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Discussion Starter · #1 ·
"When you floor it, and it keeps suckin'."


K&N Short Ram Intake

What is it?
K&N is one of many companies (Corksport, AEM, Injen) offering an alternative intake solution for our cars. It's a tube with an open-element cone filter at the end, and a heat shield. They'll claim to make more power, but they won't without a tune. Mostly just sound, which for some (myself included), is enough justification. We don't drive racecars.

What's nice?
I've owned a K&N intake in my previous car, and will not buy another brand without heavy influencing. I love this thing. Sparkling metallic silver tube, deep red cone filter, and a metal heat shield that uses OEM attachment points! Wonderful. The sound is incredible. People hear you coming, and won't think this is a 2.5L sending out that sort of noise. It growls, it screams, and it's so much fun to stomp on it. When you push the pedal past the mechanical switch to get that extra rev limit, this thing screeches. Ah man. I love it. Makes me feel some type of way. This is what I would call the first mod for any car, ever. Being an SRI, it's out of the way of splashing water in the rain. In addition, filter cleaning is every 50,000 miles, as opposed to the stock filter replacement interval. The filters are good for 100k+ miles too.

What's not nice?
It's an SRI. It's not being fed any cold air. Though the heat shield helps keep the radiator heat away, one might need supplemental tubing (see below). It's an open element, so it's vulnerable to water and the elements. This can be remedied by a pre-filter, or hydroshield, for an extra thirty bucks. Competitors such as Corksport and AEM have entire boxes around the filter, with an inlet leading to the factory air inlet (hmm). Less parts with the K&N though. With this kit, some assembly required. No big deal, but you're piecing everything from the rubber to the element together. Price is high compared to other tubes-with-filters. There's quality to be had though.

Ease of install:
It's easy. It really is. It's not a bear to remove the stock, and it's easy to install this in and enjoy it. Would probably take an experienced DIYer thirty minutes, new guy an hour or two. Minimal hand tools required.

Overall, I love this thing. I would buy another in a heartbeat. I ran some extra tubing, and it's been sexy ever since. Might be in my head, might be butt dyno, I don't know. Highly recommended.




 

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Discussion Starter · #3 ·
I'd like to say they did, if not only in throttle response. It's winter here in FL, so it's in the 70s. Once it gets hotter I'll know for sure. They're three 3" tubes, running from two inlets on the bottom, and one from the factory inlet. It looks like butts, but I'd like to think it helped. It's a lot of air to be forced up there, especially since other cars get their air from in front of the front wheel as well. Who knows. Butt dyno best dyno.
 

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Cool. Yea I am in FL too but I live in Tampa where the coldest day in 2016 was like 60. So for us a cold air vs short ram vs stock vs replacement filters is all pretty much the same. I don't think it looks bad either. I think it actually looks very cool once the bumper cover is off.
 

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Data says these things do exactly zero for power and in fact likely do harm. Yes, I have logged data to back that up.

If you just want sound, and perhaps direct and provable harm to engine life (those "gauze" filters are radically inferior to factory-style paper ones in terms of actually filtering out dust from the air) then go ahead and pay the money. But after paying the money and putting the noise-maker on do check a UOI for silicates (dirt) and see if your levels have gone up. If they have you're taking real and measurable mileage off your engine life.
 

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Discussion Starter · #9 ·
Data says these things do exactly zero for power and in fact likely do harm. Yes, I have logged data to back that up.

If you just want sound, and perhaps direct and provable harm to engine life (those "gauze" filters are radically inferior to factory-style paper ones in terms of actually filtering out dust from the air) then go ahead and pay the money. But after paying the money and putting the noise-maker on do check a UOI for silicates (dirt) and see if your levels have gone up. If they have you're taking real and measurable mileage off your engine life.
I'm curious about the data you've mentioned! To state that filter A allows more dirt than filter B would require controlled testing of each. One would need the same amount of particulates and dirt and dust, thrown in a wind tunnel, sent through the filters, to see if one or the other accepts more or less dirt. All filters let through some amount of dirt; in fact, brand new paper filters for OEM require a certain amount of dirt in order to work properly. I would imagine a well maintained cone filter would do the same, being made from similar materials. An open element cone filter gets maintained and replaced just the same as a regular filter would.

