Welcome to the North American Subaru Impreza Owners Club Sunday December 21, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
View Poll Results: Does it matter if the Air entering the turbo is HOT or COLD
YES 108 84.38%
NO 20 15.63%
Voters: 128. You may not vote on this poll

Reply
 
Thread Tools Display Modes
Old 08-23-2008, 05:40 AM   #1
arfrce
Scooby Newbie
 
Member#: 126130
Join Date: Sep 2006
Chapter/Region: South East
Location: North Western Arkansas
Vehicle:
06 Subaru STi
WRB

Default Hot Air Intake VS Cold Air intake.Poll & Discussion

Does it matter if the air is HOT or COLD as it enters the turbo?
YES or NO ?

First off there is no argueing or name calling or Hating or anything bad what so ever. This is a discussion. So if you wanna be rude take it elsewhere.
..THANK YOU...
Here's how this started. I was skipping through the posts one day and came across an advertisement for this APS Turbo Inlet, APS 65mm Cold Air Intakes from Z1 Performance. Looks like a well made part..
But, I had a question.
And here is our discussion.

Arfrce..
Hey on the turbo inlet how hot does that tube get? Since it is metal wouldn't that heat up the cold air? Is there a way to prevent that? I know all turbo intakes get hot. But I would think the silicon would insulate the air bettet then the thin metal? thanks

Z1 Performance
cold air getting into the turbo is not going to yield you any significant gains, if any at all...since the air then is compressed by the turbo, which heats it up anyway. You have to focus getting cold air into the engine, which is done via the intercooler.

ARFRCE
So your saying that it doesn't matter how cold the air going into the turbo is?
HMM I dunno about that. I think it matters how cold the air going into the turbo is. The air molecules are closer together when the air is cold. When it is hot your not pulling as much air in. Here is a test you can do. On a hot day 1-3 pm is usualy the hottest.
Drive along in second gear and floor it. Listen to the turbo. Now the next morning around 4-8 am Do the same thing. You will deffinately here a difference in the sound of the turbo, it will be working much harder. Cause the air is one colder and there for pulling more air in. And that makes more power. So if it starts out cooler then it won't heat up as much. Then the intercooler won't have to work as hard to cool it back down. Just so ya know I am not trying to start an arguement. I am just curious. thanks


Z1 Performance
yes that is exactly what I am saying - it matters very little

The turbo has no temp sensor in it...it does not know nor care how cold the air going into it is. As soon as air enters the turbo, it is compressed. That is how boost is made. Compressed air is hot air. So air going from the turbo into the intercooler is HOT...the intercoolers job is to then rapidly cool it before it enters the head/combustion chamber. An efficient intercooler has no issues cooling this air, an inefficient one will struggle. This is a primary benefit of a front mount vs a top mount. You can easily measure if your IC is adequate or not adequate for your needs by measuring the temp of the air entering the throttle body. A cold air intake might slightly drop these temps, but a better intercooler would be the proper way to tackle the issue


ARFRCE
I understand what the parts do and how they do them. And I understand the difference between cold air and hot air. And I am not contesting what the function of a intercooler is or how it works, I am well aware of both. I Know the difference in an efficient IC and an Inefficient one.. Just cause I am a scooby newbie doesn't mean I'm under the age of 21. I have had the privelage of being a mechanic most of my life.
So let's continue.

If the air going into the turbo is cooler, then the air coming out of the turbo, won't be as hot. And the intercooler won't have to work as hard to cool the air back down.

Put it this way, if your engine bay air, is 90 degrees, when it is compressed it heats up to say
200 degrees. So it goes from 90 to 200.
Thats and increase of 110*.
Now you have the Morning time, when ambient air is Say 65 degrees, and you compress it the same. So you take 65 plus 110]*. That comes to 175.
Now 175 is cooler then 200 before it even enters the intercooler?
Now if you pass that through an intercooler it won't take as much to cool down.

Now you have the intercooler.

So you take your 200 degrees and cool it to 100*. Thats a decrease of 100* degrees.
Now you do the same 175* minuse 100*. Comes to 75*.
Do you see what I am saying now?
Thanks Jeff


Z1 Performance
This isn't really the place for a technical discussion - so if possible, we can move that side of things over to an appropriate section, where it can be explored in more detail.

