This weekend I took a heat reflective cloth and wrapped the AC line under the hood that is exposed, I put small cable ties approx. every 2-3 inches. and cut a small square out for the little valve on the line. Today I drove to work and the AC was the coldest it has ever been and remained freezing cold for my 25 minute drive to work. Easy mod and takes about 15 minutes, it even adds 100 HP!!!!! J/K :D :D :D

I'll post pictures once my car gets back from getting the windows tinted.

Sounds interesting and looking forward to the pics, this would be a good DIY, pardon my ignorance, but what is heat reflective cloth and is this some you can get at an automotive store or what? Thanks.

All of foxman's questions are mine as well. Also, does anyone know AC well enough to comment on if this is a "safe" thing to do ...?

This is something that Miata owners have been doing for years, espically when they are boosted and are producing much more heat under the hood. I figured if the rotary made more heat than a normal engine it should work great. I used to have an 02 Black Miata and did the same thing. As for the cloth it is a silver reflective on one side and made of a fiberglass. I bought it at a Speed Shop and I think it was called heat cloth.

Can you post pics so we can see which line to put it on? I'm generally happy with my -8's AC performance, but with a black leather interior and no tint, could use all the help it can get.

Sound like a good MOD for South florida

can't wait to see the pics, I know i need to do mine here in TX...

This is something that Miata owners have been doing for years, espically when they are boosted and are producing much more heat under the hood. I figured if the rotary made more heat than a normal engine it should work great. I used to have an 02 Black Miata and did the same thing. As for the cloth it is a silver reflective on one side and made of a fiberglass. I bought it at a Speed Shop and I think it was called heat cloth.

Is that the same stuff used to wrap headers?

How about a move to the DIY forum when pictures are added? Can't wait to try this...

G8rboy,

It is the same idea of the tape used on headers but I didn't use a tape it was a 2 x 2 foot square piece I started with and cut it to the size I needed. It is more like a flexible thicker fabric, some auto makers use it to line the underside of the hood and underbody where the trans runs under to help control heat. I am thinking of putting some above my trans to help keep the tempatures of my cupholders down a bit.

G8rboy,

It is the same idea of the tape used on headers but I didn't use a tape it was a 2 x 2 foot square piece I started with and cut it to the size I needed. It is more like a flexible thicker fabric, some auto makers use it to line the underside of the hood and underbody where the trans runs under to help control heat. I am thinking of putting some above my trans to help keep the tempatures of my cupholders down a bit.

Gotcha- I used some of that on my Miata underside (I had rattling heat shield above the cat which I removed and used this stuff instead).

where did you guys get the stuff? I did a seach on Miata.net but couldn't find anything under heat cloth.

This weekend I took a heat reflective cloth and wrapped the AC line under the hood that is exposed, I put small cable ties approx. every 2-3 inches. and cut a small square out for the little valve on the line. Today I drove to work and the AC was the coldest it has ever been and remained freezing cold for my 25 minute drive to work. Easy mod and takes about 15 minutes, it even adds 100 HP!!!!! J/K :D :D :D

I'll post pictures once my car gets back from getting the windows tinted.

How much colder would you you say the air was coming out of the vents? Was there any difference in the "cycling" that you noticed? How hot was it outside?

Thanks!! :)

I called a local performance shop and they recommended I call Thermotec (www.thermotec.com). Thermotec recommended I use the thermoshield tape (part number 14002) which reatils for like $17 for a roll. Would this work? My worry would be the condinsation would cause the tape to fall off.....they have some other products on the site as well I'm looking over

Ok, I put a call into the speedshop where I got it from they are calling me back. They use it all the time espically on his 10 second civic. I would say it makes easily a 5-8 degree difference. Tonight I will put a therometer and check how cold the air is.

Anyone in the Naples Fl area can get it from Dave @ Liberty 1.

I pick my car up at 5:30 from the tint place and will post pics when I get home.


EDIT:
Here is a link to the material I believe: will confirm it tonight

http://www.thermotec.com/products/full/14003/14003.html

PS The outside temp this morning was 76 degrees and I had the air on recirculate. on the low setting.

http://www.thermotec.com/products/full/14005/14005.html

This one looks like it has potential for the application in question.

http://www.thermotec.com/products/full/14005/14005.html

This one looks like it has potential for the application in question.

Those are nice but since they are seamless, they would require the a/c system to be drained, the line disconnected and then the system recharged. Obviously do-able, but not a DIY for most.

I found this line of Thermotec products at JC Whitney...

http://www.jcwhitney.com/autoparts/CatalogOrderSearch?sku=thermotec&storeId=10101&catalogId=10101&searchbtn.x=23&searchbtn.y=5

Regards, Art

Attached is a photo of what I did, it is a strip of heat cloth, I fastened it with small clear cable ties approx 2-3 inches apart. This method you do not need to remove the tubing just wrap around it.

Sorry for the photo it is taken with a camera phone.

Thanks for the pic. Looks like a winner to me. Thanks for taking the time to tell us about it.

This weekend I took a heat reflective cloth and wrapped the AC line under the hood that is exposed, I put small cable ties approx. every 2-3 inches. and cut a small square out for the little valve on the line. Today I drove to work and the AC was the coldest it has ever been and remained freezing cold for my 25 minute drive to work. Easy mod and takes about 15 minutes, it even adds 100 HP!!!!! J/K :D :D :D

I'll post pictures once my car gets back from getting the windows tinted.This is great! (looks like an easy fix that Mazda should do themselves.) Can you please describe how your A/C was before this fix? Were you in the group that felt the A/C sucked?

I'm generally content with my A/C (no A/C amp) as is, and I always keep my A/C on fresh air. There are a few times in the middle of a blazing hot Hawaiian day, only when I'm stuck idling in traffic, that I think it could be a little colder. But most of the time, I think it's actually too cold. This fix looks like it might regulate the cooling affects of the A/C better.

Tigster:
Thanks so much for this info. I think you're also really on to something about heat shielding the cupholders and the center console in general. This would help decrease heating the passengers and their drinks. Ipod users have also discussed malfunctions when putting their ipods in the center console, because of overheating. This heat shield could help with that too. I wonder what is involved in getting to this area. Would this be an exterior mod, or an interior mod?

Good tip. I've been lucky, my A/C seems very cold even on 100 degree days here in SoCal.

I've been planning to do this for some time now, but I work 12 hr. days.

Pegasus Racing carries the stuff you're talking about, too. Check out the link below and there are both cut-to-fit and self adhesive aluminized heat barrier cloths.

Pegasus Racing Heat Barrier page (http://pegasusautoracing.com/group.asp?GroupID=HEATBARRIER)

Those of you thinking about using it to insulate your center console, it should work fine. I insulated the entire area above the downpipe and catalytic converter on my RX-7 and it did wonders. You need to make sure you place it so the reflective side faces the heat source (your exhaust system), but it can't touch the exhaust.

are there any other lines to do? do you just let the aircon run for a while and insulate anything that feels cold?

Good tip. I've been lucky, my A/C seems very cold even on 100 degree days here in SoCal.

That's what gives me pause. Not sure that the insulation is THE fix, since if it were the missing piece, we wouldn't get the "my AC is great in 100 degree heat" posts. But, it's simple enough. Between this, insulating the center tunnel, and heat-rejecting window film one can probably make do with the "sucky" AC that most (but not all) RX-8 seem to come with.

