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Old 01-12-2013, 04:48 PM   #121
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I totally agree and that is why I have a chaser hood. That pressure map was for air flow over a stock configured hood, add that air deflector and you create a big low pressure area behind it and a vacuum effect as it is shaped in the photo. It's not ideal but should still have some effect.
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Old 01-13-2013, 09:13 PM   #122
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Quote:
Originally Posted by triple88a View Post
According to a a pressure map of the nb hood someone did a while back. The best spots for vents are around the sides near where the overflow bottle is and the other side where the filter is at. Now of course that's kinda far out of the way to route the radiator air to. It gets worse as you get towards the center so technically the best reasonable spots are where the chaser kits have their vents. That way your vent passages don't get in the way of the intake.
Not to discredit those maps but as far as I'm aware they are only the pressure readings from the top surface of the hood. While they're a good starting point, they don't take into consideration pressure under the hood which will be the other side of the pressure differential equation and could shift where the "ideal" location is.

If I'm wrong about this and they were actual pressure differential readings, ignore my post.
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Old 01-13-2013, 09:40 PM   #123
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Correct. They were only readings on top of the hood.
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Old 01-16-2013, 05:55 PM   #124
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Quote:
Originally Posted by njn63 View Post
Not to discredit those maps but as far as I'm aware they are only the pressure readings from the top surface of the hood. While they're a good starting point, they don't take into consideration pressure under the hood which will be the other side of the pressure differential equation and could shift where the "ideal" location is.

If I'm wrong about this and they were actual pressure differential readings, ignore my post.
Highly unlikely there is an much of an uneven pressur distribution in the engine compartment. The engine compartment is pretty much is like a pressurized box of uniform pressure. If you want to suck air out of it as fast as possible cut a hole where the pressure is the lowest on the outside of it.

Bob
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Old 01-17-2013, 11:05 AM   #125
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rccote, do you have any other pictures (different angles) of that red car with the 4 small vents cut into the hood?
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Old 01-17-2013, 09:19 PM   #126
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Quote:
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Highly unlikely there is an much of an uneven pressur distribution in the engine compartment. The engine compartment is pretty much is like a pressurized box of uniform pressure. If you want to suck air out of it as fast as possible cut a hole where the pressure is the lowest on the outside of it.

Bob
We'll see. I just bought a Magnehelic gauge.
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Old 01-17-2013, 11:00 PM   #127
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Quote:
Originally Posted by mx5autoxer View Post
rccote, do you have any other pictures (different angles) of that red car with the 4 small vents cut into the hood?
that's charlie's car:
https://www.miataturbo.net/build-thr...e6/#post936763
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Old 01-18-2013, 12:50 AM   #128
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If the pressure under the hood is higher than the pressure on top of the hood wouldn't it just force the pressure out of the engine bay regardless of location?
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Old 01-18-2013, 04:36 AM   #129
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There is no point under the hood that is at a higher pressure than the base of the windshield. Hood risers are for ricers and folks that idle around parking lots trying to look cool. Once the car starts moving at any reasonable speed the riser becomes and intake which hurts pressure differential across the heat exchangers.
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Old 01-18-2013, 12:07 PM   #130
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If by riser you mean the air dam that is in front and around the sides of the opening in that hood, which is towards the middle/front, that does create a low presure area behind it as it deflects the air upward, but it also creates some drag and is why being further forward is better because you can have low air presure with out the drag from the air dam on the hood to careate that low presure behind or if some more air flow is wanted you can do the samething forward too.
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Old 01-18-2013, 12:49 PM   #131
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By hood risers he means putting a stack of washers between the hinge and the hood.
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Old 01-18-2013, 01:26 PM   #132
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Quote:
Originally Posted by hustler View Post
You basically want a vent in front of the hood-hump, slightly raised.
So, what's the consensus on this one?
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Old 01-18-2013, 01:38 PM   #133
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So, what's the consensus on this one?
I bet it would work quite well.
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Old 01-18-2013, 03:29 PM   #134
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So, what's the consensus on this one?
Bueno.
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Old 01-18-2013, 08:48 PM   #135
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Thanks rccote. That's a beautiful car. I've never seen it before. I love the plates.
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Old 01-19-2013, 11:30 AM   #136
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So let me ask - as I've come to this point of re-designing the war bird. If a 33% facial opening of cooling surface area is ideal - what's a good rule of thumb for hood vent opening area? I'm planning a v-mount setup while ducting most the air from the IC through the hood vent - radiator too if I can work it out. Take in concideration the car will be flat-paneled too.
Also designing the rear portion of the front wheel well fenders to move as much air as possible too... but the wheels are already a high pressure area and not sure what/if any engine compartment air will make it's way through there. I'm going to try and seal it up the well as much as possible, leaving openings for the suspension components.

I guess I just want to be sure the hood vent is not too small - nor too big, yet get enough airflow across the radiator and oil cooler while not 'plugging' the system up with flat panelling the car.

FYI - rocking the GT widebody from Autokonexion.

<--- no more bandaids pretty ****
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Old 01-19-2013, 12:33 PM   #137
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Could you not create some ducts for the air (Engine bay-> Rear of fender), bypassing the wheel well chaos?
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Old 01-19-2013, 12:40 PM   #138
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Quote:
Originally Posted by GeneSplicer View Post
FYI - rocking the GT widebody from Autokonexion.

<--- no more bandaids pretty ****
How well does that all match up and function aero wise on the front end. Their aero fenders in kevlar are looking really good at the moment since they weigh about 3 pounds, thats lighter than I could ever make a set, and the price is reasonable.
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Old 01-19-2013, 12:52 PM   #139
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Originally Posted by NiklasFalk View Post
Could you not create some ducts for the air (Engine bay-> Rear of fender), bypassing the wheel well chaos?
I'd have to mod the tunnel to do that (and not allowed in ST2 for cooling) - there's so much structural support aft the wheels and it's already tight as **** with 225s/245s. I could possibly add ducting through the flat panel to the sides of the car, after the front wheel - like the V8 supercar skirts (which I like). But seems more work than what it's worth.

Seems to match up evenly - covering the front wheels well - however, mine is not yet mounted. The rear quarters will need some work though, as they don't diver air flow before the front edge of the wheel. I plan on reducing the bumper opening some, use the fog holes for brake ducting. Aero-wide - we'll see, but 'seems' to be the best aero front end out there so far as a kit goes... Andrew/TSE thought the same as well.

Still haven't replaced the hood yet - which is why I'm looking at reaplcement, or modification of an OEM.
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Old 01-21-2013, 01:50 PM   #140
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So when choosing a vent shape is it ok to have a cut piece that angles down like what is on Charlie's red car

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Originally Posted by rccote View Post
or is it worth it to have a molded louver that sticks out of the main lines of the car like this?

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