While I appreciate your post and understand what you are thinking, you have alot of suppositions that may or may not be accurate (you would have to measure it to know for sure). If heat soak is a primary concern, there are many things you can do to prevent that such as various coatings, wraps, and other such items. Or you can go the next step and eliminate the J pipe altogether via a rotated kit (and then coat all the appropriate pieces). All of these can be utlized to achieve lower intake air temps pre intercooler if that is your goal.

There lack of flexibility (since its metal) and the ability to be used on both stock sized inlets and 3 inch inlets is what makes the APS one of the more desirable inlets out there.


Ok SO that is as far as we have gotten. Please don't be hating on anyone here. If you wanna be constructive then post if not, then leave. thank you

Everything you see here was taken from this thread. http://forums.nasioc.com/forums/show....php?t=1567035 Except one persons input. Just cause it didn't pertain to our discussion.
* Registered users of the site do not see these ads.
arfrce is offline   Reply With Quote
Old 08-23-2008, 05:43 AM   #2
arfrce
Scooby Newbie
 
Member#: 126130
Join Date: Sep 2006
Chapter/Region: South East
Location: North Western Arkansas
Vehicle:
06 Subaru STi
WRB

Default

I do think that the metal would heat up the air before it enters the turbo thus almost eliminateing the use of a cold air intake. I may be wrong. But, according to my data It doesn't seem that way. Thanks.
arfrce is offline   Reply With Quote
Old 08-23-2008, 10:12 AM   #3
RedRex26
Scooby Specialist
 
Member#: 133418
Join Date: Nov 2006
Chapter/Region: Tri-State
Location: middle of no where
Vehicle:
2006 DOM3 XTR WRX TR
SRR 407whp 365wtq ppg'd

Default

in my opinion it doesn't matter first off once you get moving the air teperatures are the same reguardless of a cold air intake or not. also was able to make 15 more hp and 10lb ft of torque with my spt shortram then my friend with the same car and similar mods and a cold air intake on the dyno. not to mention i had better spool up.
RedRex26 is offline   Reply With Quote
Old 08-23-2008, 11:07 AM   #4
jmanrex
Scooby Specialist
 
Member#: 15288
Join Date: Feb 2002
Chapter/Region: MAIC
Location: camp hill, pa
Vehicle:
2004 wrb sti

Default

i believe it is all in who you talk to --- if it is a manufacturer and they sell the cold air intakes they will claim it is better but if they sell a short ram they will claim it is better and both can tweak their dyno pulls to prove the other wrong

i am voted for the no it doesn't matter because back when i got my first wrx in early 02 there were only a handful of aftermarket products out there and one of the biggest was mrt from australia just because they have had the wrx ever since it came out back in the 90's -- now in researching their parts i came across an article in which they did a full on test and found out that it didn't matter whether or not you had a short ram or a cold air--in fact their finding show just a slightly better hp and tq values with the short ram and when i saying slight i mean like 1 hp/tq or less--i believe and i will have to go find my book but in their "training your wrx manual" it states the same information

also you will almost always see big horsepower builds with short rams--now most is because of space but if you are clever enough and if cold air intakes are what they really claim to be--you can always find a way to put one in--but i think most tuners now have come to realize that it doesn't matter if you have a short or long--its just simply a marketing tool

just my 2cents
jmanrex is offline   Reply With Quote
Old 08-23-2008, 11:19 AM   #5
highwayman
Scooby Newbie
 
Member#: 100697
Join Date: Nov 2005
Chapter/Region: SCIC
Location: IE,CA
Vehicle:
06 STI
CGM

Default

If it didnt matter, why would every manufacturer install an intercooler? To cool the air going to the turbo.
highwayman is offline   Reply With Quote
Old 08-23-2008, 12:17 PM   #6
Z1 Performance
Former Vendor
 
Member#: 9327
Join Date: Aug 2001
Location: Z1Auto.com
Default

Quote:
Originally Posted by highwayman View Post
If it didnt matter, why would every manufacturer install an intercooler? To cool the air going to the turbo.