I just had a look and the aircon line is already insulated on my car with foam all it needs is some reflective material

Here is the difference that I felt, in the mornings the ac was fine. On my way home (I live in Orlando FL) I found myself having to turn the fan up higher and the car never had real cold ac. Now it runs great and took only about 10 minutes (be sure not to drop any of the cable ties onto the motor).

As for the heating issue in the center console I recently put my nextel phone into the cupholder and closed the top. When I got home I got my phone out and the hinge on the flip top on the phone broke and the phone never worked again. After ordering another $250 on a new phone I am going to tackle the heating issue inside the console. I plan on putting lining on the underbody of the car using the self adhesive kind. I will write up a DIY for this. I just have to find the time since I have been working 6 days a week.

Attached is a photo of what I did, it is a strip of heat cloth, I fastened it with small clear cable ties approx 2-3 inches apart. This method you do not need to remove the tubing just wrap around it.

Sorry for the photo it is taken with a camera phone.

This is cool, Tigster. Is this the only line you insulated (the one visible in your photo) or were there other lines?

Those are nice but since they are seamless, they would require the a/c system to be drained, the line disconnected and then the system recharged. Obviously do-able, but not a DIY for most.

Perhaps this one then which can be slit.

http://www.thermotec.com/products/full/17062/17062.html

Plastic cable ties are durable enough for this application?

Plastic cable ties are durable enough for this application?
Quality ties are made of nylon and can definitely handle the heat and stress of the underhood environment.

Just be sure the tie part is not sticking up as I might get in the way of putting the engine cover back on. Not sure how close the cover is to that rear AC hose but one might want to keep the lock tie part to the side facing front of the car. Its a good idea though and makes sense as the engine sure puts out tons of heat.

Tigster,
Many thanks for a very cool DIY. It's late in the season up in the NE so I don't need the AC any more, but I'll remember this thread next Spring or Summer.

Great job and thanks for sharing. This should be moved the the DIY forum, and maybe stickied for awhile now and especially next Spring.

The only line I insulated is the one shown. the rest on the line is insulated with a rubber insulation on mine. The cable ties I used were the smaller ones (about 3" long) so the heads are not so big and the engine cover does fit over it, I just turned the little heads down to make it look a little better. Also if you look under your hood they use cable ties all over the place so they can with stand the heat

Bare with me because I am new to the forum and new to RX-8 (I bought mine 2 weeks ago)... question... is the purpose of the reflective heat wrap to keep the exhaust heat away from the AC lines? Please explain!

Thanks,
Jazper :rolleyes:

Jazper,

If you were to open the hood of your car and remove the engine cover there is a a tube that is used to bring cold air into the cab of the car. The motor produces heat (espically a rotary) and will heat up the outside of this line hence heating the air that has been cooled. By insulating the tube you are helping retain the coldness of the AC. Most of this pipe is already insulated by a foam type of insulation from the factory, so not a large portion of the tube needs to be covered. Hope this helps. :o

Jazper,

If you were to open the hood of your car and remove the engine cover there is a a tube that is used to bring cold air into the cab of the car. The motor produces heat (espically a rotary) and will heat up the outside of this line hence heating the air that has been cooled. By insulating the tube you are helping retain the coldness of the AC. Most of this pipe is already insulated by a foam type of insulation from the factory, so not a large portion of the tube needs to be covered. Hope this helps. :o

I believe the tube in question is carrying refrigerant back from the condenser to the evaporater in the cabin (which is where the air from the outside gets cooled). Since refrigerant has such a low boiling point, I'm guessing this mod will help keep the refrigerant in a liquid state until it reaches the evaporator.

It's amazing that Mazda hasn't figured this out already and made the mod to the 2005 models, especially under the center console.

I live in So Cal and the A/C worked fine even on the hottest days when driving out of a shaded garage. However, once I parked, even out of the sun, and let the car sit for a bit before getting back in, the heat from the center console heated up the interior to the point that the A/C needed quite a bit of time to cool the interior even on max/recirc.

On warm evenings, the heat radiating from the center console made using the A/C a must if just cruising on surface streets.

I'll try this mod, but it'll have to wait until next summer to see if it helps. I looking forward to lining the underside of the center console with the reflective heat blanket.

I believe the tube in question is carrying refrigerant back from the condenser to the evaporater in the cabin (which is where the air from the outside gets cooled). Since refrigerant has such a low boiling point, I'm guessing this mod will help keep the refrigerant in a liquid state until it reaches the evaporator.

Correct. The only place you'll find cooled air is in the cabin.

If I recall the mechanics of refrigeration correctly, there is a manifold in the evaporator that distributes the refrigerant to each of the evaporator tubes/coils. The pinhole in each of the manifold legs allows the refrigerant pressure to drop as it enters the evap.

If you ever find the refrigerant line that tigster insulated iced-over, it means that there is a refrigerant leak because the refrigerant pressure drop occurred before the manifold.

Are you insulating the larger suction line that goes from the evaporator to the compressor? If so, I don't see what that would accomplish. Has anyone put a set of gauges on the A/C to see what effect this mod has on line pressures?

That definitely is a good idea. I think you could get by with just regular foam insulation wrap too. (Wouldn't look as nice). Your goal is to keep the heat from under the hood off the line so it's not getting heat soaked. That line gets ice cold when the A/C is on.

It is starting to warm up so Bump.

Where and what is liberty 1 in naples???

Not sure why Mazda didn't do this in the first place. However, I know that insulation around a wire (or in this case, rod-like object) could possibly have no effect or so little it's not worth it. It's based on some heat transfer formula I wish I could remember, which gives you a critical radius of how thick the insulation can be until it is useless or harmful. This is all just theoretical shit though. In real life, I think the insulation will help :)

FS

Where and what is liberty 1 in naples???

Libetry 1 is a tuner shop in Naples Fla, he builds very fast cars.

We talked about this before - Megau brought it up and I never tried it yet.
http://www.rx8club.com/showthread.php?t=7537&page=3&pp=15&highlight=A%2FC

Guess I'll give it a go.

are you guys running the cloth down all the way to the compressor on the right side? I've done the mod from the left side firewall all the way to where the hose goes from aluminum to rubber, but not down to the compressor attached to the engine.

I only wrapped the line where it is shown in the photo, I may have to look into adding the heat insulation on the side as well... I also used the same insulation under the center console to try to keep the temps down when the center consloe lid is closed.

The reason that line is ice cold is because it is after the evaporater.

The compressor "compresses" the refrigerant. The refrigerant is hot at this point due to compression. It runs into the evaporater via the expansion valve. Expanding gases become colder. The fan blows air across the cold coils in the evaporater and it comes out the vents. It runs from the evaporator back to the compressor in lines that are ice cold to the touch where it starts over again.

Thus, I never tried the mod when we originally talked about it. Maybe though, this is keeping the refrigerant at a temperature that makes the compressor run a more efficient duty cycle?

the reason you want to wrap the line leaving the evaporator is because the refrigerant that has left the evaporator has changed from liquid to a gaseous state and any more heat added to the suction line to the compressor causes the gas to gain heat from engine compartment which is unfavorable(superheated gas)
which screws up the efficiency of the cooling system and its that extra added heat that will have to be removed by the condenser coil up front...So a good wrap of insulation to this suction line is important........

So if the refrigerant in its gaseous state enters the compressor at a lower temperature it will make life easier for the compressor. Less on/off constantly...

