Armchair theory - extreme cold air intake.

[Beer Jammer]

Hi all.

I was doing some sitting and thinking the other day. The quest for colder intake air seems to be a very worth while one, with CAI systems giving good gains in performance/response/powerband etc with the 1nz. :wink:
I know of the usual mods to acheive this. A cold air feed or position the filter to illiminate heat soak, the "throttle body bypass mod" to name but two.

Now for the armchair theory... :smile:.... if colder and more dense air makes the engine run more efficient, would there be a benefit to routing the air conditioner to feed into the air intake? :iono:
I know that the a/c saps power, but would routing its output to feed both the cabin and the engine air intake work to offset this reduction in power and make the engine give better mpg when you use a/c? perhaps then meaning that using a/c reduces mpg by 5% not 10%? :iono:

Unless the a/c unit is a very efficient one, I dont think this is a huge performace gainer, but how does the theory stand?

[Parmas]

This is one of those things that I thought of it during my build.

Although my theory was that to use the a/c only for the inlet and not also for the cabin. I never tried it and probably never will but I am almost sure the a/c sucks more power than it gives you for the "cooler air inlet". Also keep in mind that the engine bay temperature will actually effect the cool effect. IN The cabin there is no heat emission except your body and the sun but in the engine bay there is lot more heat that could effect the a/c thing.


I tell you, when an idea is worthy it costs ten and gives you twenty or more. This probably will cost you a lot of hassle and money for probably not reasonable gains to be worth to do it.

Probably if you make an external inlet at an exact horizontal with the street you will see more gains than this a/c since outside is 30C and inside engine bay is 60C or more but that's risky for water penetration.

Although keep in mind that Cooler doesn't mean 15C below!

[ddongbap]

Hi all.

I was doing some sitting and thinking the other day. The quest for colder intake air seems to be a very worth while one, with CAI systems giving good gains in performance/response/powerband etc with the 1nz. :wink:
I know of the usual mods to acheive this. A cold air feed or position the filter to illiminate heat soak, the "throttle body bypass mod" to name but two.

Now for the armchair theory... :smile:.... if colder and more dense air makes the engine run more efficient, would there be a benefit to routing the air conditioner to feed into the air intake? :iono:
I know that the a/c saps power, but would routing its output to feed both the cabin and the engine air intake work to offset this reduction in power and make the engine give better mpg when you use a/c? perhaps then meaning that using a/c reduces mpg by 5% not 10%? :iono:

Unless the a/c unit is a very efficient one, I dont think this is a huge performace gainer, but how does the theory stand?
Think, perpetual machine. Doesn't work.

[changchewsoon]

how about installing a meth kit?

[djct_watt]

The idea makes sense, but it would make no difference, and would end up reducing net efficiency. Let me explain to you why I am bursting your bubble.

1) The amount of CFM (cubic feet/minute) an air conditioner can move is insubstantial next to the amount of air an engine pulls in. It'd be like p***ing in the wind.

2) The gross inefficiency of an any and all air conditioners mean that it takes more power to run the air con than it gains by cooling the air. Simply put, you'd see more power simply by turning it off.

If it's cooler air you're looking for, then the traditional meth injection, nitrous, or other compressed gasses will substantially reduce temperatures. Also, intercooling works too, but really is only worth it on a FI type application.

[zachryboles]

how about installing a meth kit?

sorry im not getting my yaris hooked on smack :tongue:

[yarrr]

mmm perpetual cooling.

http://www.engineeringtoolbox.com/air-temperature-pressure-density-d_771.html

NA is the 0 psi column. Even if you change the temp 50 degrees the air gets less than 10% more dense. Then the MassAF reads the higher density and adjusts you back to stock power... lol

A meth kit is a good point. Even on supercharged yarii, the meth kit doesn't really add much hp if any just by cooling, it just prevents knock allowing you to pull more hp out with timing..

Put a battery powered fan and a frozen water bottle in front of the intake. Or move to alaska. I heard a yaris up there drives like a ferrari.

