Warm Air Intake?

I just heard of something called a “Warm Air Intake” today. It is as it sounds: an air intake system designed to pull warm air from the engine, heater core, and/or exhaust manifold(s). Some people seem to think that these somehow improve fuel economy. Has anyone else heard of these? Am I the only one looking at the science behind this, and ending up completely and utterly baffled? It seems very backwards from almost everything I know.

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Comments

Anonymous

hot air = more space between molecules less fuel possibly needed to keep it form running lean (need verification) but less HP after all that?! got me knackerd how this would help

12/18/2015 - 04:07 |
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Michael R. T. Jensen

In reply to by Anonymous (not verified)

It would make it run rich, which should negatively affect gas mileage.

12/18/2015 - 05:06 |
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Gary

I usually joke about it because I have a open pod filter that came on my car. But I don’t see why that would increase fuel economy. But I haven’t actually thought about it

12/18/2015 - 04:24 |
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Michael R. T. Jensen

In reply to by Gary

It would warm the fuel, which would make it combust faster. However, the warmer air would mean less air actually getting in. Seems mostly backwards to me.

12/18/2015 - 05:07 |
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Aviraj Singh

I have heard of EGR ( exhaust gas recirculation) being used in cars to improve efficiency.

12/18/2015 - 04:47 |
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EGR is common, but it doesn’t improve efficiency. Quite the opposite, actually: it recirculates nitrogen back into the intake manifold, as nitrogen doesn’t combust. It reduces the heat the engine gives off, and spouts less emissions.

12/18/2015 - 05:13 |
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cherniydiavel

my volvo has a valve in front of the air filter which is controlled by the water thermostat. when the car is warm, it is a cold air intake. when the car is cold, it switches to “hot air intake” mode, which draws air directly from near the exhaust manifold. in cold weather, this helps the engine warm up faster, which wastes less fuel because it doesn’t have to run rich as long as it would have without the hot air.

12/18/2015 - 04:49 |
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That makes sense, but having it suck in warm air in the middle of Summer, even after hours on the highway? Seems like a bad idea to me.

12/18/2015 - 05:08 |
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Petrolheart Garage

It’s a hypermiler trick, together with running the engine lean, and adjusting the intake valve closing to r*tard it.

12/18/2015 - 06:59 |
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But that means that to get going, the engine needs to run at an even higher RPM.

12/18/2015 - 13:32 |
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Anonymous

Some older cars with carburetors(vw golf mk2 for example) have it from factory - it’s needed for winter driving, so that the carb won’t freeze.

12/18/2015 - 16:36 |
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Michael R. T. Jensen

In reply to by Anonymous (not verified)

I’ve seen similar things on old carb cars, but not a full time WAI.

12/18/2015 - 19:46 |
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