Gonna have to try it.

I wouldn't bother even wrapping it.

That pipe is not a factor in how cold your a/c is going to be. You will notice that all the peeps who replied said it "felt colder" or "seems better", there are zero measured differences -
Does it get to 44*F before cutting out?
Does the compressor cycle every 23 seconds instead of every 52?
Is the outlet air temp colder at idle?
...and by how much?

Pure placebo effect/conventional wisdom - "It must be colder, because I insulated the 'frosty' pipe" :rolleyes:

That pipe goes from the evaporator to the compressor, if it is 'frosty' it means you didn't put enough cabin air over the coils, and you are wasting cooling. From there it goes thru the comp, then the drier and the condensor. Now it is hopefully back at ambient temp, ready to re-expand and do its refrigeration thing again.

The two feet of insulation on the evap outlet is irrelevant.

Sorry, but save your cash.

S

Also, in the summer time when you have it on max A/C the compressor is going to basically run non stop anyway, it will not cycle on and off nearly as much as when the temp is cooler and you don't have it on max A/C, if your system is cycling on and off really fast every couple of seconds at idle then you have problem with the system like low refrigerant

I might not be looking at the same line, but in my car that tube is pretty hot, and I haven't used my AC yet. But I've touched it while changing my oil filter, if you are reaching for it from the drivers side it would touch your right side of your right arm. Is this the same tube?

they sell a special wrap with clamps just for hoses and pipes

http://www.thermotec.com/products/full/11600/11600.html

but I have to question it's effectiveness too

Yes, it's the same tube and it does get very hot.

The A/C is colder but it will still cycle.

Now mine goes from super cold to warm and the cycles are much shorter.

Before it was: a little cold to hot and consistently cycled back and forth.

Go to: http://www.porterfield-brakes.com/

what other things can be done to the A/C?

also, is refrigerant level something that has to be checked now and then? Ever since it got warm my A/C doesnt seem as effective as it used to be.

duh......?

It's an inherrant problem. Even the 05's aren't fixed yet.

there'a TSB for faulty AC amplifier, should be factory corrected on later production vehicles though. I think there's another TSB/flash update that delays the AC cutoff rpm point so it doesn't kick off so easily during semi-spirited driving (what most RX-8 owners would call normal)

fwiw, if it was as easy as insulating a hose don't you think the manufacturer would be aware of this? They aren't that stupid you know.

hi, i really want to try this mod. Can anyone tell me where and what product exactly would tackle this mod. Thanks

would suggest an introductory course in how an A/C system works so you can make the informed decision

http://www.familycar.com/Classroom/ac1.htm

as someone so aptly put it, "insulating the frosty pipe", has no bearing on how cold the air blows out the vent :rolleyes:

fwiw the "frosty pipe" is the return line, not the supply line, too funny :D

This is an interesting thread. One one hand you have the skeptics saying "insulating the frosty pipe is a waste of time". On the other hand you have folks saying that reducing heat absorption in the system will increase effectiveness. Neither side has any direct evidence one way or the other.

Not being an HVAC expert, I'm just think this through out loud and have a couple of questions. Some people say the return pipe gets very hot and others describe it as "frosty". Am I correct to assume that it gets frosty when the AC is on and gets hot (due to high ambient under-hood temps) when the AC is off? If that is the case, then I think it is safe to assume that the (uninsulated) pipe will aborb heat, thus increasing the temp and pressure of the refrigerant gas inside.

So what is the effect of this increase on the system? Does the compressor increase the pressure by X psi? If so, then the warmer return line will result in a hotter than normal output from the compressor. Or does the compressor run enough to produce a target psi? In this case, the higher input pressure just lets the compressor do less work, perhaps decreasing its duty cycle.

Assume that the added heat of the return pipe carries through to the compressor so the temp going into the condensor is higher. At a given airflow, a hotter condensor will shed more heat than a cooler one. Whether it sheds enough heat to compensate for a higher incoming refrigerant temp is unknown. So will mod have any effect on the temperature of the refrigerant entering the evaporator? If it does, then the evaporator has the potential to absorb more heat from the cabin. Of course, whether the design can achieve this potential depends on the heat exchange properties of the evaporator such as its size and airflow and how it is controlled by the AC system.

In my mind, there are two many variables to be able to analytically say whether this would work or not. It ultimately boils down (a little AC humor there) to whether this mod impacts the temp of the refrigerant entering the evaporator.

I guess the only way to know is a controlled experiment. Measure the vent air temperature before and after the mod trying to keep other factors such as outside temperature, driving speed, starting cabin and engine temp the same. Anyone up to the challenge? :)

fwiw, if it was as easy as insulating a hose don't you think the manufacturer would be aware of this? They aren't that stupid you know.

So following that line of logic, factory installed protection for the oil coolers and a/c condenser must be really difficult for the manufacturer to envision and engineer. Otherwise they would surely have made them standard issue by now, right?.

I think the system is capable of more BTUs, but is being restricted from doing so. I noticed this the other day, doing the 4000-rpm shutdown procedure after briefly moving the car. I decided to hit the AC button. Since I was now in the garage (door open of course) it was fairly easy to hear the AC clutch engage and I also noticed a decrease to about 3600 rpm, holding the pedal position steady.

But, the compressor clutch did not stay engaged for long. The vent air began the familiar "cycling" behavior -- cool/lukewarm/cool/etc... And everytime it cycled was exactly timed with the AC compressor engaging and disengaging.

It seems to me that a good deal of the problem is related to the duty cycle being imposed on the compressor. This is part of what the upgraded "amplifier" seemed to address (in addition to enforcing recirculate-mode). But the success of the new amplifier is less than stellar by most accounts on this forum. My unit is past the VIN target for the TSB so I don't know if my cycling is more or less than what a unit with a newer amplifier experiences.

Why would the compressor duty-cycle be "detuned", so to speak? I can think of a few possible reasons

1) to aid with an already-disappointing fuel economy
2) prolong the life of the compressor
3) mitigate the heat load on the radiator
4) keep the evaporator coils from icing up

Of those, I speculate that #1 may have been the biggest driver. #4 is always important, but I don't have any idea how close or far away from an icing problem we are -- that is, how much could the duty cycle be increased before it becomes a concern?

I think my next bit of research is going to be wiring an LED into the AC-clutch circuit so I can see on my dash when the unit is operating and when it's not. I'd like to get some accurate measurements of the actual duty cycles and compare that to times when the AC seems to be doing ok and when it seems to be particularly anemic.

My end-goal in this is to see if there is any cheap and reasonable way to increase the compressor's duty cycle to a point where the driver is not constantly aware of the weak AC.

I moded mine with grey foam pipe cover from Low's. I had new AC Amp already installed for months. With new AC Amp air was cool. :cool: Wtih pipe cover it is cold. :D My .02 cents worth.

So following that line of logic, factory installed protection for the oil coolers and a/c condenser must be really difficult for the manufacturer to envision and engineer. Otherwise they would surely have made them standard issue by now, right?.


I ran an FD with exposed coolers for years and never had a problem, that said anything can damage your car at any time. You don't have a cowcatcher to avoid gatorbacks too do you? I had a bolt kick up and bust the windshield of my company car. Should they also supply a windshield screen?

FWIW, I live in TX and my A/C will freeze me out, I generally like it colder than anyone else I know

So, why do other manufacturers cover the A/C line?

