hood venting a radiator |
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hood venting a radiator |
tazz9924 |
Jun 26 2019, 02:11 PM
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#1
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Senior Member Group: Members Posts: 703 Joined: 31-May 15 From: Mooresville NC Member No.: 18,779 Region Association: None |
I found these on the interwebs: https://www.summitracing.com/parts/tak-u5512shl/
Im thinking it’ll do for venting my radiator out of the hood rather than the wheel wells like it is now. These vents are 12”/5.5” and i would run two. My engine is an ej20 turbo. Any input is appreciated |
Chi-town |
Jun 26 2019, 02:14 PM
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#2
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Senior Member Group: Members Posts: 850 Joined: 31-August 18 From: Disneyland Member No.: 22,446 Region Association: Southern California |
I plan to do the same, cutting up the wheel wells only weakens the front structure
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tazz9924 |
Jun 26 2019, 02:24 PM
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#3
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Senior Member Group: Members Posts: 703 Joined: 31-May 15 From: Mooresville NC Member No.: 18,779 Region Association: None |
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thelogo |
Jun 26 2019, 03:10 PM
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#4
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Senior Member Group: Retired Members Posts: 1,510 Joined: 6-April 10 Member No.: 11,572 Region Association: None |
Luvers look like they will work but this is
What irritates me about a rad in a 914 Venting / cutting up the hood to vent im not a fan Dont like the look . Carveing out the inner wheel wells to let heat escape Really not a fan of that and doesnt seem like a efficient Exit for the hot air too me At first i thought a rear wing rad would be the way to go But now im thinking a ruf style cut out vent between the hood and the bumper top .... Is the best route (IMG:style_emoticons/default/poke.gif) Attached thumbnail(s) |
SirAndy |
Jun 26 2019, 03:25 PM
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#5
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Resident German Group: Admin Posts: 41,618 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
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DickSteinkamp |
Jun 26 2019, 04:51 PM
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#6
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Senior Member Group: Members Posts: 500 Joined: 27-February 17 From: Bellingham, WA Member No.: 20,876 Region Association: None |
Some smart person here should be able to come up with a formula for square inches needed of the opening for air in and the same for air out. I'm not that smart.
It probably has to do with how much heat the engine is going to generate, the size of the radiator, the material of the radiator, and the CFM of the radiator fans. I took a guess. Mine is an LB9 305 Chevy making maybe 230 HP. The opening I cut in my bumper is 22.5" x 5" or 112.5 square inches. (IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-20876-1561589501.1.jpg) I felt the openings for the air out should be at least as big as the air in opening. Mine are 10" x 8" or a total of 160 square inches for both. (IMG:http://www.914world.com/bbs2/uploads_offsite/live.staticflickr.com-20876-1561589502.2.jpg) My radiator is Renegade's Ron Davis for a SBC. Aluminum. It cools fine. Running down the road, the fans do not come on. Idling they will cycle on and off. It runs right on the 160 t-stat. (Disclaimer...I don't live in Phoenix. (IMG:style_emoticons/default/smile.gif) ) The hood vents linked to are 12" x 5.5" overall. It looks like there is about a 1" mounting boarder on all sides leaving a vent area of 10 x 3.5. This would give you 70 square inches of air out. My GUESS is that this would not be enough (although Sir Andy's seems to work fine with even less space for air out...it could be the custom plenum helps?) The good news about the vents linked to is that it appears both will fit (barely) without cutting any of the hood support structure and will fit between the rad and the bulkhead in front of the fuel tank. |
SirAndy |
Jun 26 2019, 05:23 PM
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#7
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Resident German Group: Admin Posts: 41,618 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
although Sir Andy's seems to work fine with even less space for air out... Actually, the surface of the openings in my louvers is just about equal to the surface area of the opening on top of the shroud. You're just looking at it from the wrong angle ... (IMG:style_emoticons/default/shades.gif) |
djway |
Jun 26 2019, 11:39 PM
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#8
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Senior Member Group: Members Posts: 787 Joined: 16-October 15 From: Riverside Member No.: 19,266 Region Association: Southern California |
I read somewhere that due to the heat expansion of the air the outlet must be 1.2x the area of the inlet.
How much inlet required per HP I have yet to find. |
falcor75 |
Jun 27 2019, 12:18 AM
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#9
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Senior Member Group: Members Posts: 1,579 Joined: 22-November 12 From: Sweden Member No.: 15,176 Region Association: Scandinavia |
I read somewhere that due to the heat expansion of the air the outlet must be 1.2x the area of the inlet. How much inlet required per HP I have yet to find. Yes 1.2-1.5 times the size of the inlet is a rule of thumb used in aircraft design. It also depends on the distance from the inlet to the outlet, longer distance = greater ratio. |
tazz9924 |
Jun 27 2019, 05:10 AM
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#10
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Senior Member Group: Members Posts: 703 Joined: 31-May 15 From: Mooresville NC Member No.: 18,779 Region Association: None |
I read somewhere that due to the heat expansion of the air the outlet must be 1.2x the area of the inlet. How much inlet required per HP I have yet to find. Yes 1.2-1.5 times the size of the inlet is a rule of thumb used in aircraft design. It also depends on the distance from the inlet to the outlet, longer distance = greater ratio. That’s good to know actually |
JeffBowlsby |
Jun 27 2019, 08:28 AM
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#11
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914 Wiring Harnesses Group: Members Posts: 8,490 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Here are some you probly don't want to emulate:
Attached image(s) |
76-914 |
Jun 27 2019, 08:43 AM
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#12
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,494 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
I plan to do the same, cutting up the wheel wells only weakens the front structure If you cut the wheel wells you need to weld in stiffeners around the cut out. I believe all the radiated conversions will allow some hot air into the cabin unless ducted to the wheel wells. If anyone has a wheel well vented system that does not allow heated air into the cabin I'd love to see their set up. My solution: |
DickSteinkamp |
Jun 27 2019, 09:48 AM
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#13
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Senior Member Group: Members Posts: 500 Joined: 27-February 17 From: Bellingham, WA Member No.: 20,876 Region Association: None |
I plan to do the same, cutting up the wheel wells only weakens the front structure If you cut the wheel wells you need to weld in stiffeners around the cut out. I believe all the radiated conversions will allow some hot air into the cabin unless ducted to the wheel wells. If anyone has a wheel well vented system that does not allow heated air into the cabin I'd love to see their set up. My solution: Great solution! I like it. I have a friend with an HVAC biz that can make those ducts for me. I guess mocking them up with cardboard would be the best start. I would think this would also make the fan noise less obtrusive. Any details on how you reinforced the wheel well cutouts? |
tazz9924 |
Jun 27 2019, 02:33 PM
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#14
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Senior Member Group: Members Posts: 703 Joined: 31-May 15 From: Mooresville NC Member No.: 18,779 Region Association: None |
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Chris914n6 |
Jun 27 2019, 03:42 PM
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#15
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Jackstands are my life. Group: Members Posts: 3,310 Joined: 14-March 03 From: Las Vegas, NV Member No.: 431 Region Association: Southwest Region |
The front structure is strong enough to handle a reasonable size cutout in the wheel well.