an intercooler cools the air post turbo, not preturbo

to the OP - there is a simple way to test it. Get some dual zone gauges like SPA, and measure pre/post temps and post your results. I think you will find that I am correct. The temp differential will be very small, if there is any at all. My last reply was squarely on point, whether you think so or not I guess is up to you. If you want to prevent, or limit heat soak, which is what it sounds like you want to do (a good thing to do BTW) there are various methods to achieve this no matter what type of turbo inlet you have. Doing them pre turbo is not going to be where you should focus your efforts IMHO, but again, that is entirely up to you. There are also several advantages to an inlet hose such as the APS vs some of the other silicone ones out there (which we also sell BTW) which I pointed out. At the end of the day, it's up to the buyer to weigh the costs/benefits for themselves, and use what they feel is the best unit for their needs. Options exist to suit any budget, from a $200 Perrin inlet, which we sell tons of, and which has worked well, all the way up to a ~$1000 STi inlet, which believe it or not, we've sold as well to people over the years.

Last edited by Z1 Performance; 08-23-2008 at 12:23 PM.
Z1 Performance is offline   Reply With Quote
Old 08-23-2008, 12:24 PM   #7
rxer311
Scooby Specialist
 
Member#: 107099
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: Lancaster, PA
Vehicle:
'07 STI
Satin White Pearl

Default

My tuner just told me about a test he did with an '08 STi. Intake temps were 30-40 degrees cooler with the CAI...
rxer311 is offline   Reply With Quote
Old 08-23-2008, 12:30 PM   #8
Z1 Performance
Former Vendor
 
Member#: 9327
Join Date: Aug 2001
Location: Z1Auto.com
Default

^ without getting into how that test was done (it matters), saying intake temps are cooler is not really what I was asked to comment on. What does the colder intake temp pre turbo translate into the temps post turbo/pre intercooler, and then post intercooler, pre intake manifold.

Anyway, I'm going to just sit back and read now.
Z1 Performance is offline   Reply With Quote
Old 08-23-2008, 01:40 PM   #9
STINOMORMONEY
*** Banned ***
 
Member#: 183029
Join Date: Jun 2008
Chapter/Region: South East
Location: FLORIDA
Vehicle:
2007 STI- 402whp/436
OBP- uncorr./SAE-Mustang

Default

well any cooler DOES help- add 100 deg air to a 300 degree pipe and u may get 200 degree air where 150 deg air in the same pipe might get 225 deg- so VERY marginal

the GAIN is in the MAF readings- so if you have a blow thru maf then it really makes little difference but with a MAF on the intake like 75 percent of us it makes a HUGE difference on whether or not the car pulls timing

but my SUGGESTION- tho i have a regualr cai with maf and fmic- is if you have a fmic go with a blow thru maf and make a short ram intake to get as much air as fast as possible becuase the difference wont make the biggest difference in IAT and u might gain with the free flowing shorty and like i said i have the opposite


o and i may start a war with this statement but- i have noticed a difference in my hotside piping with the cai compared to my shorty- tho my measurement tool has been my HAND lol it doesnt seem to get nearly as hot- maybe im crazy

Last edited by STINOMORMONEY; 08-23-2008 at 01:46 PM.
STINOMORMONEY is offline   Reply With Quote
Old 08-23-2008, 02:58 PM   #10
modaddict
Scooby Guru
 
Member#: 95840
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Pasco, WA
Vehicle:
sold to a good bud
awaiting next car

Default

my biggest issue is with pull through maf designs, such as OEM and 95% of people use, is the IAT readings. High IAT readings pull timing (it's a safety buffer). And if tuner's "flatten" the IAT map out (so it doesn't pull timing upon high IAT readings) essentially, they are making your car LESS safe. No one will argue that.

A short ram will make your IAT readings higher.....almost always.
A short ram will lengthen the time it takes for the IAT readings to come off it's high horse. (many, many miles). I drove ~7 miles in 96*F temps and my IAT readings came down a wopping 5*F from 165*F.


A CAI will reduce the time to bring those IAT readings to that "high" level.
A CAI will help cool those high IAT readings sooner.