Believe me it works. It's not a complete fix, but helps. Helps enough that the A/C is more than tolerable. Add the AMP and it's better yet.

This is the order in which I repaired the A/C problem. Like I said id cycles less frequently and the air is colder.

What we need is someone to measure the air temp before and after the mod. Quantitative evidence. Who wants to volunteer?

~ Matt

I wrapped mine in 1/2" foam used for insulating copper pipes. I then wrapped foil tape around the foam, the same foil tape used to seal heating ducts.

I mentioned this mod to one of the technicians when I was at the dealership buying oil last week. He said that he *could see* how this could make an improvement.


Unfortunately, we are in the middle of a heat wave in Ontario and it is too hot to go outside this weekend to see how well it works :-)

I just did the insulation mod. I used glass fiber insulating band (4" wide) and wrapped it double layer. Then on top, aluminum body fixing tape (4" wide) in sections around the pipe turns, and length-wise on the strainght portions. Both were purchased from Auto Zone - nothing special. Looks kinda fine - obviously not something to rave about, but it ain't all that ugly either.
The AC worked just fine at 92F we have now in NJ (read on the car sensor). I already have the updated amplifier installed as well. Short of checking the level of the refrigerant - maybe is on the low side? - and tinting windows, there is nothing else to be done about the AC on this car...
So, instead of talking up and down and theoretise on the benefits of insulating that pipe - interested people should just do it ($10 in parts, 30 min installation).
As for the skeptics, no need to discourage people! Let them do it - what's to lose?!? I just don't get it....

And besides, I'm thinking of going on an intake insulating frenzy from the airbox to the engine and saying "piss off" to heat soak, because of this thread :p

They use this same theory on housing A/C. Check some of your lines at home for insulation.

Got mine done today using 1/2" foam copper insulation tube bought from Home Depot. The foam tube is split on one side with adhesive strips to close together, costs $6. I used aluminum tape ($2) and taped it lengthwise covering the foam surface except where the foam is split. I pulled the tube over the a/c piping, pressed the adhesive ends together, covered the remainder with some more aluminum tape then tiewrap ($2/10 tiewraps) the whole thing down. Total cost for the mod: $10.

I wouldn't bother even wrapping it.

That pipe is not a factor in how cold your a/c is going to be. You will notice that all the peeps who replied said it "felt colder" or "seems better", there are zero measured differences -
Does it get to 44*F before cutting out?
Does the compressor cycle every 23 seconds instead of every 52?
Is the outlet air temp colder at idle?
...and by how much?

Pure placebo effect/conventional wisdom - "It must be colder, because I insulated the 'frosty' pipe" :rolleyes:

That pipe goes from the evaporator to the compressor, if it is 'frosty' it means you didn't put enough cabin air over the coils, and you are wasting cooling. From there it goes thru the comp, then the drier and the condensor. Now it is hopefully back at ambient temp, ready to re-expand and do its refrigeration thing again.

The two feet of insulation on the evap outlet is irrelevant.

Sorry, but save your cash.

S

I agree! If this was a chilled air system, then this might help - but this is "freon". As soon as it hits the compressor it is going to be red hot again.

Tigster said:

If you were to open the hood of your car and remove the engine cover there is a a tube that is used to bring cold air into the cab of the car. The motor produces heat (espically a rotary) and will heat up the outside of this line hence heating the air that has been cooled. By insulating the tube you are helping retain the coldness of the AC. Most of this pipe is already insulated by a foam type of insulation from the factory, so not a large portion of the tube needs to be covered. Hope this helps

and this just not correct. The cold pipe is the suction pipe that is LEAVING the cabin of the car - the gold color pipe below this one (that will be VERY hot) is the compressed "freon" going INTO the cabin of the car.

http://www.energyquest.ca.gov/how_it_works/air_conditioner.html

http://www.edmunds.com/ownership/techcenter/articles/46869/article.html

are just a couple of the many places that explain how the A/C works - but it does not push cold air into the car at all.

Someone would need to do a proper before and after test to see if there were SOME benefit to this at all. I suppose a cooler temp imput to the compressor might make it work a little better but it is not going to be any sort of "dramatic" cool down of a car that was not cooling correctly to start with. You CAN effect a cooler system by spraying the condenser in the front of the car with cold water. This provides a better heat exchange with the hot outside air and will then remove more heat from the "freon".

Dennis

Despite my skepticism there were enough testimonials to make me try it. For what it's worth I used a roll of "Frost King" hot/cold pipe wrap that I picked up at home depot

http://plumbing.gillroys.com/Plumbing_tools_and_accessories/Pipe_insulation/Pipe_Wrap_Insulation_Tape-s420280.html

Due to the adhesive, a spiral wrap of the pipe is impractical; I just ran a couple of overlapping lengthwise strips and the obligatory zip ties...

More importantly, there may be some new info about programming the amplifier

http://www.rx8club.com/showthread.php?t=66922

I did the wrap last night and will do the reprogram before I leave work. So if it's magically better I'll have no idea how much improvement to attribute to either action. Oh well... I wouldn't want to break the spell :)

I took temperature readings on my vent, with all settings the same, over three days before doing the pipe wrap, and then after. Short answer is there was no difference. Most of the readings I took on the way to work, pre-sunrise, so no radiant heating, just ambient temperature to deal with.

The interesting thing, is that regardless of the morning readings at 77 degrees or the afternoon readings in full sun at 90 degrees, the vent always cooled to a range of 54 to 56 degrees F. This suggests an artificial limit in the system.

As an engineer, I'm pretty sure the pipe wrap is not a placebo. But I did not encounter conditions where the AC only cooled to 65. I probably needed a 110 100% humid day to test with.

I know one time I took my wife for a ride and the AC started blowing warm air and she thought that was ridiculous. It could have been cycling off to make sure the exchanger didn't freeze up or something. But that was an unusual occurrence, rather than normal behavior.

as an engineer then you should go do some basic research on refrigeration which will confirm your reading results. Kind of funny that you tquestion the conclusion of the actual results

I've only ever seen an issue when the car is not moving fast i.e. not getting good airflow into the condensor, IMO the condensor may not be sufficiently sized to handle low air flow conditions. If this is the case the freon gas will not condense into liquid form, which would result in the system blowing warm if there is gas rather than liquid at the expansion valve. It wouldn't matter if the compressor was running all the time or if the frosty pipe was insulated or not if that's the case.

there's a reason the "frosty pipe" between the evaporator and the compressor does not need to be insulated, just as there is a reason that the compressor cycles on and off, it's all related to the basic fundamental design of how a gas/liquid refrigeration system operates. I am engineer too, having been involved with industrial refrigeration systems. The only time we ever insulate the frosty return pipe is when we don't want condensate forming and dripping down off of it onto whatever is below it. If the whole basis for this kooky thread were true for a small automotive AC system can you imagine the energy savings a large industrial plant would gain by insulating the frosty return pipe?

The truth is in your results.

this entire thread is one of the greatest exercises in ignorance that I've ever seen

I agree, the proof is in the results. Which is why I ran the test, because I was tired of everyone writing conjecture.

The reason I was surprised is that most AC systems I'm familiar with don't reside next to a hot engine block. My "theory" was the close proximity to the engine meant the system could be soaking up unnecessary heat. Even the return pipe should be at a much lower temperature than the block.

