Why aren't cars that are manufactured today air cooled?
I own a ‘65 Corvair that is air cooled.An entire system,radiator,hoses,plumbing,pumps and water,that I no longer have to maintain.It is a simple,efficient design and I wonder why,with the obvious cost savings, modern vehicles do not utilize this design?
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Air cooled, for larger engines would almost have to be a radial engine as opposed to an inline V-8 or V-6 wouldn’t it?
Add. How many cylinders is your corvair?
Today’s engines run hotter
Air cooling requires much more surface area for heat transfer than water cooling, and thus would require bigger fans and radiators, making the vehicle larger than needed
Air cooling became popular because of technical problems with early water pumps, since solved.
@Adirondackwannabe -All Corvair engines were an opposing,flat 6 cylinder.For a larger engine,it would not have to be a radial,as you say.A larger air-cooled engine for larger applications would need only to be larger itself.
My mother had a Corvair for a while. I had a lot of friends who owned VW bugs made in the 1960s, too. One problem they had in common was that you froze your ass off in the winter. They couldn’t figure out how to heat the cabin efficiently from the engine heat. Some of the VWs had auxiliary heaters that burned gasoline to deal with the problem.
From an engineering standpoint, you’ve got the problem of regulating the engine temperature. This is essential for emissions controls. If the engine runs too cold, it doesn’t operate efficiently; you end up running with a too-rich mixture and no power. If it runs too hot – well, you can end up with a seized engine. Both of these problems were fairly common with VWs.
Aircraft engines work well with air cooling because they run at a more or less constant load, and there is more air passing over the cooling vanes.
Because air cooled engines ran on regular leaded gas which significantly contributed to smog and air pollution of the time. With all the new Federally mandated emission standards and competition from pony cars like the Mustang and of course Camaro, sales tanked and they stopped making it. VW limped along for years with their air cooled car but the HP of the VW didn’t cut it for most power hungry drivers of the 70’s.
@josie-Modern engines run hotter because they are designed that way.Air cooled engines are designed to run cooler.Apples and oranges.I see no reason why an air cooled design would not work in modern applications.Just because a designer designs a water-cooled engine that runs hotter,does not neccesitate that he design an air -cooled engine that runs just as hot.Everything to it’s nature.
@lucillelucillelucille What about the climate challenges. It would be tougher to keep an engine cool in Arizona, or warm enough to keep the occupants warm in NY in the winter as Ich pointed out. Water has much more stable heating and cooling properties than air.
@IchtheosaurusRex -All these issues were addressed with the Corvair and modern air cooled 2 and 4 stroke engines.Air cooled engines have blendoor heat and ducting which was fragile and ofter times would sever and flat out fail.Probably why you froze your @ss off ;)
Had the same amount of attention and engineering been paid to an air cooled application for an automobile,I can’t see why any of these issues you cite could not have been adddressed.
@lucillelucillelucille , there is something called Carnot efficiency that determines how well an engine works. I won’t go into the math, but it comes down to a relationship between heat and power; the hotter you can run an engine, the more powerful and efficient it is. A few years ago, designers were experimenting with all-ceramic engines that could run much hotter than today’s cast-iron and aluminum engines, and would thus deliver more power and better economy in a smaller platform. They didn’t work out because of durability problems – ceramics are too prone to fracturing. They’re still trying to come up with a suitable material, though. An allotrope of carbon called graphene shows a good deal of potential, for all kinds of things.
@Cruiser-You are flat out wrong.They didn’t require leaded gas to run.Unlike water cooled engines,the air cooled Corvairs were designed with hardened exhaust valve seat inserts and therefore did not require leaded gasoline.As a side note,the Corvair was replaced by the Camaro which was the competiton for the mustang and GM felt it did not want to have 2 vehicles in the same category competing against each other.This however,does not negate the superiority of the design of an air-cooled engine.
@IchtheosaurusRex -The Corvair engine,at the time,was the most technologically advanced engine produced.First to get 1 HP per cubic inch and the first production engine to hhave been turbo charged.I feel,had attention not been shifter from this design,that could have out paced today’s modern water-cooled engines and been closer to your example of efficiency than todays water-pumpers.
Air cooling affords too little temperature control. It is dependent upon speed, air temperature, and air conditions: wind speed, humidity.
Water cooling is thermostatically controlled and maintains a specific temperature. There are fewer temperature swings and fewer resultant expansion and contraction events. The engine can be optimized knowing the block temperature will be precisely maintained.
@Cruiser I think my husband’s older Porsche is air cooled and we use unleaded in it.
