i put together my turbo kit piece by piece, and discovered that my short ram intake that i had before... a cheap $25 intake, doubles as a cold-air turbo intake. although it might not help a ton, to move it from behind the headlight... to the inner fender well, every little bit counts. if i knew how to post pics... i would do so.

the short ram drops down right to the inner side of the plastic, close to where you cut it for a SMIC. still sits a good way off the ground so as to not pick up water...

just throwing in an idea for everyone that doesn't have the hahn intake.

LOL cold air intake...turbo...thats funny....and useless

get a better INTERCOOLER if you want the intake air charge cooler

Not %100 true. Granted, with our cars having the exhaust manifold in the front, there's hardly any room for a cold air intake. However, on say an SRT-4 where the exhaust is where our intake is, it's possible. Sure, no replacement for an intercooler, but the cooler the charge is initially, the cooler it'll be when it enters the turbo and the cooler it will be when it goes from the intercooler to the intake and into the engine.

Someone correct me if I'm wrong here, but that's my logic.

-Corey

Originally posted by turbo8u
LOL cold air intake...turbo...thats funny....and useless

How do you figure that it's useless?

General compressor efficiency is determined like this:

E = ((PR^0.28 * T) - T) / TR

PR = Pressure Ratio
T = Compressor Inlet Temp. (absolute)
TR = Temperature Rise

Care to explain how a cooler compressor inlet temperature is useless?

Originally posted by dougie2

Originally posted by turbo8u LOL cold air intake...turbo...thats funny....and useless

How do you figure that it's useless? General compressor efficiency is determined like this: E = ((PR^0.28 * T) - T) / TR PR = Pressure Ratio T = Compressor Inlet Temp. (absolute) TR = Temperature Rise Care to explain how a cooler compressor inlet temperature is useless?

OWNED TURBO8U IMO


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i think you meant to post this formula instead.

T rise = <(PR^.28)-1> x T amb./compressor efficiency.

that calculation can only be used w/ an absolute temp. scale like kelvin. hypothetically, lets say PR=2 and EC=.7

at 300K (about 80F)

T rise = <(2^.28) -1> x 300/.7 = 91.7978076K rise

at 285K (about 53F)

T rise = <(2^.28) -1> x 285/.7 = 87.2079172K rise

turning that back into an T(in F) rise, it amounts to about 8.27F change between inlet temps of 80F and 53F.

edit: LOL, had to clean up my poor math posting skills.

"Care to explain how a cooler compressor inlet temperature is useless?"

i dont think i SHOULD have to explain this...but i'll do so just for shits and giggles, besides...i have time.

the intake air (in the manifold) has more to do with the INTERCOOLER efficiency. the point where the air is heated up most is at the turbine, so do you honestly think a drop in say...maybe 2 degrees of air is going to help the final air temp? i could go on and on with math eqwuations yea but logic presents me with the fact that a better INTERCOOLER would obviously help more than a "cold air intake" because, its not really "cold". intake air temps with a front mount IC are about 90* say, SMIC is about 110, and normal NA is about 100 (at least in cali) the air is heated up already as it is.

the whole point of a CAI is for an NA car to breath at a lower intake air temp, (utilizing colder airs density) but on a turbo application ambient air density goes right out the window as soon as its compressed.

should i continue?

the fact is, ive logged the intake air temperature on a subaru with a AEM CAI, it DID NOT change throughout the ENTIRE rpm range when we re-routed the filter, so i guess you could say i 'know' CAI on a turbo is 99% useless because i've seen it, and have the logs too.

I don't think you understand. We're talking about COMPRESSOR inlet temperatures here, having nothing to do with intercoolers or intake manifolds.

In simple terms- the cooler the COMPRESSOR inlet temperature is, generally the compressor outlet temperature will be cooler and the compressor will operate more efficiently. Think of it in terms of the compressor and throw everything else out the window with intercoolers, turbines, manifolds, etc.

Read up on compressor efficiency and how maxium efficiency is achieved and you'll know where I'm coming from. I'm not saying you'll pick up much by moving your intake filter from behind the headlight to 16 inches lower. But if your filter is attached directly to the turbo, like many custom setups... moving it down behind an air duct in the front bumper will increase your efficiency about 4%.

Again, the compressor draws in air through it's inlet and compresses it and subsequently increases the temperature and density by doing so. How can you say that cooler inlet temperatures will not have effect on that process and it's efficiency? You likely won't see the difference by datalogging post-turbo temps either, btw. Your statements would even lead one to believe that you'll produce no more power when ambient air temperature is 70 degrees as opposed to 90 degrees.

Maybe I just don't see where you're coming from. Have you ever logged direct compressor inlet temperature and direct compressor outlet temperature? What were your results?