My experiment disproved my theory. Which just goes to show a little science could have stopped this whole thread in its tracks a LONG time ago.
:D

They use this same theory on housing A/C. Check some of your lines at home for insulation.

Home AC is a considerably different beast. The refrigerant in the system is designed to stay colder longer because the compressor is often 100-200' of pipe away from the coils. The refrigerant in car systems is, thanks to our government protecting us from ourselves, quite crappy.

Most home systems I've seen wrap only the supply line. The return line is usually secured to the outside of the wrapped supply line.

If your system is in the attic, they will wrap the condensate line to keep it from dripping due to the cold water inside condensing on the outside from the attic heat.

this entire thread is one of the greatest exercises in ignorance that I've ever seen

I agree, but logic has no place when it makes them feel better ;)

You should also go read the "Reprogramming the AC" thread - where you hold down some buttons and lose control over your AC. It will now automatically go to recirculate any time it is hot out and you have the control on full cool and in dash vent mode. No duh, on a 100 degree day that would be better than trying to recool the 100 degree air outside the car. But once it is explained that you can do this yourself using the fresh/recirculate button folks are STILL doing the "program" and declaring how much cooler they feel :confused:

Dennis

How about we sell a placebo button on EBay? A bright blue button labelled "Sooper Cold" and instruct them to glue it onto the recirc button. Could probably get $5 each. ;)

I haven't try this yet, but at first I though it was just a placebo.

But actually, by wrapping the line that goes from the Evaporator to the Compressor, the compressor will convert the gas to a slighly-colder-than-before liquid, adding efficiency to the system I guess. Then the Condenser would be able to do a more effective job of bringing the hot liquid to ambient tempeture.

The air comming out of the A/C system should be tempeture regulated; actually there is a "Evaporator tempeture sensor" inside the A/C unit. So I don't think the A/C is going to be any colder with this modification. However, I think wrapping that pipe would increase A/C efficiency, and therefore, reaching the desire tempeture faster, with less work to do and less load to the engine.

A good reference about refrigiration:
http://home.howstuffworks.com/refrigerator4.htm

Given the length of the exposed pipe and the velocity of the "Freon" travelling through it, I would have a hard time thinking it will pick up much, if any heat from the engine.

Dennis

there's a reason the "frosty pipe" between the evaporator and the compressor does not need to be insulated, just as there is a reason that the compressor cycles on and off, it's all related to the basic fundamental design of how a gas/liquid refrigeration system operates.

Are you saying that it's not possible that some RX-8 compressors aren't cycing off prematurely? Ive sat and felt the output as the compressor cycles on and off. The temperature of the output air cycled markedly along with it. I understand the concern over the evaporator coils icing but during this test the temperature of the output air gave no indication of icing being imminent -- it wasn't that cold. Isn't it possible that system can be too conservative with the compressor duty cycle?

Not sure, but I think that the refrigerant that leaves the compressor will be hotter than that returning, even before the wrap. Compressing the gas heats it up tremendously. The expansion of that same gas causes it be cold.

I agree, but logic has no place when it makes them feel better ;)

You should also go read the "Reprogramming the AC" thread - where you hold down some buttons and lose control over your AC. It will now automatically go to recirculate any time it is hot out and you have the control on full cool and in dash vent mode. No duh, on a 100 degree day that would be better than trying to recool the 100 degree air outside the car. But once it is explained that you can do this yourself using the fresh/recirculate button folks are STILL doing the "program" and declaring how much cooler they feel :confused:

Dennis

:) I'll take the heat for insulating my frosty pipe because I have a general understanding of the principles and agree the potential for meaningful amounts of heat entering there is tiny.

But, I HAVE gotten a distinct and unmistakeable improvement after having done the reprogram procedure (well, yeah at the same time as the FP insulation job). Yes, I understand how/why recirculate benefits. I used it all the time BEFORE the reprogram. This procedure did something else that resulted in improved cooling. No, I don't have thermometer readings but when you go from a car that always reminds you that the AC is barely there, to one in which you're perfectly cool, subjective evidence is enough imo. Yesterday it was 95F and full sun on the way home and it was perfectly cool in the cabin with fan set to 3. And it didn't take long to get there. This was never even close to being the case before. Prior to the reprogram that ride would have been spent with fan roaring away on 4, with recirculate and would just have begun being tolerable right about when I was pulling into my driveway. Well, maybe I was hip-mo-tized by the flashing defrost light but hey, I'll take it. :)

Since the unit is "programmable" and we do not have definitive specs, isn't it possible that a reprogram could be making changes or clearing a condition other than what is described in the brief procedure?

I think it's significant that there is a widespread dissatisfaction with the AC in this car -- among people who are not naive and have driven enough vehicles to have a basis for comparison. And, not all vehicles seem to be affected. To me this rules out any fundamental design flaw in terms of specs. That is, condenser is adequate, compressor is adequate, etc. The answer lies in finding what is different between vehicles. Given the complexity of the control systems in the car I think it is logical that the control logic could be the issue.

And that reprogramming would be.... :confused:

The reprogramming is described here:
http://www.rx8club.com/showpost.php?p=963554&postcount=8

There may be multiple ways/levels of reprogramming. It sounds like its still under investigation...

Thanks

From my experience, the air coming out the vent is not significantly colder (maybe is the same? no need to measure). But the last two days humidity was 100% and so was the temp in NJ (105F). Temp inside car was OK, I was comfortable after the car was in the sun the whole day (open parking at work). Before the updated AMP and pipe insulation, anything topping 95F would not be cooling down enough for me to feel comfortable (going once at the shore was a sweaty yucky experience). So all this theory is great, but I only care of how the car feels, not why and what changes by which law of physics... By intuition, a system that has as only purpose removal of heat cannot benefit from extra heat input. Heat removed from the air forced inside the car = heat exchanged with the outside air by the AC radiator in front. If that pipe picks up heat from the engine bay, the radiator has to work harder. This is a law of physics too; energy conservation. So, maybe it does not pick too much heat - but what if it does? Can we check? No. And that pipe will burn your hand after driving the car - at least in my case since due to the MS strut bar, the engine cover is gone (maybe that one made a difference? no idea).
Geesh... for few bucks, is worth trying, as all agree that while it might not help, it definately does not hurt anything.
Don't we have real issues to solve on this car? Insulating or not 3 ft of pipe should be at the bottom of the pile with problems...
I only post so people do not get scared reading all the contrary theories and not even try to do it. Laws of physics or not.... just try, one never know (wasn't the Earth flat at some point? how come is round now? theory changes all the time - results don't).

I never thought the thread I started would get this long with alot of lengthy explinations of why it won't work. I can say I have has this done for almost 8 months and I notice a difference. Call it a placebo effect if you must, but if you dont agree save your $5 worth of supplies and go to McDonalds.

I just thought about it, but my 05 shinka does not automatically revert to recirc mode when I turn the fan to full blast. So I decided to experiment to see if the programming works for 05 cars, and it did! Now I don't have to remember to make sure its on recirc when I need cool air ASAP, it does it for me automatically. Good thread...

Is this programming feature a factor of the flash or the electronics of the AC unit? Meaning if the electronic feature was not in the car for earlier models, it won't work.

Is this programming feature a factor of the flash or the electronics of the AC unit? Meaning if the electronic feature was not in the car for earlier models, it won't work.