[Tamago]

sorry im not getting my yaris hooked on smack :tongue:

you don't know much about water/meth then do you ;)

and the 'gains' from installing meth/water on an otherwise stock car(no engine management, not forced induction) would be almost ZERO. if you can't advance the timing past stock parameters, you won't see any torque (power) gains from this 'cooler' charge of air.

[eTiMaGo]

There's always the DEI solution..

http://www.eugeneleafty.com/DEI/Nebraska%20GM%20Modern%20Muscle%20%20View%20topic% 20-%20Turbo%20Questions%20(pg%201)_files/mht2993(1).jpg

[cfeng]

Its not a perpetual machine. Think about it this way, if the ac cooled intake yaris runs out of gas will it keep on running?

However this is not an effective way of getting power out of a yaris. Also, even if air is entering the CAI at a low temperature, it is quite a lot warmer when it enters the cylinders. The temperature to be concerned about is that of the air as it mixes with the fuel.

[cfeng]

Also someone mentioned the efficiency of an air conditioner, the efficiency of a modern air conditioner is 250+%. Meaning that the air conditioner is able to move 2.5 times heat energy from the cabin of the car to the outside, per unit of energy consumed by the compressor.

[ddongbap]

You can't use the output of an engine to make power from itself.

[cfeng]

i'll think twice before i buy that supercharger. the theory was it was going to run off the engine to make more power.

[ddongbap]

i'll think twice before i buy that supercharger. the theory was it was going to run off the engine to make more power.

Lol. I said that wrong, and thus I got owned. hahaha oops.

Its not a theory btw. The You Tube has a video on it.

http://www.youtube.com/watch?v=Wh3ryyqtnG4

[cfeng]

haha, i saw the opportunity so i had to take it.

[ddongbap]

haha, i saw the opportunity so i had to take it.

Touche. I'm defeated where I'm defeated.

[djct_watt]

Also someone mentioned the efficiency of an air conditioner, the efficiency of a modern air conditioner is 250+%. Meaning that the air conditioner is able to move 2.5 times heat energy from the cabin of the car to the outside, per unit of energy consumed by the compressor.

I really don't understand what this is supposed to mean or its significance. It is contrary to the laws of thermodynamics, and ignores all physics. You can't create more energy than is initially supplied. It honestly sounds like sales jargon from the box of an AC unit.

[cfeng]

I'll try my best to explain this.

A turbo or supercharger system is adiabatic. It increases pressure to force more air into the engine.

The system described by beer jammer is technically another forced induction system, however instead of being adiabatic, it is isobaric, where pressure does not change since the air molecules are squeezed together by cooling.

The flaw with beer jammer's idea, which probably other people see, is that using an air conditioner as a forced induction system involves more imperfect energy transfers where energy is wasted. It employs an air conditioner which cannot surpass carnots predicted efficiency (lose about 20-30% here), then it would need some heat exchangers (20-50% loss, governed by newton's law of cooling). It would be much more efficient to use a turbo or a supercharger.

[djct_watt]

I'll try my best to explain this.

A turbo or supercharger system is adiabatic. It increases pressure to force more air into the engine.

The system described by beer jammer is technically another forced induction system, however instead of being adiabatic, it is isobaric, where pressure does not change since the air molecules are squeezed together by cooling.

The flaw with beer jammer's idea, which probably other people see, is that using an air conditioner as a forced induction system involves more imperfect energy transfers where energy is wasted. It employs an air conditioner which cannot surpass carnots predicted efficiency (lose about 20-30% here), then it would need some heat exchangers (20-50% loss, governed by newton's law of cooling). It would be much more efficient to use a turbo or a supercharger.

So well put, it's near impossible to add to it. But considering the HUGE inefficiencies of using an A/C, I'm fairly certain that the cooling effect would still result in a NET LOSS of power. It'd be like having a cigarette lighter powered coffee machine boil water to power a steam generator that is connected to the crankshaft.

[cfeng]

if not designed properly, there could be a net loss of power. even if designed well, the car would operate less efficiently, more fuel would be consumed per unit of power.

