K&N or Pipercross air filter - which is best for Mk3?

Hi all

I am looking to upgrade my air filter in my 3.75 2.0 Sport Venture to get a bit power power but can’t decide which is the better filter.

The K&N is slightly more expensive (£47 on MX5 parts) and the reviews are excellent.

The Pipercross is slightly cheaper (£35 on MX5 parts) and the reviews are also excellent.

So leaving the cost out of the equation, which is best?

Would be grateful if anyone can share their experiences.

Many thanks


Hello Russ,
I have a Pipercross in my NC 1.8, defo got a nice little growl sound and I think it seems a bit swifter on the acceleration response. Though nothing scientific it could all be in my imagination.
I did some reviewing before changing and the actual power increase is fairly minimal but it’s just nice to make some upgrades I reckon.
I am sure there will be some more in-depth and knowledgeable replies from others.

As I am sure many respondents will say, the performance gains from an air filter are really not measurable. They are 95% psychological. However I would say this is more important than a couple of extra horses. The question you probably should be asking is which sounds better? There is a balance between sounding more “sporty”, but livable with and sounding very “sporty”, but the additional noise becomes wearing after a while depending on the type of use you get out of the car. If you just use it for a blast every now and then, you can afford to go for more induction noise, but as you have a later model, I suggest you probably use it more often for mixed motoring, so you do not want it to be overpowering.

All that said, I have not heard either, but I would bear it in mind… The same goes for exhausts, which give a similar output - some are too loud, but for some users, this is the effect they want.

I remember my first car - an MG metro - it was 1983!!! and I changed the air filter for a K&N and when on the motorway it was so loud that the stereo was overpowered - and as a teenager I had upgraded this too…

Some scientific research here as opposed to buyers’ reviews:

Personally, I wouldn’t bother. Better things to spend money on.


Save your money.
If you want performance gains, chuck the passenger seat out.
The weight saving alone will give you more power than an air filter.

‘Go faster’ stipes have a similar performance gain.



I also have a 3.75 2.0 sport venture.

I fitted a K & N Filter but have also changed rear box & fitted an IL Stainless Steel exhaust from MX5 parts. Combined I think I get a few more horses & I really like the sound the car has now



Buy more expensive petrol, however that’s a different area of controversy… :sunglasses:

If it makes you feel better then do it.
I have resisted on many occasions to upgrade the air filter, gains are nothing I reckon if you are just stuffing another make of filter into the standard airbox.

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The previous owner of my car seemed to have neglected it a little, (2006 mk3 ) , so a while back, within the same week I fitted a new Piper cross panel filter, had an oil and filter service, cleaned the MAS sensor , replaced the old spark plugs and had a Cobalt back box fitted, what a difference! But I have no idea which thing made the most difference, it just passed it’s mot, so the piper cross filter doesn’t seem to have affected the emissions etc, and the mpg is the same as before, and the filters last ages and can be cleaned and re fitted , you’ve got nothing to loose fitting one unless someone else knows more about these things .


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I put a pipercross in because there was a deal on and it was not more that a standard filter in fact if I replaced 2 then would be quids in plus never have to replace again, but could not tell any difference than the old one…

I have a pipercross in my mk3. Just a panel filter, not an induction kit or anything like that. It made zero difference to anything.
Strictly speaking you should also be informing your insurance company when you use one too

Iam not sure about that it’s just a long life filter no performance gains…if it was induction cone cold air feed then yes…but in saying that if you put sticker/decal on you should inform ins…

Many thanks for all your responses, I’m err-ing on the side of the K&N but will hold off until next month

Thanks again


I have a panel filter on my NC and noticed 0 difference in power or sound.

I have a K&N panel filter making no difference…it’s in a box in the garage as I fitted a skuzzle intake :grinning: :grinning:

If you have any issues with insurance at all then please feel free to drop me a line.

Save your money.

I had a NB and now have a NC. I bought a k&n filter for both and reverted back to a standard air filter as I feel the car drives better and is more responsive. Currently using Blueprint filter.

When I get a ND I will not be messing around with air filters!

Many thanks everyone, it seems odd that the reviews on the MX-5 parts website are mostly positive but your responses here overwhelming contradict this.

So on that basis, I will look to spend my money on something else for my five!

Thanks again


I think that your final comment that you will find something else to buy says it all. How often do 5 owners spend money that they wouldn’t on a “normal” car? I know I do it - I keep looking at things that I do not need. So if that is the basis, then apart from repairs etc, your car doesn’t need anything. Therefore just get it and understand that it is making you feel better rather than being an improvement as such. It may sound better and if it does, then its a win!!! If not, you can feel happy that an aftermarket filter is “superior” to a standard one, whether it is or not - its your car and money…


A bit late to the party but I’ve always been a fan of K&N filters. So when I recently picked up my Mk3.5, I immediately ordered a K&N Filter from MX5 Parts.

When I came to install it, I was surprised to find I had a rather dirty Pipercross filter already installed. Never mind, I thought, and went ahead and replaced it with a shiny new K&N.

Now I realise that most on this thread say there is no difference, but for me it was night and day. On the next run out, the old girl felt as if she couldn’t breathe. Since I couldn’t be assed to clean the original, I purchased a new Pipercross from MX5 parts and…hey presto, she’s been given her lungs back.

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