So I wasn’t looking for these but came across them - fell in to an ebay browsing hole
The K & N ones are a couple of hundred quid each but these ones are way cheaper at a fraction of that cost (£50-£80) - but are they worth it or will they just fall apart / cause problems / other issues?
https://www.ebay.co.uk/i/272737416617?ul_noapp=true
AAlso came across a few “universal” induction kits - very suspect abotu them.
It seems your mantra is ‘buy the best you can afford’ Mike
I imagine you can afford the K&N which will be the best so why put off the inevitable:-)
Yeah but I’m getting the radiator for £100 less if you take in to account my winnings, whereas the induction kits (K & N) are in the +£200 bracket
That’s true…and you do need a radiator, although if you had taken the body of advice given you would have bought the recommended cheap one for around £50 delivered.
Induction kits are not necessary and some would say a waste of money.
The Universal kits that come from people such as Fast Eddies seem little different from the branded ones, except that you will have to fab up some brackets, and it won’t look as pretty. Cotton air filters are pretty low tech, and the non-branded ones appear to be similar construction to K&N and Green Air Filters; just remember to oil them. They don’t fall apart.
No experience of Piper-X and immitators.
HKS; used a dual density foam (coarse followed by fine), with a “polymeric” coating applied at the factory (whatever that is, its a charged material to trap dust particles). There are knockoffs, which could be using bathroom sponge for all I know. Don’t use those.
The best intakes for the MX5 don’t come from K&N. The best brand depends on the generation of MX5 that you own.
i agree with the point about induction kits. The main manufacturers have spent a lot of time and money designing a system that is a good compromise between flow, noise, efficient filtration and low temperature/good air density.
Most of the induction kits available elsewhere may change that balance for one reason or another but will seldom better it. I have had good results when using oiled filters on carburettor equipped cars I’ve built myself, but been less successful on injected fuel systems. The oil from a K&N filter quietly polluted the hot wire MAF sensor on my BMW 320 straight six and took the sparkle off its performance until I realised what was happening. My son fitted one to his Honda Civic and it then repeatedly failed the MOT emissions test till he put everything back to original.
I reverted back to the original air intake and paper filter on my Beemer after that and have no plans to fit any aftermarket system to my NB.
I recall a similar thread a year or so back. Induction kits are generally a waste of money and arguably do more harm than good as the whole idea is to get more oxygen into the engine to improve the “bang”. Problem is, the filters on these kits are pretty useless so in addition to lots more air they also suck in particulates which contaminates the air and reduces the efficiency of the fuel ignition. Also, over time all those particulates will not do the internals of your engine much good. I recall an analysis that was done on some of the top end products (K&N etc) which suggested that, particulates aside, these kits actually improve performance by less than 1%. They are also compromised by the fact that they suck in hot air from the engine bay. Hot air carries less oxygen so you get less power. To have any hope of getting a noticeable improvement you probably need a forced cold air induction kit although even that still has the problem of sucking in particulates. Bottom line, don’t bother with these kits. If you want a louder sound (a by-product of induction kits) spend your money on a better exhaust.
I wasn’t really thinking of getting one, just the cheap price caught my eye. The mechanic I use says that the “extra” dirt in is a fallacy, though I tend to agree if you’re getting more air in then you must be getting more dirt in as the filter holes must be bigger. Though he was talking about H & N & Typhoon so…
Your mechanic is quite correct. The oil used on the filter is an intrinsic part of the filtering efficiency of the filter. These filters work in a very different way from a wood pulp filter. Oil that ends up deposited on mass air sensors ends up there because incompetent mechanics over oil the filters. Paper filters start to clog, and reduce in air flow efficiency from the day they are fitted. Oiled cotton filters maintain efficiency for much longer.
On the MX5 Mk1 and Mk2, a cone filter will sit on the exhaust side of the engine. Same place as the factory filter box. The factory filter is well known to be an insulator. If you use a cone filter, and set up a thermocouple at the throttle body, the temperature is pretty constant with the car moving. It will rise when the car is stationary, but will zip down quickly as soon as the car moves. Not so with the stock air box. Sitting stationary, the intake air temperature will increase, but it won’t come down quickly when the car is on the move. Sports Compact Car found in 2000, on a MX5 intake shoot out, than after sitting running, the stock air box would deliver a slug of air (40-50 celcius) into the engine, hotter than any of the intakes tested, which included the HKS intake, which is basically a filter sitting next to the manifold.
And look what Mazda did for its 1994 special edition M2-1028…
Putting a cone filter is not going to kill your engine. I’ve had 5 Mk1s since 1997, and have put on 250k miles between them. I have tracked car, sprinted cars, hillclimbed cars. The engines were fine. Its fun to mess around with different intake setups. Besides what else are you going to do with the car? Polish it?
Bit of science, an essential article:
http://www.autospeed.com/cms/article.html?&title=FreeFlowing-a-Miata-MX5&A=110680
As a seller of MAF. particularly for the MK2/MK2.5 there are obviously a lot of incompetent mechanics over oiling the filters. Either that or the proximity of the oiled filter to the MAF is an inherent issue? Certainly the number of incidences I have encountered would indicate the latter.
The other point to consider is oil and quite possibly other contaminants passing through the filter will not only hit the MAF but will inevitably get into the engine.
The idea of freer airflow indicates the possibility of fine contaminants possible breaching the filter, oiled or not. A standard paper filter is very unlikely to have this problem unless there is physical damage. Standard filters just gradually block up with contaminants over time which is their purpose and should obviously be replaced a long time before this becomes a critical issue through responsible servicing and very clear evidence that the filter requires replacing.
