Intercooler Placement IDEAs Needed., Need a better option.....Love my water to air, but open Options

[budman5201]

As all you probably know, i have a ej20 turbo subaru in my car. I love it and it runs great, but now i am at the point where i want to streamline how well the system works.......

First matter of attention is the intercooler placement. I have a small water to air intercooler tucked in front of the pulley on my subaru motor. It works great, but i am getting a little too much heat soak on the aluminum tubes leading to it. I was debating an idea of putting it in the rear trunk or in the fender since placement wouldnt be a factor because its a water to air. I do like the one members ORANGE nice turbo car on 914world here with the air/air one in the back and vent in the wing.....

Looking for ideas....

[budman5201]

another

[ghuff]

Wrap your heat tubes with nasa gold reflective foil.


Works on my GTi with cheaper stuff.

(IMG:http://img188.imageshack.us/img188/1382/p7090015.jpg)

[ottox914]

Don't know how much space you have above the intake and under the engine lid, but on my car I used a GT style double vented lid, no rain tray, and a subi intercooler with about a 2" plenum below and an 800cfm sucker fan. Never had intake air temps more than 20-30 degrees over ambient. I plan in version2 to make another plenum, and have 2-1100 cfm fans sucking thru the intercooler. I expect this to cool the intake charge even better, and while it may be a bit loud, its an auto cross car, so noise is not an issue. With the single fan, you can hear it a little over the sound of the motor, but not alot. You can put your hand 6" over the engine grill and feel the air being pulled thru. I think this also helps engine cooling a little, as the IC is located up front in the engine area, over the air intake for the engine fan. More pics can be found in the build thread linked in my sig.

[d914]

I have the same idea but instead of sucking I was going to use a pusher fan..airflow is bottom to top.. Figured I would try to take advantage of that..???

[Rand]

Airflow is which way? Stock, cooling air comes in through the engine lid. I don't think there's enough natural air flow moving through there to take advantage of... The fans are going to be what moves the air through the intercooler. I would think you would want to pull the coolest air possible through it.

[iamchappy]

As you mentioned, i put mine in the trunk using 2 fans pulling-sucking the air through.
You wouldn't have to mount it in the far back as i did, mine is there because the turbo
is there also.

[d914]

Airflow is which way? Stock, cooling air comes in through the engine lid. I don't think there's enough natural air flow moving through there to take advantage of... The fans are going to be what moves the air through the intercooler. I would think you would want to pull the coolest air possible through it.

airflow studies have been done by someone around here show the that cooling air for the flat flor comes in the bottom..hence issues with big spoilers up front..

Now will I be pulling from the coolest resource,,probably not. but I am try to exploit the natural airflow..and yes that area above the grill is a dead zone...so pulling from the engine bay will pull, maybe, more heat out.. I could possibly duct from the sides for cooler air.. also there are flaps on the bottom of the car to create tubulance to send air into the engine compartment.



Besides if Im dead wrong most of the fans are reverseable!! (IMG:style_emoticons/default/beerchug.gif)

[RJMII]

according to the huge cloud of smoke that was coming out of my tailpipe while drivin around yesterday, airflow goes UP through the engine compartment. There is a HUGE vacuum right behind the window that pulls the air up. (when there is no engine tin in position, and the exhaust dumps right after the axle)

(my fuel map was running a little rich, that's how I made the cloud of smoke for the test)

[Mark Henry]

airflow studies have been done by someone around here show the that cooling air for the flat flor comes in the bottom..hence issues with big spoilers up front..

(IMG:style_emoticons/default/beerchug.gif)

Sorry that's just wrong. All the cooling air comes from up top. of course I'm talking stock, not this app. I no clue what happens on a convert.

The "study" shows that the turbulence from the little flaps (under the car just before the engine bay) dissipates the exiting hot air faster, thus reducing temperature.
An air dam could imped this turbulence.

[d914]

airflow studies have been done by someone around here show the that cooling air for the flat flor comes in the bottom..hence issues with big spoilers up front..

(IMG:style_emoticons/default/beerchug.gif)

Sorry that's just wrong. All the cooling air comes from up top. of course I'm talking stock, not this app. I no clue what happens on a convert.

