DYI cowl air at its best :)
07-17-2004, 04:58 PM
#1
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DYI cowl air at its best :)
I tried the washer thing and it was kinda chauncey. So i went out and got 4 1/2 inch spacers and made my own custom cowl air now. when i had the washers it didnt kick the rear up enuff to get air flow in. hopefully this helps a little with getting cooler air in . im also trying to get another driver side headlight and gonna hollow out the high beam and feed it right into the turbo inlet. . . anyway enjoy .looks kinda ricey, but function over form .
07-17-2004, 05:52 PM
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Re: DYI cowl air at its best :) (Jordo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jordo »</TD></TR><TR><TD CLASS="quote">WTF i dont understand what exactly you did?</TD></TR></TABLE>
i can see someone didnt read the post or look closely at the pics.
i took 4 half inch spacers and jacked up the back of my hood toget more air flow under the hood, to cool things down . my under hood temps are sickly hott
i can see someone didnt read the post or look closely at the pics.
i took 4 half inch spacers and jacked up the back of my hood toget more air flow under the hood, to cool things down . my under hood temps are sickly hott
07-17-2004, 05:53 PM
#6
some theories about this.... some people say that area is a low pressure zone, some say it's a high presure zone (a la cowl induction hoods of the muscle car era, and current nascar cars)
may not be helping at all. but i know nothing. simply playing devil's advocate
may not be helping at all. but i know nothing. simply playing devil's advocate
07-17-2004, 05:56 PM
#7
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Re: (soccaian)
it might not. but even if it doesnt suck air in , it might let air vent out easier.
i will datalog at the track with this set up see if it works. if not i might cut a custom vent in the hood or i am thinking of spraying nitrous on my intake manifold before runs at the track .heatsoak is a bitch on event days
i will datalog at the track with this set up see if it works. if not i might cut a custom vent in the hood or i am thinking of spraying nitrous on my intake manifold before runs at the track .heatsoak is a bitch on event days
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07-17-2004, 06:08 PM
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Re: (itr206)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr206 »</TD></TR><TR><TD CLASS="quote">it might let air vent out easier.
</TD></TR></TABLE>
Nope, sorry, it's not letting any air out at all.
Rule: High pressure will always move towards a low pressure, not the other way around.
So we have two major high pressure regions on the front of a car- the bumper area, and the base of the windshield. The bumper is generally higher for two reasons- it's working in cleaner air, and it's also bigger.
Now, the air that enters through the grill is at a higher pressure than the air that enters through the rear of the hood in your case, however, the air entering through the grill is forced down and out through the bottom of the engine bay by the engine and transmission and the lower pressure under the car (remember the rule).
That having been said, the air coming in through the grill will not pressurize the entire engine compartment, especially the rear, enough to allow the under hood air to overcome the pressure at the base of the windshield.
Either way, it will help, but if you have heat issues, the best way to resolve this is to install an air dam on the front of the car and to add a properly designed vent in the hood. I say properly designed because if you add a dam and miscalculate the inlet CFM value (air coming through the grill) vs. the pressure drop immediately above the vent in the hood, the air dam will create a low enough pressure under the car to draw air through the hood vent, giving you lift. Part of the purpose of a hood vent is to create some downforce if properly ducted.
Hope that helps.
</TD></TR></TABLE>
Nope, sorry, it's not letting any air out at all.
Rule: High pressure will always move towards a low pressure, not the other way around.
So we have two major high pressure regions on the front of a car- the bumper area, and the base of the windshield. The bumper is generally higher for two reasons- it's working in cleaner air, and it's also bigger.
Now, the air that enters through the grill is at a higher pressure than the air that enters through the rear of the hood in your case, however, the air entering through the grill is forced down and out through the bottom of the engine bay by the engine and transmission and the lower pressure under the car (remember the rule).
That having been said, the air coming in through the grill will not pressurize the entire engine compartment, especially the rear, enough to allow the under hood air to overcome the pressure at the base of the windshield.
Either way, it will help, but if you have heat issues, the best way to resolve this is to install an air dam on the front of the car and to add a properly designed vent in the hood. I say properly designed because if you add a dam and miscalculate the inlet CFM value (air coming through the grill) vs. the pressure drop immediately above the vent in the hood, the air dam will create a low enough pressure under the car to draw air through the hood vent, giving you lift. Part of the purpose of a hood vent is to create some downforce if properly ducted.
Hope that helps.
07-17-2004, 06:43 PM
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Re:
the theory is to extract more heat by creating an opening (vent) on the hood down stream.
the evo is a modern example of this.
In combination with an upper front air dam, its thermo & aerodynamically benificial (relieves the high pressure area at the front of the hood).
btw, the tsx uses an upper front air dam and has a slight opening at the cowl to extract heat
How could you do this in a DA ?
Im trying to figure out how without gettin' a rice hood
the evo is a modern example of this.
In combination with an upper front air dam, its thermo & aerodynamically benificial (relieves the high pressure area at the front of the hood).
btw, the tsx uses an upper front air dam and has a slight opening at the cowl to extract heat
How could you do this in a DA ?