My understanding is it requires the new version of the AC amplifier, so your vehicle either has to fall outside of the VIN range for the TSB, or you need to get the improved amplifier under the TSB. For a list of TSBs, go here

http://www.finishlineperformance.com/rx8/bulletins_index.html

I also noticed a significant improvement in the A/C after I reprogrammed it to recirculate automatically when set on maximum. I've tried manually selecting recirculate before and didn't perceive it to work as well as it does now. Either way, it works well enough now to be acceptable.

I agree retro ... there is a significant improvement (no placebo) in the temp of the air exiting the vents with this configuration. It has been in the mid to upper 90s here in Atlanta with plenty of humidity and there is no doubt my A/C (10/03 build) is much improved since I went through this procedure.

Not only is it acceptable, it's comfortable.

[QUOTE=Nubo]My understanding is it requires the new version of the AC amplifier, so your vehicle either has to fall outside of the VIN range for the TSB, or you need to get the improved amplifier under the TSB. For a list of TSBs, go here

TSB was acknowldged by the dealer two weeks ago and the new AC amplifer was ordered. Thanks for the clarification.

I understand the concern over the evaporator coils icing but during this test the temperature of the output air gave no indication of icing being imminent -- it wasn't that cold.

When an evaporator ices, the output air temp rises because the air cannot flow through. The ice blocks the airways. Icing is usually caused by refrigerant leaks, not excessive compressor run times (actually they can be connected in an automatic climate control but not in a manual like the 8.)

Ok, after reading through the entire thread, I didn't find evidence supporting or not supporting this mod or the re-programming. Sooo, today, I bought two different thermometers. One a dial face, one a digital. In the store they both read the same temp. So I am making an assumption that both are somewhat calibrated and at least are on the same page as far as temps. Here are my results:

Ambient air temp - ALL tests - 85 degrees - 6pm - 7:30pm
Engine temp two ticks below the thermometer on the dash guage
No Mods
No pipes wrapped
No programming done
2004 RX8

Idle for 5 minutes
AC on RECIRC
Fan on High
Max temp - (after cooldown from the store) - 56 degrees
Low temp - 54 degrees

Highway
Speed 66mph
RPM - 4000
5 minutes
AC on RECIRC
Fan on High
Max temp - 54 degrees
Low Temp - 50 degrees

After the above Highway temp, I wondered if speed/rpm would do anything.
Highway
Redline 1st & 2nd
7000 rpm in 3rd - Held for 3 minutes - about 80 - 82mph
High Temp 52
Low Temp 49

After doing some driving around both city (35 mph) and Highway speeds (55mph) I did find that the temp got cooler. This obviously was due to the cabin cooling down and the AC's RECIRC function working like it should. Lowest temp was 41. I did repeatedly get my lowest temp (41) while the tach was at 3500rpm. Before all of this, I too thought my AC was crappy, but cooling at 41 isn't crappy. I will try a similar test on both of my GM vehicles and see what the low temp is there. In my opinion, just like elbows, everyone has a couple, I don't think the pipe wrapping will do anything one way or the other, but for $5, I'm going to test it to see and will post something here when I do (unless someone else wants to do that part that has already done the wrapping :D ) I have noticed on much hotter days that the AC will switch to the "normal" mode or fresh air mode. This is normal according to my Dad (who is in the refrigeration/AC field) I know my GM vehicle does this by drawing in fresh air to cool, which as mentioned earlier, is cooler than the stagnat/stale air in your car. I think the Mazda does the same. All I can tell you is spend the $10 for a temp gauge and prove it to yourself before trying this stuff. :cool:

No animals were harmed in the testing, however my nipples did get hard a time or two when I redlined it. :D

good objective testing, hawgwild... Looking forward to your next segment. Thanks!

After the above Highway temp, I wondered if speed/rpm would do anything.
Highway
Redline 1st & 2nd
7000 rpm in 3rd - Held for 3 minutes - about 80 - 82mph
High Temp 52
Low Temp 49


Dang. Even after the AC TSB and a system recharge and on recirculate, my system can not get below 51 deg.

Nice write up.

Dang. Even after the AC TSB and a system recharge and on recirculate, my system can not get below 51 deg.

Nice write up.

Keep in mind the important value is the difference between the outside air temp and the vent temp.

ple, I don't think the pipe wrapping will do anything one way or the other, but for $5, I'm going to test it to see and will post something here when I do (unless someone else wants to do that part that has already done the wrapping :D )

Once you are ready to wrap, you should take some pre-wrap readings - otherwise the numbers may mean nothing. If it is cooler or hotter after you wrap than the day you tested the temps will be different just for that. Higher or lower humidity and more or less sunshine may effect it too.

So if you want to be precise then check it moving and standing still, then wrap and recheck.

I would agree than a system blowing 49 or 50 degree air when it is 85 outside seems to be working pretty good.

Dennis

i just installed mine over the weekend. It took only 15 minutes to do. I havent tested it out yet but hopefully my ac will run colder now.

FYI...Had the AC Amplifier replaced under the TSB and it appears to be colder. I haven't tested it with a thermometer though.

I never thought the thread I started would get this long with alot of lengthy explinations of why it won't work. I can say I have has this done for almost 8 months and I notice a difference. Call it a placebo effect if you must, but if you dont agree save your $5 worth of supplies and go to McDonalds.

It's not $5 of material. It's $25 to $30.

You nedd to use the good stuff if you want it to work.

That's the wrapping they use on dragster for fire prevention.

go to : http://www.porterfield-brakes.com/

So we ever get any final results from someone who measured before and after temps?

Yes. Differences were minimal, possibly within boundaries of error.

I have several cars and IMO the problem with the AC is not the temperature, but the way it's ducted and the power of the blower. It needs more oomf. Because of that the air takes forever to cool down. Once again, I'm no expert and I have not measured the temperature, but the blower and ducting is seriously lacking.

I have this same stuff too. I also felt a difference in the cold.

I wrapped mine with self-vulcanizing rubber tape, then with the thermal insulation. I didn't want the insulation touching the metal, as I don't know what it's made of and therefore its effects on the metal under heavy condensation. Before and after temps may be the same, as some have said, but my A/C no longer has the warm/cold cycling. Cold all the time, now. $20 and about an hour of work, and I'm happy with the mod.

I know their is a difference because mine is blowing condensation which never happen in the year I have had my car

I have spent the time endlessly reading this post which is god-awful long. There is one think not mentioned in this post, and for those of you who are over this thread, just ignore this you crabby asses :cwm27: ....

I have never had my own Mazda, but my husband has a Miata. It sucks with the AC. I always thought that was because it was a soft top. When I got my 8 I was frustrated by the AC, not because of the coolness but the constant lack of air while accelerating. I felt that the AC system sucked in general because I didnt understand the Mazda. The 8 was my first new car and I was thinking luxury when I was thinking sports car.

When I mentioned this irritation with my husband he looked at me and said, "It's a sports car honey." All Mazda sportscars drop the AC at full throttle. So although the fan speed is cranked and the air coming out is cold, we manuals will feel a decrease in air during acceloration if you are driving the car like a sports car.

The Service guy at the dealer confirmed that the 8 has that same benefit that the Miatas have to keep it from losing power during a desired push. I have been straightened out and am a die hard 8 lover. I may have leather...cough cough plastic seats but I am a sports car minded gal now.

Who uses the AC anyway....

