Radiator hood vent?? Aero, cooling, WAI, all in one??

[freebeard]

Who, me?

I had a look at offical hoodless car pics thread! - Honda-Tech

The situation the OP asked about won't obtain in your situation unless you box in the fan with ductwork to an exhaust vent. As the hood slopes forward, the presumed vent will be faced with oncoming air and choked off unless the flow velocity is matched.

Your best bet might be some louvers at the rear hood corners behind the Macpherson strut towers. Possibly angled toward the corner per aerohead's suggestion.

[whatmaycome14]

Yes, but if the radiator is fully ducted, will it matter if it is not on the centerline of the hood and instead offset to the drivers side of the car by 10in? OR if is only on half the width of the radiator?

[freebeard]

How many inches from the front face of the traverse engine to the rear face of the radiator? I'm not seeing room for a duct, the whole engine head is in the way.

In any case, if you are punching louvers macht nix. If you create a sealed duct, wrap an airfoil sleeve around it.

[whatmaycome14]

Originally Posted by freebeard

How many inches from the front face of the traverse engine to the rear face of the radiator? I'm not seeing room for a duct, the whole engine head is in the way.

In any case, if you are punching louvers macht nix. If you create a sealed duct, wrap an airfoil sleeve around it.

I'll post a picture later. I've got the radiator angled forward quite a bit, so there is plenty of room. However the upper radiator hose is what is in the way most of all.

[aerohead]

Originally Posted by whatmaycome14

Yes, but if the radiator is fully ducted, will it matter if it is not on the centerline of the hood and instead offset to the drivers side of the car by 10in? OR if is only on half the width of the radiator?

If the inlet duct is airtight,the static pressure differential across the heat-exchanger matrix will induce the flow.Some 1/4-inch hardware cloth ahead of the radiator could help distribute the turbulent air more evenly across the core if the air was attempting to hug one side.
Ideally.you'd have a gentle,divergence.

[whatmaycome14]

So here are a few photos that should help explain what I'm referring to (please forgive my horrible drawing skills):

The black represents the approximate proposed location for the vent in the hood -



And yes, there is plenty of room, I've angled the radiator forwards. From the top of the radiator to the front part of the support (which will be cut out of the car soon enough here) it is 9" and another 8" straight back before you hit anything on the engine -



So would it matter that it isn't in the center of the car and is offset to the drivers side?

[freebeard]

The pictures help. Take note of the pictures aerohead posted.

I don't see a problem with the hose being exposed in the duct. It's easier to reroute the water than the air. Consider a 90° elbow and cap at the pump outlet to give a clean run of hose forward.

I think the bigger problem is the original radiator header. Maybe cut it out and replace with a piece or pieces of round tubing? Or make a duct floor that is stout enough to replace the header. (It's pretty important to the integrity of the front end sheet metal)

[kach22i]

On the current Porsche 911 water-cooled car there is a tiny air exit slot at the leading edge of the hood just behind the bumper for the center radiator.

On higher powered models the two flanking radiators vent into the wheel wells.


Point being the size for exiting air is much smaller than air intakes. Meaning it may be of higher velocity, but lower pressure.

See post number 15
http://ecomodder.com/forum/showthrea...p-27982-2.html

[aerohead]

I'm not qualified to advise you.This is the sort of thing which costs $100,000 in a full-scale wind tunnel to figure out.
The over-the-bonnet extractors have been primarily the domain of race cars,which are more for down-force than drag reduction

Kamm placed his extractor at the base of the windshield,using the flow to help energise the flow over the windshield.

The same thing was done on some of the Jaray cars

Mercedes did the same with their C-111 III,but again,this is a 'race car' designed for down-force.
Morelli spent $100,000 or so at Pininfarina to optimize the extractors on his 1978 CNR 'banana' car.

Today,Tesla is credited for allowing 'engine bay' air to escape only 'under' their cars.
No low-drag concept cars,except the CNR car have used over the bonnet extractors.
Mine,on the T-100 will be tested open and sealed to see if they hurt things.

[freebeard]

That's a really good angle to show the form of the 'banana car'. I'd like to see it with the Urban car ring-tail and/or a 50% morph with the Volkhart-Sagitta V2.