Since you say you have the data I'm very curious about it! I'd hate to purposefully damage the vehicle, as you claim it can.
 

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I'm curious about the data you've mentioned!
On the "more horsepower" claim that one's simple. You have several sensors in the vehicle; let's start with the MAF and MAP. The MAF can be (and is, by many "SRI" pipes that have constrictions in them) cheated and thus it is only good for comparison if installed in a pipe of the exact same diameter.

HOWEVER, the MAP cannot be cheated. In a non-turbocharged engine, unless you can figure out some way to force induction, the maximum MAP is 1 ATA. A stock intake that restricts airflow will result in a MAP under 1 ATA at full throttle and maximum RPM. A "replacement" intake that improves airflow will result in a MAP closer to 1 ATA.

In addition cooler air is more dense (and thus has more oxygen) than warmer air. Since the mixture is computer-controlled (and we know the AFR as well as the computer reports that), the fuel rail is pressure-regulated and we *also* know injector duty cycle we know fuel flow. Finally, we know charge temperature because there is also a sensor for that. All of these can be logged, and I have.

The SRIs lose. They lose because there is no gain to be had in flow since the stock air system is not restrictive on these cars (MAP is indistinguishable from 1.0 ATA at full throttle), but there is density to be lost due to taking air from under the hood instead of in front of the radiator. The latter is cooler, ergo, denser. This is trivially proved by logging intake temperature and MAP with both the stock airbox and the SRI. You will thus find the SRI loses; it must, due to the facts of physics.

There is a final issue and that is one of tuning. The stock airbox setup has a resonator designed into it. The SRI lacks this by design and intent; it's a straight pipe. The result is that the flow of air is actually less-linear and the MAP readings are less-consistent. This results in more ECU "hunting" which on these engines turns out to matter quite a bit. On older, slower, less-complex ECUs it might not make much difference but it does on the SkyActiv engines.

I have seen all of this, never mind the fact that in multiple timed tests the removed stock air intake produced an actual *slower* rolling 20-60 acceleration time over a whole BUNCH of runs on an identical piece of pavement and as a result I put the stock airbox back on the car. SRIs, in short, do nothing for performance and in many situations (e.g. nice, hot Florida summers like we have here) hurt it quite badly. In fact I saw close to a 50F (!) difference in charge air temperature during my testing.
To state that filter A allows more dirt than filter B would require controlled testing of each. One would need the same amount of particulates and dirt and dust, thrown in a wind tunnel, sent through the filters, to see if one or the other accepts more or less dirt. All filters let through some amount of dirt; in fact, brand new paper filters for OEM require a certain amount of dirt in order to work properly. I would imagine a well maintained cone filter would do the same, being made from similar materials. An open element cone filter gets maintained and replaced just the same as a regular filter would.

Since you say you have the data I'm very curious about it! I'd hate to purposefully damage the vehicle, as you claim it can.
Cone filters have *far* less surface area than pleated paper filters. A filter's effectiveness is, in the main, a function of media pore density and surface area. The greater the surface area the smaller and more labyrinth-like you can make the pores without damaging restriction at a given airflow.

Modern paper filters are *extremely* effective, mostly because of their greater surface area and thus lower velocity over a given area of filtering surface. Media has radically improved over the last 20 years or so; modern "paper" filters have extremely well-controlled pore size, pore geometry and paths. The science on them has come a LONG way in the last few decades and modern OEM air filters are EXCELLENT.

Oiled gauze was a reasonable choice decades ago but it no longer compares favorably.

Actual, scientific tests are expensive -- but you'd think the oiled filter folks would buy the tests IF the results would prove up their claims. They haven't published those results and the reason is that they don't show what they want you to see.