I will have to try this but my AC is really good anyhow

so can u pick up that heat cloth at like any motorsports place??? or auto parts store??? im lookin to find one if not in riverside, ca then close to it, but hey 5-8 degrees minimum difference in riverside heat in the summer makes a big difference..... so if anyone can tell me a place that would have it, i would really appreciate it.

So we ever get any final results from someone who measured before and after temps?

Close. I drove an hour to the RX club meet then we went up the mountain.

It went from 82 at the beech to 105 plus.

We compared temps. They ran 50 to 55 degrees, and when stopped at a light they would get 75 degrees.

I could not test in tow conditions at lights. Mine ran 48 to 50 degrees. Most of the time 48 degrees going up the mountain.

When I had a chance to get to 46mph it dropped to 46 degrees.
I suspect if I were on the freeway I could get 46 degrees.

So if you use the high temp fire resistant material you should get 1 degrees possibly 2. Note his high was 55, while mine stayed steady at 48 to 50.

Unfortunately we need a new thread to really fix the problem.

I checked the temp at the center consoule from the out side. It was 90 degrees!

The real fix is to insulate the cabin which is another DIY.

Two methods: One from the inside Second from the outside under the car.

I'm gonna check out the second. The culpate is radiant heat from the transmission and engine.

Don't ask about the cup holders. The temp in there seems like it could boil water. just kidding.

A/C systems will only drop a temperature a certain number of degrees, so even if it is operating at its best, as the input temp rises the output temp will rise accordingly. It is not going to put out the same temperature air at an ambient of 105 degrees as it would at 85 degrees, assuming fresh air input at both. I wonder if the frequent cycling of the compressor some cars are doing is a problem with an RPM/load cutout switch or something similar.

I would like to have better insulation in the car to block heat coming from the drivetrain and exhaust, but that sounds like a BIG job to do right.

So if you use the high temp fire resistant material you should get 1 degrees possibly 2.

I am not clear on your test methodology, did you use 1 thermoment or 2? If 2, did you compare them in a single car to be sure they indicated the same temperature?

I would think a 1 or 2 degree differences would be within the error in most thermometes, and probably within the tolerances in between 2 car samples. In others words, if you checked 2 cars without wrapped pipes you might see 1 or 2 degrees of difference between the cars.

Dennis

It was one thermometer. You missed the point. his was cycling 50 to 55, mine was almost a constant 48. His cycled 5 degrees. his peak was 5 degrees higher than mine.

While I did see 46 degrees as a low at 46mph his low was 50, thats's a 4 degree difference.

While a variance of 2 could be normal 4 is out of the range, what caused this? The heat wrap for dragsters. Don't use that garbage crap you read about.

Think I'll start with the ac amplifier upgrade first. Need to get the dealer off their asses with that already.

I don't think the cycling is caused by lack or heat wrap - or having wrap on. I think that is the infamous "A/C amp" and that needs to be replaced.

In addition, I think the software "load" on the car can effect this. I swear after getting my car back from the gas tank recall - where I assume the insulated the tank and load new code into the car - that my AC now cycles off with a very slight hit on the go pedal. Before I would hardly notice it and wondered what folks were complaining about.

Dennis

Nice mod Tigster :worship:

I tried this and it works. My A/C is noticably cooler now, even on a sunny 95 degree day. Instead of heat wrap I used pre-formed foam pipe insulation that comes in 6-foot lengths that you can buy in any hardware store. Total materials cost: $1.75

:D:

there'a TSB for faulty AC amplifier, should be factory corrected on later production vehicles though. I think there's another TSB/flash update that delays the AC cutoff rpm point so it doesn't kick off so easily during semi-spirited driving (what most RX-8 owners would call normal)

fwiw, if it was as easy as insulating a hose don't you think the manufacturer would be aware of this? They aren't that stupid you know.


Youre right, theyre not. They can save $1/car for NOT doing this plus the manpower to do it, times hundreds of thousands of vehicles, if not millions per year if you count ALL cars they make.

Does this make a difference? Yes, for the same reason you insulate this line for your home A/C, its all about efficiency..every BTU counts.

Does it matter enough to do it at the factory? No..typically if the air is "cold" people wont complain.

Its a simple $ to consumer-comfort equation, the manuf. isnt stupid. Just us for debating simple efficiency mods. Its a no brainer if youre looking to refine your car a little more.

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.

Yes, for the same reason you insulate this line for your home A/C, its all about efficiency..every BTU counts.

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 :hahano:

Dennis

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/modify/rx8_console/rx8_console.html

I have several cars and IMO the problem with the AC is not the temperature, but the way it's ducted and the power of the blower. It needs more oomf. Because of that the air takes forever to cool down. Once again, I'm no expert and I have not measured the temperature, but the blower and ducting is seriously lacking.


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...... :)

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.

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...... :)

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.

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...... :)

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.

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

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.

...$2 for the foam wrap (Home Depot Motorsports FTW), another $3 for metal tape (look next to the dryer vents)...

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

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.

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

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.

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.

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.

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 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.

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.

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,

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

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

what about using tin foiL????
ahaah

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.

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

That will work.

I going to do it for the extra 100 hp :)

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

http://i30.photobucket.com/albums/c336/XDEEDUBBX/6.jpg

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.

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

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

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. :(

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

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

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


490 grams.

How much per gram?

How much per gram?

I suppose 1cm^2 before it sublimates.

after reading this whole thread and the "reprogramming thread" I just want to kick a puppy.


fyi, i have some magic beans for sale

dam...well my lady was complaining that the ac wasnt as cold as she would like...so since i felt bad telling her to suck it up since shes caring my baby boy in her stomatch. had a buddi supply me with some carbon fiber sheats and i insulated the ac pipe...i dont knowthe technical shit about all this but is seems to be colder...and she hasn't complained.... by the way...i used carbon fiber because 1. it was free, and also cuz someone told me it deflected heat...this true???

yeah thsiis def a great mod to do

after reading this whole thread and the "reprogramming thread" I just want to kick a puppy.


fyi, i have some magic beans for sale

Steady, Jack. The reprogramming actually makes a huge difference, if you have the applicable "amplifier".

you and I have a different definition of the word "huge"

That's what she said

adobe clay works much better, those indians weren't stupid you know ....

you and I have a different definition of the word "huge"


Not necessarily. Note, I said "if you have the applicable amplifier". In my case it was (Jan 2004 build).

This was no placebo. I went from a system that could barely keep up with low-90's temps with fan at max and recirculate, to where I am comfortable with fan at 1 up to about 85 degrees, fan 2 will take me into the mid 90's. I recently drove through 116 degree temps and was switching back and forth from fan4 to fan3, max fan was just too cold after awhile.

In short I went from an AC that was basically uncomfortable on an average summer day, to one that has more than enough cooling for scorching temps. So, does that sound like a huge difference to you?

In my zeal to "fix" the lame AC, I wrapped the pipe and made the programming change at the same time. Logically I don't think the wrap contributes much but there you are. No other changes were made.

I just did this with some Thermotech Thermoshield by cutting it into small strips lengthwise. My problem is that it isn't staying stuck down completely. When I turn on the ac, it will not stick as well, but it will still stick a little. What can I put over it to fix this issue? Thanks.

zip ties

So put zip ties on every single strip?

Summer is coming up.

There is still debate if insulate AC pipe helps or not.
But the project cost $2.5 and 5 mins, it worth a shot.


