View Full Version : Air Conditioning
Urchin 07-20-2003, 10:22 AM The air conditioning on mine does seem weak. Just when it starts getting cold it cycles off. When the fan is on 3 or 4, it blows luke warm air. This is even in the evening when the temp is under 100. Not sure if it is freon related or what. How is the air on others?
rxeightr 07-20-2003, 10:32 AM Mine is the same way. It is not as potent as other vehicles I have owned.
Still keeps us cool, but it does cycle regulary.
Spin9k 07-20-2003, 10:38 AM I noticed something like this as well. It's either cold, cold, or seems like it's not on and blowing warmish air. I'm used to climate control in my Acura, which of course auto controls temp, blower speed, etc. Now THAT is the way they should all be!
In MHO I think maybe Mazda cut a corner a little too close here in perhaps capacity (to keep from affecting power too much??) and comfort with no climate control (to keep price down??).
I found that by putting fan on Hi, pointing ducts away from me so I don't get freezing, it's just about right when it's hot and muggy. Seems to mix the air and equalize out.
***Maybe too there is an ecocomy seeting we're in or permanently designed in to the system, cause this is how my other car (old Eagle Summit w/manual air) works when in econo mode air conditioning setting??
PERHAPS MAZDA CAN TELL US WHAT'S UP HERE?
Boozehound 07-20-2003, 10:50 AM Same problem here too... I've been taking my car through S. Texas for a little break in and the AC seems to blow freezing cold air and about 30 seconds later, there's a 5 second burst of warm air. Maybe there's a valve that's circulating hot water through a heat exchanger when it's not supposed to (essentially turning the heater on periodically). I dont know why it is so noticable, it doesn't act like the compressor shut off for a second and you're just getting recirc, its like its bringing in outside air (even with recirc on) or heating the charge and hitting you with it.
I'd be really interested to know from Mazda whether this is a real problem, or just how the system was designed. And on that same note - how to best utilize the current system...
RobDickinson 07-20-2003, 11:22 AM lol suspicious 5 seconds.
The RX-8 switches off the A/C compressor for 5 seconds when throttle hits 65%
Maybee if you all wernt driving like nutters it'd be cooler...
StealthTL 07-20-2003, 11:35 AM That must be it.......a/c cut at 65% throttle.......I should slow down for a while, see if it cuts back in...........naaaah!
Rob isn't it time to rewrite your sig?
Maybe 'medium' power would be more appropriate?
Kidding! KIDDING!
S
RobDickinson 07-20-2003, 11:37 AM Originally posted by StealthTL
Rob isn't it time to rewrite your sig?
4 that you die riiiight after Mazda UK...
Anyhow, soon be back to 250ps :)
Urchin 07-20-2003, 12:32 PM It is not thh cut off at 65% throttle since I drove like a grandma for thh first 100 miles. This happens at steady cruising at 50-55 mph. I will ask the dealer on Monday (gotta finish paying for the car) and post if I learn anything interesting.
RX-Nut 07-20-2003, 01:22 PM Yup, I've noticed it too, and thought it was just me. The air does seem to go cold and warm, cold and warm regardless of throttle..
Hmm.. Mazda can you help answer our question?
Gamera 07-20-2003, 02:50 PM Aha, so that's it. Yesterday my wife said she kept seeing a white puff of air (probably just moisture-ladened) coming out of the vent every now and then. I never caught it, but it sounds like what you guys are describing.
It's been about 85-90 F these past few days, and bit more humid than normal for SoCal (side effect of the hurricane in the Gulf), I thought the AC was plenty cool with the air recycled, but just okay when pulling outside air. Blowing air without the AC compressor running seems to always result in warm air, mabye a result of the vent intakes being so close to the engine (actually, I haven't yet checked whether they are located at the base of the windshield like most cars).
Boozehound 07-20-2003, 05:02 PM Definitely not the throttle cut out. Cruising in 6th gear at 70mph isn't going to cut the throttle. As for the puff of white air, a switch to recirc should cure the problem. But the cycling... that's a good one for Mazda.
miata2rx8 07-20-2003, 05:27 PM the a/c is weak- keeps cool but not cold- even my miata or a friends 10 year old truck is colder.
its been around 100 around here
Good Duck 07-20-2003, 05:58 PM Originally posted by miata2rx8
the a/c is weak- keeps cool but not cold- even my miata or a friends 10 year old truck is colder.
