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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Injen or AFE or BMS



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      03-24-2009, 11:48 AM   #23
jcarlucci1
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You are stating these things as FACT, and they aren't facts..they are your opinions. Until you put a CAI on and test AIT in comparison to the DCI, they will continue to remain your opinions. I am sure many people on here would bet that a cai will decrease your ait's further. Just for the record, I have a BMS DCI on my car, but that doesnt change the fact that your theories are very flawed.


Quote:
Originally Posted by Former_Boosted_IS View Post
I am not trying to be difficult, but you simply are not correct. Buy a DCI, save the $300 and you are closer to getting an intercooler. The CAI does nothing.

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, 11:54 AM   #24
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Quote:
Originally Posted by jcarlucci1 View Post
You are stating these things as FACT, and they aren't facts..they are your opinions. Until you put a CAI on and test AIT in comparison to the DCI, they will continue to remain your opinions. I am sure many people on here would bet that a cai will decrease your ait's further. Just for the record, I have a BMS DCI on my car, but that doesnt change the fact that your theories are very flawed.

I am not stating opinions. I posted the formula to calculate outlet temperatures based on ambient temperature, inlet temperature, and intercooler efficiency. You can do the math yourself.

I didn't say a CAI wouldn't decrease you AITs possibly. I said the difference would be negligable. I am done arguing. I will offer my car for testing if someone wants to send me a CAI.

I will leave the thread and I apologize for the interuption.
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      03-24-2009, 11:55 AM   #25
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We need someone to do a test where they look at IAT with the BMS DCI versus the Riss intake(with scoops and plenum). Both are open element so we would see if having the air colder and any potential ram effect will lower IATs. I have the BMS DCI currently and will have the Riss intake/plenum/scoops delivered any day. Just wish a have a means of comparing the IATs.
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      03-24-2009, 11:58 AM   #26
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Quote:
Originally Posted by Former_Boosted_IS View Post
Fair enough. The turbos are forcing air into the engine. That creates a positive pressure on the manifold above the atmospheric pressure. If you are +14 psi, then the turbos are forcing about twice the atmospheric pressure(14.7 psi) into the engine. That is how boost is created.

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.
Sorry for the confusion - I was talking about compression ratio of the turbo's, but you thought I was talking compression ratio of the engine.

I found an interesting site that shows a bunch of good equations regarding turbochargers - http://www.gnttype.org/techarea/turbo/turboflow.html

I really like this equation from that site for

How Hot is the Air Coming out of the Compressor?

Tout = Tin + [Tin x [-1+(Pout/Pin)0.263]]/efficiency

Example: the inlet temperature is 70 deg F, the suction pressure is -0.5 psig (a slight vacuum), the discharge pressure is 19 psig, and the efficiency is 72%. What is the discharge temperature?

Tin= 70 deg F + 460 = 530 deg R
Pin= -0.5 psig + 14.7 = 14.2 psia
Pout= 19 psig + 14.7 = 33.7 psia
Pout/Pin = 33.7/14.2 = 2.373 (this is the compression ratio)

Tout = 530 + 530 x (-1+2.3730.263 ) = 717.8 deg R - 460 = 257.8 deg F
0.72

So the theoretical outlet temperature is 257.8 deg F. I sure would like to have an intercooler to cool that hot air down before it goes into my engine!


So if you can lower Tin and raise Pin, you can lower the temperature coming out of the turbo. But what the community has found so far is that raising Pin (by having a less restrictive intake) makes the best positive impact overall, even though it raises Tin.

I just wish some intake existed that would have the same higher Pin as DCI's and a lower Tin as well. This together with the upgraded FMIC would be ideal!!
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      03-24-2009, 12:08 PM   #27
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Quote:
Originally Posted by Klepper1 View Post
I just wish some intake existed that would have the same higher Pin as DCI's and a lower Tin as well. This together with the upgraded FMIC would be ideal!!
With the riss intake alone people have shown similar dyno gains to the BMS DCI. The problem is without the scoops and plenum the air probably is just as hot as the BMS DCI. WIth the addition of the plenum and scoops, surely the air entering the filter will be colder. So maybe we can get the higher Pin and lower Tin as well.
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      03-24-2009, 12:08 PM   #28
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Quote:
Originally Posted by Former_Boosted_IS View Post
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.
Wow, that's quite the assumption. I actually do understand it very well - it's what I do for a living.

I design systems to move gas from lower pressure pipelines into high pressure pipelines using turbines with aftercoolers. The two ways we use to get the most out of our compressors is to raise suction pressures to reduce compression ratios to keep the gas cool, and use aftercoolers to cool the gas post compression. Sound familiar?
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      03-24-2009, 04:16 PM   #29
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umm anyway, for what it's worth...

i'm absolutely 100% satisfied with my injen intake!
sounds great, and the throttle response is instantaneous! love it, you definitley will not regret it!
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      03-26-2009, 03:26 AM   #30
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Thanks. That's what I am wanting to know. Should i get rid of my AFE Dual Cone for the new Injen Dual Cone?
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      03-26-2009, 03:40 AM   #31
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Quote:
Originally Posted by Klepper1 View Post
Wow, that's quite the assumption. I actually do understand it very well - it's what I do for a living.

I design systems to move gas from lower pressure pipelines into high pressure pipelines using turbines with aftercoolers. The two ways we use to get the most out of our compressors is to raise suction pressures to reduce compression ratios to keep the gas cool, and use aftercoolers to cool the gas post compression. Sound familiar?
honestly, when its warmer outside, i feel a lag with my DCI that i dont when its cold.. i do agree when running higher boost, more air is better. I just dont like any of the CAI out there. I think the stock airbox is sufficient enought esp with a drop in air filter
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      03-26-2009, 01:17 PM   #32
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Quote:
Originally Posted by Bizout77 View Post
Thanks. That's what I am wanting to know. Should i get rid of my AFE Dual Cone for the new Injen Dual Cone?
i personally would say yes, but if you're satisfied with AFE, why bother?

injen definitley delivers and i have been nothing but satisfied with this product!
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