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Hi all,

Was just wondering, i know there are the air ducts on the side of our cars which direct air into the engine bay.

what about the air that passes under the car? none of it is directed into the engine bay? especially for the guys with turbo conversions, the extra cooling would be beneficial.

same principle for the bottom mount intercooler. it does not get much air passing through it.

i'm contemplating putting some sort of scoop to direct air into the engine bay and another to push air onto the cooler.

your thoughts?
 

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I have a very reasonable drop on my Tanabe springs and I still hit stuff quite a bit. My oil pan took a good hit at some point...I almost lost one of the plastic trim pieces near the fuel tank to a rock. If you do a scoop, I'd suggest plastic, and I'd suggest you attach it to something other than the intercooler.

Some kits used to include a scoop...Hass, I think.
 

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I have given a lot of thought to this. Specifically, the question about what the hell is going on with air flow through the engine bay. From what I can tell it interacts with four other pressure zones: a low pressure zone on the top causing air to evacuate from the bay through the grill in the hood; a low pressure area behind the car, forcing air to escape through the rear grills; a higher pressure area under the car, forcing air to come up and into the engine bay; then last, air being rammed into the bay through the side scoops.

When I was building my last PC I got to the point where I had to think about cooling everything, as I am running two GPUs in SLI mode, overclocked, and an overclocked CPU- there is a lot of heat being generated there. I learned that one wants more air being forced out than air being forced in. This creates a low pressure zone and the air flow through the tower will be expedient as long as their are no large obstructions. What you don't want is air loitering around in there and getting hot.

Based on that lesson, I think it is better to force air from the engine bay than to force air in. For that reason, if I ever found myself needing more cooling, the first thing I would do is take a standard double fan radiator and attach it to the rear bumper, setting it up to expel air out the back. I'd also remove the plastic grill and the license plate to do so (and relocate the plate or whatever).

This should col the engine bay more efficiently than a scoop, and it won't cause drag. I think.
 

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Ahh this brings me back to our attic fan as a kid. My dad had a huge hole cut into the ceiling of our hallway in which a huge (loud) fan could be placed. When it got hot in the house he would climb up there and drop it in the hole and fire that baby up -sucked the air out of the house into the attic.

with the windows open the whole house would get ventilated. Works far better than forcing air through a window.
Had the same setup in my house growing up. Did a great job of keeping things cool and I also liked falling asleep to the hum of the fan running.
 

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I agree with SDSU and T-bone, that you'd be better off forcing more air out than trying to shove more in. If you still wanted to make a scoop, I would make a full undertray from the fuel tank to the rear bumper and integrate a diffuser. Near the firewall, install a couple of NACA ducts to direct airflow into the engine bay, like the Elise does. They won't hang down like a scoop, and still pull air up. Although with all this I would cut the bottom portion of the bumper off, modify the crash bar, and take out the surround from the license plate area to evacuate the most air possible.
 

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I agree with SDSU and T-bone, that you'd be better off forcing more air out than trying to shove more in. If you still wanted to make a scoop, I would make a full undertray from the fuel tank to the rear bumper and integrate a diffuser. Near the firewall, install a couple of NACA ducts to direct airflow into the engine bay, like the Elise does. They won't hang down like a scoop, and still pull air up. Although with all this I would cut the bottom portion of the bumper off, modify the crash bar, and take out the surround from the license plate area to evacuate the most air possible.
Yes, this is a good idea. Instead of naca ducts being incorporated into the undertray, I was playing with the idea of putting a horizontal fan there as well to suck air from under the car. This was just as much for cooling purposes as it was to take air from under the car. Probably highly illegal in most racing bodies, so it's a fantasy more than anything. There would have been a bgger fan in the rear of course and perhaps a fan on the hood as well to facilitate convection.

I like this discussion.
 

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Or just get some larger side vents like the Varis ones and install a slim line fan on the engine cover lower pan like the one EU model had.
 

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Pardon my rant but I don't understand what the original problem is.
I understand if you need to cool off an intercooler or oil cooler and unless you have that what is the point.

How do you measure that it is of any benefit. If this is the case and people like to solve a problem which hasn't existed for over 10 years then I think I may start selling my my oil filter cooler since in theory it's suppose to work but my data yielded no measurable benefit what so ever.