Older vehicles with R-12 refridgerant are always much colder than the current R-134A.
tribal azn2 07-20-2003, 06:03 PM my a/c is prefectly fine.
i live in southern ca AND i have to park outside. when u get in ur car, roll the windows turn, turn a/c to full, start driving, after few seconds close windows, make sure its on recycle mode.
eccles 07-20-2003, 09:19 PM I didn't notice a problem during the couple of days I had one on loan from Mazda South. The only times I noticed it cycling on and off as some folks have described, was (a) when I was heavily on the gas, and (b) if I I didn't have the temp knob cranked all the way to max cold.
Unlike the Miata, which runs the AC continuously if the button is pressed and blends in hot air from the heater if the control is turned towards hot, it appears that the RX-8 will cycle the AC on and off if the temp control is anywhere other than max cold, and only appears to start mixing in heat once you get past about half-scale on the temp knob. This seems like a more fuel-efficient method to me.
Wolfer 07-20-2003, 09:30 PM If notice if the floor and dash vents are both on not much air comes out. But if just the dash vents are on it seems fine.
Now if I just have the floor vents on I don't feel any air from below.
Not sure if floor vents are working. Doesn't seem like it.
P00Man 07-20-2003, 09:36 PM yeah, i noticed that too, if thats the case (make sure of it when my car comes) im just not gunna get it, i can pay a lot less if i want something that doesnt work
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BUBBLER PIPE (http://bubblers.net/)
Urchin 07-20-2003, 09:38 PM If notice if the floor and dash vents are both on not much air comes out. But if just the dash vents are on it seems fine.
It not the amount of air coming from the vent, but the temperature. Got a vent thermometer, and the air coming out goes down to 45-47 degrees, but then the compressor cycles off and the temp goes up to 50-53 degress before the compressor comes back on. The temp control is all the way left (cold). Does anyone know if there is a way to control the temp where the compressor cycles off? It gets down to 45 easily, just does not stay there.
P00Man 07-20-2003, 09:48 PM eyah, but it seems like its hardly blowing...this issue is really starting to get to me....
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TJRX8 07-20-2003, 11:44 PM In the 90's all weekend here and I didn't notice any problems with the A/C. It spent most of it's time in fan speed 1 or 2. I also didn't notice any cut-off of the cool air either. I'll have to watch for it.
8_wannabe 07-21-2003, 12:06 AM I concur with Wolfer. Dash vents blow fine, then I shift to floor + vent and I cannot feel anything coming out of the vent. Though I do then feel it on my feet. If I crank up the fan a bit more (3 or higher) I can barely feel something out the vents. Since many of you apparently aren't experiencing this problem I just may make a note of it in my first service check. I keep a/c constantly at the coolest setting, with outside air coming in. I'll try recirc tommorow to see if that's any better.
akrx8 07-21-2003, 12:18 AM just a observasion but my current cars ac only blows ac air thru dash vents only,the way its made i guess.turn on heat and floor vents rock.if you think your floor vents are not working id first try heat and see if it blows hot air.
8_wannabe 07-21-2003, 01:46 AM Originally posted by akrx8
just a observasion but my current cars ac only blows ac air thru dash vents only,the way its made i guess.turn on heat and floor vents rock.if you think your floor vents are not working id first try heat and see if it blows hot air.
No, actually the floor vents work fine. The problem is, when you have a/c on and try to use floor plus dash vents, all the air comes out the floor vents. Bummer. I'm sure they also work fine for heat, but it's too damn hot now for me to try.
Wolfer 07-21-2003, 08:57 AM I guess its fine the way it is. I just hope the heat will blow from the bottem. I hate the heat coming out the dash during winter.
Seems to be cool enough if just the dash vents are on.
DisneyDestroyer 07-21-2003, 11:24 AM I drove over 400 miles this weekend through 90+ heat (midday LA and north-of-LA-desert).
Over that time the AC got better and better. I sincerely think that there is a calibration time needed for the ECU for the AC operation / shutoff. On the way up I would keep it at about 3, all the way cold, and still be on the warm side. Heading back yesterday afternoon, I had it on 1 and was comfortable.
Give it some time, I think the situation will improve.
ZOOOM 07-21-2003, 11:48 AM Has anybody noticed the heat build-up around the the driver's cabin especially when the air is turned off and the fresh air passage is open meaning (no recirculating) I noticed that last night while it was kind of cool outside 55F normaly on other cars you get almost the same outside air temerature from the vents I am thinking it is because the higher temperature the rotary engine runs on. I didn't like that but I still love the car:D
OmegaBob 07-21-2003, 01:26 PM Hey, just a thought....
You think the problem with the AC might have to do with the fact that Mazda might have included that cabin air filter with these cars? Hence the reason why the air flow seems to be blocked.
