Why can't radiators be moved under the body?

[aerohead]

Have you ever looked under Toyota's first generation van?

[Frank Lee]

Yes. In fact I lost some skin and blood under one.

I once had a Type I Beetle with AIR CONDITIONING!!! The condensor was underneath the car, flat to the bellypan. And it was beat to helll.

[Snax]

The 'ducted radiator' concept is a very valid idea. Formula1 teams have taken radiator duct design to the point where they actually produce a net thrust from the heated air expansion. The thrust is miniscule, but it illustrates the point that a radiator does not have to induce drag. (The whole system is still a net loss in power when the energy required to pump the coolant to the radiator is factored in.)

[Frank Lee]

Formula 1 cars never run on gravel roads.

[Snax]

Well if you want to get all technical and stuff.

Actually, while that is a relevant concern for underbody mounting, NACA style ducting could be utilized to direct airflow to a position safely away from stray road debris.

I'm chalking this idea up under the category of "far more trouble than it is worth" however.

[IndyIan]

Snowmobiles have their radiator above the track under the seat, but they rely on the huge cooling effect of changing snow to water. Some snowmobiles will overheat just idling as there is no snow or airflow over the radiators.
I'd imagine 3 or 4 snowmobile rads would cool something like a metro once underway but with no good way to blow air over them, the car would overheat in city traffic.
I think that's the biggest problem, the radiator would have to be sized to cool the engine even with no air flow... You might need to do have the whole bottom of the car act as a radiator and maybe part of the top...
Ian

[Tango Charlie]

This is a fun concept to think about. It was discussed awhile back, here.

[Sunwapta]

Yes - I see the idea of sandwiching one between belly pans and protection with ski plates was discussed.

I don't think it would work on most small cars BUT on SUVs and pickup trucks there should be loads of space down under. Moreover, aren't trucks and SUVs the worst offenders when it comes to aerodynamics? (i.e. pickups and SUV have the greatest room for aerodynamic improvement and the greatest potential cost and environmental savings.)

Could you even downsize a radiator by mounting it as far back as possible so the coolant would be partly cooled by the time it got there? (Maybe add heat sinks / fins to the coolant lines.) Protect the lines and radiator with a vented/channelled belly/skid pan and you'd gain even more aerodynamic benefits.

Any thoughts on a short but wide upfront radiator that displaces the traditional positioning of the headlights? Where headlights are currently mounted why not put a radiator. Then have, say, two quite wide banks of headlights lights sitting above or below it - or a single band of LEDs right across the entire front of the vehicle. (Or mount the headlights right into the face of the grill in front of the radiator - or in the bumper or both.)

[Christ]

Look into the light range of LED's... you're trying to get something from nothing.

I, however, understand the idea of relocating the radiators. MR-2's and Fieros could easily use a smaller radiator and keep the same engine temps (mostly b/c of the utilized area of the radiator itself) because of the length of the coolant hoses. Easily enough, you could actually just add bands of aluminum foil to the radiator lines, and they've just become mild heat sinks, which bleed off heat from the coolant as it passes through.

In theory, you could just run a single large line that would allow enough flow over/around fins placed on it anywhere under the vehicle to allow for cooling of the engine coolant. Ideally, that line would be the same size as the rubber lines you currently have, allow for unrestricted flow of coolant (saving pumping losses at the engine), and be made of a non-reactive, heat conductive material (like ceramic (not good), or aluminum (good, but soft).

Said pipe would, of itself, be a heatsink, but could also benefit more from added surface area by heatsink application.

Oil can be cooled with simple pipes being added through the oil pan's sump cavity, while crappy airflow under the vehicle removes the heat from the open area inside the pipe.

Automatic transmissions could benefit from the same idea as the engine oil.

Why won't OEM's do this?
1. Cost prohibitive
2. Too far from the accepted "norm".
3. Engineers don't get paid to think.
4. It might help a situation that they're all trying to pretend does not actually exist.
5. They have the added burden of making sure they've taken into account ALL possibilities... and normally fail horribly at that for at least the first 3 years of production, then change the design on the 4th year, making themselves look bad after finally getting something right.

Take your pick... you'd be OK to try it yourself, but as far as mass-implementation, it would simply cost more than anyone would get back from it initially, and that's IF you could sell the idea at all, due to lack of consumer-based image involved with it. (read: number 2)

[NachtRitter]

Sunwapta - I still don't understand why you think someone that is looking to buy a truck or an SUV would want to pay extra for the kind of changes you are suggesting...

If I understand the general U.S. public correctly, the vast majority of truck and SUV buyers specifically do NOT care about efficiency or environmental savings... how could you possibly market such a costly feature to this majority??