on a car, can i hook the ac output up to the intake for more horsepower?

Question

or possibly hook it up to my intake plenum to cool the intake charge? has anyone done this ever? wouldnt it work?why wouldnt it? wouldnt it be similar to a "poor man's nitrous system"?

Answer 1

I saw an engineering journal article about 20 years ago that examined cooling the inlet of natural-gas, power-generating turbines. As a way to increase power on a hot day (when electrical consumption is high).

It was only minimally viable. Like 5% more power or so. Even though the air could be made a fair bit cooler, the power needed to run the refridgeration eliminated much of the power boost. But it would require a lot of equipment for only 5%. Versus just installing an additional turbine - that gives 100% more power.

The obvious solution for the power grid, in my mind, would be to cool a large and deep section of ground. And then pull air through that soil when cool air was needed to increase the power output.

Similarily, the scheme someone described above in which a mass is pre-cooled for a short blast of cool air to the engine intake is viable. And can be done on the cheap.

For instance: Put a garbage can in the back seat and fill it with ice from a hotel with an ice machine. Put a 12-volt water pump in the bottom to pump the melt water. Run the melt water through a large heater core worked into the intake plenum.

30 gallons of ice cubes, 60% solid, would give about 20,000 BTU of cooling before it all melted. That would take almost 2 hours to melt with 250 cfm (4-cylinder engine rev'ing faster) being cooled from 100F to 60F.

Going from 560 Rankine to 520R would increase the air density by 8%. (560/520=1.08)

Not quite a nitrous system boost. But something. Any cooling scheme would work best on a very hot day (relative to standard cars).

Consider that the more you lower the temps, the more likely you will get icing in your heat (cooling) exchanger. Not an issue for short burst, but an intake restricted but ice will really drop your power.

How about adding O2? It will come off the tank cold and, if you've got an O2 sensor, fuel fuel and power will increase. Caveat: lots of bad things can happen to people who play with pure oxygen. We fried 3 astronauts that way.

-David in Alaska

Answer 2

Technically...it could be done, but i really don't think the time, effort, and money would be worth it. It wouldn't turn it into a poor man's natrous system..more like a poor mans intercooler system. what you're hoping to do is cool down the air mixing with the gas in your car in an attempt to maximize the ammount of air and gas fireing in your pistons. It's not going to be worth doing...and i'll tell you why. if you jerryrig your ac to your air imput, the engine heat is going to heat up the air as it's mixing with the gas. you want to cool the air down after the gas and air has been mixed, not before. That's what an intercooler is for. if you don't have a supercharger or better yet...a turbocharger on your car, you really don't need an intercooler. if you put one on your car that didn't have a super or turbo on it...would it increase your horse power...yes....most likely, but you would only notice a small change in horsepower. it would be a better idea than the airconditioner idea though....would probably end up costing you about the same in the long run....but the difference would be the intercooler would work better than the ac because it cools the air after mixture as opposed to before like the ac would.....not to mention that if you did that, you would most likely not be able to use your ac inside your car when it was hot.....AND you would have to run your ac at all times when your car was on or else your airflow to your intake would be restricted.

Answer 3

It's not even worth trying. It's true that cool air entering your engine should give you more horsepower due to the fact that cool air is more dense meaning more oxygen. But, driving your a/c compressor takes horsepower from your engine. In other words, you take horsepower from your engine to try to increase you power output. The problem is that you don't get that much more horsepower by cooling the intake air. It would not compensate the energy necessary to drive the compressor. The a/c compressor can take as much as 5-6 horsepower and cool air would give you only 2 maybe 3 hp. So in total, it would result in a 3 to 4 hp loss. Take into consideration that driving auxilary equipement such as a/c, alternator or power steering introduce more friction loss. Using an intercooler to cool the intake air would be much more efficient because it doesn't use the engine power to cool this air. Furthermore, taking off your a/c compressor would result in power gain because the engine doesn't have to rotate this equipment anymore.

Answer 4

A while back 10 or 15 years, I seen a concept car may have been a Mustang that used a modified AC system to cool a 5 gallon tank of coolant to around -70°F. When you wanted a boost that super cooled coolant was pumped thru an intercooler and for something like 30 seconds you could get like 50 more HP. It would then take 10 or 20 minutes to chill the tank back down.
____________
Andre' B.

Answer 5

the power added by having cooler and more dense intake air is less than the power used to cool that air by the AC

Answer 6

Any horse power gain would be robbed from the draw of the compressor. Plus there are cold air kits for cars.

Answer 7

If you want the power, turn the AC OFF.....

Answer 8

no!