Originally posted by dougie2
moving it down behind an air duct in the front bumper will increase your efficiency about 4%.

ok iknow what you're saying and yes, the turbine inlet temp and outlet temp are in direct proportion, and lowering the inlet air temp will effect the outlet temps SLIGHTLY. i dont think the "gain" wheter it be better turbo efficiency is enough to say a CAI on a turbo is helpful. all im saying is re-routing the filter location is cool and all but how much colder is the air down there? like what, maybe 5 degrees? lets test this though shall we

have you ever heard of adiabatic efficiency? 100% would be no loss or gain of heat, adiabatic is normally around 60-75% (raising this would be the only benefit of a CAI on a turbo)


lets test this though shall we

test #1 = intake air temp (at filter location) 75*F
test #2 = intake air temp (at filter location) 70*F

test #1

the formula for ideal outlet temperature=

(t2 = t1 (p2/p1)^0.283

where-
t2= outlet temperature *R
t1= inlet temperature *R
*R= *F + 460
P1= inlet pressure absolute
P2= outlet pressure absolute

lets assume an inlet temp of 75*F and we want 10psi boost, to find t1 in &R do this:

t1= 75+460=535*R

P2 inlet pressure is 14.7 or 1atm. p2 outlet pressure is 10psi + atmospheric

p2= 14.7+10 = 24.7psi

-to find t2-

t1 = 75
p1 = 14.7
p2 = 24.7

formula will now look like this:

t2 = 535(24.7/14.7)^0.283 = 619.6*R

subtract 460* to get *F

619.6 - 460 = 159.6*F ideal outlet temp

this is an ideal temperature rise of 85%, if the compressor had a 100% adaiabatic eff, this is what we'd expect from the outlet temp

ideal outlet temp/adiabatic eff = actual outlet temp rise (but we wont go into that)

test # 2

assuming the only variables are inlet/outlet temps, pressure stays constant

t2 =
t1 = 530 *R
p1 = 14.7
p2= 24.7

t2 = 530 (24.7/14.7)^0.283 = 613.8 *R

613.8*R - 460 = 153.8*F ideal outlet temp

so all this shows a drop in about 6 degrees air temp after the turbo, woopty doo...so what would be the USE of a drop in 6 degrees? my original statement was its useLESS as in, whats the point?

a USEFUL alternative, is better intercooling.

edit:

Originally posted by dougie2
Manifold air temp has NOTHING to do with intercooler efficiency OR compressor efficiency.

i quite honestly, on all accounts, beg to differ. its directly proportional. if you know all the varaibles such as intake air temp (before the intercooler) and boost pressure, etc

hey guys.. i gained 4whp by rigging up a cold air intake for my 20g turbo.

cooler air is still cooler air.

you can see my video install on www.gsturbo.com/james/eclipse

James

Originally posted by siueclipse
hey guys.. i gained 4whp by rigging up a cold air intake for my 20g turbo. cooler air is still cooler air. you can see my video install on www.gsturbo.com/james/eclipse James

hey, badass :) how do you know you gained 4whp from that though? you could snag an extra 4 just with the tuning

Originally posted by turbo8u

Originally posted by siueclipse hey guys.. i gained 4whp by rigging up a cold air intake for my 20g turbo. cooler air is still cooler air. you can see my video install on www.gsturbo.com/james/eclipse James

hey, badass :) how do you know you gained 4whp from that though? you could snag an extra 4 just with the tuning

dyno and g-tech

James

"so all this shows a drop in about 6 degrees air temp after the turbo"

LMAO, we used a variation of the same forumla and got almost the same results. i used a wider margin of intake "coolness" though, thats why my math showed an 8 degree difference.

before i say anything else, let me say i have next to zero experience with "real world" turbo experience. im only good with theory. with that said..

a 4HP gain can be attributed to any number of variables. to truely test if the CAI is better, you would need to at least perform a longitudinal study over time, switching back and forth frequently between the "filter on turbo" and "CAI filter" (the independant variables) and logging the HP on a dyno with each switch (the dependant variable). then you would need to find baseline research on the average HP variance of the eclipse and test the data you collected against the standard deviation of the basline numbers. if you fell within a reasonable alpha level, you could then conclusvly and empirically say that the CAI on a turbo nets more power. as for the sound change...you are effectivly lengthening the resonant chamber of the sound portal and moving it to a naturally anechoic environment for higher range frequencies. those two factors in combination probably resulted in the sound difference.

i would LOVE to see some before/after inlet temp logs. ill look up the specs on the turbo and see if the formulas really match what you are seeing in the "real world". THAT is scientific, and im alls about that. ;)

good discussion BTW folks!

