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I was wondering what everyone is putting on their X. I installed the Injen Cold Air and would be surprised if anything is better. Most noticable power gain and boost spools so much quicker. Before with BOV no flutter at all now im getting full boost by 2800 in 5th gear flutter of the BOV spring at 2500. Anyone have any other Intakes? how are they? i strongley recommend the Injen.
 

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After i saw the crappy heat sheild that Injen was shipping for the RSX, I was VERY put off.... the last time I checked they were at like a 4th gen, and ppl were still getting cracks...

Not to mention on the RSX the AEM dynoed better....


I helped a friend put in an AEM CAI into his WRX, and after all was said and done and I thought about it, cleaning the filter is going to be a pain...

the CAI definetly made the car sound cooler, but I didn't drive it before and after so I can't comment on response.


Personally, if i get a wrx i'll prolly go with a drop in K&N or the blitz just to make changing/cleaning the filter easier....i'm a real lazy SOB.
 

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I have AEM intake on my WRX. I like the setup. I looks really nice under the hood.
About power, I dought any intake makes much power. Real dyno test by people totally unrealated to the products on the market show very little power increase.
In hot and humid conditions I noticed no increase in performance/track times with my intake.
I also know that the Injen intake showed no increase in hp on Turboxs's dyno. They did mention it made like 3-4hp on a modded WRX when cut down into a short ram but that was about it.
So I would just be happy with the new look and sound.
 

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get a short ram if you want better performance than the stock intake tract.

the CAI's are too long and bendy. drawing cold air for a F/I car is useless, as the turbo will heat it up anyway to very high temps. if you want better cooling, get a better scoop or IC, if you want a better intake, get a shorter, more straight intake tract.

CAI's in theory, and on the dyno do nothing for the wrx.

dR
 

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Blitz SUS short ram.

You guys need to lose the normally aspirated attitude, CAIs do not benefit a turbocharged engine, dynos have proven this. The turbocharger just heats up the air when it's compressed anyway so your turbo is defeating the purpose behind your CAI.
 

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Flyboy said:
Blitz SUS short ram.

You guys need to lose the normally aspirated attitude, CAIs do not benefit a turbocharged engine, dynos have proven this. The turbocharger just heats up the air when it's compressed anyway so your turbo is defeating the purpose behind your CAI.
thats because the turbo is too small, and the induction path is being heat soaked by the manifold, motor and heat from the intercooler.

charge temps from the volute are influenced directly by ambient temps in the compressor inlet.

if you were to wrap/insulate the intake path, this would reduce the heat soak
 

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Marcolus said:


thats because the turbo is too small, and the induction path is being heat soaked by the manifold, motor and heat from the intercooler.

charge temps from the volute are influenced directly by ambient temps in the compressor inlet.

if you were to wrap/insulate the intake path, this would reduce the heat soak
I don't think that heatsoak is that big of a problem (unless your sitting in a traffic jam, of course, or driving it really hard like at a track and sit in line...). Also, what do you mean by heat from the intercooler? Granted the intercooler should get warm, indicating that it's doing its job, but I doubt that it would create enough heat to overheat the intake charge. The action of compressing the air within the turbo is what causes the intake charge to be heated (that's what dR and Flyboy are referring to, I believe). The size of the turbo would matter from the standpoint of pushing more air through, but just because the stock turbo is small doesn't change the fact that even a huge turbo will still heat the intake charge. All that energy from the compression has to go somewhere, and it's liberated through heat from friction of the air molecules, etc.
 

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Marcolus said:


thats because the turbo is too small, and the induction path is being heat soaked by the manifold, motor and heat from the intercooler.

charge temps from the volute are influenced directly by ambient temps in the compressor inlet.

if you were to wrap/insulate the intake path, this would reduce the heat soak
what's becasue of the small turbo? the induciton path through the IC is the cooling cycle, there is no heat soak there, just the opposite. the IC is probably one of the cooler spots under the bonnet due to its distance from the exhaust manifold and location under the scoop. intake charge is LOSESits heat at the IC stage, not gains (heatsoak) as you mentioned.

the heatsoak isn't the issue. its the tremendous heat in the compressor unit that heats up your intake charge. that's why F/I cars need an IC. not becaue of heatsoak, but becasue of the compressor.

dR
 

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WRXed said:


I don't think that heatsoak is that big of a problem (unless your sitting in a traffic jam, of course, or driving it really hard like at a track and sit in line...). Also, what do you mean by heat from the intercooler? Granted the intercooler should get warm, indicating that it's doing its job, but I doubt that it would create enough heat to overheat the intake charge. The action of compressing the air within the turbo is what causes the intake charge to be heated (that's what dR and Flyboy are referring to, I believe). The size of the turbo would matter from the standpoint of pushing more air through, but just because the stock turbo is small doesn't change the fact that even a huge turbo will still heat the intake charge. All that energy from the compression has to go somewhere, and it's liberated through heat from friction of the air molecules, etc.
the intercooler is just a heat exchanger and it does get hot, thats like saying an oil cooler will not heat up components around it, conduction, convection, radiation

yes compressing the air itself will heat the air up, but by how much is dependant of atmospheric conditions

any turbo will heat the intake charge, but by how much is the difference, at equal boost levels the temp charge of a larger turbo will be smaller than a smaller turbo as larger turbos dont need to spin as fast to push the same amount of cfm and support the same amount of pressure as a smaller unit would.
 

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Marcolus said:


the intercooler is just a heat exchanger and it does get hot, thats like saying an oil cooler will not heat up components around it, conduction, convection, radiation
the heat your feeling at your IC is the heat removed from the intake charge as it cools. so it's not heatsoak. its the exact opposite. he didn't say it didn't get hot. it just doesn't act as a source of heatsoak for your intake charge.

Marcolus said:


yes compressing the air itself will heat the air up, but by how much is dependant of atmospheric conditions
very little is based on atmospheric conditions. your engine bay temp (EGT and other temps) are actually VERY consistant no matter whether it's december or august. the inital period of warm up is the only real time there will be a drastic diff. once the car is at operating temp, those conditions make less of an impact.

Marcolus said:


any turbo will heat the intake charge, but by how much is the difference, at equal boost levels the temp charge of a larger turbo will be smaller than a smaller turbo as larger turbos dont need to spin as fast to push the same amount of cfm and support the same amount of pressure as a smaller unit would.
but a larger turbo will not run at the same cfm. you go larger to push more cfm. otherwise, why upgrade? so larger or smaller, the rpms of the turbo will be comparabe (the cfm doesnt matter, becasue turbos all push diff #s), thus creating the inverse of your explanation. a larger mass spinning at comparable speeds will produce MORE heat, not less.

dR
 

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Just want to add that I'm glad you guys aren't busting out the math equations to prove that a CAI is better than a short ram like they do on I-Club...man that's annoying. They really do think over there that CAIs make a big difference...
 

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it's not a mathematical issue. your turbo is hauling gobs of exhaust at 700+ degrees.

i'm blown away that people thing a measly 10-20 degree diff in intake air through the scoop will not be suceptable to that, let alone pulling it through a longer heat soaking tract of a CAI.

<shrug>

dR
 

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Not saying your wrong dR...I totally agree with you...but this person on I-Club disagreed with me and will probably disagree with you too...and this is why I mentioned the mathematical thing since it annoyed the hell out of me:

Ok, you can believe the above. Or, you can believe mathematical fact:

1. Temperature increases at the compressor inlet are directly linear at the compressor output. 15 degree increase in ambient air is a 15 degree increase in output compressed air.
2. The "masking" "not affected by" "turbo cars aren't yada yada" hoo ha comments stem from the fact that the intercooler is dropping a % from the original air temp relative to ambient (to keep things simpler for the moment). So obviously, a 75% reduction of the difference between 200 and 100 is going to be larger than a 75% reduction of the difference between 175 and 100. And guess one will have the lower post-IC temperature. Yep, the lower compressor outlet temp, which is directly related to the inlet temp.

To those of you who continue to insist that the inlet temp doesn't matter relative to the outlet temp, all you have to do is look at the formulas readily available on the GN/T-Type boards, for example, and see that you are plainly wrong.

Urban-myth check, people. Your 'buddy' is wrong.
The guy seems very certain that I'm full of ****. :rolleyes:
 

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Bernoili Effect: As a gas is compressed, it produces heat, as a gas expands, it dissapates heat and gets colder. The amound of heat generated has nothing to do with how fast the blades are spinning, it's depends on how much the air is being compressed.

Now, sure, I can see that a 5% decrease in inlet temp. would lower the outlet temp a little (don't know if it would be the same percentage). However, in a NA car, say the temp between using a CAI vs. stock intake are say 90deg and 100deg respectively (just theoretical not actual). This would be a 10deg. difference and a 10% difference between the cold air induction and Underhood induction. So the intake reduces the temp by 10% of what it would be if it was sucking in the enginebay air.

However, on a turbo, suppose the CAI was 90deg, and the stock intake was 100deg again. Now, if we beleive what was said on i-club, sure the outlet of the turbo, might be 10deg difference between the 2 intakes, however, because the turbo heated them up, we're not talking about 90deg and 100deg, it would be more like 140deg and 150deg AFTER the Intercooler(again theoretical...I don't know how hot it gets from the turbo). Well this isn't 10% difference anymore, it's only like 6.6% difference in temp.