Can anyone who has their car check to see:
1 - where the filter is at (my guess, behind the glove box)
2 - is there a filter in there
Rx4FUN 07-21-2003, 01:31 PM When I test drove an 8 last week in Phoenix (only 108 that day), the AC was fair. About the same as my Z28. I think both cars have the same issue. The engine sits far enough back that part of it actually sits right under the dash and all the AC ducting. As the engine heats up the heat rises and the area under the dash gets very warm. The cooled air from the AC condenser has to make its way through this heated duct work before entering the cabin. While the compressor is running the air is cool (although not as cool as some other cars), but when the compressor cycles off, the air is then heated under the dash before exiting into the interior. I get a nice blast of hot air in my Z under hard acceleration when the compressor cycles off. It's even worse in the Z after it sits in the sun for a while (big windshield and big dash).
I'm also guessing that the temperature pickup in the 8 for the AC compressor cycling is located fairly close to the condenser and doesn't take into account the additional heating that happens further along in the duct work. Thus accounting for the large variation in temperatures.
Just a guess...
Boozehound 07-21-2003, 02:30 PM Everybody's saying the compressor cycles... why should it be cycling at all under max cold contions? There's no auto climate control, the driver adjusts temp and fan speed, and I would assume at full cold conditions with full fan, and recirc, it shouldn't cycle off period.
I suppose there could be a cabin mounted thermocouple that lets the ECM know how cold/hot the cabin is and engages/disengages the compressor clutch accodingly. Which is pretty much all an automatic climate control does. If this is the case, I hope there's a fix. Either give us an automated system, or full control - not something where the user gets overrided periodically for conditions not driven by performance/ engine use.
Rx4FUN 07-21-2003, 04:04 PM You don't need to have auto climate control for the compressor to cycle. The AC system in a car needs to keep the evaporator from freezing otherwise it will become a block of ice from condensation and no air will be able to flow through it. There are two ways to control the minimum temperature of the evaporator, either cycle the compressor, or cylcle the suction of the compressor on the evaporator. I'm not sure which method is used by the RX-8.
Here is a link that explains how it works:
http://www.delanet.com/~pparish/ac_works.htm
91vert 07-21-2003, 09:15 PM I'm really wondering if there is some design issue with Mazda A/C when it comes to trying to mix the air through the dash vents and floor vents.
I have a 99 Millenia S, and I have noticed on that car that if I have the air coming out of the dash vents and the floor vents that it doesn't cool as well as just having it coming out of the dash vents only. Air actually does come out of the floor vents, but very little.....barely noticable unless you have the blower cranked.
I hate the auto climate control, so I never use it. When it is 90+ here in St. Louis (and it is usually humid as hell here), my Millenia A/C works best on recirc and the blower on the second speed. It blows ice cold and usually cools the car down quickly. I hear (never feel) the compressor cycle on and off sitting in traffic with everything set this way. Usually cycles on and off in about 30 second intervals.
I hope my 8 A/C will at least work just as well as the current ride. If not, I am going to be very disappointed.
I'm glad other people are finding the A/C annoying - I thought it was just me. After almost 3 months with the car the A/C is my #1 complaint. For me it's not the cycling on and off but the actual capacity of the unit being too low. This weekend I was driving for 2 hours with the air on recirc & desired temperature at 24C. It was 30C ish outside (but 38-40 on the ambient sensor) and the fan never went below 5 out of the 6 speed range. There has to be something up with that. The air coming out is cold if you direct it at your body but the unit never manages to cool the cabin.
If you shut the side vents you get lots more air out of the centre console. If you use the floor setting it does reduce things considerably. On that setting air also goes to the back from outlets under the front seats.
TybeeRX-8 07-21-2003, 09:23 PM I suppose this should concern me, but I'll have see for myself.
In my Miata, the ac seems to work fine when using the dash vents and somewhat less when using both dash and floor vents. I usually leave it set on #3 fan speed and slightly off maximum cold. Of course, when it's really hot and the top is up, I use recirculate to cool things down. When driving, it will blow warm air if the pedal is on the floor around 5k rpm. You can feel the clutch disengage and once I back off to cruise, it cools again.
FredB 07-21-2003, 09:40 PM After hear owner say that the blower sends out very warm air (AC off) even on cool day I'm going to propose this theory about at least part of what's going on.
