farinj

Just my 2 cents. (I am actually an HVAC engineer licensed in NJ DE and MD.)

BTUH (Cooling Capacity) = CFM (mass flow rate in cubic feet/minuite) x 1.08 (constant) x delta T (change in temperature).

So if you do want to test this correctly you must do the following:

Buy parts to insulate.

Prior to installing parts record the following:
Record Cabin Temp, Record discharge temp (temp of air from vent), Record Outside air temp, and you want to do all of this after the engine is warm. Don't even turn the A/C on until the engine is warm. Use the recirculation mode and a specific fan speed say 3. Take readings every 30 seconds of both the cabin and the discharge for about 3 minites.

BTUH = (Cabin Temp - Discharge Temp) x 1.08 x CFM (who cares it's the same in both tests)

Insulate the pipe.

Then wait unit the cabin temp is back to where it was previously and take tests again just like you did before. Assuming the Outside air temp. hasn't changed in the 20 minutes it took to insulate.

The assumption is that the fan setting will produce the same CFM (mass flow rate) and the only thing that will change will be the cooling capacity BTUH of the compressor (actually the efficiency of the compressor).

Personally my A/C seems to work fine but the car seams to hold heat after it has been sitting in the sun all day. The $9 sun shades I bought at Wall Mart has made a dramatic improvement on that.

I like the idea of adding some insulation below the center consol I may have to give that a try.

dwynne

Actually, they normally insulate the lines to prevent condensation from forming (and dripping) on the suction line and prevent damage/injuries from the hot high side line. Also the lines in a home install can be many, many times longer than the ones found in an automobile. Under your hood, there would normally be no danger that someone would touch a hot line and the condensation on a cold line will quickly dissipate.

Again, the line folks feel under the hood that is COLD is the line coming FROM the interior of the car. This is not a chilled water system - it does not cool the interior by running a cold liquid into the car. It sends in compressed refridgerant (in liquid state) and that evaporating back into a gas is what allows your car to cool. So insulating the "cold line" is after the heat exhange has taken place so I would think little would be gained. The only advantage would be slightly cooler refridgerant presented to the compressor and would not have a dramatic effect on cooling the car. If you are going to insulate I would do both lines - to prevent the "hot pipe" from picking up more heat from the engine compartment BEFORE it enters the cabin on the car. I would think insulating THAT PIPE would have more effect than isulating the line that is coming FROM the cabin.

In any case, it is inexpensive to do and not much work and the placebo effect (if nothing else) will make you FEEL like the AC is working better

Dennis

RX8Carnage

I found this wondering the web at night it looks easy have not done it myself but planning on it
http://www.hi-impact.org/ryang/modif...8_console.html

Muthafodder

This could go somewhere.....

I want to see someone put this heatshield stuff aroung all of the plastic tues that distribute the air into the car....much like you see on central heat and air in housing....probably would have a bad effect in winter though when you want hot air.

This thread is pretty heated......

Vasichko

iTrader: (1)

Finally got some time off from work, sitting at home bored so I decided to give it a try.

I had some Thermo Tec wrap here already.

Living in Dallas, TX, it is 101 right now. I took it for a drive to get the zip ties, just took it for a spin for about 15 minutes. I have measured the air temp at 9 degrees cooler.

Of course there may be some error in my methods, couldnt find my temp gun so I had to use a thermometer and stick it as far as I could in the center vent.

Speedtoys

Not a bad idea, just that the volume of air back there is pretty small, not like under a house or in an attic where theres a TON of surface area on the plumbing and tons of very warm summer air to steal it.

GatoEnFuego

Heat in a vehicle has nothing to do with the A/C lines...

I have just done this "mod" as living in AZ the summers are brutal, 111 today. I can't say it's a definate "oh my god it's soooo cold" result, but the good ol' placebo effect does tell me it's a bit better. $2 for the foam wrap (Home Depot Motorsports FTW), another $3 for metal tape (look next to the dryer vents) and 10 minutes it's probably worth the effort and would do it again.

ken-x8

Maybe not, but getting it out does depend on the lines.

IMHO, insulating the low line would help. The AC is a closed system that pumps heat out of the inside of the car and dumps it outside. Add heat anywhere to the system, and it's that much less heat it can carry from inside. Since heat flows from hot to cold, and contact area matters, insulating the large-diameter cold return line will keep under-hood heat from entering the system.

