lepichichi

iTrader: (10)

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

krijpipudht

^
You are welcome.

ASH8

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.

Butters

iTrader: (1)

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?!

longpath

iTrader: (1)

I am debating this modification due to my car's AC becoming temporarily non-functional under the following conditions:

• 100F/37C ambient
• 3.5 hour highway trip across 4 states in the US (CT, NY, NJ, & PA)
• daughter (2.5 years old) fell asleep half an hour before my wife, daughter, and I arrived at our destination
• our room was reserved under my wife's name so she insisted that while she got us checked in, my daughter and I stay in the car with the engine running in order to keep the air conditioner running
• coolant temperatures reached 243F/117C according to my ScanGauge II

My only cooling-related modification to date was switching to Evans waterless coolant late last Summer.

My RX-8 is a late 2004, made in June of '04 and purchased in October of '04. I am the original owner. I do not know if the amplifier was upgraded or not prior to my taking delivery of it; but it did not happen while the car has been owned by me.

I tried the "reprogramming" sequence this morning; but the blinking of the rear defroster indicator that was supposed to show that the reprogramming was successful never happened. I made five attempts, following the steps from the forum to the letter, failing every time.

If I implement this process, I will perform before and after measurements. I am also considering wrapping the OEM header to reduce under hood temperatures, and opening up the front fender well thermal exhausts for the oil coolers (I should mention that it was hot enough that my tyre pressure climbed to over the 42psi that my gauge could read and tripped the tyre pressure warning light on the dash).

FastFreddy61

We have an 04 6speed, the aircon works so well,after about 10 min driving on the autocest (Hiway),at around 180 k's,the air is so cold it exits the vents looking like steam, scared the crap out of me and the wife the first time it happened.

longpath

iTrader: (1)

My main concern is not AC when on the highway. It's when the car is idling. I'm wondering if the problem I'm seeing is more a matter of whether the fans aren't able to move enough air through the engine bay when the car is stationary and the AC is running. Could the refrigerant be seeing such high temperatures at the condenser, that it is remaining a gas? If so, perhaps a more powerful fan and/or relocating the battery and switching to the Mazdaspeed intake might improve airflow in the engine bay. Given the angle of the fan and the sandwich of the condenser and radiator, I'm debating a vented hood/bonnet as well, if I could get one where the vents lined up with the direction of air flow.

longpath

iTrader: (1)

After looking at this page on the HVAC system:
http://isomerica.net/~fluffy/Ren/RX8%20FSM/10Hvac.pdf

I am wondering if I might want to insulate the return line from the condenser to the compressor. Bear in mind that the time that I had a specific failure, where even on recirc the AC was blowing hot air, the engine coolant temperature had spiked to 243F/117C and the ambient temperature was at 100F/37C. Now I am also hypothesizing that I erred in letting the engine idle instead of bringing the revs to 3000 r.p.m.; but I think that would have only made the difference between the air emerging from the vents as cool instead of cold, not actually hot. I don't know what the temperature was at the vents; but I would say it was at least 80F/27C and very likely significantly warmer than that (if I equate it to water temperatures, the air emerging from the vents felt as warm as any jacuzzi I've ever been in). I am going to get a refrigerator thermometer and keep a log of temperatures (coolant, ambient, and vent).

When I saw something similar starting to happen again last weekend, I opened the hood/bonnet while the car was pulled over and parked. This kept the AC running acceptably well while I was waiting for my wife and my daughter and I waited in the car.

laythor

i hate this thread.

If your AC is weak the first thing you should be doing is checking that you have enough refrigerant in the system.
At idle the compressor spinning slowly and the lack of air movement make the AC less effective.

Wrapping these lines is a placebo

Highway8

iTrader: (11)

I agree but I disagree.

yes if the ac is not cold you have a problem, and at idle the ac is not going to be very effective.

However, insulating the lines doesn't hurt, and it's actually fairly common for lines to come insulated from the factory, usually when near a heat source. Because the mentioned lined on our car is not near the exhaust or cooling system mazda felt insulating it was not needed.

IMHO, test it. If it makes the ac colder, then great. If not, then lesson learned.

longpath

iTrader: (1)

In my own case, I was thinking of insulating the low pressure line between the condenser and the compressor, which is, in my opinion, exposed to heat from the radiator.

