Air intake - any advantage changing to an air pod

[Thevak]

The air intake on a 147 ts is quite elaborate with many chambers leading to final intake under wheel arch near battery.

Is it worth replacing with a simple K&N air pod?

[V AR 164]

I have one on the 164, and honestly makes no difference apart from some sweet intake noises.

Another thing to consider, is that the factory intake is probably more efficient as it is routed inside the wheel arches where there is cold air. A pod in the engine bay typically sucks up hot air and looses some power.

However, they look and sound awesome. But I also believe they are illegal, don't quote me on that, but just have a look at the rules and regs on the vicroads website.

Andrew.

[bonno]

Hi Thevak
You have several options for the 147, from simply replacing filter element, through to full cold air induction system. Find link to K&N webpage that provides relevant information for each.
https://www.knfilters.com/search/appsearch.aspx

[kaleuclint]

Talk to Matty at Alfa Men.  He knows...  And he'll tell you it's a waste of time and money.

[bazzbazz]

I concur with kaleuclint, they may sound better but you won't get any noticeable/worthwhile increase in performance.

Just my personal opinion & experience.

Baz

[Citroënbender]

I quite admire the OEM intake trunking, especially the little resonator off to the side. Have seen a few factory filter boxes where internal bits are removed, suppose the idea was to delete an imagined restriction.

Gut feeling is that the first limiting factor in a stock TS engine is intake cam specs.

[kaleuclint]

I concur with kaleuclint, they may sound better but you won't get any noticeable/worthwhile increase in performance.

Just my personal opinion & experience.

Baz

Baz knows too!

Minor power loss seems all too common with pods.  Water ingress a more serious issue.

[aggie57]

Why would you replace a cold air intake with something that draw warm air from inside the engine bay?  Defies logic.

[johnl]

An oiled element filter? It seems to be not uncommon for MAF sensors to become contaminated by the oil used in such filters (causing MAF to fail because the 'hot wire' becomes dirty). I haven't used an oiled filter with an EFI engine (have with Dellorto carburettors), so this is not a problem I have had, only heard about. It might be that this is an issue caused by over oiling such filters...?

Also, at least in NSW (it is my understanding that) they are not legal, unless enclosed in some kind of casing that isolates it from the engine bay. I think the rationale with this is to do with suppressing backfires through the induction system, that might cause an engine bay fire...?

Also, it seems (from just about everything I have read on this) that they rarely if ever flow more air than stock paper element filters, which are generally excellent filters that do not restrict airflow in any significant degree (there are probably rare exceptions). There are good reasons why paper is almost universally used as the filtering medium by nearly all car manufacturers (cotton element Toyota filters notwithstanding).

Also, hot air drawn from the engine bay can have an at least measurable affect on power. The 147 (and 156?) TS engine induction doesn't seem to be a 'proper' cold air intake, but inducts air from inside the engine bay (albeit from off to one side away from the radiator and exhaust). It might be more worthwhile trying to create a real cold air intake, than fitting a device that inducts air from a hotter part of the engine bay than already happens...

Regards,
John.

[Colin Edwards]

A previous owner of my 75 replaced the paper element with a K&N product.  After cleaning and re-oiling the K&N element I held it up to the light and could see through it!!!  Applying more oil may have filled the holes but surely that would STOP air flow. 

Maybe the elements have a finite life.  After a number of "cleans" maybe much of the cotton / wool material is lost and holes remain.  When they get to this state may as well have no filter at all!  Tossed the K&N and reverted to an Agip paper filter.

Colder the air the better.  Ever wondered why the engine usually feels stronger on a cold morning?  Bypass the intercooler on a forced induction engine and see how much power is lost.

[warsch]

If I were to replace intake, I'd go with something like this:

https://www.knfilters.com/search/product.aspx?prod=69-0500TWR

At least the intake is in the same location which is good temperature wise. It would likely weigh less than standard intake. I had K&N standard size insert on my 2.0 16v Seat Ibiza, it came with the car. Couldn't notice any difference whatsoever even when running in motorkhanas.

[johnl]

A previous owner of my 75 replaced the paper element with a K&N product.  After cleaning and re-oiling the K&N element I held it up to the light and could see through it!!!  Applying more oil may have filled the holes but surely that would STOP air flow. 

Maybe the elements have a finite life.  After a number of "cleans" maybe much of the cotton / wool material is lost and holes remain.  When they get to this state may as well have no filter at all!  Tossed the K&N and reverted to an Agip paper filter.

This is how they work, i.e. the holes in the filtering medium are much larger than the holes in paper elements, which is what supposedly allows a less impeded air flow. The dirt isn't captured because the particles are too large to pass through the holes (which is how paper works), but because they get stuck to the thick / sticky oil coating the filter medium. Old school oil bath / mesh filters worked very well on a similar principle, i.e. the filtering mesh (like coarse steel wool scouring pad material coated with oil that 'wicks' up from the oil bath) had quite large holes through which air passed easily, but the dirt particles were caught on the oily surfaces of the mesh.

For X filtering area the oiled filter medium (of a K&N type filter) may well have a greater air flow potential than a paper element of the same area, but often (as I understand it) paper element filters generally have a much larger area through which to draw air, so often may have a greater flow capacity. The paper medium is pleated / folded many times, which is why they have a very large area (if you were to flatten the pleats out). Oiled elements seem to have fewer folds / pleats, so less filtering area (probably because the medium tends to be quite a lot thicker, so not as many folds can be fitted into a given size filter package).

It's probable that an oiled filter may well capture smaller particles than a paper element, simply because particles that are small enough will pass through the tiny holes in the paper (i.e. very very small particles). The same particles should get caught on the oil with an oiled medium.

Some oil from an oiled filter will eventually get 'sucked' through the filter, especially at first and if the filter is over oiled. My understanding is that this coats the 'hot wire' element in the MAF and acts as an insulating layer, so the airflow cannot cool the 'hot wire' as effectively as it should. To make this worse, the oil on the wire may get baked to become a carbonised coating when the ECU runs the MAF through it's 'burn-off' cycle at start up (i.e. the ECU heats the wire till it is momenterily red hot in order to help burn off any matter that might be expected to be stuck to it, and sticky / thick oil isn't an 'expected' contaminant...).

The ECU will then recieve a signal from the MAF that is indicative (to the ECU) of less air flowing over the wire than is actually the case (because the wire is insulated by dirt, it will not cool as much for X air flowing past it), so the ECU will lean out the fuel ratio, at least momentarily before it trims according to the O2 sensor reading. This may result in poor throttle response, even if max power is not so affected...?

Colder the air the better.  Ever wondered why the engine usually feels stronger on a cold morning?  Bypass the intercooler on a forced induction engine and see how much power is lost.

Yes, I agree. I also find the engine may well perform better (on partial throttle, so feel 'livelier') when it's still cold, which is I think because it's running in open loop mode, rather than closed loop. This means the ECU isn't yet trying to maximise fuel efficiency, and open loop maps tend to be richer than closed loop, and richer - within reason - tends to be better for power.

Regards,
John.

PS, it is possible to clean paper element filters (agitiating in a sink with a strong laundry detergent, with rinsing under a tap flow). I've done it a few times and it works fine. I'm sure it's not quite as good a a brand new filter, but a lot better than a dirty one.

[Thevak]

Thanks for the open discussion and I am convinced that weighing up the pro and cons that it is not a valued modification.

[bonno]

If you looking for a reasonably inexpensive performance upgrade, then I suggest that you look at remapping the ECU.  There are various places out there that provide this service and can even be found on this forum.

[warsch]

Bonno, would you please name a few?