[eTiMaGo]

So well put, it's near impossible to add to it. But considering the HUGE inefficiencies of using an A/C, I'm fairly certain that the cooling effect would still result in a NET LOSS of power. It'd be like having a cigarette lighter powered coffee machine boil water to power a steam generator that is connected to the crankshaft.

I don't think the OP realizes just how much power the AC saps. you could try this, start the car, AC off, then start driving at part throttle in second gear, then turn on the AC and feel how much the car lurches...

But, upon thinking about this more, there is *one* way in which this idea could work. Suppose in a normal driving scenario, you are not at full throttle all the time, sometimes you are slowing down, sometimes you are just cruising at part throttle. These would be the times when the AC compressor is engaged and generating a charge cool air, but this cool air does not go into the intake, there is a valve to prevent this. But, once you go to full throttle, the AC is disconnected by the pulley clutch, the cold air valve mentioned above is opened, so you get a small charge of cooled air into the intake, And, whatever air follows is still cooled to a certain amount by the still-cold evaporator... It would be a very short-term effect, but it *could* work. I sorta experimented with the same thing in an effort to use the AC without wasting fuel, only engaging it when I am in DFCO. It works, but not very efficient :p

[djct_watt]

^ true. But then again, the gains (if any) would be VERY minimal with an NA engine.

[eTiMaGo]

yeah you obviously can't expect a NOS-like effect!

[djct_watt]

AC just kicked in yo!!!!

[Beer Jammer]

Wow! I guess I stirred up a load of controvesy here.. :wink:

Anyway, as stated in the OP, this is 'Armchair Theory' and I have no intention of setting this up in any way or think that doing this would make my yaris super quick. The basis of this post is that 'Colder air in the intake allows the engine to perform better.' which is a very universally agreed concept and why products like the K&N Typhoon are highly recommended. My fervent mind just thought about this in a more extreme way.:eek:

I am agreeing with everyone here in that feeding the intake with a/c conditioned air will not increase performance and part of my OP stated:

I know that the a/c saps power, but would routing its output to feed both the cabin and the engine air intake work to offset this reduction in power and make the engine give better mpg when you use a/c

So the theory is that on a hot day you are using your a/c anyway, so why not channel some to the engine? It will never make the yaris perform as good as turning the a/c off, but it may reduce the difference, so the big boys like Mercedes, GM, Toyota and the rest could have the time and money develop this to a way to increase the efficiency of their a/c systems and be more 'green' ?

[djct_watt]

It wouldn't do much based on the volume of cooler air supplied. The net result will be a less cool cabin with a negligible difference in economy.

[jcemitte]

what if instead of routing direct air from the a/c directly into the intake, what if you took the freon from the a/c system and made some kind of housing that has the freon cooling the air flowing through it effectivly cooling the air? would the motor compensate for the colder air?

i had a armchair theory about this once but a little different.

since basically a turbo or supercharger increases the psi in the intake to force air in the motor. ive heard off off roaders using there a/c compressor for on board air, so why couldnt you plumb that into the intake. or if its cheaper whynot put a little compressed air tank in your trunk and just use it like a shot of nos?

both not very plausible theories and at that point just buy a turbo or some nos lol.

[cfeng]

One interesting point is that many engineering applications try to recycle heat into engines using regenerators for higher efficiency, not cool their engines. This theory described in this thread works the opposite, however tries to achieve more power.

Rankine and brayton cycles involving turbines are made more efficient by heating the working gas.
http://www.energysolutionscenter.org/distgen/Tutorial/CombTurbine.htm

Some one might want to start a thread of another arm chair theory of achieving higher efficiency by preheating air and fuel for higher efficiency. Others can knock it down saying it causes detonation.

[PHXDEMON]

The idea makes sense, but it would make no difference, and would end up reducing net efficiency. Let me explain to you why I am bursting your bubble.

1) The amount of CFM (cubic feet/minute) an air conditioner can move is insubstantial next to the amount of air an engine pulls in. It'd be like p***ing in the wind.