Well, guess what -- a few people HAVE arranged for this sort of test, and the oiled filters have, when tested, lost. Badly. Like, for instance, here: K&N Air Filter Review - Debunking the Myths (and why OEM is better)

Oiled gauze filters lose for the reason you expect them to lose -- they have far less surface area in which to capture dirt and thus the velocity of air over a given surface area is higher. They thus not only cannot capture nearly as much dirt before they get loaded, they restrict more-quickly as they do get loaded AND they let more dirt through.

So says the actual, controlled, scientific testing.

If you like your engine then use the manufacturer's filter.

Here's what oil analysis looks like if your filter is doing its job. Note the very low SILICON levels after initial break-in (silicon is also found in sealants, so a new engine will "leach" it into the oil for a while. It is also one of the primary elements found in *dirt*, so its level in a UOA tells you a LOT about how well your air filter works.) I have a nice, consistent record that shows levels well under "universal averages" -- that is, my engine is ingesting materially *less* dirt than the average for this particular engine in all the tests Blackstone runs. In addition there are effectively no insolubles detected (which covers anything they don't specifically look for.) And the wear numbers? I'll probably wear out before this engine does.
 

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On the "more horsepower" claim that one's simple. You have several sensors in the vehicle; let's start with the MAF and MAP. The MAF can be (and is, by many "SRI" pipes that have constrictions in them) cheated and thus it is only good for comparison if installed in a pipe of the exact same diameter.

HOWEVER, the MAP cannot be cheated. In a non-turbocharged engine, unless you can figure out some way to force induction, the maximum MAP is 1 ATA. A stock intake that restricts airflow will result in a MAP under 1 ATA at full throttle and maximum RPM. A "replacement" intake that improves airflow will result in a MAP closer to 1 ATA.

In addition cooler air is more dense (and thus has more oxygen) than warmer air. Since the mixture is computer-controlled (and we know the AFR as well as the computer reports that), the fuel rail is pressure-regulated and we *also* know injector duty cycle we know fuel flow. Finally, we know charge temperature because there is also a sensor for that. All of these can be logged, and I have.

The SRIs lose. They lose because there is no gain to be had in flow since the stock air system is not restrictive on these cars (MAP is indistinguishable from 1.0 ATA at full throttle), but there is density to be lost due to taking air from under the hood instead of in front of the radiator. The latter is cooler, ergo, denser. This is trivially proved by logging intake temperature and MAP with both the stock airbox and the SRI. You will thus find the SRI loses; it must, due to the facts of physics.

There is a final issue and that is one of tuning. The stock airbox setup has a resonator designed into it. The SRI lacks this by design and intent; it's a straight pipe. The result is that the flow of air is actually less-linear and the MAP readings are less-consistent. This results in more ECU "hunting" which on these engines turns out to matter quite a bit. On older, slower, less-complex ECUs it might not make much difference but it does on the SkyActiv engines.

I have seen all of this, never mind the fact that in multiple timed tests the removed stock air intake produced an actual *slower* rolling 20-60 acceleration time over a whole BUNCH of runs on an identical piece of pavement and as a result I put the stock airbox back on the car. SRIs, in short, do nothing for performance and in many situations (e.g. nice, hot Florida summers like we have here) hurt it quite badly. In fact I saw close to a 50F (!) difference in charge air temperature during my testing.

Cone filters have *far* less surface area than pleated paper filters. A filter's effectiveness is, in the main, a function of media pore density and surface area. The greater the surface area the smaller and more labyrinth-like you can make the pores without damaging restriction at a given airflow.

Modern paper filters are *extremely* effective, mostly because of their greater surface area and thus lower velocity over a given area of filtering surface. Media has radically improved over the last 20 years or so; modern "paper" filters have extremely well-controlled pore size, pore geometry and paths. The science on them has come a LONG way in the last few decades and modern OEM air filters are EXCELLENT.

Oiled gauze was a reasonable choice decades ago but it no longer compares favorably.

Actual, scientific tests are expensive -- but you'd think the oiled filter folks would buy the tests IF the results would prove up their claims. They haven't published those results and the reason is that they don't show what they want you to see.

