Hello everybody!
I spoke with a motorbike mechanic (the guy who sold the car to me actually..)
and he told me that the oem air filter is much better than any aftermarket one.
But he did not expain to me why and I really like the looks of an aftermarket airfilter pipercross etc.
Please light the truth here and which is better for my engine.
Rescued attachment bfb7_0.jpg

There's nothing intrinsically wrong with swapping from a OEM to an aftermarket filter- but it might mean that you'ld need to rejet (or adjust the maps if you're EFi).... you may need to do this anyway if you're using a non-standard exhaust......

The gains to be had by using a OEM filter can be marginal. There's an interesting section in "forced induction" by G. Bell which shows how sometimes, despite the claims made by companies like K+N, the power increase can be marginal....

I'd be tempted to keep the original air box for three reasons:-

1. Noise, the existing air box will be (a lot) quieter than a sausage filter. This will help reduce your overall noise if you ever decide to try trackdays. It's suprising how loud the induction side of things can be. Fitting bigger silencers is expensive.

2. Air flow, get two lengths of flexible hose, attach them to the air intakes on the air box and run them to the front of the car, preferably in the nose cone, in front of the bonnet. This will help you lower the air intake temperature. Lower the temperature, the denser the air, more oxygen, better burn, more power. At the moment the engine is getting hot air from inside the engine bay, which has already cooled the radiator.

3. Cost. A decent large sauasage type air filter, plus a blank back plate is going to cost you upwards of £75. A replacement panel air filter from K&N is going to be £25?

Hope that helps.

Mike

from what I have read in the past, the paper elements flow as good as after market ones until they start to clog; that is when the after market ones take over.

I don't know how many miles it takes but probably less than you'd like so you would need to keep replacing them far more frequently. (+ cost too)

I bought the car mainly for trackdays so low noise levels is mantatory for me.
But still for everyday use I wouldn't mind a little bit more noise.
I use the oem MK indy exhaust
but still I reckon that if I change to a sausage air filter will be best if I remap

This is something my son and I are always arguing about when he starts farting around with induction kits on his GT4 Celica.
As I say to him would toyota, honda, yamaha etc have spent millions designing an air intake system if a £30 bit of foam worked better.
Still thats only my opinion
Tony

That bit of foam though, only has 1 job, filtration. The maunfacturers have other things to worry about, such as induction roar, common parts across a range, cheapness etc. They also don't want it to last a long time, as they'd never be able to charge you for a new one! It is a bit different for bikes, and high performance cars as they require high flow filters to start with, and noise is less of an issue, maybe even a benefit.

[Edited on 4/4/07 by DIY Si]

I admit that I dont know much about kit cars, maybe I dont know a lot about car in general but when I changed the oem filter in my MR2 turbo to an aftermarket one I could feel the difference and I could here the noise as well.
Even when I changed this aftermarket filter to another aftermarket filter I saw some difference!
They do make a difference espacially to turbo cars (3sgte like the GT4 eg)

judging by the pic mine was the same , this is how it is now i've modified it to get it in the cool air
OK Sorry it's a large photo

[Edited on 5/4/07 by mad-butcher]
Rescued attachment air filter mod.JPG

I cant see the photo unfortunatelly

ok I saw it aventually
Are these ducts coming out side of the bonnet of sitting right below MKs bonnet air duct?