Performance air filters, can they deliver?

This is what a performance air filter on ebay promises..
** Green Filters Performance Replacement Elements simply drop into the original airbox, replacing the original restrictive paper air filter with a performance, high flow element. No other modifications, parts or accessories are required. **

The pleated green cotton and mesh gauze filters have been designed to improve air flow and horsepower, offering a crisper throttle response and superior performance for improved acceleration and greater driving enjoyment. All this with the highest level of filtration, giving the ultimate protection for the engine. With improved efficiency and less restriction on the airflow, you can also see improved mpg figures, possibly giving important savings on fuel.

Can it really be that simple to get such effects on the engine? Do they deliver what they promise? Anybody tired them?

In the MGF unless one by-passes or even better removes the resonator box and moves the intake to the N/S vent then you won't get much improvement at all. The std air intake is on top of the rear sub frame behind the engine and thus sucks in warm then hot air with a hot engine which reduces it's efficiency.

A proper enclosed cold air feed will improve performance but by how much it seems is variable depending on other improvements. A good free flowing exhaust will enhance the intake by allowing better engine breathing.

Oh in case you are not aware removing the resonator box is a trial indeed as you have to cut it up in situ to get it out as it's put in place BEFORE the sub frame is fitted.

"Elsie" my 97 VVC has a K&N open cone filter fitted which was on her when she arrived here. I would not waste my money on one personally as they are not exactly cheap and I seriously doubt it makes much difference to the performance. In fact I have still not found the fabled intake roar that they are claimed to provide. The only time one can hear it is when cold and if one listens very closely indeed. In due time once other more important things are done, fixed and fettled I will obtain a proper enclosed cold air intake feed for her.

Also bare in mind that the resonator box doubles as a splash gaurd for this side of the engine bay. I cut min in situ to retain the splash gaurd effect.

I definatly have induction roar from the K&N Appolo I have on my VVC but I used a short inlet pipe to this.

There is definatly an improvement over O/E, mostly in mid range torque.

I had a K&N O/E spec filter in the O/E box in my maestro, a slight improvement but quite expensive for what you gain.

Though it has been nine months, I speak on this topic, I mount carbon airbox and filter sponge ITG maxogen, the same that is mounted on elise s1

I run the K&N Apollo as well gives a very roar. Never thought of the now missing splas guard... i'll have a look if I can make some. Thanks for the advice.

Well i hear something interesting on this, for sound go K&N, for performance go pipercross. I doubt i would have got much on performance but having never used a performance air filter before i just bit the bullet and bought a K&N panel filter for about £33 from ebay. To be frank, my VVC didnt sound great, wasnt loud enough and sounded a little flat. I installed the K&N with mild anticipation of what might happen and wasnt overly impressed when i fired her up, sounded the same. a mile of gentle driving until i hit a nice long straight and went for it, WOW! what a sound! couldnt be more impressed with it now. More HP? not really and if there is i cant tell but seeing as i was after "that sound" anyway, well. Recommended to everyone now who uses stock paper ones.

I had the same results with mine. Lifetime guarantee too I believe?