The efficiency of any filter, paper or oiled will immediately reduce with contamination. The real issue here is what is the point of the induction kit?
If, like the Mazda engine brace, it makes you feel better fit one. I would say the car looks better with both parts and no doubt sounds better with the induction kit. I would not fit one on principle and when I sold my MK2 1.6 deliberately removed one fitted by a previous owner and refitted an original airbox and filter to stop the kind of potential buyer I eventually sold the car to being put off.
K&N Response to Mass Air Flow Sensor Concerns
For those interested, worth a read of the full report. For those not interested, ignore.
If you google ‘K&N filter damaging MAF’ there are two sides to the story.
I ignore both and in particular BS from a company with a serious vested interest.
My limited personal experience derived by speaking to actual people with MAF problems and oiled filters, both K&N and other makes is that there is the potential for a problem and very likely that oiled filters limit the life of a MAF.
Like the K&N, a MAF should last the lifetime of the car and strangely enough they appear to do just that when the standard paper filters used.
Stick to the standard filters and you are very unlikely to have a problem.
K&N would have you believe that paper filters are another way for dealers to make money from service items - beware false gods:-)
It remains the fact that playing with filters is a fun pastime and makes the cars sound good. Sticking to original factory parts in all respects (filters, pads, oil coolant, radiators) is certainly a risk aversion approach to car ownership, that suits some people. My approach has suited me for 21 years. It might not suit everyone.
Literally thousands of K&N Miata users over on Miataforum. Few MAF problems. Real World evidence for you. Probably a generational difference. Some like tinkering, some don’t.
https://web.archive.org/web/20080616192558/http://www.racingbeat.com:80/intake.htm
https://web.archive.org/web/20100202084224/http://www.racingbeat.com:80/PDF/56501.pdf
https://web.archive.org/web/20081120065111/http://www.racingbeat.com/intake_review.htm
https://web.archive.org/web/20051202012941/http://www.flyinmiata.com:80/tech/dyno.asp
Some appreciate that added noise without an associated performance increase and with possible related reliability issues may not be worth the bother.
No comparison with the logical upgrading of radiator, brakes, etc where use of car requires it. I have a structured mentality(ex computer programmer) so adding these mods when they are not needed would make no sense to me…but if that works for you.
Still genuinely enjoy regular use of my MX5, Eunos and motorbike - Perhaps need to opt for a Jaguar when I am a generation older.
"Oil that ends up deposited on mass air sensors ends up there because incompetent mechanics over oil the filters. Paper filters start to clog, and reduce in air flow efficiency from the day they are fitted. Oiled cotton filters maintain efficiency for much longer."
As far as incompetent mechanics over-oiling filters goes, there must be some on the production line at K&N. My previously mentioned problem of a an oil polluted MAF on my BMW came from a brand new, pre-oiled filter, out of the box. After a few hundred miles I could tell the engine had lost power. I dismantled the intake system and noticed a film of oil in the intake pipe. The MAF on those engines consists of a pair of fine resistance wires fitted at ninety degrees to each other across the throat and the majority of those wires were coated with a layer of oil and fine dirt, which certainly hadn’t been there when I fitted the new filter. I cleaned the wires up very carefully using cotton buds and carb cleaner. The lost performance returned. A few hundred miles later, same thing again. I reluctantly removed the K&N and put back the paper filter and airbox, after which the problem didn’t recur.
I do think they are OK on some engines, but not all. I have a K&N cone filter on the car I built myself. This isn’t a problem because the MAF is downstream (after the supercharger) and isn’t the same type. The problem I did have with that car was a melted MAF sensor, caused by a backfire into the manifold. That seems to have been caused by hugely excessive oil pressure on a cold start due to a stuck PRV in the oil pump - it was high enough to keep at least one inlet valve from fully closing - but there you go!
I also have a similar cone filter type on my Royal Enfield 350 - with a carburettor there is no MAF sensor so a bit of oil in the intake isn’t a problem. I’ve also fitted twin K&Ns to another engine I built with twin SUs, on a prototype manifold setup I helped develop.
Air filters is something that I’ve wondered about in the past, and with one exception I’ve stuck to the standard filters.
When you add up the dosh, taking into account the cost of the standard filter and the induction kit (with re-usable re-oilable filter), and looking at how many filter changes you might make on ,say, an MX5 NC over the period of ownership (in my case, 8 years and almost 90k miles) - which one is cheaper? (I’ll let you work it out!)
The exception - a Triumph Spitfire - well, 2 in fact, one many years ago (a Mk2) and one about 10 years ago (a by then 30-yoear old MK4 1500).
The Mk2 - I swopped out the standard filter for an induction kit, and had the carb jets and springs modified to suit. Result? After a few months the insides of the carbs etc. were full of muck! So the standard setup went back on.
Fast forward a few years to the 1500 - it came with a pair of nice chrome-plated wire mesh filters that could be cleaned and oiled. In fact, needed to be cleaned and oiled and it was a pain in the nether regions. and the carb throats were mucky. This car had clearly not been re-jetted (you could tell by the way it simply stopped revving at 70 in top 'cos the mixture was too weak). This time I got hold of a second hand standard filter box, plus 2 nice new paper filters and the hoses that ran from the box to a point forward of the rad. And cleaned-out the carbs (on the old SU the muck could make the pistons stick - thus need for more cleaning-out!) Result - much better acceleration, much cleaner running, would rev right up the range, and the only noise then came from the exhaust! And the carbs needed stripping and cleaning less often.
I know which I preferred.