K&N oil filter: overkill or worth the extra cost?

When I say worth the extra cost… It’s marginally more than a standard one so I’m not fussed about that…

But for the next service, I was going to buy a K&N high flow oil filter, I’m also going to go for the Mobil oil instead of the Magnatec 5W30 I usually use… No real reason but everyone seems to love the Mobil one!

Question is, is the filter a bit overkill for normal road use?

I’m one of those people that likes the peace of mind of having the best quality parts irrespective of whether or not they’re actually necessary (the car won’t be going on a track day, for example). However, the fact that it’s a high flow filter gives me an indication that perhaps the filter media isn’t going to trap contaminents as well as an OEM one might, simply by the virtue that there must either be less filter material, or the material itself perhaps isn’t as compact, thus allowing more oil to pass through overall.

What do we think about this chaps?

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OEM is best in my opinion. Can’t go wrong with ‘standard’. Lots of pattern filters MAY be just as fine, especially with an old engine, any weird requirements should be well understood and pattern parts tweaked to suit by now.
High Flow is just marketing. If the filtration is the same, the flow rate will be very similar. Nothing wrong with it (that I am aware of).
I would consider the ease of fitting/removal - is the K&N the one with the nut attached meaning a spanner can take it off? That could be a good thing in the restricted access on the NC.

Any in spec oil is fine. Many types of Mobil-1 meet API-SN so a 5w30 ESP it will be fine.

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Yeah the nut on the bottom would help, but at the same time I’ve got a really good tool to remove them which has always worked a treat.

The K&N one is only £2 more than the OEM one though, it’s more just a case of trying to gauge what is definitively the best - harder than it seems!

There are hundreds of posts on this in the NC section of the Miata.net forum in the states. It’s worth an hours reading to hear their views. The original Mazda filter has been produced in several different countries and factories since it’s inception and the part numbers have changed as well. There was even a recommendation not to use the SH01 prefix filter on the LF engine. If you change oil and filter regularly as most enthusiast diyers do there should be no need to worry about using a good aftermarket filter. I use Mahle at the moment.

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I bought my first MX5 (MK3 ) about a year ago , the performance was stodgy for want of a better word, so I had it serviced including new spark plugs, fitted a Cobalt back box , and a Pipercross re-usable air filter, what a difference , I realise that this was down to all the various things I’ve had done, but even if the filter helped just a little , i’m OK with that.

Boz

Mahle filters are very well thought of in the Ducati world.
I believe K&N oil filters are made for them by one of the big filter manufacturers and are the same internally as their standard filters but do have the ‘nut’ pressed into the bottom.
The nut can be a mixed blessing. Useful if the filter comes off easily but prone to tearing if it doesn’t.

Could it have a larger surface area ? I would trust a know aftermarket product but not a cheap knock off job, surely OEM must be more than up to the job ?

Oem won’t be made by Mazda. Mahle are widely held to be the best.

I presume thats the same Mahle that makes pistons, if it is and they are well thought of in the Ducati world that would give me confidence.

I was on a GT4 owners club years ago, there was a member working at a factory in the U.K. making filters and most, including OEM, where made by the same production line and just had different names printed on them. This started a debate about performance filters. I don’t remember how K&N came out but there was little difference in flow rate and particulate removal between any of them. HKS, K&N, blue print, OEM, the list went on. The only improvement any of them offered was some would flow better than others when heavily soiled, but again marginal differences.

If your engine is producing enough crap after 1200 miles to need a filter that badly then it’s scrap anyway, once the bores are cut and bearings had their tiny high spots scraped that’s it, debris should be all but zero.

If your filter is seeing enough debris to get blocked then your engine is fubar beyond repair already.

Regular oil changes is the answer not expensive filters.

If you fit a magnetic sump plug it will catch iron filings as yours bores are cut post engine build, after a few hundred miles that’s it, you’ll never see an iron filing on it again! If you do, it’s problems.

Oil filters will help catch white metal debris from bearings but if your engine is healthy there won’t be any.

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I must have changed hundreds of oil filters in my time, never once have I had any issues with aftermarket ones.
Change them at specified intervals or sooner, along with the oil and I don’t see any issues.

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I stick to Bosch or Mann, as long as its changed I guess it won’t make much of a difference.

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I’ve an idea Mann and Mahle are the same company.

Funny you should say that… I’ve hunted high & low for a magnetic sump… 10 points to Gryffindor for whoever finds one!

(not some piece of cheap crap where the magnet will come off inside the sump!)

I’m surprised they’re hard to find.
Are they an obscure size??

Not that I’m aware of…?

There’s a few cheap Chinese versions around but I’d rather not bother at all than have one come apart and leave the magnet inside the sump!

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A quote from the Ducati forum:

" I use the Gold Plug AP-22 2000 Magnetic Sump Plug Oil Drain Bolt;Plug size: 22mm – 1.5 Part No: AP-22

https://www.amazon.co.uk/Gold-Plug-…Plug+AP-22&qid=1580116451&s=automotive&sr=1-1

Constructed from a 303 stainless steel body that houses the strongest, highest temperature, n45sh neodymium magnet available."

Magnetic sump plugs for the car engine is a bit pointless. Shells and bearing material that wears is not magnetic, so by the time you get iron filings in the oil it is too late.
Bikes that run gearboxes and engines in the same oil bath are a different proposition.

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Magnetic sump plugs catch iron filings after a rebuild. Unless you plateau hone the bores (rare as rocking horse poo) the massive amount of iron as bores cut rings and rings scrape bores is all dumped into the sump, without one it goes thru the oil pump and into the galleries. All of the engines I rebuild get one. Even after plateau honing there is still a lot of iron cut, less that’s all.
Once run in there will be no iron or white metal in hour oil if the engine is healthy. More than engine protection a magnetic sump plug is an indicator of engine health.
The biggest problem oil faces is hydrocarbon contamination. Turns the oil to acid as well as being too small for an oil filter to remove. Oil companies and recycling centres ‘polish’ used oil and it is re used, a car filter can’t do that.
A rich air fuel ratio will wash the oil from the bores and glaze them, glazing is a result of the oil being liquored down by petrol and providing no lubricating protection. The scope of the cross honing in the bores is to retain oil to be carried past the oil wiper and compression rings so once it’s gone the engine needs a rebuild. So I reiterate, oil filters are much of a muchness, clean oil is imperative.

Incidentally on a turbo charged engine oil contamination is attributed to just about every turbo failure, when a turbo is rebuilt It’s clear to see the mode of failure and oil is just about always the crux of it. People vastly underestimate the importance of oil changes.

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And do not forget old minis and other cars where the gear box is in the sump and uses the same engine oil. Absolute must in these cases, it always looks like a Christmas tree when you take it out.
:heart:

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