I use pre-slice, peal and seal insulation foam tube, designed hot water copper pipe.
One insulation foam tube from Home Depot is 2 yards, cost around $5 &
can be installed for 2 cars.

Peal and seal. No zip tie.

Planing is 10 mins, and you can skip this.
Installation is < 5 mins.


Picture is pretty self-explanatory.

Note: Length of the tube will change a little if tube diameter change.
Better engine bay view coming up. I just took a snap shot with my phone.

looks much better than zipties. i might have to try this out.

Summer is coming up.

There is still debate if insulate AC pipe helps or not.
But the project cost $2.5 and 5 mins, it worth a shot.


I use pre-slice, peal and seal insulation foam tube, designed hot water copper pipe.
One insulation foam tube from Home Depot is 2 yards, cost around $5 &
can be installed for 2 cars.

Peal and seal. No zip tie.

Planing is 10 mins, and you can skip this.
Installation is < 5 mins.


Picture is pretty self-explanatory.

Note: Length of the tube will change a little if tube diameter change.
Better engine bay view coming up. I just took a snap shot with my phone.

I did it this way and didn't notice any difference. The heat transfer from that pipe is minimal. Cost me $7 and 15 mins and didn't hurt the car so go for it!

I did it this way and didn't notice any difference. The heat transfer from that pipe is minimal. Cost me $7 and 15 mins and didn't hurt the car so go for it!

By the same logic, why not paint it a soothing shade of cool blue?

No difference, didn't cost much and can't hurt?

Go for it.

S

Uninsulated AC tube: 62.4-62.7 degrees...engine at normal operating temperature and 1500 RPM when AC turned on...using outside air at 84.5 degrees...fan speed on 1...77% humidity...car parked in shade.

Insulated AC tube: 54-56 degrees...same conditions 2 days later. It took awhile to get the temp down because the compressor kept cycling on and off when the air temp got to 62. It seemed like the compressor was engaged less than half the time.

[Temps were measured with a little SkyScan Atomic Clock. It agrees within a fraction of a degree with a couple of other Atomic Clocks I have.]

The insulation: Armacell foam hot water pipe insulation. Home Depot item #803014117517. Set me back $1.46 including sales tax. HD sells it in 6' lengths. The display box says it's 5/8", but the inner diameter is a 16th larger so it isn't a tight fit. The outer diameter is 1.25". The wall is 5/16" thick. The surface is not totally smooth, but it's dark gray with a slick finish and I think the color looks nice in a TGM engine bay. HD also sells a black foam insulation without a slick finish that would collect dirt fast and be tough to clean unless you could find something to seal the surface. Multiple very light coats of clear spray lacquer?

The instillation: It was a bit of a battle with some swearing and was done in sections. This thick walled foam insulation does NOT like being bent and I probably got more Super Glue on my fingers and palms than the seams and joints. Acetone, fortunately, is a great Super Glue solvent. There is a 7" strip where I had to cut a slot in the Armacell because the AC pipe is too close to the firewall insulation to get the Armacell around the pipe. Also had to use some spray detergent on the firewall to get the insulation around the pipe in another spot. I used electrical tape on the joints in an effort to keep hot engine bay air out.

Kudos to Tigster for suggesting the MOD!!! It never would have occurred to me. I wish I'd done the MOD on my black IROC and my arrest me red Z28 with a black roof and huge amount of glass.

Great post. But does it translate into colder air blowing on me? Use your equipment to measure that. :)

I'm going to start selling my polar bear repellent. 1 dollar + s & h, never get attacked by a polar bear in your home, guaranteed.

After several years of thinking about doing this mod, I bought some "Cool Tape" by Design Engineering, Inc. and wrapped the tube that others have suggested to wrap in this post. I used "Cool tape" because it is extremely thin and there isn't much room between the back wall and the tube. I used forceps to apply the tape, it's hard to use your fingers. It took me about 15 minutes to do.
I don't know if it makes the air colder as I didn't measure, but comparing back to back on identical days I definitely noticed a difference. Most importantly, during city driving, I could turn down the fan speed one setting below what I would usually use to achieve and maintain the same comfort.
The "cool tape" was $20 and looks like webbed aluminum when finished, a clean look. Do this mod!

Afterr eading this thread it is apparent there are strong feelings on both sides. Is it a waste of time? Is the analysis of the engineering dept. a correct one?

Well, like elbows, I've got two and I've been known to be an even bigger one. Sometimes in product development there comes a time when you have to "fire the engineer and ship the product."

Funny how everyone forgets what is at the heart of a placebo..... it "fools" you into thinking you're getting cured. What most forget is that sometimes people heal themselves unexplicably (and some on placebo.) Could it be that they just needed to "feel" they were getting better so their body would kick in and heal?? Dunno, I'm not a doctor.

As for the mod here's my .02 - MY AC SUCKS so I will try it. My friend has an AC Master's licence and was formally in the electronics field where he worked on some contained liquid cooling systems for processors before starting his own business. My cost for the armorflex insulation = $0.00! I'll just re-use some old one off a house that got new stuff.

Hopefully I won't get friggin critiqued for "WASTING" 10 minutes of my life trying this. It's been over 100 for many, many days around here in Texas and the AC in my 1993 POS Grand Cherokee feels much better than the RX-8. While I'm at it, I will check the Cabin Air Filter also but I'm not sure this will have much to do with it as the CFM at the vents seems fine. Funny, I don't remeber seeing any mention of the CAF in this thread but maybe it was because I was skimming?

i actually just did this and am yet to try it out ... will post here if i notice any change

hmm... I'm somehow dubious this procedure will yield the claimed results. Perhaps the colder A/C temperatures was due to different atmospheric conditions--clouds, cooler day, less humidity etc-- or perhaps the temperature variance was falsely perceived by the subject, ie it was all a placebo effect.

It would certainly be easy to set up controlled before-after test. Not as easy as doing the mod and NOT testing of course. Then again...if the mod does nothing but make people feel like they're cooler maybe that's good enough!

I'd try it but..my AC worked fine before it stopped working completely. No amount of pipe wrapping can help me now!

jds

I have a natural way of getting colder A/C.

The Nature MOD.

While driving in the country at midnight with your wife and 6month old in the car and still 1h30mins to go on your trip...

1. Hit a Racoon at 125km/h on the road.

2. Inspect damage

3. Rip off front lip and complete undertray

4. profit... uh I mean COLDER A/C.

:wiggle:

Summer is coming up.

There is still debate if insulate AC pipe helps or not.
But the project cost $2.5 and 5 mins, it worth a shot.


I use pre-slice, peal and seal insulation foam tube, designed hot water copper pipe.
One insulation foam tube from Home Depot is 2 yards, cost around $5 &
can be installed for 2 cars.

Peal and seal. No zip tie.

Planing is 10 mins, and you can skip this.
Installation is < 5 mins.


Picture is pretty self-explanatory.

Note: Length of the tube will change a little if tube diameter change.
Better engine bay view coming up. I just took a snap shot with my phone.

hey man i did mines like yours last week and i couldnt be happier, thanks!

^
You are welcome.

This mod is only necessary for Left Hand Drive Cars..

RHD 8's have "plumbing" on the same side as the compressor and evaporator, therefore they don't have the pipe that goes over top of engine left to right.

After all this time, no one has decided to find some definitive results by measuring the temp of the air blowing into the cabin before and after the mod?!