Thanks for the tip! I was thinking Home Depot myself, but not quite sure where to look.

VA isn't AZ - not by a long shot - but my AC was right at the limit during some of the 98 - 99 degree days we had here. Okay when moving, but a little shy when stopped at a light.

Ken

GatoEnFuego

I'm not sure you fully understand how our A/C system works, it does not pump heat or cold in/out of the cabin. It compresses the freon in the compressor which makes the freon hot, that is the hot line. Then it pushes that hot freon into the evap unit where it rapidly decompresses making the freon very cold at that point a fan blows past the evap "radiator" pushes cold air into the cabin. The cold freon then returns to the compressor, thats the cold line we're insulating and the process starts over. The reason I insulated the cold line is because it is much easier to access than the hot line and keeping that colder may help the overall efficiency. I'm still doubtful it did anything.

ken-x8

Yes, I do know how AC works.

Don't get too bogged down in the details, and don't view the components as unrelated. Overall, it does exactly what I said: it removes heat from inside the car and dumps it outside.

You picked the right line to insulate. How much good it does is another matter, but it definitely makes more sense to insulate the low side than the high.

Ken

Nubo

Of course it pumps heat out. Otherwise, the heat would stay in! Any AC unit is a form of heat pump. What you think of as "creating cold air" is actually the removal of heat from hot air.

You've got that jumbled a bit. The hot freon goes to the condenser, where it *dumps a lot of heat* into the outside air. It then travels into the dash, to the evaporator, where it expands rapidly and absorbs heat in the process. Air is blown over the evaporator and the heat from that air is transferred into the evaporator and into the freon, which carries it away. The air that comes out is therefore colder.The reason to choose the cold line over the hot line is Newton's Law of Cooling, which states that the rate of cooling (or of heating, which is the inverse), is proportional to the difference in temperature. Therefore the cold line will accept much more heat from the engine bay per second than the hot line. You are wise to be doubtful of the effect, because the thickness and relative shortness of that pipe means that the heat transfer is modest. But I still did the mod anyway . I had far more of an improvement from reprogramming the amplifier.

ken-x8

Don't forget the state change: turns to liquid in the condenser ("condense"), dumping heat, then back to vapor in the evaporator ("evaporate") absorbing heat.

Without latent heat of vaporization, air conditioning would be really difficult. As would cooling off by sweating or panting.

Ken

DMRH

For reference.........

Who knows the correct capacity of the A/C system........??

Most cars are around the 750-Grams mark, unsure of the R-8

Say it was 750-Grams. How many more grams of R-134 would it take to trip the "high pressure" switch in the circuit.

REgards

jessedrifter

iTrader: (4)

what about using tin foiL????
ahaah

firebirdude

iTrader: (3)

Surely this has already been noted, but guys have been doing this or similar to this for years. When I owned my Firebird, people wrapped the entire condenser. If it was exposed, it got wrapped. We used a thinner self adhesive type stuff. Don't remember what it was. Used refrigerator thermometers in the vents to measure the difference. Solid performance mod.

Razz1

Tin foil don't do crap. Use the real stuff drag racers use to prevent a fire.

That will work.

Scappini

I going to do it for the extra 100 hp

XDEEDUBBX

here's a snap of mine...did the ac wrap back in 2004...

jea1989

ok so ive read this whole thing and gotten nowhere...

all i wanna know is where. in town. i can buy the proper heat wrap material.
not expensive. not being shipped. right in a normal place.

TeamRX8

iTrader: (25)

buy a box of pampers and a bag of ice, that will be more effective than wrapping the frosty pipe ...

Spinning Sushi

iTrader: (21)

I used carpet insulation, warped it around the AC line, and put foil over it.

champi0n

iTrader: (1)

I thought I had an AC problem because i could feel the "cycling" going from cold, to not so cold.

Plus while it does help cool the car relative to blistering heat outside... every other car i've had would give girls hard nipples and goosebumps.... the rx8 ac however does not.

Spinning Sushi

iTrader: (21)

Yep, our car's AC suck... it's weak as hell.

MazdaManiac

iTrader: (3)

490 grams.

Razz1

How much per gram?