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Re: 2nd place in class at BBORR - video
[Re: feets]
#1849827
06/15/15 07:42 PM
06/15/15 07:42 PM
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Joined: Dec 2003
Posts: 22,697
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
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Lifting the back of the hood will hurt air flow under the hood.
The base of the windshield is a very high pressure area at 130+ mph. It will flood more air under the hood.
Closing off the hood scoop or ducting it to the throttle bodies would help alleviate some of the problem.  sealing the scoop is a given, however I doubt its getting much air in the first place with flat front. As soon as he gets some pressure/test readings, I think he will get a better idea of what direction to pursue. A go Pro and some tuff/yarn video would also be useful around the scoop.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: 2nd place in class at BBORR - video
[Re: Uhcoog1]
#1851369
06/17/15 10:12 PM
06/17/15 10:12 PM
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Joined: Dec 2003
Posts: 22,697
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
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2 things that stood out to me in the link, 1. raising the rear in our nasty aero cars in their test, actually increased drag, I would have thought getting the undercarriage slightly (1"?) higher would be an even or a plus, and 2, raking the windshield further showed no improvement, however I think that is the case of the sheetmetal in front of it causing such an aero mess, additional rake achieved little..
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: 2nd place in class at BBORR - video
[Re: feets]
#1852045
06/18/15 07:53 PM
06/18/15 07:53 PM
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Joined: Nov 2008
Posts: 1,491
Lethbridge, AB, Canada
dangina
pro stock
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pro stock
Joined: Nov 2008
Posts: 1,491
Lethbridge, AB, Canada
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Does the radiator have bypass flaps to allow high speed air a route through when it overwhelms the fan? I don't even run a shroud, just a mechanical 17" fan 1/2" off the radiator. Radiator is a Howe Racing 19x27" dual 1.125" core aluminum crossflow generic. The car stays cooler with the air dam since it keeps pressure down under the hood. Your scoop is doing the opposite and offsetting the gains from the dam. Raising the rear of the hood is iffy if it is too close to the high pressure zone at the base of the windshield. Think about the NASCAR guys using the windshield base cowl induction for power gains. Same high pressure as a scoop without the drag.
this is pretty cool, I did not know this, I thought it was more for aerodynamics to have the flat hood in nascar with the windshield base cowl The NASCAR cowl intake system serves two purposes. It gets a little higher pressure air into the engine (poor boy supercharging) and it relieves the pressure at the base of the windshield. Very few high speed cars have conventional hood scoops outside the drag racing community. does this apply to all cars? I should try rerouting my fresh air intake on my car to this area...which brings me to another question. Why are most aftermarket fresh air intakes piped to the inner front fender of front portion of engine bay? If the high air pressure accumulates under the front windshield, wouldn't you want it piped to this area instead? thanks for the good read! I'm loving this thread BTW, so much good info 
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Re: 2nd place in class at BBORR - video
[Re: dangina]
#1852058
06/18/15 08:16 PM
06/18/15 08:16 PM
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Joined: Jan 2003
Posts: 28,068
Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,068
Irving, TX
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does this apply to all cars? I should try rerouting my fresh air intake on my car to this area...which brings me to another question. Why are most aftermarket fresh air intakes piped to the inner front fender of front portion of engine bay? If the high air pressure accumulates under the front windshield, wouldn't you want it piped to this area instead?