The "study" shows that the turbulence from the little flaps (under the car just before the engine bay) dissipates the exiting hot air faster, thus reducing temperature.
An air dam could imped this turbulence.

http://www.cassidy-online.com/porsche914/a...2008_poster.pdf

read the engine section. "Air flows up in Porsche 914 regardless of configuration"
"The results of the engine compartment were
consistent with the expected result. Air flowed up
through the compartment for all configurations.
However, the amount of air flow was reduced for
configurations that had the rain tray."
"

[Katmanken]

Cooling air for a non-stock engine might come in from the bottom.

Aiircooled 4 and 6 cyl engines for street use use cooling tin to prevent airflow from bottom to top, and flaps under the car to promote turbulance and cooling when moving.

Remove the stock engine, engine tin, and seals, and yer on yer own as to which way the air flows and when.

It's a safe assumption that when a car without engine tin is stopped and the engine is warm, that warm air will rise. When the car moves with missing tin, it's your configuration and your test.

There was a guy who placed a subie engine and a radiator in the engine compartment. He built an under-car scoop to get air for the radiator and discovered (big surprise!) that ground air is hotter than air a few feet up..

[d914]

there is also one that drove cross county with one..!!?? My car is not running and again a simple switch of wires will save me if Im wrong!!!! (IMG:style_emoticons/default/smile.gif)

The area behind the targa is relatively dead...Im just thinking I might be able to get rid of some extra heat and get air flow by the intercooler at the same time..... I COULD be dead wrong..lord knows it wont be the first time..

[Katmanken]

Greg,

You didn't read enough...........

Under engine compartment theory it sez......

"Porsche 914 is powered by an air cooled engine.
The engine sits behind the passenger seat and is
cooled by a fan. This fan sucks the air from the engine
bay and sends it out the bottom of the car
The air pressure along the car is
different along its contour. Finding
the coefficient of pressure (Cp)
can assist in determining the
airflow through the engine. A
positive coefficient pertains to high
pressure, a negative one
corresponds to low pressure."

And, it shows a flow picture with air moving top to bottom...

The conclusion supports this view by saying...."The results of the engine compartment were consistent with the expected result."

The author then made a boo boo and said "Air flowed up
through the compartment for all configurations."

[d914]

Im just going to have to say I dont see it... The area behind the targa is the same as that behind the cab of a pick up...swirling low pressure. I see no dramatic air flow from top to bottom.

To be truthful I dont see a huge airflow up from the bottom either...the stream flows under the car and as per stated the original seals kept top and bottom separated.

I think we need tony to chime in since he has played in real world..

[Rand]

It doesn't matter which way the air would flow naturally. In stock form it comes from above - the tin blocks the bottom off and the fan sucks cool air in through the engine lid.

All that is really a moot point, because you are not going to have a lot of air naturally wanting to flow either direction in such a velocity as to be useful for this application. It's the fans that are going to move the air through your intercooler and natural airflow isn't going to make any significant difference.

Therefor, my point was you will want those fans to be moving the coolest air - obviously cold air works better than hot air. If you move the air upwards, it's going to be coming from the engine bay... a much hotter air source than the outside air you could pull down from above.

I would put it near a cool air source and pull it in from outside. The engine lid is a sensible choice. The wheel well or under the car is dirtier and warmer. Anyplace else you'll have to do some cutting.

[ottox914]

Therefor, my point was you will want those fans to be moving the coolest air - obviously cold air works better than hot air. If you move the air upwards, it's going to be coming from the engine bay... a much hotter air source than the outside air you could pull down from above.

I would put it near a cool air source and pull it in from outside. The engine lid is a sensible choice. The wheel well or under the car is dirtier and warmer. Anyplace else you'll have to do some cutting.

Which is how and why my IC ended up where it did- source of cool air, and behind the targa is a spot of low pressure, making the job of the fans pulling cool air thru the IC that much easier, and if pulling air thru the IC would happen to provide a slight air pressure increase to the engine fan, so much the better, since with a stock cooling motor and tins, the cooling air goes from top down.

