecting huge gains when I fit the AC Autotecnik cold air induction kit, but the lads on CRX-UK that have them fitted say it makes the car more driveable in that it pulls a bit better. The Honda airbox is known to be very good anyway, but it's nice to not have to change the filter so often.

[BEECEE]

a well placed induction kit should make a noticable differance ,my read on that report is that a change of filter only wont give any power gains , a change of system i think would .

[mcoffey]

Yeah, if the induction kit draws colder air than the stock intake it's denser air and it will give you real hp gains.

[BEECEE]

im guessing the same would apply to exaust back boxes from a bhp piont of view , very little in it from make to make .

[mcoffey]

When it comes to the exhaust, the cat is by far the biggest restriction. replace that with a pipe and your laughing performance wise, but a shiny stainless back box always looks nice!

[Mcandmar]

It’s all relative, the best intake the world will make no difference if you have a stock exhaust and cat restricting the flow.. Any gain to be had are small and only at the high end of the rev range, low down below 3000rpms they generally hurt performance.

Filtering isn’t very good at all with K&Ns, i binned mine in the Audi as it would cover the MAF sensor wires in oil and grime after a few thousand miles. Only real difference was the noise. BUT every car is different.

[crx92ie]

Hmm, sounds like replacing the filter with the AC CAI and putting on the new Mongoose exhaust (if it ever gets here) should make quite a noticeable difference then (not sure if there is a cat on mine as it already had a Fujitsubo exhaust fitted).