Here's the statements where I don't understand your logic:

>> "Care to explain how a cooler compressor inlet temperature
>> is useless?" i dont think i SHOULD have to explain this

You shouldn't have to explain it because a cooler compressor inlet temperature is ALWAYS useful.

>> the intake air (in the manifold) has more to do with the
>> INTERCOOLER efficiency.

Manifold air temp has NOTHING to do with intercooler efficiency OR compressor efficiency.

>> the point where the air is heated up most is at the turbine,
>> so do you honestly think a drop in say...maybe 2 degrees of
>> air is going to help the final air temp?

Actually, the exhaust gases are COOLING as they're going through the turbine. Where did you learn that "air is heated up most at the turbine"? And why is your inlet air coming out of your turbine? Yikes!

>> i could go on and on with math eqwuations yea but logic presents
>> me with the fact that a better INTERCOOLER would obviously
>> help more than a "cold air intake"

That's true but we're not talking about intercoolers, we're discussing your comment that a colder compressor inlet temperature is useless... which isn't fact.

>> the whole point of a CAI is for an NA car to breath at a lower
>> intake air temp, (utilizing colder airs density) but on a turbo >> application ambient air density goes right out the window as soon >> as its compressed.

I have yet to see or hear of a compressor that direcly took in AMBIENT air. And CAIs are not for NA engines only... they're for any application in which you need COOLER AIR.

>> should i continue?

Please... no!

I'm really not trying to be a dick... it's just that your logic goes against everything I've ever tested or studied. I'll see if I can post some logs from my Accel DFI using the compressor inlet temp sensor and the sensor mounted at my compressor outlet. I log with both a CAI and a filter directly on the compressor inlet of my Super 20G. I hope I have time this weekend. This is a good discussion here though!

I used my old Ractive short-ram for intake piping. Had to chop a little off, but it worked for about 5 months. I guess it loosened a little, fell out, and i ran over it.

Hehe, yeah I was on the highway and the intake fell off! I stopped and ran a couple of feet back and I found a silver flattened metal. I was kind of pissed off but the intake only cost me $20. O well. But yeah, I kinda do feel a little difference at alleration or maybe it's just me. How does your's feel Blitz?

Well I drove myt friend's turbo GS-R with and without a 'cold-air' and can say that it does help it. Especially when you think that the compressor is right next to the turbine which is producing mad heat. I'm bout to do the same too. And some people can't afford a $400 intercooler so why not a $30 pipe, every bit helps right? Sidenote: Don't know why but adding a pipe on the end of the inlet changes the way my Greddy BOV sounds at low boost. It went from a sharp whistle to a howling, sharper type whistle.

i still think its retarded

i have a short ram so i wont have to ever worry about suckin water into my turbo like you 'CAI'ers. also...hahn side mount and water/alcohol injection. i can boost as much as i want and my intake charge is cooooooooool.

fuck ambient air temps, my intercooler is in charge <no pun intended }(>

My car sounds hot with the "CAI".

i didnt mean to start a huge argument,

just throwing in my idea... it looks good, and from the heat off of the engine, compared to off the ground, any bit of colder air is better... MAYBE NOT A HUGE difference, but its better than throwing away your old Short ram, and buying a new turbo intake. just trying to help out anyone that i could. :). pieces.



oh ya, um... i have a question..

is 15.2 a decent time when boosting 4psi? (1/4 mile) i have no other aftermarket parts... at all, cuz i'm broke. i am fixing the boost tonight. just wanted to know. TIA.

no argument started, just a great discussion! and hey, there really isnt any harm in throwing on the old short ram as long as you dont suck any water into it. ;)

the 15.2 is great at only 4lbs of boost. with a little more traction (and weight redux???) you will be in the 14.9s. congrats man, looks like you have a nice setup and you are getting some great results.

You know guys, one of the things I like most about my car hobby is the way subjects like math never come up. All these formulae and postulate-spouting c'mons are making my already weary brain even more weary. Please stop the insanity and keep all mathematical discussions to no more advanced than this simple equation:

truth = T>E
Where T = Talon and E = Eclipse, imo.

Originally posted by DR1665
simple equation: truth = T>E Where T = Talon and E = Eclipse, imo.

very good point

here's a little food for thought....I used a lot of my old CAI in my custom turbo set up.



notice the turbo intake pipe bends down toward the drivers side wheel...thats part of the old CAI (along with the part that on the intake manifold)...the bottom of the filter ends up just above the lower edge of the plastic sheild that separates the wheel from the engine compartment. When I data log intake air temps I get a whooping 115* when crusing, but once I start boosting the intake temp drops to just above the outside air temp. I always acredited it to a super efficent SMIC....but who knows. :shrug I'll see if I can get a log of it tonight to post for you all.

*edited for clarity*