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2008 FG2, CAI, J35, PLM 4-2-1, anti reversion chamber, Envida, TSX cams, Hondata
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Discussion Starter · #1 ·
So here's my current design irritation of my CAI. Absolutely no math was harmed during the making of this design. With the concept of more is more, I found this shape on ebay and adapted it for my uses.
Did I feel any difference over my 3 inch design? But dyno, not really, but lambda says .2-.3 leaner. Another interesting observation is the IAT is another 10 degrees (f) warmer compared to the previous design. I read that the plastic housing doesn't allow the IAT to be as accurate as it could be as compared to using aluminum the design material. This was frustrating because of the extent I went to to design a cold air inlet/box to contain the outside air in the fender well. Perhaps there is a way to modify the housing of the IAT to more accurately represent what air is actually being ducted in.
Anyway, curious to see what everybody has come up with that's not just writing a check.
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What engine mounts do you have? It looks like the filter is touching the chassis. If you have stock mounts, the engine will move that filter into the chassis and will break the intake over time.

Bjorn is right about building a enclosed housing around the filter. Right now it is drawing air from the engine bay and from the duct feeding it.
 

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2008 FG2, CAI, J35, PLM 4-2-1, anti reversion chamber, Envida, TSX cams, Hondata
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Discussion Starter · #4 ·
Sorry, I didn't show the part where there is a custom made foam section separating hot engine air from cool clean air entering the removed fog light (about 4") and a curved ductwork diverting the air directly air the filter. Any gaps in the fender liner are sealed attempting to contain only outside air in that area.
The mounting is not hard attached to anything and moves freely with the stock engine mounts. Potential wear issues will be monitored and corrected.
 

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Arouse the DAMPFHAMMER!
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But dyno, not really, but lambda says .2-.3 leaner.
Leaner should indicate an higher air mass per stroke. The sources for the root cause of that can be manifold. It can come from more air mass flux at intake or by an lower rate of burned fuel or by more mixture lost through scavenging and so on. On a first impression leaner should indicate a higher VE by the intake design.

Another interesting observation is the IAT is another 10 degrees (f) warmer compared to the previous design. I read that the plastic housing doesn't allow the IAT to be as accurate as it could be as compared to using aluminum the design material.
The IAT sensor and it's position in the OE system is calibrated into the tune. The sensor is by far no measurement too I would use for any absolute measurement but for comparison measurement it has some value. A 10 °F increase is plausible as the CAI system has no closed cold air environment, but over 70 % in connection with the enginebay. The bell mouth type and diameter guarantees a homogeneous airflow over the circumference angle (beside obstacles in the air flow way). 30 %, so my assumption, is from the CAI support and 70 % is from enginebay area. When velocity of the car increases the game my change as the flow of air through the enginebay and the CAI support line now supply different conditions, but the enginebay always supply a hotter air then the CAI. So for me the increased IAT would be plausible if I would know the previous design.
 

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Discussion Starter · #6 ·
I agree the IAT sensor is for mostly comparsion purposes. But the tune would be effected if the sensor is seeing stop-and-go summer traffic and conditions with less heat soak.
I realize I changed 2 parameters of this experiment. I will try to reinstall the original version. This will allow me to see only the change I made to the incoming air. I would consistently see 10 degrees over ambient (for comparison purposes). This is using my Ultragauge to see what the ecu is seeing. I'll share what I find out soon.
Side note: I did notice the sound wave coming out of the new version is noticeably less angry sounding with VTEC, which is unfortunate, lol.
 

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Arouse the DAMPFHAMMER!
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This is using my Ultragauge to see what the ecu is seeing. I'll share what I find out soon.
That's great, I am looking forward to it.

Side note: I did notice the sound wave coming out of the new version is noticeably less angry sounding with VTEC, which is unfortunate, lol.
Juuup, I use that technology to reduce the noise level too, but it is still noticeable.



 

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Discussion Starter · #8 ·
Small update. I had an extra sensor and modded it by removing the plastic housing surrounding it. Reaction time of the sensor improved slightly and the temp was reduced by two degrees (f). Now best scenario is about 12 degrees above ambient at highway cruise. Next is to attach K type thermocouple in the air cleaner.
Also thinking of relocating the sensor closer to the TB, thus increasing the velocity of the air passing the sensor.
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and the temp was reduced by two degrees (f). Now best scenario is about 12 degrees above ambient at highway cruise
What about a CAI housing around the air intake location (air filter)?
 

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Discussion Starter · #10 ·
Small update. I installed a K type thermocouple at the start of the air inlet just to see what the temps look like there. My guess is I didn't do an adequate job stopping residual air from the radiator sneaking by into the cold area.
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Great job, you put the values on the table with your measurement. Thanks for sharing those :)!

