Another silly idea, ducted fans for a radiator! |
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Another silly idea, ducted fans for a radiator! |
TonyAKAVW |
Nov 10 2005, 05:36 PM
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#1
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That's my ride. Group: Members Posts: 2,151 Joined: 17-January 03 From: Redondo Beach, CA Member No.: 166 Region Association: None |
So I've been thinking about different ways to get air up to the radiator in the subaru conversion where the radiator is in the engine bay. The standard way to do it is to have a couple of normal radiator fans sucking air from beneath the car.
Here's another idea... What if I constructed an array of ducted fans as in the diagram below. Basically they would force air up the shroud and through the radiator. One advantage to this is that it would take advantage of the entire surface of the radiator, rather than a round section that a fan would push through. Something I'm trying to figure out is the conversion between thrust and CFM of air moved. Most of these fans are for hobby RC airplanes and are rated in ounces of thrust, rather than moved volume of air. -Tony Attached image(s) |
Andyrew |
Nov 10 2005, 05:42 PM
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#2
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
What do they equal in CFM?
I would want some forced air in there as well... like a scoop, like scotts.. |
bondo |
Nov 10 2005, 05:42 PM
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#3
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Practicing my perpendicular parking Group: Members Posts: 4,277 Joined: 19-April 03 From: Los Osos, CA Member No.: 587 Region Association: Central California |
A PVC elbow for each fan! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) |
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WRX914 |
Nov 10 2005, 05:46 PM
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#4
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2.5 WRX STI hybrid powered beast Group: Members Posts: 782 Joined: 16-September 04 From: Las Vegas, NV Member No.: 2,771 Region Association: Southwest Region |
Looks like it should work...
Would the fans be on constantly? If so, what are your plans around the fan noise? |
lapuwali |
Nov 10 2005, 05:47 PM
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#5
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
I've ruminated on a chimney-effect idea, which it looks like you may have room for. Duct the outlet so the air has to rise, and esp. if you made a crude venturi at the exhaust end, you should get a natural convection draw using no power at all. If it exhausted just aft of the rear window, you should get even more of an effect at speed, as that should be a significant low pressure area.
I have a pet theory that too many people spend too much attention to the inlet side of the radiator and ignore the outlet side. |
Mueller |
Nov 10 2005, 05:47 PM
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#6
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914 Freak! Group: Members Posts: 17,150 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
do you still plan on installing "puller" fans to the radiator?
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SLITS |
Nov 10 2005, 05:48 PM
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#7
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"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Add a couple more and you could have a 2J Sucker Car (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)
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TonyAKAVW |
Nov 10 2005, 06:01 PM
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#8
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That's my ride. Group: Members Posts: 2,151 Joined: 17-January 03 From: Redondo Beach, CA Member No.: 166 Region Association: None |
I had actually thought of having the exhaust of the radiator ducted up to a GT-style engine lid and exiting right below the rear window. Instant defogger and a good place to exit the air. It wouldn't take a whole lot more sheetmetal work to make an exhaust shroud. Fiberglass would be a nice way too.
The whole idea here is that I want to get away form having to use a scoop. The thought of having a scoop below the car worries me a little. Especially if I want to ever lower the car (which I do). Fans on the exit side would be a good idea too. However at this point I'm starting to suck up a lot of amps to drive all these fans. The ducted fans each seem to draw something like 10 amps, but that could probably be throttled back a bit with a PWM controller. This particular fan pushes nearly 10 oz of thrust, but what does that mean? And it also draws 12.5 amps. I could easily fit 7 of those, so that is up to 87.5 amps, or 1050 watts. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) -Tony edit.... Yes. about the sound. I think the sound of these would dominate over the sound of the engine... that would suck. literally.. |
Aaron Cox |
Nov 10 2005, 06:04 PM
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#9
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
LMFAO! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif) |
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Andyrew |
Nov 10 2005, 06:15 PM
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#10
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
what if you shrouded scoops to the sides of the car? put some mesh in it, and throw some fans in it?
also what about dirt, leaves and ect? The fans would just suck those things from the ground if they are aimed at the ground...... Especially at low speeds. |
jim_hoyland |
Nov 10 2005, 06:17 PM
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#11
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Get that VIN ? Group: Members Posts: 9,418 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California |
Tony,
I've got a couple of in-line Detmar brake duct fans that might fill the bill. PM me if interested |
Rand |
Nov 10 2005, 06:18 PM
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#12
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
The stock air-cooled setup pulls the cool air from above and exits below... Isn't part of the reason because of the difference in air pressure between the underside and top of car - especially at speed? In other words, by trying to pull cold air from below and exit at top, are you fighting the natural air pressure? Wouldn't the air flow considerably easier from top to bottom? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) I dunno, just throwing more ideas around...
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jd74914 |
Nov 10 2005, 06:21 PM
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#13
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Its alive Group: Members Posts: 4,796 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
it seems like it should be a low pressure area behind the targa bars so I would think that air would like to rush that way (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)
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Aaron Cox |
Nov 10 2005, 06:22 PM
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#14
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
i thought there was a HUGE negative pressure at the rear window.... IE air rushing over the targa sucks air from the engie bay (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) |
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Rand |
Nov 10 2005, 06:24 PM
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#15
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
The expanded metal grill in the engine lid is the air INTAKE on a stock 914, is it not? The impeller is above the engine seal, so it sucks cool air from above, right?
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Aaron Cox |
Nov 10 2005, 06:25 PM
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#16
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
makes sense... but id think of it like a cowl induction on a nova (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) or the air flaps under the 914, that create yet another neg. pressure area. |
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Andyrew |
Nov 10 2005, 06:28 PM
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#17
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
the expanded metal grill in a stock 914 has a raintray under it..
the air inlets on a 914 are the small grills about 2x4 inches on each side. IIRC havent seen a stock 914 in a while (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) |
TonyAKAVW |
Nov 10 2005, 06:29 PM
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#18
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That's my ride. Group: Members Posts: 2,151 Joined: 17-January 03 From: Redondo Beach, CA Member No.: 166 Region Association: None |
It is the intake, but its probably not the best area for an intake...
Scoops on the side would be great, but the ducting gets complicated pretty quickly. Also, I'm not so sure I want ducts on the side of my car... I know that way back when, someone had numbers and measurements around the 914 for air pressure while driving... -Tony |
Aaron Cox |
Nov 10 2005, 06:30 PM
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#19
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
chuxter on rennlist |
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Rand |
Nov 10 2005, 06:31 PM
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#20
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
Yes Andyrew, but there is a gap all the way around the rain tray so air still comes in above the tray and around all sides. While it can be argued that removing a tray will increase air intake, the tray doesn't block / restrict air flow to just the 2x4" sides.
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