Well, guess what -- a few people HAVE arranged for this sort of test, and the oiled filters have, when tested, lost. Badly. Like, for instance, here: K&N Air Filter Review - Debunking the Myths (and why OEM is better)

Oiled gauze filters lose for the reason you expect them to lose -- they have far less surface area in which to capture dirt and thus the velocity of air over a given surface area is higher. They thus not only cannot capture nearly as much dirt before they get loaded, they restrict more-quickly as they do get loaded AND they let more dirt through.

So says the actual, controlled, scientific testing.

If you like your engine then use the manufacturer's filter.

Here's what oil analysis looks like if your filter is doing its job. Note the very low SILICON levels after initial break-in (silicon is also found in sealants, so a new engine will "leach" it into the oil for a while. It is also one of the primary elements found in *dirt*, so its level in a UOA tells you a LOT about how well your air filter works.) I have a nice, consistent record that shows levels well under "universal averages" -- that is, my engine is ingesting materially *less* dirt than the average for this particular engine in all the tests Blackstone runs. In addition there are effectively no insolubles detected (which covers anything they don't specifically look for.) And the wear numbers? I'll probably wear out before this engine does.
Based on your previous posts I decided a while ago to stay with the stock air filter.

Also, based on your oil analysis, I can start pushing my car to 7,000 mile oil changes instead of the 5,000 recommend by the dealer.

Sent from my SM-G935V using Tapatalk
 

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Discussion Starter · #12 ·
That was a very informative read! Thank you for the explanation, article link, and chart you submitted as well. Certainly all factors to consider.

I would suggest that on our cars, at least, there's no restriction of air flow compared to stock, on a comparable lightly used filter. Our stock airbox only lets in that small inlet of air through the front; the rest of the box is sealed. With an open element like the K&N, you're pulling air from all directions, at all times. This runs the risk of hotter air, yes. There's also the issue of hot weather and not enough air reaching the filter. I won't deny any of that. I would say that it's not restrictive by build sense.

Based on the reading of the article, the K&N didn't last as long as the other filters did by a fair margin. Most of that can be solved with regular cleaning. What really stood out to me is how much dirt accumulated beyond the K&N filter. That's what's concerning.

Thank you for the read. There's a lot of good information in there!

Since it talks specifically of filters - was there an OEM standard comparison included? If not, I'll likely swap the K&N filter for an applicable filter that's better performing. It seems ACDelco doesn't sell cones, and neither does Baldwin. AFE and AMSOIL sell cone filters, and judging by the tests, performed far better than the K&N did. Looks like I have some shopping to do!
 

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A cone filter has less surface area than the panel filter. ALL the aftermarket panel filters outperformed the cone (by a lot) and it's physics that are responsible.

The OEM paper did better than the aftermarket, and given that the surface area is likely similar between the two the difference there is media. Simply put the OEM costs a few dollars more and that extra money went into better media, which matters.

You can't get around physics. More surface area means less velocity at any given location through the filter, which in turn means the filter can be designed to be more effective at a given level of airflow restriction. I'll pay the few extra dollars for the OE air filter given that it's good for ~30k miles or thereabouts. I check it when I change the oil and that's about the change interval I've wound up running on my car.
 

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Just to play devils advocate here...

Two things: one, the link posted is to a series of tests run on replacement panel filters, not complete intake systems. The test, to me, shows two things visa-vie oiled cotton gauze filter material. It allows in more dirt...and more air. That sort of makes sense. The difference in filtering efficiency between the best (most restrictive) paper filter and the K&N is about 2%. (99% vs. 97%)

Two, regarding the claim that there are no hard dyno numbers to prove that the K&N intake does anything...K&N actually publishes dyno results for their T-69 intake on the Mazda 6 2.5. K&N 69-6032TS Air Intake, Intake Kits
It shows a peak gain of about 5 hp/7 ft-lbs of torque on the vehicle they tested. They do, of course, point out that these numbers "may" vary.

So, what are we to make of this? Well it seems like there are several important points to consider...