OK, so say on a NA car there is 10% diff between the intakes and on a turbo car, there is 6.6% difference. Now a CAI only adds about 5HP to a NA car anyway, so the turbo car with the same intake would see less than 3HP gain. 3HP probably can't even be felt by the butt dyno. I can find a better way to spend $240 for only 3HP!

Now ofcourse, when you get a bigger turbo/intercooler, the temps at the throttle body will start falling down closer to the temps on a NA car, so the CAI would start being more usefull.

Welcome to the world of "Jason's Logic".
 

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Verdugo said:
Not saying your wrong dR...I totally agree with you...but this person on I-Club disagreed with me and will probably disagree with you too...and this is why I mentioned the mathematical thing since it annoyed the hell out of me:

The guy seems very certain that I'm full of ****. :rolleyes:
that guy is blowing more hot air out of his mouth than my TD04 is out of the compressor. :D where did he get this physics information? quote me a source that there is no critical mass in temps at the turbo. the fact that there is a temp ceiling and the air just gets pushed to thatmakes much more sense to me. i don't believe inlet/outlet temps are proportional. i think everything get's heated up to the ceiling. i have no more proof than he does though.

bottom line, whoever you listen to, the gain is tiny. even with his math.

dR
 

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jmussetter said:
Bernoili Effect: As a gas is compressed, it produces heat, as a gas expands, it dissapates heat and gets colder. The amound of heat generated has nothing to do with how fast the blades are spinning, it's depends on how much the air is being compressed.
OK, Jason, that's the ideal gas relationship.
Bernoulli Effect: For horizontal fluid flow, an increase in the velocity of flow will result in a decrease in the static pressure. The equation describing this effect is known as Bernoulli's law. The most practical example of this is in the action of an airfoil. The shape of an airplane wing is such that air flowing over the top of the wing must travel faster than the air flowing under the wing, and so there is less pressure on the top than on the bottom, resulting in lift.

http://scienceworld.wolfram.com/physics/BernoulliEffect.html
-Jim
 

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Ha Jim! You got me!

OK it's not the Bernoili Effect that states this, I was going on 10 year old memories of me not paying attention in school. The correct name is:

1st Law of Thermodynamics: "However, mechanical work done on a body can also increase its internal energy; e.g., the internal energy of a gas increases when the gas is compressed. Conversely, internal energy can be converted into mechanical energy; e.g., when a gas expands it does work on the external environment." -- www.encyclopedia.com

Also related to the " kinetic-molecular theory of gases".

My photographic memory must be outta film!
 

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I saw the K&N short ram/ cold air unit in short ram mode. It's neat, but the filter should be bigger when you run it in short ram, the room is there, but not if you run it in CAI.

It would be cool to try the intake setup both ways back to back at the track and see which K&N setup works best. This would be a true apples to apples comparison! I think I'll do it!

-Jim
 

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Ah well I'm not going to read through the whole thread (I'm really tired), but I will add my own hard data to the discussion. I have silicon inlet and IC hoses, and sitting and idling (the turbo isn't heating the air by compression) the air will get up to 150+ degree farenheit before and the same after.
The IC does nothing when you are sitting still. Maybe a few degrees. Once you get rolling, the immediate effect is the air has to cool the IC, not the other way around. If you are driving in town, this can take quite a while. It will still take a few miles on the highway. I have thermocouples in the inlet tract to prove this. When cruising, the turbo will be putting out 150F air that gets dropped to pretty much ambient (with an STi scoop and a Quantum Racing splitter), but when boosting (ProfecB at 16 psi) the turbo will spit out up to 300 F air that gets up to 150~160 post IC eventually. Usually it hovers around 100 until you keep on it for a while. This is without the Quantum Racing Waterspray. :)
I have let the car idle (for 30 minutes) and completely heatsoak so that pre and post were both 180F and after doing some short bursts of the Waterspray kit, the pre was still at 180 (I was sitting still the whole time) and the post was dropped down to 130F or less.
When I had my Link (equivalent to using a Unichip or anything else that's going to maximize timing and fuel) I noticed that you could boost with air up to about 130~140 post IC at 15~16 psi before you start to knock. This is with the QR splitter and scoop, mind you. Without that, you would probably have to compromise a bit. The waterspray kit has shown to hold the temps down a bit better during steady state, but ultimately, it's a recovery system.
When you are boosting, heat is exchanging between the intake air and the aluminum. The aluminum to outside air (or water mist) happens at a slower rate. The water definitely improves this but ultimately you just need more aluminum there to pull heat.
I'm rambling... :)
 
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