Im trying to figure out how without gettin' a rice hood
07-17-2004, 07:58 PM
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Re: (Loco Honkey)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Loco Honkey »</TD></TR><TR><TD CLASS="quote">
Nope, sorry, it's not letting any air out at all.
Rule: High pressure will always move towards a low pressure, not the other way around.
So we have two major high pressure regions on the front of a car- the bumper area, and the base of the windshield. The bumper is generally higher for two reasons- it's working in cleaner air, and it's also bigger.
Now, the air that enters through the grill is at a higher pressure than the air that enters through the rear of the hood in your case, however, the air entering through the grill is forced down and out through the bottom of the engine bay by the engine and transmission and the lower pressure under the car (remember the rule).
That having been said, the air coming in through the grill will not pressurize the entire engine compartment, especially the rear, enough to allow the under hood air to overcome the pressure at the base of the windshield.
Either way, it will help, but if you have heat issues, the best way to resolve this is to install an air dam on the front of the car and to add a properly designed vent in the hood. I say properly designed because if you add a dam and miscalculate the inlet CFM value (air coming through the grill) vs. the pressure drop immediately above the vent in the hood, the air dam will create a low enough pressure under the car to draw air through the hood vent, giving you lift. Part of the purpose of a hood vent is to create some downforce if properly ducted.
Hope that helps.</TD></TR></TABLE>
I disagree, while in theory you are correct. Relality is a different story.
colw flaps on aircraft serve a purchase and actually do cool the engine down. They are based off this same idea but the flaps is proped out the bottom of the engine. But your theory is correct clow flaps wouldn't work, because air flow over the engine is going to create the high pressure thus creating a lower pressure air going through the engine as cooling.
Here is my theory. The hood and windsheild of the car act as a cambered surface. They act like a venturi in a way. The air flow over the top side of the car is going to increase in velocity creating a lower pressure. This will allow the higher pressure air from under the hood and the high pressure air from flowing under the car to come up through the hood vent there.
Modified by MachAF at 1:58 AM 7/18/2004
Nope, sorry, it's not letting any air out at all.
Rule: High pressure will always move towards a low pressure, not the other way around.
So we have two major high pressure regions on the front of a car- the bumper area, and the base of the windshield. The bumper is generally higher for two reasons- it's working in cleaner air, and it's also bigger.
Now, the air that enters through the grill is at a higher pressure than the air that enters through the rear of the hood in your case, however, the air entering through the grill is forced down and out through the bottom of the engine bay by the engine and transmission and the lower pressure under the car (remember the rule).
That having been said, the air coming in through the grill will not pressurize the entire engine compartment, especially the rear, enough to allow the under hood air to overcome the pressure at the base of the windshield.
Either way, it will help, but if you have heat issues, the best way to resolve this is to install an air dam on the front of the car and to add a properly designed vent in the hood. I say properly designed because if you add a dam and miscalculate the inlet CFM value (air coming through the grill) vs. the pressure drop immediately above the vent in the hood, the air dam will create a low enough pressure under the car to draw air through the hood vent, giving you lift. Part of the purpose of a hood vent is to create some downforce if properly ducted.
Hope that helps.</TD></TR></TABLE>I disagree, while in theory you are correct. Relality is a different story.
colw flaps on aircraft serve a purchase and actually do cool the engine down. They are based off this same idea but the flaps is proped out the bottom of the engine. But your theory is correct clow flaps wouldn't work, because air flow over the engine is going to create the high pressure thus creating a lower pressure air going through the engine as cooling.
Here is my theory. The hood and windsheild of the car act as a cambered surface. They act like a venturi in a way. The air flow over the top side of the car is going to increase in velocity creating a lower pressure. This will allow the higher pressure air from under the hood and the high pressure air from flowing under the car to come up through the hood vent there.
Modified by MachAF at 1:58 AM 7/18/2004
07-18-2004, 10:36 AM
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Re: (MachAF)
Originally Posted by MachAF
colw flaps on aircraft serve a purchase and actually do cool the engine down. They are based off this same idea but the flaps is proped out the bottom of the engine. But your theory is correct clow flaps wouldn't work, because air flow over the engine is going to create the high pressure thus creating a lower pressure air going through the engine as cooling.
