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?
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.
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
Talk to Matty at Alfa Men. He knows... And he'll tell you it's a waste of time and money.
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
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.
Quote from: bazzbazz on January 10, 2018, 10:59:18 PM
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.
Why would you replace a cold air intake with something that draw warm air from inside the engine bay? Defies logic.
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.
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.
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.
Quote from: Colin Edwards on January 11, 2018, 09:41:12 AM
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...?
Quote from: Colin Edwards on January 11, 2018, 09:41:12 AM
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.
Thanks for the open discussion and I am convinced that weighing up the pro and cons that it is not a valued modification.
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.
Bonno, would you please name a few?
Warsch I will send you a PM on several contacts.
I said:
"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."
And, it now occurs to me, open loop ECU mapping for cold start air / fuel ratio will be quite rich because this causes a high exhaust gas temperature and consequently promotes a rapid heating of the catalytic converters (i.e. not just a 'safe' default AFR, but something more deliberate for a specific reason).
Is this the single instance of an emmissions control measure improving engine performance...??? Maybe, though ignition timing is not unlikley to simultaneously be considerably retarded for the same reason (high exhaust temperature until the cats 'light up'), so perhaps a gain on the roundabout and a loss on the swing?
Regards,
John.
I thought rich mixtures burned at a lower temp than lean mixtures. Seriously, have I got this wrong for the last 25 years?
I don't think you're wrong, but I don't think it's entirely as simple as that.
My understanding from this and that I've read and heard, FWIW, right or wrong:
A lean mixture burns more completely and hotly inside the cylinder because lean combustion is rapid and all available fuel gets burnt in cylinder. The lean burn exhaust gas may still be very hot as it exits the cylinder (maybe hot enough to burn valves), but the temperature quickly decreases as it passes into the exhaust system. This is because all the fuel was consumed and it is no longer burning in the pipe.
A rich mixture burns cooler in the cylinder, but more fuel is left uncombusted. Since rich burn combustion tends to be slower than adiabatic or lean burn, remnant unburned fuel and oxygen can keep burning as it passes into the exhaust pipe. This cooler / slower rich burn creates lower in cylinder temperature, but higher (than for lean burn) temperatures further along in the pipe, and so exhaust gasses are hotter when they reach the catalytic convertor, which heats it up somewhat more quickly. This is why excessive fuelling can burn / melt cat cores (especially if there were also to be some misfiring, or a pre cat exhaust leak, which means a lot of oxygen as well as fuel in the exhaust stream).
I have heard that in order to promote a rapid cat warm up, some engines (Mazda I think, rings a bell) deliberately misfire some of the cylinder 'firing' strokes on cold start so that more unburnt fuel and oxygen is introduced into the exhaust. This is not so much because of the extra unburnt fuel from the 'misfire', but it introduces the oxygen needed to more fully burn any fuel that is in the pipe. Something similar can be done by artificially introducing air into the exhaust with a pump, and running rich at start up.
At any rate, I have noticed significantly better partial throttle performance (power, throttle response, general 'eagerness') when the engine is stone cold than exists after the engine has warmed up somewhat (well, I never floored it with a cold engine...). I only suspect this is due to the AFR being richer, for whatever reason. It may be that it is only richer to enhance ignition at lower charge temperature, or it may be that it is also richer to enhance cat warm up. I don't really know, just guessing based on snippets I at least think I know.
Speculating; if an engine were runing significantly lean, then at high load the exhaust headers might glow red hot (due to the hot in cylinder burn) for the first few inches of their length only because the heat quickly goes out of the exhaust gas though the pipe wall. On the other hand, if an engine were running significantly rich, then at high load the exhaust might glow red for a substantially greater part of its' length, because the fuel is still burning in the pipe and heat is being generated actually inside it, so the pipe gets hotter instead of cooler? Maybe.
Regards,
John.
Trivia Time -
Without realising it John has just explained how a DPF Regeneration works. During the regeneration extra fuel is injected into the system, the unburnt fuel continues to burn through the exhaust system, including the DPF, and raises the exhaust system temperature to the point where it burns out all the deposits in the DPF, and it very often will glow red hot !
It is also the reason that when doing a Forced Regeneration one must make sure the vehicle is on a concrete/bitumen surface and that there are no flammable items near the vehicle. So unless you want to do some planned back-burning one should not attempt this on the front lawn !