First and foremost - "Figures lie and lairs figure." Both dyno graphs and column charts can be manipulated to show predetermined outcomes...or, at the very least, bias the viewer into making assumptions that are not completely borne out by the data. I'm not saying that anybody has done that here, but I'm just saying that I tend to take every chart and graph I see with a grain of salt.

Next, does the K&N intake actually improve the performance of my car? Hard to say. K&N says "yes, and we have the dyno chart to prove it." However, I already know that this dyno graph only shows one particular run on one particular vehicle. "Your results may vary." Some folk's anecdotal evidence says "yes" some says "no"." Now my personal impressions tend to back up the K&N dyno. I've owned cars where intakes seem to do nothing but make noise and I've owned cars where intakes actually seem to reduce low-end performance. However, on my car the K&N does "seem" to pull harder from about 4000 - 6000 rpm at full throttle. And I've tried both back to back and there is a viseral difference to me. Whether this as actual increase in power or just the motor climbing out of a big torque pit created by the intake, or my own wishful thinking, I don't know. I would need to actually put my car on a dyno and run back to back pulls with the OEM intake/filter and the K&N intake/filter. That seems to me to be the only way to "prove" the claim to my satisfaction. Unfortunately, that's not going to happen in my near future.

Then there is the issue of filtration. The K&N filter does seem to allow in both more air and "dirt." Like I said, this makes sense. But, how much dirt is too much? - this seems like its the real question here. Well, as mentioned before, we are looking at about a 2% difference in filtration. Well, what does that mean? Will 2% more "stuff" sucked into my intake cause my motor to be worn out at 200k miles? Or 100k? Or 50k? I guess the only way to prove this would be to take two identical Mazdas and run one with and one without and see what happens over the life of the cars. Actually, we'd probably need to run a whole fleet of cars to get a better idea. Sorry, way out of my price range.

Finally, there is the issue of intake air temperature. We know that the Skyactive engine is very temperature sensitive. The SRI sucks in more air - but its likely to be heated engine compartment air, and ambient air temp. has a huge impact on this. The stock intake is more restrictive (maybe) but is better able to regulate intake air temperature. So, it looks like its another case of "this or that." Cooler air vs. more restriction...maybe.

Just some stuff to think about. I'll leave you with these words from the 'Sage of Baltimore,'

"We are here and it is now...beyond this, all human thinking is moon-dust."
 

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Discussion Starter · #15 ·
@tickerguy

I won't deny a smaller surface area on the cone filters compared to paper. That much is likely true, especially depending on the paper filter you have installed. What I'm saying though, is that on our cars, the air inlet only brings in X amount of air. No matter how big a filter is, it'll only let through that X amount of air. The bigger the filter, the more air it lets through, yes. But if a filter is being fed a constant stream of air, it doesn't matter how large it is. It'll only take in that constant stream of air, i.e. our factory filter inlet.

Another question. One could have a bunch of pleats/folds on a paper filter, but if they're so close, how much air are they really letting through? They could have a monstrous surface area, sure, but isn't the total passage of air determined by the square dimensions of the filter? Such that no matter how many folds there are, it can only let in up to the size of the filter L x W? More pleats would just mean more surface area to allow for more filtering. But does that mean that there's more air coming in before there are more pleats (surface area)?
 

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@tickerguy

I won't deny a smaller surface area on the cone filters compared to paper. That much is likely true, especially depending on the paper filter you have installed. What I'm saying though, is that on our cars, the air inlet only brings in X amount of air. No matter how big a filter is, it'll only let through that X amount of air. The bigger the filter, the more air it lets through, yes. But if a filter is being fed a constant stream of air, it doesn't matter how large it is. It'll only take in that constant stream of air, i.e. our factory filter inlet.
Correct. The engine only flows "X" amount of air at a given RPM. Without forced induction that's a physics problem and is resolved by arithmetic -- the engine displaces "X", it turns "Y" RPM, and if there is no restriction (1 ATA) then the amount of air that flows through it is a known number. Restriction lowers the total airflow by volume. Temperature, given constant restriction (which cannot be less than zero, obviously) controls *MASS* of air, and it is mass of air that is consumed in combustion. In other words cooler intake air is always better if the goal is to maximize the number of available molecules of oxygen for combustion.
Another question. One could have a bunch of pleats/folds on a paper filter, but if they're so close, how much air are they really letting through? They could have a monstrous surface area, sure, but isn't the total passage of air determined by the square dimensions of the filter? Such that no matter how many folds there are, it can only let in up to the size of the filter L x W? More pleats would just mean more surface area to allow for more filtering. But does that mean that there's more air coming in before there are more pleats (surface area)?
Yes, if there was no filter in there at all! But there is.