All of this is also climate dependent. *Me* living in the desert, get's heatsoak and crazy high IAT's logged at 165*F IIRC on a Perrin short ram. (stock tmic ->moved to fmic on stock turbo).




I will never own another SRI. Only CAI's from here on out. (and mines wrapped because I have had issues with the high ambient temps and heatsoaking). my .02

modaddict is offline   Reply With Quote
Old 08-23-2008, 07:41 PM   #11
drkramm
Scooby Specialist
 
Member#: 159156
Join Date: Sep 2007
Chapter/Region: Tri-State
Location: catasauqua, pa
Vehicle:
2007 wrx
wrb

Default

well on the same tune i had a spt intake and a modified stock box

the spt would start to pull some timing due to intake temperatures

the stock box never pulled any timing

if this was a cai vs sri argument i would say the cold air or atleast a very well shielded sri would be best

cold air means more gas...
drkramm is offline   Reply With Quote
Old 08-23-2008, 08:36 PM   #12
fastnoypi
Scooby Specialist
 
Member#: 6886
Join Date: May 2001
Chapter/Region: Tri-State
Vehicle:
MY01 EJ207 HTA35r
nothing to see, i'm stock

Default

CAI makes sense IMO, any cooler air into the turbo will increase its efficiency, even if it will be compressed.
to me, its HS physics.. energy output/energy input x 100% = efficiency rate

IMO, CAI's get a bad rap on the board because of lack of MAF scaling tuning and expected instant HP per vendor advertisements as a straight "bolt-on" mod.
fastnoypi is offline   Reply With Quote
Old 08-23-2008, 08:38 PM   #13
nhat
Scooby Guru
 
Member#: 140163
Join Date: Feb 2007
Chapter/Region: MAIC
Location: 3MI Racing
Vehicle:
03 STi
hellaflunctional

Default

well...harman motive did testing on several intakes and all added ~10whp without any tuning, and another ~5whp with maf scaling.
nhat is offline   Reply With Quote
Old 08-23-2008, 10:07 PM   #14
MB38
Scooby Specialist
 
Member#: 51588
Join Date: Dec 2003
Chapter/Region: SCIC
Location: Burbank, CA
Vehicle:
2006 WRX TR
1997 Supra Turbo

Default

Whether or not the actual air temperature has a real, significant affect on the temperature of the charge air downstream of the turbo... it will have an affect on the MAF reading and - accordingly - the timing and power of the engine.

CAI>HAI.
MB38 is offline   Reply With Quote
Old 08-23-2008, 10:15 PM   #15
import111
Scooby Specialist
 
Member#: 24447
Join Date: Sep 2002
Chapter/Region: SWIC
Location: Tucson, Arizona
Vehicle:
2010 Evo GSR
GG

Default

I voted yes and here is why.

Yes the turbo compresses and heats up the air before it hits the intercooler, but it does not heat it up to a set temp does it?.....NO. So the cooler the air going into the turbo the cooler it will be entering the intercooler. Then the intercooler will have cooler air to cool down before it hits the intake manifold.

CAI is like dropping an ice cube into a bowl of soup. Your mouth is 98.6 degrees no matter what, but you can eat your soup sooner with the ice cube than you can without.
import111 is offline   Reply With Quote
Old 08-24-2008, 04:02 AM   #16
seattle944t
Scooby Specialist
 
Member#: 18308
Join Date: May 2002
Chapter/Region: NWIC
Location: Seattle, WA
Vehicle:
2005 WRX STi
Silver

Default

The turbo compresses air, compressing hot air gives hotter air than compressing cold air. Its simple physics. Here is a web page that has the math:
http://www.autospeed.com.au/cms/A_109789/article.html
Quote:
How much hotter the air gets as it is being compressed depends on the pressure ratio (how much it is being compressed) and the efficiency of the compressor. This means that the theoretical outlet temperature can be calculated if three factors are known: the inlet air temperature, the compressor efficiency, and the pressure ratio.

Before this can be done, the temperatures and pressures need to be expressed in the right units. Firstly, temperatures need to be converted to Kelvin (K), a measurement of absolute temperature.

