Has Mazda published specifications for the rotational rate that should be expected respectively for the S1 and S2 motors? I didn't find them in my shop manual (maybe mine is obsolete) but instead found the seemingly insane instruction to make sure that they aren't rotating backwards. Is this something that they realistically could malfunction into doing?

 

Yes, I was surprised to Read that "an Overheating Condition" in the S2 WS Manual could be the Motors/Fans Running Backwards!!...which is somewhat concerning as you would hear your fans running but are they going in the correct direction??...you would have to get out and put your hand in front of the Air Con Condenser and "feel" the draft direction.

All Instructions I have seen refer to fans at Low, Medium and High, S1's do not have the Medium speed...there is no RPM figures given.

You cars PCM determines watts to motors depending on info from Temp Sensor.

IMO I believe these fan motors are going to "slowly" go south with age/use..speed wise.

I would also go out on a limb and 'suggest' all motors should be replaced at about 7 years of age/use.

 

I do find it troubling that there's no real test in the shop manual for whether the motor is actually turning fast enough and therefore performing as desired.

On the other hand, I've been unable to perform the testing I wanted because my car only seems to malfunction after conditions of 98F/37C, direct sunlight, and running the car well past fully warmed up. I've not had a weekend afternoon available to me in several weeks where the weather cooperated by giving me hot enough conditions to reproduce the failure I saw earlier in the Summer. Irritatingly, my AC and engine temperatures have all been annoyingly normal for weeks.

On the other hand, I am still working out the feasibility of swapping out the S1 motors and shroud, if only because the cost of the parts is lower than replacing my 2 S1 fan motors.

I am also looking to insulate the exposed metal line that emerges from the condenser and feeds to the compressor as it seems that on very hot days, that line would be exposed to very high air temperatures from the radiator. I did notice that the air inlet temperature to the engine would climb to well over 20F above ambient under those conditions where I saw malfunctions, so I am guessing that there was a very hot air bubble around the radiator. If my guess is correct, and since Mazda does insulate the bulk of the line from the condenser to the compressor, it seems reasonable that this exposed metal line could cause degradation of AC efficiency on very hot days, especially if air flow rates are reduced.

 

Advance auto parts sell cool tape . But it only goes up to 400f.. Degrees. Is that good enough? 18.00 a roll 15 ft.

 

IMO the Fan Motor issue is also another "Heat" one, the durability of the little motors sandwiched between all that Summer Heat...more than likely the S2 motors will go the same way over time.

What I have to caution you in using S2 motors in an S1 are the connections, the S2's are a 4 pin plug..the S1 could be the same?, more than likely they are.

Would be interesting to compare the Sales Stats for these motors in Cooler climates like Germany and UK.

The S2 Factory WS manual says Current Draw between 7.7 and 10.7 AMPS with a fully charged 12V battery, both fans on.( I guess max speed)....it does not say..
Just says replace fans if not running smoothly or correctly.

 

It should. I used this with no problems so far:

http://www.summitracing.com/parts/DEI-010408/

I like that it is not just pure aluminum, but has a little fiberglass to help with insulation (and not just reflection). Because a tape is so thin, I took some fiberglass (not urethane!) water pipe wrap, wrapped the tube with that first, then put the tape around that. It's not as "neat" but gives much better insulation. I also put just the tape around the black hoses coming from the A/C compressor. That helps reflect heat from the engine sitting 6" away.

This little trick makes a big difference. During last month's heat wave, the interior remained passibly comfortable with 100 deg F outside temps while the comfort limit was only 85-90 F before.

It is interesting to note that the temperature of the water coming from the radiator (measured in the lower radiator hose), rises by 10-12 deg F when the AC was switched on while cruising down the highway at 75 mph in ~90 deg outside heat.

 

Pics please.

 

There sure is a lot of confirmation bias in here...

I did this mod, and saw zero improvement. I live in florida where it has reached 100F quite often these past couple weeks, which is why I tried it. Until someone makes a video showing a *measured* improvement I will remain skeptical.

What did make a huge difference, however, is getting a reflective sun shade. I didn't realize how much of a difference those could make, but now my car is almost colder than the parking lot when I come back to it. My A/C now takes about 5-10 mins to get the car cool and comfortable compared to 30+ mins. And it was just as cheap.

 

Agree with above. And tinting the windows helps. I'm glad I wrapped my line, though. It makes me cold when I think about it.

 

You have a very apt user name then ....

 

Well, I can't see where insulating or covering the "Cold" exposed pipe would not hurt, and IMO has to help as the pipe would be insulated/protected from engine heat, it may not make the air cond "colder" but it would improve it's efficiency...compressor on/off cycling.

Remember Left hand drive RX-8's ONLY have this long pipe which travels over at top of bulkhead (firewall) and back down to the right side into cabin and evaporator.

Right hand drives have a very short pipe as Evaporator inlet is on the left side of car, as is the Compressor position/mounting for both Left and Right drive 8's.

 

anyone checking the a/c charge? May just need some freon or whatever they call it now a day?

 

With the 100 degree days here in DC lately, in figured I'd give this a try. I have an early 04 production model with no A/C amplifier. It's alwya been ok, but idles a tad rough when the A/C is running. Gotta clean the MAF next.