@lucillelucillelucille , just picking a nit here, but the 1957 Corvette “fuelie” achieved 1hp/cu in from a 283 CID cast-iron engine – normally aspirated, and it had a radiator.
The ceramic engine I mentioned would not use a liquid coolant. It would, however, be able to operate at temperatures far higher than what you could achieve with an iron or aluminum block without warping. I’m not saying the problems couldn’t be solved, but there have been lots of designs that have ended up on the scrap heap for a multitude of reasons. For example, GM abandoned multiple carburetor designs in 1966, except for the Corvette, for cost reasons that had nothing to do with engineering. Air cooling ended up on the scrap heap.
@josie -The Corvair came with either high or low compression engines.85 HP low-compression,high torque for trucks up to 185 HP turbo for the Corsa.Had this not been abandoned,who knows what we could have had?
@worriedguy -Corvairs were designed to run at 120 ambient temperature at full throttle non-stop! They were shielded and thermatically controlled in order to keep a constant steady temperature.Operating conditions did not matter;)
@lucillelucillelucille
The big hurdle for air cooled engines is achieving FEDERAL MANDATED emissions, VW bugs of the seventies could not meet the air emissions—no more air cooled bugs.
@Tropical_Willie It’s not that it couldn’t have been done and the ‘67—‘69 Corvairs had what was called the “smog engine”.Had it not been abandoned,it could have met any emissions standards.
@Tropical_Willie Didn’t the emission rules kill the big low compression V-8s in general, and not just the air cooled engines?
@lucillelucillelucille Bottom line as @Tropical_Willie and I both said it is/was all about the Federal emission standards. Air cooled just couldn’t cut it, end of story….
“With the increasing emphasis on low emissions, fuel efficiency, larger displacements and heat producing ancillaries; air-cooling was no longer an option. Air-cooled engines traditionally ran slightly rich to reduce combustion temperatures. Unfortunately, this both reduces fuel efficiency and increases hydrocarbon emissions. In addition, the cooling system of most modern cars has to cope not only with engine heat, but the heat generated by the air conditioning condenser and power steering and transmission fluids. These additional loads tip the balance well in favor of a liquid cooling system.”
@Cruiser -I don’t buy it.It could have been done.End of story. +6 for you.
@lucillelucillelucille I don’t disagree they couldn’t “do it” as you say because they did!! Just ran out of options to engineer it to the next level and compete cost and performance wise with the liquid cooled power plants that simply blew them away. Simple is not always better and we have made that our mantra of the modern age! I still have my ten speed I will never get rid of!
Anyway….GQ +5 ;)
This will probably get modded, but you two reaffirm my belief in intelligent life.
@Cruiser -Simple is always better.It was abandoned because it was too far advanced for the trends at the time.If it wins on Sunday,it sells on Monday
@lucillelucillelucille Absolutely and unequivocally untrue there although I wish it were true! If it were the case we would still have your air cooled beauties being produced along with your steam engines you so love and I would have my DOS operating system back!! Let’s have a beer and commiserate over this mess we now find our selves in! XD
Another +6 for your persistence! ;)
@Cruiser -You can’t get around it! There is air everywhere and is all I need to cool down my engine.While you sir,better pray you don’t lose your water—or your cool—;).Here’s +2,700 for your being wrong again!
Not that I know anything about this subject, but I’m a bit surprised no high performance computer builder has jumped in.
Air is horrible as a heat dissipater so you’d need to have a larger surface area to get rid of any heat if you wanted to increase the power or, I guess, anything that would generate more heat. In the computer world this means adding a huge heatsink covered in cooling fans. Wouldn’t there be a point where it wasn’t practical to increase the size of the engine, or add huge radical cooling fins, just to cool the engine down? And, of course, a larger engine would mean additional weight.
Anywho, just an additional question. And I think it’s great that you have a Corvair, the poor vilified thing.
@mrentropy That brings up another thought. The heat that is removed represents wasted energy. In computers it’s a by product of the electricity. In cars it’s wasted energy that could go towards propulsion. I’m just thinking this through.
@mrentropy -It is an aluminum engine with finned cast iron cylinders and is very efficient at dissipating heat with the fan and shroud system.It was vilified unjustly and is actually a very fascinating vehicle when analyzed objectively. :)
@lucillelucillelucille After reading your objective presentation of your information I will hop on my my air cooled ten speed and cloths pin playing cards to the wheel supports to get the same put-put superior feel of your little air cooled wonder. I’ll race ya!! ;)
bptbptbptbptbptbptbptbptbpt…. XD
@lucillelucillelucille It may be efficient as it is, but if it continued to evolve then I imagine that it would need to go through some changes. And I’m a fan of the Corvair and know that it was unjustly critiqued.