K =C + 273.15

A temperature of 35C is therefore the same as 308.15K (or 308K for our purposes).

Boost pressures also need to be converted to pressure ratios. Note that 1 Bar = 14.5 psi.
Boost Pressure in Bar + 1
Pressure ratio = -------------------------------------

1

A boost of 1.5 Bar therefore becomes a pressure ratio of 2.5.

Let's have a look at an example.

If the inlet air temperature to a turbo is 20 C (293K) and the boost pressure is 1.1 Bar (pressure ratio = 2.1) the theoretical outlet temperature will be:

Theoretical outlet temp = 293 x (2.1)0.286

= 293 x 1.236

= 362K (89 C)

This means that there is a temperature rise of 69 C (89 - 20 = 69 ).

However, this doesn't take into account that the compressor efficiency will be less than 100 per cent. If we assume a compressor efficiency of 70 per cent (typical for a good turbo):
69
Actual temp increase = ------
0.7
= 98.6 C

This is a temperature increase of 98.6 which when added to the ambient temp of 20 means that the actual outlet temp will be:

20 + 98.6 = 118.6 (119 C when rounded)
So, in the above example using 20 C the output temp was 118.6. That is not going to be a constant, so doing the same equation with 25 C inlet them yields 125.5 post turbo temp. 7 increase in output temp from a 5 degree inlet temp change.

So, a CAI is going to be much better than a short ram. As far as the CAI being metal, it probably will transfer some heat into the intake air, but it should still be cooler than the intake air drawn in from a short ram.
I did IAT testing between my K&N typhoon and prodrive CAI (metal tube) and saw 70 degree lower temps on the prodrive in some cases (summer, A/C on, stopped). In this worse case scenario, prodrive was at 90 degrees F (32.2C), K&N was 160(71.1C). These numbers didn't change until some time at speeds above 35MPH.
Plugging these numbers in to the equation nets:
Prodrive turbo outlet temp: 275.26 F (135.15C)
K&N turbo outlet temp: 368.89 F (187.16C)
Now, assuming a 70% efficient intercooler gives these post intercooler temps:
Prodrive: 145.5F
K&N :173.8F

So, all else being equal, a nearly 30 degree rise in temp going into the motor.

Last edited by seattle944t; 08-24-2008 at 05:01 AM. Reason: Fixed math - added numbers using my intake temps
seattle944t is offline   Reply With Quote
Old 08-24-2008, 04:18 AM   #17
subiefast
Scooby Newbie
 
Member#: 184150
Join Date: Jul 2008
Chapter/Region: South East
Location: Hickory, NC
Vehicle:
wrx 6265 turbo
8000 rpm built EJ257

Default

The intercooler, will cool the charge way more than any CAI will. I dont think you will find ANY difference in post intercooler temps with a CAI vs short ram.

As soon as the air hits the turbo it's HOT no matter what temp the air is being sucked in. Then the intercooler cools it down. On top of that, a shorter intake is much less restricitive than a longer one.

For example, if I drop a drop of water, on a 2000 degree stove, it immediately evaporates no matter if it's hot water or cold water. I dont think the air going into the turbo matters since it's going to immediately get really hot anyways.
subiefast is offline   Reply With Quote
Old 08-24-2008, 04:25 AM   #18
mugenXP
*** Banned ***
 
Member#: 155272
Join Date: Jul 2007
Chapter/Region: SCIC
Location: SoCal
Vehicle:
2006 WRX
Panda AE86

Default

by using my common sense, it seems that there will be a difference but not enough to make any real difference to brag about.
mugenXP is offline   Reply With Quote
Old 08-24-2008, 07:34 AM   #19
Z1 Performance
Former Vendor
 
Member#: 9327
Join Date: Aug 2001
Location: Z1Auto.com
Default

Quote:
Originally Posted by import111 View Post
I voted yes and here is why.

Yes the turbo compresses and heats up the air before it hits the intercooler, but it does not heat it up to a set temp does it?.....NO. So the cooler the air going into the turbo the cooler it will be entering the intercooler. Then the intercooler will have cooler air to cool down before it hits the intake manifold.

