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BMW 3-Series (E90 E92) Forum
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Injen or AFE or BMS
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03-24-2009, 03:08 AM | #1 |
Hank
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Injen or AFE or BMS
Just wanted to get some thoughts. Which intake do you think is best for my 335? I have the AFE Dual Intake already but I am liking the new INJEN Dual Intake. Any thoughts.
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03-24-2009, 03:15 AM | #2 |
Gruppe Titan
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Drives: 08 E92 SG/Coral
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I'm in the same boat.
My opinion is that if you already have a DCI, then all you are basically doing is paying for looks. The Injen looks the best, but also is pricey. Go for what you think looks good.
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03-24-2009, 05:37 AM | #5 |
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My AIT testing above proves the DCI is more than sufficient. The "cold air" intakes are nothing more than pretty and expensive, but there is no performance gain.
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03-24-2009, 08:57 AM | #6 |
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I dont really see how it proves that unless you test a CAI and compare numbers. Just because you have fairly low AIT's with your DCI doesnt mean a CAI wont bring them down another 10-20 degrees or more..
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03-24-2009, 09:38 AM | #7 |
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Are you serious? I am not trying to bash at all. Intakes are about one thing and one thing only on an intercooled car and that is providing a means for the turbo to draw the highest volume of air. The surface area of the filters is the highest priority for intakes, hence the reason we see intakes sitting next to the turbo even on giant turbo cars. I am not sure I can convince anyone, but I am willing to bet you will see nearly no difference between the DCI or the UR CAI or the Injen Intake. If someone wants to send me a CAI or Injen, then I will test them to prove the point. I am not doing dyno testing, but real world results.
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03-24-2009, 09:59 AM | #8 |
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Very good point, although I think all would agree that a higher volume of cooler air is better than a higher volume of warmer air.
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03-24-2009, 10:02 AM | #9 | |
Joint Chiefs of Staff
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Mike |
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03-24-2009, 10:22 AM | #10 | |
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Here is the efficiency equation: Eic = Intercooler Efficiency Tin = Inlet Temperature Tout = Outlet Temperature Tambient = Ambient Temperature Therefore, Tin - Eic*(Tin - Tambient) = Tout Through my testing we can approximately figure out the inlet temperature doing some simple math. If I use your 20 degree cooler air entering the filter then that will result in 2 degrees F colder air leaving the outlet side on an intercooler with a 90% efficiency. Only 2 degrees. Buy the dual cones and use the remaining $300 to put toward an upgraded intercooler like the Active Autowerke one I just installed on my car. |
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03-24-2009, 10:52 AM | #11 | |
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All I was trying to point out was that the ideal situation on our cars is to have a filter that is as free flowing at the DCI's, but ALSO has a source of cold air. It is not ONLY about free flowing. The real reason you want free flowing in the first place is so that the compression ratio for the turbo is not as high so it doesn't heat up the air as much during compression (free flowing gives a higher "suction" pressure for the turbo). And the reason for the fmic is to cool the air post compression. In reality, we are trying to get high pressure, cool air into the engine. The more oxygen molecules we can jam in there, the more fuel we can burn which means - more power!! |
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03-24-2009, 10:58 AM | #12 |
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1 vote for the DCI. Simplest solution is really the best right now. I agree that you're paying for looks for other intakes, but that may be important to some.
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03-24-2009, 10:59 AM | #13 | |
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Listen to what I am saying, the AITs were 151 after only three pulls. I have proved that cooling AITs is solved in one way and that is through an upgraded intercooler. The bold area also makes no sense at all? Compression ratio of the turbos? There is no compression ratio on turbos? What the? Can someone else please jump in here so we don't confuse those trying to learn. |
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03-24-2009, 11:13 AM | #14 |
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What about the "ram effect" with an intake like the Riss set-up with the scoops and plenum blowing air directly onto the intake. It seems like this "ram effect" might make it even easier to suck the air (less resistance) and on top of the the air would be 20-30 degrees colder. Couldn't this theoretically provide gains?
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03-24-2009, 11:18 AM | #16 | |
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I don't want to bash anyone or any intake, but I just want you guys to know that you can save a lot of money here if looks are not your top priority. If looks are, then I completely understand you choice. |
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03-24-2009, 11:26 AM | #17 |
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I am certainly not trying to be difficult either. We are all trying to learn here.
Instead of saying "you are simply not correct", please explain why. The turbo's are indeed compressing the air. That is their whole function. The ratio of their suction pressure and their discharge pressure is called "compression ratio". You have proved that IAT's are lowered with a better fmic. You have not proved that they can NOT be lowered further with a better intake (and I am not saying one exists). All I am saying is that an intake that is as free flowing as DCI's but that take in colder air would be better and produce lower IAT's. |
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03-24-2009, 11:29 AM | #18 | |
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03-24-2009, 11:34 AM | #19 | |
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I'm just trying to look at the resistence the turbo has in drawing in air. It has been shown/proven that decreasing resistence of air entering the turbo provides gains (the open filter). If the air is colder/denser than that would also make it easier/less resistance for the turbo to draw in air. |
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03-24-2009, 11:39 AM | #20 | ||
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03-24-2009, 11:41 AM | #21 | |
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Compression ratio is how much that air that is in the cylinder will be compressed when the piston reaches its TDC (Top Dead Center) position. So if the compression ratio is 11:1, then the as the piston rises the air will be compressed to about 1/11 of its original volume. If you have a compression ratio of 8.5:1, then it will be compressed to about 2/17 of its original volume. Now, compressing air (with all else equal) will cause adiabatic heating with both the compression stroke or the turbos boosting. I hope that helps clear up the difference. |
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03-24-2009, 11:45 AM | #22 | |
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I am trying to help, but you simply don't understand the concepts of a turbo car. I really am not trying to be rude, but you are hurting the forum by spreading these mis-information in the forums. This has been a major issue on this forum. An intake is for one thing, providing enough air for the turbos to pull. If there is sufficient surface area on the intake then it does its job well. Intercoolers lower AITs. Simple. If you want to send me one of these intakes I will gladly log AITs. I suspect they would not want me to do that because the data will show nearly no difference in AITs. Ask Shiv or Terry what they think? Or see what they sell. |
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