Yes. All cars have a high pressure area where the windshield meets the hood. Some are greater than others. Aero is different at highway speeds vs 100 mph and different again at 200 mph. At highway speeds the pressure at the base of the windshield isn't too high. The faster you go the higher it gets. Most fresh air kits draw from the front because it's convenient, easy, and fairly consistant.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
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Re: 2nd place in class at BBORR - video
[Re: feets]
#1852256
06/19/15 12:26 AM
06/19/15 12:26 AM
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Joined: Dec 2003
Posts: 22,697
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
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"The NASCAR cowl intake system serves two purposes. It gets a little higher pressure air into the engine (poor boy supercharging) and it relieves the pressure at the base of the windshield." Not sure about the second point being a plus, or more then an opinion or how even much pressure is really "relieved" by engine consumption. This high pressure area might be actually an improvement in streaming the rest of the air over the roof less abruptly, maybe like the the advantage measured of having the tail gate up creating a high pressure area and smoothing air flow in the back of a pick up vs having tailgate down, and very turbulent. And I believe its high pressure because of the rebound of air from striking the front nose of the car at speed, and less so from slope of the windshield, which the latest HR posted link might also indicate 
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: 2nd place in class at BBORR - video
[Re: jcc]
#1852614
06/19/15 04:37 PM
06/19/15 04:37 PM
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Joined: Jan 2003
Posts: 28,068
Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,068
Irving, TX
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"The NASCAR cowl intake system serves two purposes. It gets a little higher pressure air into the engine (poor boy supercharging) and it relieves the pressure at the base of the windshield." Not sure about the second point being a plus, or more then an opinion or how even much pressure is really "relieved" by engine consumption. This high pressure area might be actually an improvement in streaming the rest of the air over the roof less abruptly, maybe like the the advantage measured of having the tail gate up creating a high pressure area and smoothing air flow in the back of a pick up vs having tailgate down, and very turbulent. And I believe its high pressure because of the rebound of air from striking the front nose of the car at speed, and less so from slope of the windshield, which the latest HR posted link might also indicate For crying out loud, put down the micrometers and stop questioning everything everyone says. Air being forced into the engine does relieve the pressure build up at the base of the glass but not to any massive degree at the high speeds NASCAR runs. Having a high pressure area at the base of the glass is not a good thing for aero. Trucks are different because they are pulling a bathtub behind the highest point of the vehicle and that is where the circulation arises.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
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Re: 2nd place in class at BBORR - video
[Re: Uhcoog1]
#1852634
06/19/15 05:03 PM
06/19/15 05:03 PM
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Joined: May 2005
Posts: 723
Houston Tx
Uhcoog1
OP
super stock
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OP
super stock
Joined: May 2005
Posts: 723
Houston Tx
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If I recall - this is the test they stuck foam in the aero scoop they had. Because that's the best way to replicate the actual high speed conditions, and the tunnel only spins at 85 mph. One would think the same would apply to the cowl, with the same rule applying - not until a certain speed is reached.
-'02 Dodge Viper Ex-World Challenge racecar
-'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course
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Re: 2nd place in class at BBORR - video
[Re: feets]
#1852851
06/19/15 10:29 PM
06/19/15 10:29 PM
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Joined: Dec 2003
Posts: 22,697
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
|
"The NASCAR cowl intake system serves two purposes. It gets a little higher pressure air into the engine (poor boy supercharging) and it relieves the pressure at the base of the windshield." Not sure about the second point being a plus, or more then an opinion or how even much pressure is really "relieved" by engine consumption. This high pressure area might be actually an improvement in streaming the rest of the air over the roof less abruptly, maybe like the the advantage measured of having the tail gate up creating a high pressure area and smoothing air flow in the back of a pick up vs having tailgate down, and very turbulent. And I believe its high pressure because of the rebound of air from striking the front nose of the car at speed, and less so from slope of the windshield, which the latest HR posted link might also indicate For crying out loud, put down the micrometers and stop questioning everything everyone says. Air being forced into the engine does relieve the pressure build up at the base of the glass but not to any massive degree at the high speeds NASCAR runs. Having a high pressure area at the base of the glass is not a good thing for aero. Trucks are different because they are pulling a bathtub behind the highest point of the vehicle and that is where the circulation arises. 1. I am not crying 2. Nobody on this site can here me cry 3. The link if you bothered to read it, discusses aero changes measured in counts, or thousandths, regarding measurement units, your concern is with them, not me. 4. I only question what I disagree with or statements that have little to back them up, will admit, some get bothered by the public scrutiny 5. This latest nascar statement is ether backpedaling from your earlier remarks made or a contradiction by itself, I can't figure out which. 6. Having a high pressure area might be a good thing vs having a low pressure turbulent area, with out data/measurement to support it either way with certainty, is rather presumptuous. 7. Air doesn't care if its a car or a truck
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: 2nd place in class at BBORR - video
[Re: Mr.Yuck]
#1853390
06/20/15 08:29 PM
06/20/15 08:29 PM
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Joined: Dec 2003
Posts: 22,697
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
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Since cowl air intake was introduced I believe in the early 60's, My thought was it was more to retain a stock look, it wasn't illegal by the rules, it offered cooler air, was easy, it was always higher pressure area, and air had less dirt when then they ran dirt tracks, and made it easy to introduce "windshield washer fluid" on last lap, but not sure. 
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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