a/c intake cooling

[coos]

I have been toying with this for a while. While the a/c is running, everyone knows that the car loses horsepower. What i want to try and do is compensate for this lost of horsepower, by using that a/c to cool the intake charge. What I was thinking was running the low side a/c lines through the upper intercooler piping thus during a/c operations lowering the air temp, thus raiseing the density of the air= more horsepower. And it will only happen during a/c operation so during racing there will be no effect because the a/c is off. What do you guy's think?

 

[Defiant]

Not enough cooling there to matter. If you were to put the evaporator in front of the IC, or run the intake air across the evaporator, it still wouldn't make enough difference to make up for the load of the compressor.

I'd ballpark a guess at a 6% gain, versus a 14% power loss, because percentages are always bulk wrap.

 

[pneumo]

OK, so how about you weld a box around the stock IC and plug the AC lines into it. That way you have refrigerant flowing around the IC core. You could make the box oversized so there is enough cold refrigerant to last for a 1/4 mile pass with the AC compressor off. Just turn on the AC on the return lane and staging lane to recharge the system.

 

[Defiant]

Noble in concept, but folly in practice. The amount of cooling we like -dropping a small volume (250 cubic feet?) of cabin air from 150° to 75° doesn't compare to cooling the turbocharger's multiple-thousand cubic feet/minute of air from 220° to 175°. You'll do much better with water-spraying the IC, and much, much better with water injection.

 

[coos]

This is not for any kind of horsepower gain as far as tracking the car. It just for a daily driver application. Well the low side lines are around 35 to 40 degree's on a properly operating a/c system. So if the lines enter at the throttle body bend and exit near the intercooler, that's about 2 feet of 1 inch 30 degree pipe running with the compressed air. But, I am unsure that there will be a difference felt, just one of my theories i have been toying with.

 

[pneumo]

In theory it sounds good. The big question would be, how much would it help? You're talking about improving performance when driving normally on the street with the AC on. That's not the kind of situation where you need to squeeze every little bit of power out of the engine. Besides, if you did run the AC line through the UICP it would warm the AC line, and you'd have to turn up the AC, which would make the engine work harder to power the AC. round and round.
This kind of stuff is fun to think about, but when it comes time to actually do it you need to step back and ask, is it really worth it?

Defiant, to be factually acurate, our cars don't flow "multiple thousand of cubic feet/minute" it's more like 450 cfm for a 14b turbo at max, 505 cfm for a 16G, 650 cfm for a 20G etc. and much less at part throttle cruising.

 

[Defiant]

Originally posted by pneumo
Defiant, to be factually acurate, our cars don't flow "multiple thousand of cubic feet/minute" it's more like 450 cfm for a 14b turbo at max, 505 cfm for a 16G, 650 cfm for a 20G etc. and much less at part throttle cruising.

I was wondering about that- I was just multiplying 120ci X 4000 rpm /1728 and jeeze I hate math in my head.... thanks for the correction, I was wondering what the hell I was doing.

 

[coos]

Originally posted by pneumo
Besides, if you did run the AC line through the UICP it would warm the AC line, and you'd have to turn up the AC, which would make the engine work harder to power the AC.

Accually when the a/c is on no matter how high it is, it is putting the same load on the car. The only difference is the blower motor speed. And out side ambent temp on the low side lines is good after the evaporator, on its way to the condensor would make the a/c run more efficently because on the low side you have low pressure low temp liquid, so if you heat up the low side before the condesor you can (A.) get more efficentcy out of the condensor, or (B.) use a smaller condesor because it dose not have to work as hard changing the state from a liquid to a gas. besides if the pipe is say 2 feet long running at 34 degrees you don't think this will make any difference. What is the difference of running a near freezing pipe and shooting NOS on the intercooler to cool the charge.

 

[LaserRST]

This is a noble effort! i have thought of it too. Fact of the matter is that the load depends on the efficiency of the condensor. If the condensor stays warm like on a hot day and there isnt enough line to cool, the load will actually increase on the compressor (depending on the type of compressor used) because it will have to compress the freon to points of up to 300+ psi. If you can keep the condensor ice cold than the load will be closer to 60 psi on the high side. On our cars i believe it turns itself on and off depending on the demand, most imports do this. The evaporator can actually reach temps of 2 deg F. There is a load of science here for instance the amount of freon that needs to be in a system like that. What you will set your low side to vs where your efficiency point on your high side will be. If liquid freon enters your compressor it will ruin it. Also as mentioned before the gains need to be measured. With the amount of effort your talking about, water injection, a larger IC, and propane injection will help you increase your boost levels saying you have a turbo that can support the increased potential air flow. A freezing cold intake pipe is ideal, but will it cool enough of the air when it flows 500 cubic feet per minuite? Hmm... more to chew on...