Filters are pleated to increase surface area. The reason for doing that is two-fold -- you want to increase the area of the filter because you want to increase the amount of dirt it can hold before the restriction reaches the service limit but you *also* want to increase the surface area because the more surface area you have the lower the velocity of air passing through a given square inch of media. All other things being equal the slower the velocity the more effective the media is.

Depth-based oil filters are set up on a bypass system for heavy equipment for exactly this reason. You cannot get that sort of effectiveness with a full-flow oil filter because the size of the filter would be prohibitive to get the velocity down enough for it to work. So in those applications you rig a second filter, this one with a restrictor fitting on the inlet, that bypasses a small amount of oil through a second, much-more-densely packed filter at a slow rate. This allows you to run a very small pore size and the velocity through that filter is very low (comparatively), which removes a LOT more of the crap from the oil than the full-flow filter does.

This is why the cones always lose; they have (far) less total surface area (which is easily determined; disassemble it and unfold the pleats, laying both out) which means they are forced to run a higher velocity of air through a given square inch of media. This means they are less effective. If the media on a cone filter is 40 square inches while the media on the pleated paper filter is 200 square inches then the paper filter has a huge advantage both in terms of the amount of dirt it can hold before restriction becomes unacceptable and in filtering efficiency.

As to how much service life you're giving up in terms of engine longevity that's a much harder question to answer. One decent qualitative answer can be had by looking at silicon levels in your used oil, because some percentage of the dirt that gets into the intake will wind up in the crankcase oil, and you can detect it there. You can also get some sort of read on whether it's impacting your service life by the wear metals in your oil as well, which a UOA will also tell you.

But the real question to ask here is why buy such a device at all? If it's simply for the noise factor then *perhaps* it's worth it. But here's the thing -- I have an OVT tune on my car, which means I have a Tactrix that can log data at high speed. There is a large thread here with other people's results, some of whom have and still are running SRIs. None of them have put up any sort of statistically valid difference in power output .vs. what I get without one, and between all of us there's a HELL of a lot of data exposed for anyone who cares to look.

If AFR is constant and so is RPM then given that fuel rail pressure is regulated and fixed then injector duty cycle is truth (unless you've replaced the injectors with ones that flow more fuel, of course!)

What's interesting is that a few people with various SRIs have reported statistically-significant "improvements" in MAF. However, we know those numbers are bunk (that is, they're gamed by the geometry of the SRI) because they have not resulted in commensurate increases in fuel flow and output. The problem with trying to "trick" airflow numbers into the ECU with a modern engine is that it doesn't work because the ECU manages fuel in order to produce a given AFR and it has closed-loop sensors downstream in the exhaust to allow it to do so with very high accuracy. The result is that if you tamper with the MAF sensor output by tricking it (e.g. by using a venturi) you gain nothing because the ECU will very quickly reset its internal mapping multiplier. Remember that MAFs, like all other instruments, have tolerances and drift over time, so the ECU has to be able to compensate for that -- and it does, almost immediately.

In short the DATA says that an SRI makes no more power in this particular application because there is no appreciable restriction in the stock intake that can be improved upon. The DATA also says that a cone filter on an SRI allows in more dirt. Whether that dirt translates into materially-less engine life is an open question but since the gain is zero in terms of output and in fact may be a net loss, especially in warmer areas, due to hotter air being ingested then what possible purpose does putting one on the car have, other than emptying your wallet?
 