Also, to touch on the cowl flaps a little more... the reason they help cool the engine is because they allow a large low pressure area to exist in a location that vents the cooling air. Again, we come back to the high pressure moving to the low pressure rule. High pressure exists at the cowling inlet, low pressure exists behind the flaps soley becuase they extend into the slipstream. Remove the flaps (the outlet area remains the same), and the openings ability to evacuate the air in the cowling is vastly diminished because there's no low pressure area there. To prove my point... drive down the road at 60 MPH and close your windows and turn your AC fan on. Now tilt your sunroof up, simulating a cowl flap. Notice how the air coming out the vents increases in velocity? Now slide the roof back? See how the air coming out the vents decreases in velocity? Use a lit cigarette in front of the vent so you can actually visualize what the air is doing.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">Here is my theory. The hood and windsheild of the car act as a cambered surface. They act like a venturi in a way. The air flow over the top side of the car is going to increase in velocity creating a lower pressure. This will allow the higher pressure air from under the hood and the high pressure air from flowing under the car to come up through the hood vent there.</TD></TR></TABLE>
Close but no cigar. A cambered surface that produces lift will always have the center of lift at the MAC (mean aerodynamic chord), which is at 33% back from the leading edge of the surface. The MAC can vary slightly depending on camber profile, and angle of attack, but that's irrelavent here. The hood and the windshield of the car do not act as a cambered surface, because they have two distinct angles of attack. On top of that, we come back to what I said before about the change in direction at the base of the windshield. Now, if the hood and windshield were flying through the air on their own without any car attached to them, in the same formation that they hold on the car, then yes, there would be a low pressure area... but it'd be on the back side of the windshield and hood, and they'd essentially be "flying" upside down; that is, they'd be creating downforce. A car's center of lift is somewhere around or aft of the B pillar, generally speaking. Hence, wings on race cars to hold the rear end down. Because of their angle of attack, the windshield and hood create some downforce (ask anyone who's played with different bodies on RC touring cars) because of their angle of attack. Am I repeating myself here? Anyway... no, I'm sorry, but the only low pressure areas on a car when viewed in a profile are on the roof and behind the car. There are some on the hood, depending on design and rake. Definetly NOT on the hood, and certainly not at the base of the windshield- that's the second highest pressure area on the whole car.
07-18-2004, 11:37 AM
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Re: (Loco Honkey)
I'm not saying that this mod doesn't work because many who have done this have reported good results, but I do agree that the cowl area is a high pressure area. I say this because when I'm on the highway, I can feel the air coming out of the vent a lot faster. This may be dumb logic, but at least it makes sense to me. 
07-18-2004, 12:50 PM
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Re: (B18bEK)
I never realized how much heat turbo cars generate, until I learned first hand. at firat, I thought about trying this route (spacers to raise the hood). However, I decided to start thermal coating (HPC) heat soaked parts. If the heat can't get out, it's better all around. Underhood temps decrease and the turbo spools quicker 
The first to "feel the heat" was the hood release cable. Melted...and broke.
The first to "feel the heat" was the hood release cable. Melted...and broke.
07-18-2004, 01:14 PM
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Re: (rondigs)
wellim trying the free/cheap options first. i dont wanna rip everything apart to coat it and b out of money and turbo parts for a while
07-18-2004, 03:44 PM
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Re: (rondigs)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rondigs »</TD></TR><TR><TD CLASS="quote">I never realized how much heat turbo cars generate, until I learned first hand. at firat, I thought about trying this route (spacers to raise the hood). However, I decided to start thermal coating (HPC) heat soaked parts. If the heat can't get out, it's better all around. Underhood temps decrease and the turbo spools quicker
The first to "feel the heat" was the hood release cable. Melted...and broke.</TD></TR></TABLE>
so true.
i cant even touch my IM or my strut bar and i can just feel the heat coming from the valve cover. it's horrible
didnt think it would be this bad. guess i'll try this and see how it works.
The first to "feel the heat" was the hood release cable. Melted...and broke.</TD></TR></TABLE>
so true.
i cant even touch my IM or my strut bar and i can just feel the heat coming from the valve cover. it's horrible
didnt think it would be this bad. guess i'll try this and see how it works.
07-18-2004, 05:51 PM
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Re: (Loco Honkey)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Loco Honkey »</TD></TR><TR><TD CLASS="quote">Jacking up the rear of the hood will cool things down in there, but it will not let hot air out like people think. It draws cool air in. </TD></TR></TABLE>
Hence the cowl "induction"
</TD></TR></TABLE>Hence the cowl "induction"
07-18-2004, 06:32 PM
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Re: (Loco Honkey)
For those that have yet to assemble your setup, I highly suggest looking into getting parts thermal coated. Like the guy mentioned above, it does suck to have to pull everything apart, resource out for coating, and wait for the process to conclude. If you want to eliminate downtime, its best to do it ahead of time...
07-18-2004, 07:49 PM
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Re: (soccaian)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by soccaian »</TD></TR><TR><TD CLASS="quote">some theories about this.... some people say that area is a low pressure zone, some say it's a high presure zone (a la cowl induction hoods of the muscle car era, and current nascar cars)
may not be helping at all. but i know nothing. simply playing devil's advocate</TD></TR></TABLE>
thats exactly what happens. it sucks air in rather than vents it out. my friend used to work on nascar cars and he told me thats why their intakes are mounted so close to the windshield.
it acts like a ram air for them . really cool
may not be helping at all. but i know nothing. simply playing devil's advocate</TD></TR></TABLE>
thats exactly what happens. it sucks air in rather than vents it out. my friend used to work on nascar cars and he told me thats why their intakes are mounted so close to the windshield.
it acts like a ram air for them . really cool
07-18-2004, 09:00 PM
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Re: (psileepR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by psileepR »</TD></TR><TR><TD CLASS="quote">
it acts like a ram air for them . really cool </TD></TR></TABLE>
Then again, how effective is ram air...?
it acts like a ram air for them . really cool
</TD></TR></TABLE>Then again, how effective is ram air...?