CAI is like dropping an ice cube into a bowl of soup. Your mouth is 98.6 degrees no matter what, but you can eat your soup sooner with the ice cube than you can without.

Like I said earlier, prove it Show me temp readings, don't assume this is the case - that is all I was saying in my original discussion on the topic. You are taking a very big leap of faith that marginally cold air in=colder air out. I know way back when, when I had a turbo Subaru, I had the datalogs to show the basis of my opinion. That car is long gone, but global warming aside, it still holds true today

The relocation of the MAF with many of the CAI's to outside the engine bay, is the primary benefit the CAI affords you (as well as less degredation of the filter media due to heat). This will lead to a more consistent tune as many have found.

Just an important point of clarification - keep in mind though that the original question posed to me was the "heatsoak" that the OP theorized would be greater with a solid pipe, like the APS (which is stainless), vs a silicone one, like a Samco unit. The CAI was not part of the OP's original question to me, though it is a natural extension of the intake path that feeds the turbo.

Last edited by Z1 Performance; 08-24-2008 at 08:02 AM.
Z1 Performance is offline   Reply With Quote
Old 08-24-2008, 09:33 AM   #20
arfrce
Scooby Newbie
 
Member#: 126130
Join Date: Sep 2006
Chapter/Region: South East
Location: North Western Arkansas
Vehicle:
06 Subaru STi
WRB

Default

ARFRCE
Here was the first question.

Since it is metal wouldn't that heat up the cold air? Your answer.. cold air getting into the turbo is not going to yield you any significant gains, if any at all...since the air then is compressed by the turbo, which heats it up anyway. You have to focus getting cold air into the engine, which is done via the intercooler.

Then We started the discussion on the Cold air vs Hot air.
SO there are a few jobs that the cai does. 1) provide cold air. 2) Take out any obstructions so the air flows faster. .
This is not debated, it is fact.
A shorty just provides the free'er flowing air. Also fact.

Ok So SUBIFAST. You said this. As soon as the air hits the turbo it's HOT no matter what temp the air is being sucked in. Then the intercooler cools it down. On top of that, a shorter intake is much less restricitive than a longer one.
Reply.
Here is something I would like you to try. Take two hair dryers. Turn one on high heat and feel of the air. Pretty hot. Ok now keep that one on and turn the other on. And put the nozzle up to the others intake. And then feel of the heat. The second would be considerable hotter because the air in it is already hot. Your just making it hotter. So you see the intercooler would have a harder time cooling the air down.

Also remember colder air is densor. Thus more oxygen particles..


As far as the Cai And the shorty I think the shorty helps out so much because of the increased air flow. Now if you could make a vent out the hood for the shorty to get cold air you notice an even bigger gain. I do like the insulated hose pic.

I hope this Thread helps people out; there is some very good info here. And thanks for being civil. I hate how some people can't debate with out insulting someone. Great job.

I will contact K&N's Research department on Monday and ask for some hard facts to see if we can put a close to this. Thanks guys. keep the opinions coming.

Z1 Performance. If you will send me an APS and a Samco intake I will get the Hard fact on which one provides cooler intake air. You will get both pieces back of course with no damage. Think about that. Thanks Jeff

Some one PM'ed me for this info. For the record I have an AEM cold air intake. I have not decided on an approach for the intake tube.
arfrce is offline   Reply With Quote
Old 08-24-2008, 02:37 PM   #21
kellygnsd
Scooby Guru
 
Member#: 32669
Join Date: Feb 2003
Chapter/Region: SCIC
Location: Rancho C
Vehicle:
2007 2.34LR, EFR7670
LINK G4 hybrid STi

Default

Quote:
Originally Posted by arfrce View Post
I do think that the metal would heat up the air before it enters the turbo thus almost eliminateing the use of a cold air intake. I may be wrong. But, according to my data It doesn't seem that way. Thanks.
Heat transfer is not instantaneous. The intake charge is in contact with the pipe for such a short period of time the rise in temp just from contact is minimal.

Quote:
Originally Posted by subiefast View Post
The intercooler, will cool the charge way more than any CAI will. I don't think you will find ANY difference in post intercooler temps with a CAI vs short ram.