I used this stuff
http://www.thermotec.com/products/17...ermo-flex.html

Bought 1" diameter x 3' long, and slit it so it wrapped around the line and scutes with cable ties. Tomorrow is supposed to be quite hot, so I'll give it a road test.

Probably gotta get to the store for contact cleaner for the MAF next...

I got some catching up to do with my mods and tweaks as I've been stock for too long.

 

Quote:

I have an early 04 production model with no A/C amplifier

HUH??....
I am pretty sure ALL RX-8's come with an Amplifier... how does your AC system work without one??

There is a "modified unit" just for your car...can give you the Part Number if you are interested, or look in the TSB's..

https://www.rx8club.com/showpost.php...91&postcount=2

https://www.rx8club.com/showthread.p...19#post3258119

APPLICABLE MODEL(S)/VINS
2004 RX8
VIN: JM1FE17**40 000001-118171 (up to 9/11/03 production).

FEY2-61-540 A/C Amplifier $490.54!!...OUCH!!

 

http://www.rotaryinsider.com/diy-tac...eset-gap58.htm

RX8 AC reset

AC RESET:

1. Make sure the car is off AND the HVAC fan is off AND the A/C on/off button is off.
2. Press and hold the front defroster (on the left) AND air source (recirc/fresh air) buttons
3. Continue pressing the buttons in step 2 and turn the key to ACC for 3 seconds
4. Continue pressing the buttons in step 2 and further turn the key to ON (NOT START) for 3 sec.
5. Verify the programming update by observing the REAR defroster LED blink 3 times.
6. Release the two buttons from step 2 and start the car.

Has anyone ever try this? came across this info on the web...

 

Not to be the bearer of bad news but I do a lot of A/C work. By this I mean that I used to be a heating and cooling engineer for Ford. Wrapping the lines may give you colder A/C but you also risk freezing up the EVAP core.

This system should have a post EVAP temperature sensor. This will cause the A/C to cycle more often and creating more stress and load on the A/C system. When the HVAC module monitors the EVAP temperature, if it sees near freezing, it will start to pulse the compressor on and off to alleviate an EVAP freeze up condition.

 

Cant speak for RX-8 but earlier Mazda's had the Evaporator Temp Sensor located In the EVAP Fins...so if it gets too cold or freezes, compressor turns off as you said..

So how can this be an issue.

RH Drive RX-8's have a more direct line into EVAP from Compressor (LH Side of Engine), (no long exposed pipe going over top of engine)..and it is not an issue.

 

Ok, a few things. If your AC is cycling then insulating your lines is probably useless, the most likely causes are an overcharged system or dirty condenser causing it to cycle on high pressure, or a dirty evap or even more likely dirty cabin filter causing it to cycle on low temperature. If it's running full blast and not cooling then it's probably a low charge, but the previous conditions can also cause inferior cooling if they aren't bad enough to cause the system to cycle.

Is insulating your lines usefull? Probably. It lowers the heat load on the system, and in the case of the high pressure liquid line it can also lower the pressure if the line is hotter than the condenser. But either way it would increase overall efficiency, but should not make or break the cooling cycle.

I really can't believe in 10 pages nobody mentioned the cabin air filter. Between that and overcharged systems I bet 90% of the cooling problems could be solved.

 

There is an evap temp sensor (see page 31 of the FSM). Are you saying there needs to be a second one?

Too, remember that the RHD Japanese/British version doesn't have the long pipe over the engine. Insulating that pipe in the LHD versions will still not bring it up to the effeciency of the RHD's, so one would think the system would have to take that into account anyway.

 

I just did the re-program as well, got the 3 blinks for confirmation, and guess what? No measured difference. I dug up the official mazda bulletin, and all this re-program does is makes the re-circ default. Really, more confirmation bias/placebo effect?

 

Yes, and the LHD's have a different Amplifier Control Box to RHD.

 

Check out the TSB's here...
There is one on the Temp Amplifier Box, and a "modified" version is also available for Customers who complain of poor AC Cooling Performance, I think within a certain MY or VIN numbers from my memory?)

 

No, you would not need a second one. The original one is just fine.

I really wasnt that clear on how to explain this.

The HVAC module will have programming to keep the compressor cycling. This will monitor the a/c pressure and the EVAP temp sensor. If you wrap the lines, this will raise the pressure of the high side. The compressor will cycle more due to the higher pressure and the lower EVAP core temperature.

If you try and lower the temperature, the EVAP core will freeze. This will all depend on ambient temperature, humidity, and altitude.

 

But I don't think the target temperature will be changed unless the controller is reprogrammed. With the wrapping, in principle, the compressor will cycle more, which, carried to extremes, is bad. However, in practice, at least with an all-black car and in 80-85 deg plus temps, I'm not detecting any cycling at all from the compressor. Without the wrap, it was running 'full blast' all the time. With, and with the air mixing flapper closed, I have to manually shut off the the AC intermittantly, 'cause it gets too cold in the cockpit.

Anecdotal I know, but wrapping seems to help.

 

Not sure if this is the ideal location but I do have a question and searching has failed me, My HVAC fan speed 2 doesnt work, All the others work fine. What should I check or look into? I wouldn't imagine there is a fuse for individual fan speeds, so what do I look at? Thanks guys.