When using AC the compressor is going to go off and on in response to your setting and what the sensor says the temperature is. I don't know where that sensor is but that may be part of the issue. The other is that there's just too much heat around all the ducting for the AC as so as soon as the compressor shuts off the temperature of the delivered air rapidly rises. It increases in any vehicle but at a much slower rate. The RX-8 like the RX-7 places the engine and transmission closer to the driver than other vehicles. In fact I think they moved engine further back on the RX-8 than the RX-7 by an inch or so. All of this is supported by the fact that the cosole seems to be getting somewhat warm. So in addition there is a large heat load on this AC as well as the delivered air being heated by its surroundings.
I don't know if this explains the entire issue but maybe part of it. Maybe the temperature control accuracy is also not matched very well to this environment and the AC stays off too long, allowing the air temperature to rise too quickly. Maybe some sort of radiant barrier or insulation might help. Lastly it could be a compressor gas charging issue as well although I doubt that all cars would suffer from this unless they just got it wrong. I'm sure Mazda will have to come up with some fix for this if enough complain about it. But a lot of this makes sense if you consider that you get warm air when running on a cool day without AC. The RX-7 also created a lot of heat but as I remember, the AC more than kept up with it. Just a theory for now. What do others think?
Urchin 07-21-2003, 10:32 PM Thanks RX4Fun. From the link you posted, the thermostatic switch cycles the compressor off when the evaporator gets too cold.
Question: Is it possible to adjust the switch to control the temparture at which the compressor cycles. Any A/C technicians out there? 40 degrees or less would be good. My '88 Vert cycles off in the low 30's, and never have had problem with ice on the evaporator.
And please do not take this as a gripe, love the car. The A/C is just an observation that might make the car even more fun (110 today in Phoenix.)
bassik277 07-24-2003, 01:42 PM I live in Los Angeles, where it gets pretty damn hot, and i was wondering to those who have the car, is the air-conditioning so poor that it leaves the cabin unbearably hot? Or is everybody just exagerating e little bit
DisneyDestroyer 07-24-2003, 02:09 PM I was driving through downtown LA, SFValley, and SCValley last weekend in the middle of the day (90+ in all three) and was never uncomfortable due to lacking AC. It did seem to improve over the course of the few hundred miles I drove that weekend.
At the beginning of ownership I was keeping it at notch 2 or 3 (out of 4), but now I'm fine at 1 almost all the time.
Good Duck 07-24-2003, 02:40 PM Originally posted by bassik277
I live in Los Angeles, where it gets pretty damn hot, and i was wondering to those who have the car, is the air-conditioning so poor that it leaves the cabin unbearably hot? Or is everybody just exagerating e little bit
It all depends on personal preference really.
Today at midday, it was about 93+ outside. I had to turn the A/C on to full blast for the first 10 minutes. After that, I left the fan setting at "2". That was enough to keep the cabin relatively cool. It seems to have the same performance as my Civic. Although, the only gripe I have is the fan speed setting needs to be more variable. I'm used to my Civic fan that function more like a rheostat rather than just 4 speeds.
Originally posted by bassik277
I live in Los Angeles, where it gets pretty damn hot, and i was wondering to those who have the car, is the air-conditioning so poor that it leaves the cabin unbearably hot? Or is everybody just exagerating e little bit
I work in the SF valley... it is uncomfortable when at idle, but when cruising, it cools down quite a bit.
Master Phu 07-24-2003, 02:51 PM I live in Reno where the weather changes every 5 minutes or so. Two days ago it was 103F and i kept the AC on 3, recirculating with only the dash vents blowing directly at me and I was fine even at idle. I really don't care whether the cabin is cool or not as long as I'm cool so that might be why I can bear the AC better than most here.
8_wannabe 07-24-2003, 03:15 PM I don't like putting the fan above 2 'cause it gets noisy, so that probably contributes to my problem. At settings 1 or 2 it struggles to keep the cabin cool if outside temp is above maybe 80 or so. If I set it to blow on feet and face, it goes 95% to feet and 5% to face; very unsatisfactory. Therefore, I leave it on face only. With no pax, I shut the right-side vent and increase my airflow. And during all the above, the compressor cycles on and off, so air temp from vents fluctuates widely.
I'd say it's a slight disappointment but in no way reduces my satisfaction with the car. Everything else is so wonderful that the a/c problems fade into the woodwork. I'm just puzzled as to why this is an issue at all. Clearly, Mazda could have done better and I don't know why they didn't. I've got 540 miles on the car. If it improves with age I oughta be seeing that pretty soon. I'll let you know. Please don't let this be the deciding factor in a buy/no buy decision. I think at worse it's just a minor annoyance; doesn't seem to bother my son at all in the same car.
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