 

[coos]

well laser, accually there are a few flaws in your coments. On all a/c systems the high side will run at 200 to 250 psi and the condensors job is to change the freon from a low pressure(50 psi) low temp (32-35 degrees) LIQUID to a high pressure(200-250psi) high temp (90-120 degrees) GAS. The job of the condensor is not to cool the freon but to raise the temp. Freon boils somewhere around -35 degrees, R-12 is lower then r-134 but they are around this temp. The evaporator also does not get to 2 degrees, there is a theromsate that turns off the compressor when the evaporator gets to 32 degrees to prevent ice from forming on the evaporator. Right

 

[LaserRST]

Actually the high side is to change the coolant from gas to liquid form, and yes it might not need to be at 300 psi. On a hot day though it will rely more on pressure and altitude than ambient temp to "condense" the gas to liquid. Most a/c systems run at 32 deg to prevent icing on the pressure valve which can block the system entirely, but a VIR (valves in reciever) system can reach much lower temps because it no longer relys on the slow reacting capillary tube. Ideal for R-134a. The low side can range from 10 - 70 psi depending on the system and ambient temp the lower the low side is the colder the system gets... of course depending on how efficient the system is. You have the right idea... but got it kinda backwards, its gas cold, liquid hot.

 

[coos]

You know what i did get it backwards, but you kinda of did too.. This a/c stuff is confusing sometimes hahahahaha. The refrigerant does enter as a gas but it is a high temp, high pressure gas. The heat is then dissapated from the refrigerant as it passes through the condesor tubes by the air flowing through the condenser fins. The refrigerant then condenses into a high pressure high temp liquid. (your right, just not the gas cold liquid hot) Because the refrigerant is both states on the low and high side.

I was also wrong talking about the evaporator, the low side out of the evaporator is YOUR RIGHT (laserRST) a low temp, low pressure gas. BUT the heat on the lines if running in the hot UIP makes no differance to the performance of the condenser because the low side lines run into the compressor first, where it is heated anyway and trasfered to a high side gas. so it is just going to be heated anyway.

 

[CrazyGSX]

has anyone ever used the A/C system for the intake cooler on are cars?

 

[wret]

It wouldn't work. It takes energy to make "cool." You would use more energy than what you gained.

 

[CrazyGSX]

i think they would work ok. i have seen kit. and they are not for max hp

more just to cool well to get the job done, itf it was for a 3/4 ton diesal tuck pulling something.

 

[Boosted98gsx]

No, it wont work okay. You will suck down more power than you will make with this mod PERIOD. There is no argument against this. You could get it to work, but you'd be better off just making a pipe to stick your filter in your fender well.

 

[wret]

It would be the equivalent of leaving your refrigerator open to cool your kitchen.

 

[CrazyGSX]

i didnt know man. i just seen it years ago


http://www.coolflow.com/fuel.html this s cooler.

 

[wret]

That's different. Energy is used (from A/C or other source) to cool oil, not to make power. You can't pick yourself up by the beltloops and you can't blow your own sails.

 

[Boosted98gsx]

You can't pick yourself up by the beltloops and you can't blow your own sails.

Good metaphors.

 

[thekellbeast]

Corky Bell talks about this in Maximum Boost. To repeat everyone else, and Mr. Bell, I'll say that the A/C draws more power than you gain from cooling.

Now here's my idea for it. Run a water cooled setup that uses the A/C to chill the resevoir when you're stopped.

 

[Boosted98gsx]

Now here's my idea for it. Run a water cooled setup that uses the A/C to chill the resevoir when you're stopped.

That is a good idea.

 

[CrazyGSX]

like on track day. you have you plug the cooling pack into the car for lite wight

 

[Defiant]

has anyone ever used the A/C system for the intake cooler on are cars?

No, and here's why.

 

[boosted86]

ok, well i have been battling high intake temps for a while now,and i finally got them in check(within 5* of ambient temp) but the only problem is that i live in south florida and in summer ambient temps are in the mid to low 90's! so no matter what i do im still getting my timing retarded do to high temps.

today i was was going to the beach, and i got in my girlfriends car, and the A/c was blasting!(freezing)...i sad to myself"what if this cold ass air couild be injected into the motor?" i started to think about it realized that it could be done! bring temps way way bellow ambient temp, and cooling the intake charge tremendously! acting like a gased methanol if you will.

I figured, make a hole in the ac vents under the dash, route some a/c piping(or equivalent) to the the intake funnel( mines in my fender...cai) and have it dumped either pointing at or in the air filter.

the only down fall i see, would be that you would have to have the a/c on while doing pulls, but for people in south Florida,Texas,Arizona etc. we have are A/C's on the whole time, so why not put it to good use.

What do you guys think?....is it feasible?
i think people could see some really good results? looking for some feedback, thanks.