AFM adapter plate for 1.8 when upgrading air intake

I am currently trying to upgrade my air intake. I feel like the aftermarket kits are too expensive and I’m confident I can make one myself. However I cannot find an adapter plate for the AFM on the 1.8, plenty of examples advertising they work for the 1.6. Will the 1.6 adapter plates work for the 1.8? If they don’t, does anyone know where I can get an adapter plate for the 1.8? Thanks

1.8 doesn’t have a AFM, it has a mass air sensor; its round.

Most sock filters will come with a few rubber ring adapters. Its what I did with a Ramair filter.

You need to figure a way to support the MAS, by jury rigging a bracket

An adapter plate is required for the MK1 / Eunos 1.6 only as it has a Mass Air Flow meter, Commonly known as a MAF Meter with a relatively complicated mate with the airbox, involving threaded studs and in inboard port.
MK1 1.8 and indeed all MK2 / MK2.5 cars have a hot wire system commonly known as a MAF Sensor. These are all effectively tubular, so lend themselves completely to easy modification to fit to rubber/plastic tube or directly to a cone filter.
My advice is to remove your MAF sensor from the airbox end and you will see what you need to join to. The MK1 / Eunos 1.8 even has a rubber seal to fit neatly into a tube or cone filter end. This can be removed if not appropriate to your homemade fitments.
The Ramair cone is a good choice. If you take my advice, avoid oil infused filters, especially in close proximity to the MAF sensor as the oil can and has regularly contaminated and damaged the efficacy of the sensor.

Have you ever seen this?? Me neither probably urban myth
K&N Response to Mass Air Flow Sensor Concerns (

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Hi Richard

Yes, I have.
My basis for judging oil infused filters it the amount of sales, ie. supposedly positive for me, experience. I talk to my customers and all too often the question asked ‘why did your existing MAF Sensor fail, when it should really last the life of the car, do you have a paper/foam filter or an oil infused one?’
You can guess the answer, I actually benefit but the truth is out there and K&N can stick their bullshit assurance where the sun don’t shine. Another self serving, totally inaccurate crock. They would be far better off calculating the length of tube that needs to be between the MAF and oiled filter to effectively minimise the obvious problems.
Once the hot wire is contaminated and the Sensor compromised, the damage is done; a replacement will be required.

And K&N is not the only manufacturer of these types of airfilters.

If there is an oil effect, its more likely to be due to inappropriate cleaning and reoiling on the filters. Panel filters will only need oiling/cleaning every 100k miles (50k in heavy conditions) and cone filters every 40k miles, both of which are probably well in excess of what anyone will do on these filters. Yet people will buy the oiling kits from Halfords etc

Also, Ramair, PiperX etc are also oiled filters. Thats why Ramair and PiperX sell cleaning/oiling kits. They are not dry filters. The only “dry” foam filter is HKS, and that needs changing every 10k kms. Its pre-oiled at the factory. Halford sell a filter, but it looks a lot like the sponge used on a floor mop. Maybe its high tech, and not a sponge at all.

Note, both the M2-1001 (panel filter) and M2-1028 (cone filter) came with oiled cotton filters from the factory.

Chevy TSB on the issue; not; over oiled air filter. If you follow the manufacturer instructions, there is no problem. If you are someone who gets a new K&N and then oils it, well, you’re an idiot. I suspect there are some people who think you have to dump the whole can on the filter before use.

Next up; does anyone remember Blitz air filters? Anyone got one on an engine that doesn’t rattle like a bag of nails. The ultimate dry filter.

Filtration efficiency discussion can get complicated. We saw that during COVID, when some numpties expressed disbelief and a misunderstand of FFP3/N95 face masks (the ability of a virus to pass through a face mask is not based on pore size).


We have had this debate before and nothing has changed!
It is quite simple, new and used oil infused filters, K&N or other cause issue with hot wire MAF Sensors, it is really that simple, proven!!
You appear to have moved to a far more sensible Ramair foam filter after all the previous debates and your online MOT issues with emissions. This is a foam filter with no oil infiltration, To save me checking, what is the reg. no. please?

The Ramair filter uses oil, like most other foam filters. Probably you will adjust your advice.

This is an oil-free filter though. Perhaps you’ll recommend this

Debate before, nothing proven. I have seen no appropriate control experiments from the anti-K&N camp (who curiously focus on one company only). So I am not convinced about your anecdotes. User error remains the most likely explanation.

The emissions issue was solved; it had nothing to do with the MAS. I had already described this in a previous posting, so nothing to do with this topic. Start a new thread on that (the MOT woes, actual or imagined), of my car of 17 years ownership, with 26 years and 270k kms running on various oil/“polymer” (aka oil) coated filters, pretty much since new, rather than further diverting this one.

You are hard work despite obviously changing to a foam filter.
Back in the day, I remember you defending K&N with 2 cars fitted with their filters and cars that struggled with emissions, compliments at the time of the new MOT history avaiable.
You now have the one car, so if your assertions are are justifiable, why the change to a foam filter?
You have my reasoning, so as an individual, interested as to how you justify your individual findings against the collective… and by collective I mean the plethora of owners, whose cars have needed replacement MAF Sensors because of an oil infused air filter screwing them?