2) The gross inefficiency of an any and all air conditioners mean that it takes more power to run the air con than it gains by cooling the air. Simply put, you'd see more power simply by turning it off.

If it's cooler air you're looking for, then the traditional meth injection, nitrous, or other compressed gasses will substantially reduce temperatures. Also, intercooling works too, but really is only worth it on a FI type application.

/thread

[cfeng]

In no way will this theory give you more efficiency.

However the two points above need to be reconsidered. Think of having a very inefficient supercharger on the yaris, you will have more power but with a loss of efficiency.

[TEHxFALLEN V1.2]

Here's my theory:

Connecting a very sophisticated box that holds ice cubes in the "ice box" chamber would cool down temperatures in the stock airbox. Check out the dyno chart.

[djct_watt]

The crudeness of that picture just makes it THAT much more awesome.

[cfeng]

HAHAHAHAHAAA

[cali yaris]

LOL, good one.

People DO ice down the intakes when trying to get an "extra special" dyno pull.

Speaking of which, has anyone done back to back dyno pulls with the AC off and on?
Do we actually know in measurable terms what effect it has on the motor's power/efficiency?

This whole thread is based on a premise that the AC's single pulley makes a really big difference. I'd like to know what hard data supports that. (And yes, I can feel it with my butt just like everyone else).

[Y@R15]

this is also true the A/C is only effiecent in the 60+MPH range. in this speed having the windows down would kill your MPG as well. what your talking about it trying to gain by saving. you cant gain power and MPG when you have the A/C on. now a way to i think see a little less fuel consuption would be to use an aftermarket A/C pulley. like the crank and altinator pulleys. other then that. your not gonna see anything by useing the A/C air... i think i confused myself.

[Yoda]

LOL, good one.

People DO ice down the intakes when trying to get an "extra special" dyno pull.

Speaking of which, has anyone done back to back dyno pulls with the AC off and on?
Do we actually know in measurable terms what effect it has on the motor's power/efficiency?

This whole thread is based on a premise that the AC's single pulley makes a really big difference. I'd like to know what hard data supports that. (And yes, I can feel it with my butt just like everyone else).

I did this last year but I can't seem to find the dyno graph. It was about 2.5 whp lost as I remember. I did the first run with the a/c on not knowing it was. Then turned it off for the second run and showed gains.

[cfeng]

if someone tells me the mass flow rate of the air, or mass flow rate of the fuel, that passes through the engine, i can tell you how much more air can be consumed by an air conditioner operating 1.5-2 kw, cooling about 4-5 kw. i can approximate what power gains may be achieved.

correction to previous post, this would not be considered a forced induction at all, since pressure does not change due to cooling.

[Yarisduder]

LOL, good one.

People DO ice down the intakes when trying to get an "extra special" dyno pull.

Speaking of which, has anyone done back to back dyno pulls with the AC off and on?
Do we actually know in measurable terms what effect it has on the motor's power/efficiency?

This whole thread is based on a premise that the AC's single pulley makes a really big difference. I'd like to know what hard data supports that. (And yes, I can feel it with my butt just like everyone else).


+1, I too would love to see the quantified data instead of the "hear say" and "I feels"

I had thought of sticking a halogen light bulb in the intake to increase inlet temperatures for better fuel efficiency, but I like the ice box idea better :headbang:

[djct_watt]

Just do a MPG check, one with AC always on and one without. Last time I did it, I saw almost a 5% reduction in MPG, so it should be close to the same in power draw. Don't forget that small numbers are usually within margin of error for dyno pulls.

Here's a link to a discussion about HP draw of an AC unit.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1944982

[cali yaris]

I saw almost a 5% reduction in MPG, so it should be close to the same in power draw.

You're saying it's a 1:1 proportion of MPG to power? That doesn't sound right at all.

[djct_watt]

You're saying it's a 1:1 proportion of MPG to power? That doesn't sound right at all.

I mis-phrased, lol. Definitely not 1:1.