My guess is I didn't do an adequate job stopping residual air from the radiator sneaking by into the cold area.
...yeah, I was suggesting that as the actual solution doesn't support a CAI as mentioned above.

What about a CAI housing around the air intake location (air filter)?
I meant this one...
 

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Discussion Starter · #12 ·
Update. So I made another location to mount the sensor. Closer to the throttle body. Wanting to find out if anything changes when the air velocity changes going past the sensor.
So the test was a work project where my commute was 170 miles round trip. Drove a full tank, filled up again and relocated to the sensor to the higher velocity location.
Tracked the fuel economy. Higher velocity location: 32 mpg. Lower velocity location: 29
Weather conditions and traffic fortunately were consistent for the test.
Did the car feel any different? No, not really. Butt dyno really couldn't tell any difference. But apparently the sensor/motor likes it better in the higher velocity location.

What's next? Trying to find out if the material the CAI is made out of makes any difference. I'm frustrated by what the thermocouple sees at the beginning and what the oem sensor sees. You would think there would not be so much heat soak between the two points.
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But apparently the sensor/motor likes it better in the higher velocity location.
The higher velocity increases the heat transfer to the sensor and increase the domination of air temperature at the sensor, which has also other sources for heat in its surrounding. For my doctoral thesis I modeled every temperature sensor location of the test bench to see what is the balance temperature at the sensor measurement point. What did I learn from this? Temperature measurements, which should be accurate below 5 °C, could already need a correction of the systematical error when the heat flux from the sensor basis is in the margin of that of the to be measured fluid or material. It is always good and has a huge impact on the accuracy to have a heat transfer coefficient ratio of e.g. > 10:1 between that to the to be measured fluid/material and that of the sensor basis.

Another point system immanently issue could be the surrounding conditions. I've tuned today an engine, which had an ineffective CAI, WOT-IAT was around 18 °C bigger than atmospheric temperature. We changed the CAI intake location nearer to fresh air input location and reduced the difference at WOT down to 3 °C. This helps a lot with ignition timing advance as well gives more room to performance reducing corrections by IAT. Especially at speed-density-fuel control systems this can give the engine for a wider range of atmospheric temperature a better performance. Not only because of more VE also because of the bigger distance to knock margin.

A thing which can't be seen in the MAP, too low resolution for reason, are the pressure amplitudes, which can be used to improve performance. They are design depended: length, diameter, filter area, flow guiding.
 

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Discussion Starter · #14 ·
So at this point I've taken this design about as far as I care to go with it.
LotueElise, I was thinking about building another from scratch and would appreciate any design suggestions. I'm sure anything you can come up with will have a better VE than what I have been messing with. Thanks
 

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I'm sure anything you can come up with will have a better VE than what I have been messing with
The scene called this type of intake in German Whale Dick, which is quite good with respect to flow coefficient. The ICE has a different character, flow is no continuous thing, it is more an lateral and vertical oscillating fluid and changes the character with a more far location from engine to the continuous thing. Therefore it depends quite much on the engine setup what design will give your engine more VE with respect to the applicated operation range.

Before going into detail of the VE related basics, I would like to see how closed the CAI housing is and how the feed looks like. Would you like to share pictures?
 

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The scene called this type of intake in German Whale Dick, which is quite good with respect to flow coefficient. The ICE has a different character, flow is no continuous thing, it is more an lateral and vertical oscillating fluid and changes the character with a more far location from engine to the continuous thing. Therefore it depends quite much on the engine setup what design will give your engine more VE with respect to the applicated operation range.

Before going into detail of the VE related basics, I would like to see how closed the CAI housing is and how the feed looks like. Would you like to share pictures?
you are asking to see more pictures of the inside, correct?
 

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Arouse the DAMPFHAMMER!
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you are asking to see more pictures of the inside, correct?
Ah, may I wasn't clear on that. I would like to see the CAI housing (= the encapsulation of the air filter), the inner concept/design there and how it is feed with fresh air. I go through this with every tuner customer as this is a very simple but very effective lever-arm to keep knock margin far in the advanced IGT region. It is not directly and always a power adder, but definitely one who guarantee a smaller loss in hot days. I have many customers in TX and CAL in the US how see very high temperatures outside. On not optimal, to be diplomatic, CAI setups, e.g. like header air sniffer setups, I saw up to 55 °C IAT at part load and still around 48-52 in WOT conditions, which kills quite allot ponies. A temperature offset to atmospheric condition of 7 °C should be the aim at least.
 
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