Interior Air Intake
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Interior Air Intake
While driving today, I noticed how hot it was (about 115F) and thought about how much hot air the car must be sucking in. Then I thought about something, probably a stupid idea which won't really work but... Has anyone ever done a mod where by the flip of a switch, instead of intaking air from "outside" the vents could switch to the "interior" of the car and suck in cool air conditioned air? Would this work?
Edit: Another thing, it's going to be 120F this Wednesday the 4th, any precautions I should take with my W124?
Edit: Another thing, it's going to be 120F this Wednesday the 4th, any precautions I should take with my W124?
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From: Australia
300E
lol man that sounds like perpetual motion, the engine drives the A/C which keeps the air colder which produces more power which drives the A/C harder.
But I guess it could work, if you cooled the interior down and then switched off the A/C you could get a couple seconds of extra power the only thing is a 3L engine at max rpm sucks in about 140L of air per second
But I guess it could work, if you cooled the interior down and then switched off the A/C you could get a couple seconds of extra power the only thing is a 3L engine at max rpm sucks in about 140L of air per second
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
While driving today, I noticed how hot it was (about 115F) and thought about how much hot air the car must be sucking in. Then I thought about something, probably a stupid idea which won't really work but... Has anyone ever done a mod where by the flip of a switch, instead of intaking air from "outside" the vents could switch to the "interior" of the car and suck in cool air conditioned air? Would this work?
Edit: Another thing, it's going to be 120F this Wednesday the 4th, any precautions I should take with my W124?
Edit: Another thing, it's going to be 120F this Wednesday the 4th, any precautions I should take with my W124?
It has a small red indicator light on the bottom of the switch and an engraving that looks like arrows going in a circle.
Used to exclude intake of outside air and recirculate conditioned interior air
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You should have a "recirculation switch" mounted in the row above your temp control unit.
It has a small red indicator light on the bottom of the switch and an engraving that looks like arrows going in a circle.
Used to exclude intake of outside air and recirculate conditioned interior air
It has a small red indicator light on the bottom of the switch and an engraving that looks like arrows going in a circle.
Used to exclude intake of outside air and recirculate conditioned interior air
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E-ZGO 53hp., 1999 E 430 sport, 2004 E 55, 2008 Tahoe LTZ on 24"s
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Engineering
This is an interesting thread, and touches on my area of expertise.
OK, assume your engine is taking in 200 CFM of air. That air, if being drawn from the cabin, will be replaced with hot outside air. Let's say you want to maintain 72 Degrees in the cabin and it's 100 degrees outside. That's a 28 degree Delta T. I estimate that the capacity of the AC system in the car will need to increase by 22% to handle the additional load, and that assumes a dry climate. (I would hope it's dry if it's going to be 120 Deg. ) The additional energy used by the AC system will negate any benefit of having cooler intake air.
The verdict: You would get the same benefit by keeping your interior at a warmer temperature, thus causing less of the energy developed by the engine to be used for removing heat from the cabin. So, save yourself some work and roll the temp knob up another 5 degrees.
OK, assume your engine is taking in 200 CFM of air. That air, if being drawn from the cabin, will be replaced with hot outside air. Let's say you want to maintain 72 Degrees in the cabin and it's 100 degrees outside. That's a 28 degree Delta T. I estimate that the capacity of the AC system in the car will need to increase by 22% to handle the additional load, and that assumes a dry climate. (I would hope it's dry if it's going to be 120 Deg.
) The additional energy used by the AC system will negate any benefit of having cooler intake air.The verdict: You would get the same benefit by keeping your interior at a warmer temperature, thus causing less of the energy developed by the engine to be used for removing heat from the cabin. So, save yourself some work and roll the temp knob up another 5 degrees.
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From: Australia
300E
. I've herd of some race drivers turning up the heater in their car to dissipate more heat from the engine.
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I am not an expert, for experts are perfect and are never wrong about anything in their fields. If you don't like what I have to say then by all means have a good laugh and move on.
....not an expert, eh?
just kidding man. what is your profession though?
....not an expert, eh?
just kidding man. what is your profession though?
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Hmmm, I guess I was kind of forgetting the engine doesn't suck in such small amounts of air, lol. Also yes, thank goodness, it is dry here hah. I just can't wait for winter again, ugh, back to some nice driving 
hah. I just can't wait for winter again, ugh, back to some nice driving
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From: Melbourne
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hint!
That is true, if you thermostat ever fails your car is heating up you don’t know what to do just turn on heating to the max and fan to the max it will take down temp. Law of physics energy is never lost just converted from one state to the other
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
I added that "not an expert" disclaimer for when I say something stupid because of my lack of experience with these strange and wonderful cars. I have a lot of experience with cars in general, but sometimes the W124 throws me for a loop!
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people seem to think that only cold air is good for the engine. incorrect. warm air has molecules more spread apart and more "active" (for lack of a better word) and they being already energised, are easier to spark than cold ones that are bonded together more tightly.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
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88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
people seem to think that only cold air is good for the engine. incorrect. warm air has molecules more spread apart and more "active" (for lack of a better word) and they being already energised, are easier to spark than cold ones that are bonded together more tightly.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
Meaning that per volume, cold air contains more molecules of oxygen.
The more oxygen molecules you can get into the cylinders the better.
Because more oxygen means more of an "explosion" when the air/fuel mixture is ignited.
P.S.
Isn't this the theory that applies to cold air intakes and intercoolers ???
Last edited by RBYCC; Jul 4, 2007 at 08:13 AM.
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
people seem to think that only cold air is good for the engine. incorrect. warm air has molecules more spread apart and more "active" (for lack of a better word) and they being already energised, are easier to spark than cold ones that are bonded together more tightly.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
this of course doenst matter in modern cars with fuel injection and electronic ignition. but take a look at some old cars that have the intake and exhaust manifold on the same side. an 1960s mercedes 250 for example. each intake was positioned next to an exhaust manifold, to warm the intake charge so it would "spark" easier. i guess i just dated myself a bit there.
im not an expert, but i did stay at a holiday in once.
On many domestic vehicles, there was a damper that directed warm air from the exhaust manifold to warm the intake air when the engine was cold. More sophisticated Japanese cars used hot water to circulate around the intake just below the throttle plate. The reason for this was to prevent ice from forming around the throttle plate in cool, humid weather which would cause poor idle, or no idle. They do the same thing in small aircraft. On these vehicles where I've seen this, there is always a thermostat that disables this feature when the intake warms up to a certain temperature. I'm not sure if the Mercedes was something like this, or completely different.
It makes sense what you say about warm air having more active molecules. I do know that on a cool, crisp morning around 65 degrees, my car is much more powerful than on a 90 degree day with high humidity. I wonder why the difference?