And with ducting like 76-914 or what I did with my a/c holes in the floor, you can keep some of the trunk space. There is no formula for air holes to hp. I started with measuring the inlet for the car I took my motor out of plus rad core size and tried to match it. There is a point where airflow from moving is greater than the CFM from the fans, usually 20-30mph. |
Andyrew |
Jun 27 2019, 04:19 PM
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#16
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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 |
I believe that the calculation should be for air flow area to cubic inches....
I think engine size makes a much greater difference than total HP. My 400hp+ 1.8L motor can barely stay warm enough with my toyota celica radiator which is about half the size of my old 5.7+L v8 motor's radiator and it barely kept cool enough. |
76-914 |
Jun 27 2019, 04:54 PM
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#17
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,494 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
I plan to do the same, cutting up the wheel wells only weakens the front structure If you cut the wheel wells you need to weld in stiffeners around the cut out. I believe all the radiated conversions will allow some hot air into the cabin unless ducted to the wheel wells. If anyone has a wheel well vented system that does not allow heated air into the cabin I'd love to see their set up. My solution: Great solution! I like it. I have a friend with an HVAC biz that can make those ducts for me. I guess mocking them up with cardboard would be the best start. I would think this would also make the fan noise less obtrusive. Any details on how you reinforced the wheel well cutouts? Dick, I cut and welded 1" strips of 16ga steel around the perimeter. Shaped just like the edge guard you have now only wider. That is also where I attached the 90 degree aluminum flanges that the ducking is tied into at the wheel well. Just don't forget where the plug welds are located as they are Hell to drill thru. BTW, the ducting is the 2nd best improvement I've made on that car. The first being the Suby conversion and the 3rd would be the addition of the AC system. Highjack over. (IMG:style_emoticons/default/beerchug.gif) |
DickSteinkamp |
Jun 27 2019, 06:06 PM
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#18
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Senior Member Group: Members Posts: 500 Joined: 27-February 17 From: Bellingham, WA Member No.: 20,876 Region Association: None |
Dick, I cut and welded 1" strips of 16ga steel around the perimeter. Shaped just like the edge guard you have now only wider. That is also where I attached the 90 degree aluminum flanges that the ducking is tied into at the wheel well. Just don't forget where the plug welds are located as they are Hell to drill thru. BTW, the ducting is the 2nd best improvement I've made on that car. The first being the Suby conversion and the 3rd would be the addition of the AC system. Highjack over. (IMG:style_emoticons/default/beerchug.gif) Thanks! Did you operate the car before the duct work? If so, was there a difference in engine temp and/or how often the fans came on? BTW, I hope the OP doesn't consider this a highjack. Great info that I think ties in nicely. |
tazz9924 |
Jun 28 2019, 05:53 AM
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#19
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Senior Member Group: Members Posts: 703 Joined: 31-May 15 From: Mooresville NC Member No.: 18,779 Region Association: None |
Dick, I cut and welded 1" strips of 16ga steel around the perimeter. Shaped just like the edge guard you have now only wider. That is also where I attached the 90 degree aluminum flanges that the ducking is tied into at the wheel well. Just don't forget where the plug welds are located as they are Hell to drill thru. BTW, the ducting is the 2nd best improvement I've made on that car. The first being the Suby conversion and the 3rd would be the addition of the AC system. Highjack over. (IMG:style_emoticons/default/beerchug.gif) Thanks! Did you operate the car before the duct work? If so, was there a difference in engine temp and/or how often the fans came on? BTW, I hope the OP doesn't consider this a highjack. Great info that I think ties in nicely. i dont mind |
jd74914 |
Jun 28 2019, 07:21 AM
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#20
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Its alive Group: Members Posts: 4,780 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
I believe that the calculation should be for air flow area to cubic inches.... I think engine size makes a much greater difference than total HP. My 400hp+ 1.8L motor can barely stay warm enough with my toyota celica radiator which is about half the size of my old 5.7+L v8 motor's radiator and it barely kept cool enough. Kinda. Engine efficiency (and radiator air-side efficiency) is really the controlling parameter. Your old V8 was literally likely 50% less efficient than the 1.8T; so the heat load was proportionally higher. Looking in terms of engine size is more or less a surrogate way of thinking about thermal efficiency. |
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