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Posted by: Shivers Sep 1 2023, 11:06 AM

Been doing some more reading, keeping in mind the up side down airfoil shape of the car, I decided to vent out the hood. I’ve seen lots of examples but they all seem to take up most of the trunk. The out the wheel well system uses less trunk space but again I don’t want to mess with the air flow. So I’m thinking some creative ducting and vent out the holes drawn in. The hole is surrounded by bracing so why not add channels like the stock ones and a couple added pieces of trunk rubber seal. Going to use some factory light bucket funnels to drain any water out the bottom. My question is: it seems that these holes in the hood would be no smaller than the holes I’ve seen with the wheel well cooler exhaust systems. What do you guys think?

Posted by: brant Sep 1 2023, 11:11 AM

I have the big hole in the trunk lid with ducting

Tried two other set ups first but the big hole (same cooler) brought oil temps down more than the first two attempts (measured oil temps)

You want your output duct to be about twice the volume of you input side

Posted by: Shivers Sep 1 2023, 11:30 AM

So what you are saying is I’m going to have to do some math. Oh boy
lol Thank you very much. I got the size for the inlet from Eric, so it is GT size. Might be close. Or is that a horse shoe and hand gernades and not holes in my hood, kind of thing? If I can I’m trying to save as much frunk as possible. The Mrs. has fond memories of the trips we made in the car. I’d like to give her a few more. Thanks

Posted by: Shivers Sep 1 2023, 12:11 PM

That is a big hole. Maybe I can figure a way to put it in the middle but at the same latitude and waterproof the frunk.

Posted by: brant Sep 2 2023, 08:19 AM

Not much math
I just eye balled double the size
My cooler is about the same size as a license plate
The air gets warm as it passes through the cooler causing it to expand
So you need a large exit to evacuate it.
And hopefully some scavenging pressures as the air passes over the car

Posted by: brant Sep 2 2023, 08:21 AM

Picture



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Posted by: Shivers Sep 3 2023, 08:51 AM

Thank you brant. I’d already drawn in something similar, even though it was raining.

Posted by: SirAndy Sep 3 2023, 11:39 AM

My shroud is removable and there's still enough space for a tool box and some other odd bits.

Posted by: slowrodent Sep 3 2023, 12:17 PM

The folks who've done it certainly know the most, but I, for one, like your originally proposed outlets. Maybe not feasible once you look into it a bit, but they are handsome and I understand your logic for venting them as you did.

Kevin

Posted by: Shivers Sep 3 2023, 12:47 PM

Thank you sir, I’m shooting for maybe two and a half tool boxes. But it does look cool. I noticed your fixed first louver on the hood. I figure there must be a reason
for this. Is there an angle to shoot for?

Posted by: SirAndy Sep 3 2023, 01:22 PM

I'm sure there is some physics formula out there to give you the best angle but i was just eyeballing it.

You want a decent lip to be able to generate turbulence and low pressure to help with the air flow.

Posted by: SirAndy Sep 3 2023, 01:29 PM

Maybe this is more in line with what you're looking for?


I believe this is @http://www.914world.com/bbs2/index.php?showuser=19241 LS car

Posted by: Shivers Sep 3 2023, 02:08 PM

@http://www.914world.com/bbs2/index.php?showuser=179

Thanks again dude

Posted by: Shivers Sep 3 2023, 02:28 PM

As cool as that is, it looks like this is to vent the whole frunk. I went out and looked and the picture does not appear to have headlamp motors. Dang. Well back to the middle.

Posted by: tygaboy Sep 3 2023, 03:16 PM

Yes, that's my LS car and its hood vents. Also yes: no headlight motors. If I were to do it again, I'd try a GT3 or GT4-like vent that's wide and sorta shallow across the hood. Dimension to work/look good.
And for sure you need a vane or some sort of desiign element to create a pressure differential. The noses of our cars tip down so without this, your vent will be a scoop.
If you reviewed that part of my build thread, you saw I made a number of different versions and even did a yarn test to prove out the flow was doing what I wanted.
If I can help provide additional info or lessons learned, let me know.

Posted by: Shivers Sep 3 2023, 03:34 PM

@http://www.914world.com/bbs2/index.php?showuser=19241

Thank you! If you mean these I had one like that in the middle in mind.

Posted by: tygaboy Sep 3 2023, 03:59 PM

I was thinking more like this:


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Posted by: Shivers Sep 3 2023, 04:00 PM

I took a pic

Posted by: brant Sep 3 2023, 06:28 PM

Room for 2 tool boxes

Not waterproof
The hood sets inside of the duct
I clean after driving in the rain
It used to be a trailered race car,
Back when I cut the hood in the 90’s

I trash bag the luggage if my wife attends events
RRC in two weeks!!!!!!

Most pics from my street car thread in sig
First picture from today as I pack

Dad did the sheet aluminum duct work
I put ultra-grey on the seams to help with waterproofing


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Posted by: Shivers Sep 3 2023, 06:43 PM

Yes, that’s the ticket. Thank you. That looks great. I’ll try to keep it as shallow as I can...Maybe two and a quarter boxes