Aero info: http://www.cassidy-online.com/porsche914/a...aids/index.html

[DBCooper]

All true, except Budman's car has a watercooled engine and no more engine tin, meaning the air will flow through the engine compartment basically without impediment and probably from high pressure to low. That makes the student's statement "The results of the engine compartment were consistent with the expected result. Air flowed up through the compartment for all configurations" very curious. Curious because their professor's car was aircooled, meaning air flow through the engine compartment could only have been top to bottom, from the cooling fan intake above to hot air exhaust below. This is from the presentation summary and I didn't see a link to the full report, so maybe the "for all configurations" is explained better there.

I'm interested because my car has the same WRX engine with an aftermarket air/air intercooler on top. It's a little different in that I vented the IC opening like this:

(IMG:http://i379.photobucket.com/albums/oo234/paulillick/IMG_0012-1.jpg)

In the future I intend to replace the expanded metal on the lid with solid metal, sort of the reverse of doing a GT lid, so the only opening will be for the intercooler. Then I'll do my own tuft testing to see which way the air is being drawn through the engine compartment (high pressure to low) then add a spoiler or two to "encourage" more of that natural flow. For example if the air is flowing up because the lowest pressure is being created by the drop of the top behind the rear window I'll try to increase that flow by putting a little duck tail on the rear of the targa top to create more low pressure there. If it's flowing downward I'll try to increase it by putting a flexible duck tail across the bottom of the car just below the front of the engine compartment. With the closed decklid the intention is to channel all the top to bottom or bottom to top airflow through the only opening, which will be that intercooler cutout.

I'm looking forward to seeing how the flow with fans works out. Just in case. In the meantime I've limited boost to 10 lbs. Also just in case.

[ottox914]

In the future I intend to replace the expanded metal on the lid with solid metal, sort of the reverse of doing a GT lid, so the only opening will be for the intercooler. Then I'll do my own tuft testing to see which way the air is being drawn through the engine compartment (high pressure to low) then add a spoiler or two to "encourage" more of that natural flow. For example if the air is flowing up because the lowest pressure is being created by the drop of the top behind the rear window I'll try to increase that flow by putting a little duck tail on the rear of the targa top to create more low pressure there. If it's flowing downward I'll try to increase it by putting a flexible duck tail across the bottom of the car just below the front of the engine compartment. With the closed decklid the intention is to channel all the top to bottom or bottom to top airflow through the only opening, which will be that intercooler cutout.

I'm looking forward to seeing how the flow with fans works out. Just in case. In the meantime I've limited boost to 10 lbs. Also just in case.

Interesting thought, closing off the grilled section, could result in a smooth, cool. custom look for the back of the car. You'll gain a bunch of IC cooling if you can duct the opening in your engine lid to the intercooler. Air will take the path of least resistance, and right now, assuming your airflow is top down, that would be thru the hole in the lid, hitting the IC, and rolling off the sides. True, some will be going thru the IC, but you're loosing alot of flow around it also. To duct the cooler to the lid, and add fans and a plenum below (assuming you have the space) to push/pull, whatever you determine is the correct direction of airflow for that motor in that car with that IC set up, would make for a more efficient IC. I was going to just mount my fan to the back of the IC, and a couple friends, one who is the leading HVAC guy in our town, and another who works for CAT designing IC systems for their earth moving equipment, both got all over me for not using a plenum on the back of the IC to better direct the airflow thru the intercooler, rather than just have the fan blow air at the intercooler. The CAT guy was showing me testing data that where the centerline of the blades was in relation to the plenum was, so in effect mounting the fan on the back of the plenum, inside the plenum, or with the blades even with the back of the plenum would have a measurable effect on the cooling ability of the system. A little to picky for my little project, but shows that having the plenum/ducting makes a difference.

[budman5201]

Hey iamchappy.....

What kinda temps are you seeing with your rear intercooler? I think i might go this way and keep my water/air intercooler so i wont need to vent it anywhere. I will save heat in my tubes in the engine bay and be able to make them shorter.....well depending on which larger water/air intercooler i decide to use in the future.