This scoop is not going to lower oil temps or water temps. One may think you are pushing out this tremendous amount of hot air outside this car but that hot has always been in existence and will not put a dent in the cooling. Why simply because that air is emanating from the header. On other cars the header is up by the fire wall and there is no reduction of temps it's just that you don't feel it as the observer looking under the hood.

If you want to stop that radiant heat then your best option is the contain it by using a header shield.
 

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Yes, this is a good idea. Instead of naca ducts being incorporated into the undertray, I was playing with the idea of putting a horizontal fan there as well to suck air from under the car. This was just as much for cooling purposes as it was to take air from under the car. Probably highly illegal in most racing bodies, so it's a fantasy more than anything. There would have been a bgger fan in the rear of course and perhaps a fan on the hood as well to facilitate convection.

I like this discussion.
The fan sucking air is reminiscent of the Chaparral 2J. A great race car, that has always been criticized as being ugly to the average person, but if you look at it from an engineering point of view, it's a beautiful masterpiece that was ahead of it's time. It used a snowmobile engine to suck air from underneath the car.

Dev, I don't think there is a problem, especially with a near stock engine. You could start to argue the point that it might be beneficial for turbocharged spyders, or if you directed the ducts directly at an oil cooler or intercooler like you mentioned. Sometimes it's just fun to theorize though.
 

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Pardon my rant but I don't understand what the original problem is.
I understand if you need to cool off an intercooler or oil cooler and unless you have that what is the point.

How do you measure that it is of any benefit. If this is the case and people like to solve a problem which hasn't existed for over 10 years then I think I may start selling my my oil filter cooler since in theory it's suppose to work but my data yielded no measurable benefit what so ever.

This scoop is not going to lower oil temps or water temps. One may think you are pushing out this tremendous amount of hot air outside this car but that hot has always been in existence and will not put a dent in the cooling. Why simply because that air is emanating from the header. On other cars the header is up by the fire wall and there is no reduction of temps it's just that you don't feel it as the observer looking under the hood.

If you want to stop that radiant heat then your best option is the contain it by using a header shield.
Dev, OP indicated he's running a turbo and intercooler in the rear. I thought people running turbo setups were documenting higher ambient temperatures in the bay? I might be wrong.

The fan sucking air is reminiscent of the Chaparral 2J. A great race car, that has always been criticized as being ugly to the average person, but if you look at it from an engineering point of view, it's a beautiful masterpiece that was ahead of it's time. It used a snowmobile engine to suck air from underneath the car.
Yes, the Chaparral is what I had in mind. What a great car. Also, a more recent example: the McLaren F1 used fans on the bottom, and I think the more recent Italia does as well.
 

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Using a boosted engine runs alot more heat in the engine bay. You could feel it 3 feet away from the car.
 

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Dev, OP indicated he's running a turbo and intercooler in the rear. I thought people running turbo setups were documenting higher ambient temperatures in the bay? I might be wrong.
I just read it again and you are right but the wording from the OP was a bit vague as it could be either or.

In that case I see nothing wrong with a scoop directed to the intercooler however in regard to containing the heat from a turbo and manifold from entering the fore end of the engine bay I would use shielding and blankets.
 

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A very shallow NACA duct would work the best for directing air into a heat exchanger. NACA ducts are excellent tools for moving lots of air with minimal drag. I'll be doing one for my heat exchanger on the air/water setup.
Make sure to document that when you get around to it. Inquiring minds want to see how that works out. I'll be FI some day so it's relevant to my interests.
 

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Please remember that air is not the only thing down there. There is also dirt, water, road debris, etc. I think there is a logical reason the main air intakes are up on the side of the car. Water is the thing I would worry about the most. A couple of times I have got caught in a down pour, maybe at least 3 or 4 inches of water on the roadway, what then?
 

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There will always be a scenario that makes every idea impractical....
Dirt, water, and debris are pretty common scenarios. :lol:

I forced air to inside the rear fender, where the AEM cold air intake places the filter, with some dryer hose. My car was lowered fairly well, so that tube must have been picking up air from no more than 5 inches from the ground. I never had any problems, and driving through the rain and over puddles didn't appear to soak the filter.

I don't know if the ram air idea worked, but I do know it didn't cause problems in California weather. Then again, any water getting into that tube would have had to travel up at least 6 inches and go round a bend to reach the filter.
 
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