Just picked up my '05 RX-8 yesterday and am pleased with our purchase thus far. The a/c, however, acted odd on the way home. It went from cold (I'm in SW FL) to BLAZING hot in an instant. My wife then played with the temperature know from cold to hot and then it went cold again and stayed that way the rest of the time. Any ideas what causes this?

 

I have noticed the same kinds of hot cold issues with my rx8 as well. I think that this is a common thing with the 8s. Basically if you have the AC set to cold, but then do some spirited driving, the engines heat turns your super cold air into lukewarm and your lukewarm into hot air. i.e. when you floor it all the way to 80 or so I would not be surprised at the blazing hot air, but only temporarily.

Essentially, the 8 runs hot and the AC lets you know.

But man is it worth it...

If it really is killing you though, there are some easy mods to improve the AC's cooling. Check out the doityourself forums and it should be easy to find.

 

There are issues with the temp control ****, and DIY's for that. There are also issues with airflow on at least the early ones where the AC will not work if stopped, even if the fans are running. There are also the fans..

There are 2 threads in my signature, the $100 one will walk through several recommended mods or enhancements. You can do all of them for $100. Several are related to AC performance (I live in Central Florida, Oviedo) and understand your pain.

 

The best results I've personally seen, is actually cheap, putting pipe insulator over the a/c line that runs on top the engine along the firewall. That and reprogramming the ac amp have improved my ac by leaps and bounds.

New Orleans, La, and I stayed nice and cool over the summer.

 

Its 24 degrees outside my house right now. Thanks for rubbing it in.

 

Why would you insulate the pipe exiting the evaporator? How does this improve cooling?

 

go get it charged or its freeon that u need

 

I don't know, got the idea off of a few members here. Try it and see for yourself, only cost like $3 at homedepot.

 

Hmn, I find it interesting that you would perform a mod on your car and not know what it does or how it works. I did find the thread in question, as a matter of fact I came across that thread a few months ago and dismissed it despite the fact there are several pages of replies. I am still convinced it's not worth reading. In short that line that you and apparently a few others have insulated is the line that is after the evaporator. meaning it's cooling capability was already utilized inside the cabin. Despite the fact that the mod is cheap, it is still worthless.

To the OP best thing for you to do is insure that your compressor is operational. Test to insure that the blend door is operating as it should. If not perform the DIY to solder the loose joints. If that does not help, evacuate and re-charge the system and report back.

 

@^^
That line will soak up heat from the engine compartment, that will raise the pressure in the line and lower the pressure differential across the expansion valve, which will run less freon through the valve, which will increase the back pressure on the high side which will cut off the compressor. Also, any heat that goes in that line will also have to be removed. Less extra heat in, less extra heat that has to be pulled out through the condenser.

OP, best to do both lines.

 

I have noticed the same kinds of hot cold issues with my rx8 as well. I think that this is a common thing with the 8s. Basically if you have the AC set to cold, but then do some spirited driving, the engines heat turns your super cold air into lukewarm and your lukewarm into hot air. i.e. when you floor it all the way to 80 or so I would not be surprised at the blazing hot air, but only temporarily.

Essentially, the 8 runs hot and the AC lets you know.



Wrong, just plain fantasy.

Most cars, including '8s, switch off the compressor at 75%/80% throttle position, to 'free up' more power, then the a/c gets warm. No magic, no "car telling you it's hot," just the standard throttle position cutout.

S

 

Lol , wow you know I did not even pay attention to that post. Good catch.

 

If you don't want to do it because you think it will have no effect, then by all means don't do it. it takes all but $3 and 5 mins of your time to try it. And maybe 30sec to undo it.

 

It's not up to me to prove you wrong - there is zero data that this mod does anything.

It can therefore be dismissed as wishful thinking, at best....

 

And the location of the data proving it does not to work is...?

There are plenty of other car forums including rx7club and corvetteforum that mention doing this to improve ac performance. Have you tried it and saw no results?

 

+1 on that

 

It is hilarious, how some people act like their word is law, with no facts or testing to back it up... It's just another case of "Let's make **** up and call it facts day." .

Theories are often proven wrong when put to use in the real world. I'm not going to do like last time and post video proving data, enjoy the heat with your ignorance.

 

No one is making up anything. Automobile air conditioning is not theoretical, it has been proven to work. There are principles about the way the system works and no amount of insulation will change that. If that line were upstream of the evaporator I would not be so quick to dismiss it. You don't need empirical data when I and engineers the world over know how the system operates. You seem to be enjoying the placebo effect and that's fine.

When I asked why you performed this mod and how it works, your answer was "I don't know, I got the idea from a few members here". If nothing else you are less than qualified to offer advice on automotive air conditioning systems. Certainly not informed enough to imply that the other people who have replied to this thread are ignorant.

 

The "I don't know, I got the idea from a few members here." is basically a half fast job at replying on my phone and maybe suggesting for you to search for that info, and I honestly do not remember much of the thread or what was said, that was sometime last summer. Sorry, I can't read minds, so I did not know you had already read it.

All I can tell you is I keep one of those little cheap temp probes in my vent and I saw results instantly. Don't believe me? Then don't. You think I have stock or something in pipe insulating foam? I don't. Why would I sit here and say it does work, if I didn't see it for myself?

Not sure where you live, but it gets hot and muggy here all the time. Every little bit is noticeable and helps.



-Shawn