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Correct. The engine only flows "X" amount of air at a given RPM. Without forced induction that's a physics problem and is resolved by arithmetic -- the engine displaces "X", it turns "Y" RPM, and if there is no restriction (1 ATA) then the amount of air that flows through it is a known number. Restriction lowers the total airflow by volume. Temperature, given constant restriction (which cannot be less than zero, obviously) controls *MASS* of air, and it is mass of air that is consumed in combustion. In other words cooler intake air is always better if the goal is to maximize the number of available molecules of oxygen for combustion.


This is exactly why the aftermarket SRI or CAI would provide a benefit though. MAF/MAP sensors may regulate the amount of fuel being fed into the chamber for combustion but the cooler, denser air should trigger more (stronger) combustions. This would intern translate to more power.
 

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This is exactly why the aftermarket SRI or CAI would provide a benefit though. MAF/MAP sensors may regulate the amount of fuel being fed into the chamber for combustion but the cooler, denser air should trigger more (stronger) combustions. This would intern translate to more power.
Except that you don't GET colder air with a SRI. You get HOTTER. And thus far it has proved to be damnably difficult to get even equally-cool air than the stock intake provides with an aftermarket airbox replacement. That's what the data shows.

In short the stock intake is surprisingly effective at doing the job of getting air at or near ambient into the engine.
 

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Except that you don't GET colder air with a SRI. You get HOTTER. And thus far it has proved to be damnably difficult to get even equally-cool air than the stock intake provides with an aftermarket airbox replacement. That's what the data shows.

In short the stock intake is surprisingly effective at doing the job of getting air at or near ambient into the engine.




I didn't see any charts/graphs with Temperature. Maybe I am missing the link. I have an OBD2 reader in my car so I can take some samples of stock and then reinstall the short ram and test. I will make sure to do it immediately to maximize as much control as I can.


Also, the test was done against K&N which is an oiled filter and uses the same media across the company. What about other brands. Dry filters?


Modifying SRIs is also going to change things. I have only used a SRI on 2 cars and both times I have modified the little box/heat shield to have some feed from wheel well/fog housing areas. Many people do this. That essentially is creating a hybrid CAI/SRI and should thus have an impact on temps.


Also consider weight. If you remove the stock air box, and the the piping, there is a noticeable difference in weight compared to the aftermarket.
 

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I didn't see any charts/graphs with Temperature. Maybe I am missing the link. I have an OBD2 reader in my car so I can take some samples of stock and then reinstall the short ram and test. I will make sure to do it immediately to maximize as much control as I can.
There's a hell of a lot of my data in the OVT tuning link (charts, graphs, etc.)
Also, the test was done against K&N which is an oiled filter and uses the same media across the company. What about other brands. Dry filters?
Surface area wins. It's not complicated from a physics perspective.
Modifying SRIs is also going to change things. I have only used a SRI on 2 cars and both times I have modified the little box/heat shield to have some feed from wheel well/fog housing areas. Many people do this. That essentially is creating a hybrid CAI/SRI and should thus have an impact on temps.
Maybe. In the "6" case this is quite difficult to do in any sort of effective fashion however; the shrouding (under-vehicle aero) gets in the way. If you don't have fogs you could potentially run ducting to the stock blanking plate and slot it, but if you do have fogs that option is foreclosed as the airpath is severely obstructed by the foglamp housing. In addition taking air that low has other dangers unless you rig a water trap/airbox (which gets fairly complex to fabricate effectively in a sealed fashion and adds weight back.)
Also consider weight. If you remove the stock air box, and the the piping, there is a noticeable difference in weight compared to the aftermarket.
The stock airbox comes out as one piece and separates into two. It doesn't weigh much at all (it's plastic) and the replacement has mass too, especially if you start fashioning heat shielding/partitioning and ductwork! If you're to the point that you're arguing over ounces or low-single-digit (like two or three) pounds then perhaps it might matter, but the average driver will do just as much for performance by getting the carbs out of their diet for a couple of days.
 
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