As soon as the air hits the turbo it's HOT no matter what temp the air is being sucked in. Then the intercooler cools it down. On top of that, a shorter intake is much less restrictive than a longer one.

For example, if I drop a drop of water, on a 2000 degree stove, it immediately evaporates no matter if it's hot water or cold water. I don't think the air going into the turbo matters since it's going to immediately get really hot anyways.
And what people don't seem to get is the turbo doesn't just heat the air up to a certain temperature. Its heat transfer, it you add X amount of energy to something being compressed it heats up by X number of degrees. If you start with a lower temp your outlet temp is lower and that lower temp propagates down the line making the whole process more efficient.

Quote:
Originally Posted by mugenXP View Post
by using my common sense, it seems that there will be a difference but not enough to make any real difference to brag about.
Its the little things that add up to make big things.
kellygnsd is offline   Reply With Quote
Old 08-24-2008, 05:35 PM   #22
mugenXP
*** Banned ***
 
Member#: 155272
Join Date: Jul 2007
Chapter/Region: SCIC
Location: SoCal
Vehicle:
2006 WRX
Panda AE86

Default

that statement is true only for weight reduction
mugenXP is offline   Reply With Quote
Old 08-24-2008, 07:47 PM   #23
Z1 Performance
Former Vendor
 
Member#: 9327
Join Date: Aug 2001
Location: Z1Auto.com
Default

If you want to purchase any/all of the inlets we offer and conduct your own test using multi temp probes and a datalogger, you're certainly welcome to do it. I've got the equipment, but it's not something I'm lending out to someone (I just spent the last 3 weeks doing this exact series of testing on one of my own cars for an upcoming project we're working on where temps at various points in the intake tract were critical to design - on an NA car). We can't donate parts to an unknown person and then take them back after they have been installed and used though unfortunately. IMHO - I think what you will find, if there is any significant difference between the air temp at the outlet of the IC with one intake vs another, or one inlet pipe vs another, is that you're intercooler is not sufficient for the job you're asking it to do, not that one intake provided more cold air, or that one inlet allowed for less heat soak.
Z1 Performance is offline   Reply With Quote
Old 08-24-2008, 11:24 PM   #24
subiefast
Scooby Newbie
 
Member#: 184150
Join Date: Jul 2008
Chapter/Region: South East
Location: Hickory, NC
Vehicle:
wrx 6265 turbo
8000 rpm built EJ257

Default

Quote:
Originally Posted by kellygnsd View Post
Heat transfer is not instantaneous. The intake charge is in contact with the pipe for such a short period of time the rise in temp just from contact is minimal.



And what people don't seem to get is the turbo doesn't just heat the air up to a certain temperature. Its heat transfer, it you add X amount of energy to something being compressed it heats up by X number of degrees. If you start with a lower temp your outlet temp is lower and that lower temp propagates down the line making the whole process more efficient.



Its the little things that add up to make big things.
I have pretty much ambient temps going into the throttle body while on the highway. You CANNOT get better than ambient without some other form of external cooling. A CAI isnt going to make the air any cooler.
subiefast is offline   Reply With Quote
Old 08-24-2008, 11:50 PM   #25
rxer311
Scooby Specialist
 
Member#: 107099
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: Lancaster, PA
Vehicle:
'07 STI
Satin White Pearl

Default

^^^but afer sitting at a light for a minute...or low speed cornering...
rxer311 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
cold air intake vs ram air?? rex86 Newbies & FAQs 5 05-18-2010 04:37 PM
short ram intake vs. cold air intake 2008scooby18 Newbies & FAQs 7 07-17-2008 03:54 AM
FMIC vs TMIC & cold air intake vs ram air IllNastyImpreza Normally Aspirated with bolt-on Forced Induction Powertrain 2 02-24-2004 09:49 PM
ram air intake vs cold air intake Shaji Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 62 07-21-2002 10:05 PM
cold air intake vs. mass air meter nav Normally Aspirated Powertrain 11 03-29-2001 06:31 AM


All times are GMT -4. The time now is 09:09 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.