@Cruiser -I’ll put a 2200lb Corvair Corsa up against that aesthically challenged,60’s wanna be new Camaro you want so bad. You’ll be pedaling home on your tricycle! XD
@lucillelucillelucille You are on!! I will be at the bar ahead down the road waiting with a beer air cooling for you when you get there!! XD!
Just as an exercise in hypothetical questions, if you wanted a 500HP Corvair, what kind of changes would need to be made to the engine and body?
I owned a 1965 Corvair convertible. it was a sharp car that i ordered from the factory. if i am not mistaken, the biggest majority of the engine was made of aluminum. maybe, this is why the engine was just air-cooled.
@mrentropy -500 hp?Like a drag car? Are you trying to kill me? XD
I was thinking 500 HP would be cool!
@lucillelucillelucille No, not at all. And 500HP on a car isn’t all that rare anymore. I’m just wondering what it would take to get your flat 6 up to 500HP. Or even up to 400HP.
Like, would the aluminum hold up? Would the body need to be modified to allow more air flow to the engine bay? Stuff like that.
@Adirondackwannabe A 500HP Corvair would probably blow a lot of minds at the stop light.
@mrentropy The power to weight ratio would probably be up there with a sprint car. I don’t know if the frame could take it. It might not have enough traction to make that a major concern
@Adirondackwannabe Ooh, that’s right. The engine over the rear wheels is good, though, because all the weight will be pushed over those wheels. But you’ll need some big tires back there.
But… really, that’s all immaterial. The question is really one of scale. Would an air cooled engine be able to scale up and could it be done cost effectively and aesthetically effectively. I’m just kind of brainstorming here.
@mrentropy That’s kind of what lead me to ask my question about the radial engine, like a P-47
@Adirondackwannabe @mrentropy Porsche did it with this super charged custom built engine built out of aluminum, magnesium and titanium parts and couldn’t imagine the price tag on that power plant….
_“To reduce torsional stresses on the long 12-cylinder crankshaft, all takeoffs for power and ancillary drives were taken from the center of the crank. In 911 fashion, each cylinder had its own individual aluminum head. These were topped with a common camshaft carrier, one per bank. The dual overhead camshafts, four in all, were gear driven. Low weight, both in terms of the complete engine, and the rotating masses within, was a key priority. The crankcase was aluminum-magnesium alloy and the cam carriers and cam covers were magnesium. Cylinder barrels were aluminum with nikasil liners. The connecting rods, rod bolts, fan drive shaft, auxiliary and output shafts and other miscellaneous hardware were made of titanium. The fan shrouding, cooling fan and intake stacks were fiberglass. The cooling fan displaced up to 148 cubic meters of air per minute.
Like the 911, the 917 employed a dry sump oiling system. This one utilized no less than seven pumps. A triple unit in the sump provided pressure and scavenging of the front and rear of the crankcase, and four small pumps located at each end of the exhaust camshafts allowed for scavenging oil from the cylinder heads. The system held 30 litres of oil. Each cylinder had dual spark plugs, ignited by two seperate distributors. Fuel was supplied by Bosch mechanical fuel injection. The initial batch of 4.5 litre versions produced 520–580 hp at 8500 rpm, the turbocharged versions generated up to 1580 hp on full boost“_
@Cruiser So…. probably not cost effective? At least not to anyone wanting to buy one.
@mrentropy-People do modify Corvair engines to race,but I am not sure what they do to them.
@Cruiser-What a joke.That is just a restored race car that someone is selling for 2.2.
Corvair engines were not expensive to manufacture.
Welp, I didn’t find much on Corvair racing. Well, I found this which is the funniest thing I’ve read in weeks.
@Cruiser That’s a beaut, all right. But it is a restored race car so the price might be inflated a little bit.
@lucillelucillelucille It serves to illustrate that producing a fuel efficient air cooled engine that met Federal emissions standard AND provided horsepower to plow the modern highways AND be affordable just wasn’t doable and the water cooled just did it better!!! Do the research!! I did!! It’s all right there and you can see for yourself!! You now have your answer!!! ;)
I would think that smaller engines have a greater surface-area-to-volume ratio, volume being a varying term that includes the complexity of the entire engine, and that the same amount of air over two differently-sized and differently-“technologized” engines would give very different reflections in temperature control.
That’s a good question! My very first car was an old VW Beetle that had an air-cooled engine. It ran forever, drank hardly any gas, and was practically maintenance-free compared to today’s cars. I wish I had kept it :-(
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