Thinking about replacing the air filter, { Mk.2.5 1.6 litre} but which is the best? The K&N or pipercross? I would appreciate opinions please. Have heard of the oil on the K&N contaminating the air flow meter. Has anyone any experience of anything like this? Once again all opinions welcome.
Regards Geoff Peace.
Hi Geoff
Never heard this with the K & N’s???,both options will make a hell of a big differance,a lovely note from the back,pick up a hell of a lot faster,and you will not use as much fuel.
The k & N is the cheaper option but that by no means that it is a poor option to the pipercross,it’s all down to your pocket,and which one you personaly prefer,but both are good in my opinion.
Regards
Which is best?..
Sorry couldn`t resist 
I have the K&N Typhoon & it looks, sounds & performs great IMO
Just to confuse things more,this is what i have on the Mk 2 1800cc
http://cgi.ebay.com.au/Mazda-MX5-NB8C-98-00-N-A-APEXi-Power-Intake-Filter-Kit-/380216403612
regards
Back in my VW days, this was kind of received wisdom - the MAFs on the VWs aren’t cheap, and a deteriorating one gives slightly worse performance - you don’t notice it happening as it’s very gradual, and so paranoia’s rife. Claims were that some of the oiled filters could pass oil onto the MAF, degrading it. Green Cotton and Pipercross were allegedly less susceptible.
Having had all of these, and having cleaned and oiled my filters many times it’s down to how much oil you spray on them - from the factory I’m sure they’re all perfectly fine, and all could potentially suck oil on the MAF if you over oiled them.
In short: don’t worry. The K&N 57i is a very neat fit in the engine bay though.
I am also looking into doing the same and fitting an aftermarket cone filter to my 1.8 MK2 and have been reading (probably too much) stuff on the internet claiming that they all allow more particulates into the engine and increase wear. Is this true, and does it matter that much? It has made me a little concerned about it all, but I would really like that extra aural pleasure that a cone filter gives!
I have been looking at the K&N 57i and Typhoon models as well as the Apexi power intake and Pipercross models. Is there much between them in filtration and air flow?
sorry if this all sounds a bit geeky, but I want to be sure it isn’t going to do some horrible damage.
My MX5 has a Pipercross filter on the turbo. After 3,00 miles the intercooler and it’s pipes were full of dust thick enough to write your name in.
Depends on the particulates. Tiny gains of sand are definitely hard enough to wear the cylinder bores of even an iron block, and you really wouldn’t want them between a valve and the valve seat either.
Truth is that manufacturers never test how much engine wear some dirt in the inlet systems causes, because they always use the OE filters which are designed to meet the spec required for engine validation. You change from OE spec at you own risk, because no one, especially the people who make aftermarket filters, does any kind of rigorous validation testing.
There are enough race cars kicking about with no filters at all to show that a bit of dirt isn’t instant engine death, but long term? Fit one and find out. Many people have, and most of them don’t have problems.
It’s only an engine - £300 to replace, and people have spent way more than that on shiny inlet systems.
There was a fleet test in the US, where one half of a fleet of Caprices were put on K&Ns, and the other on normal paper. User was an owner of construction yards, so the cars were under arduous load conditions. After so many thousand miles, they started tearing into engines, and found, lo and behold, the K&N engines were in a poorer state.
In other tests, the oiled cotton filter filters (K&N, Green) performed better than the open cell “oiled” foam filters such as Piper-X. Interestingly, HKS filters, which, on a cursory examination, look similar to Piper-X, except that HKS specifically say you cannot re-oil these like Piper-X (they actually have very short working lives). There is a coating on the filter, but my hunch is that the HKS filters filter more on the basis of charge deposition than nominal pore size (foam filters will have a less controlled pore size than the cotton filters). I believe the oil used won’t really harm flapper AFMs, but may damage hot wire MAS used on 1.8s.
In normal driving conditions, K&N panel filters only need cleaning/reoiling every 100k, 40k for cone filters. HKS filters; bin them after 20k miles max (HKS say 10k miles or something). Its probably pointless cleaning/oiling more often than that, but I suppose it sells oil. Personally, I’d go for the HKS filter, and swallow the cost of filter changes; they’re not expensive.
Thanks for the help everyone. I have put this on hold for the time being as Car Mechanics magazine are publishing a report in the June issue on uprated parts. Air filters, plugs, HT leads stainless steel exhausts etc. May prove interesting.
Regards Geof Peace.