I am also considering insulating the line that goes over the engine along the firewall because the instance where my AC was completely inoperative, my engine's temperatures were climbing through the ceiling (I regard 243F as extremely high).

I don't know if the problem was that a stable bubble of hot air in the engine bay is preventing air from flowing through the condenser or if the problem is due to the compressor being unable to overcome the load of pressurised refrigerant having its pressure increased even more due to extreme heat in the engine bay. I don't know enough about the design of the compressor to even know if the latter conjectured scenario is even possible (HVAC engineers, please feel free to chime in here).

I purchased a thermometer with a long probe to let me monitor the temperatures in the centre AC vents. I have observed temperatures ranging from 47F to 55F. On my drive home this evening (19:15 EDT - 19:30 EDT) at ambient temperature of 80F, the vent temps showed as 47-53F. Intake temperature stabilised at 100F and coolant temperature was about 200F most of the trip home. The car was in a concrete parking garage all day, so it was not exposed to direct sunlight. I set the AC to re-circulate.

I am taking these initial measurements to establish a baseline of what the AC can actually do. Once I have some more readings, I'll insulate the lines I indicated above and then take new readings to compare. I will, in particular, take readings before and after on the actual day the modification is made, so that hopefully we can finally determine if this is mere placebo or actually achieves some detectable benefit.

longpath

iTrader: (1)

Assuming the whole real issue is nothing more than inadequate airflow through the condenser when the car is not moving, is there an aftermarket fan that moves more air and will fit?

laythor

or just realize the AC will be so-so at idle

longpath

iTrader: (1)

"so-so at idle" would be an improvement over hot like a hair-drier. Hot like a hair-drier is what I observed and what I am trying to work around. If I can get it to be only "so-so at idle" I'll be quite happy.

It works perfectly well when the car is moving. My problem is when the car is stationary. If you have suggestions on how I might correct that, feel free to make them; but accepting the current situation is not an option and neither is moving further from the equator until Summer is over.

Opening the hood/bonnet does work. Does anyone have any suggestions on how I might achieve the same result without having to get out of the car? That's why I asked about the possibility of an aftermarket fan. I did not mean for the ventilation system. I meant a better fan for the engine bay, radiator, and AC condenser.

Highway8

iTrader: (11)

The ac stopped working on you because the ect were too high. The ecu might have done it automatically or it was just a result of heat. Adding another fan is not a good option, the stock fans flow plenty of air. You need to address the overheating of the vehicle. Over 240 is tooo hot at idle, it's too hot period. I see you changed to evans npg. Is that the NPG-R? Remember the car will run warmer with it but you shouldn't be 240w at idle.

Check all your basics first. Good rad cap? Make sure there is no air in the system including the heater core and of course that it's full but not overfilled.

If it checks out, go with upgrades. Battery in trunk and AEM for better air flow, BHR or mazmart radiator, mazmart pump and t-Stat.

longpath

iTrader: (1)

I'm using NPG+. I'll double check the levels and see if air has gotten into the system. The radiator cap and thermostat are original (the care is from 2004).

I'd also been thinking of applying Ash8's front fender liner mod to increase air flow through the oil coolers. The day I saw the coolant temperature spike, the air temperature was 100F and I'd been driving on the highway for about 3 hours beforehand. I'd spent another half hour in stop and go driving before arriving at our destination.

Thanks Highway8!

Highway8

iTrader: (11)

Air should not get into the system unless you have had hoses off. Easiest sign you have air is that the ECT are very erratic, big temp swings and you can also hear water moving from inside the car. Be sure to turn the heater on so it circulates through the heater core.

I have doen the oil cooler thing too. It makes a small difference with oil temps at free way speeds but not when going slower and the ect wont really come down if at all.

You should be using NPG-R, it has a higher viscosity and will do a better job of removing heat. Although evans npg is not needed unless you are tracking the car a lot.

5 minutes or 5 hours on the freeway wont make much difference. I have a supercharger with the intercooler on my car blocking air flow and I was driving freeway and stop and go the other day in 100 deg weather and I never went above 210. You have another problem if you are seeing 240+deg anywhere except the race track.

If I was you. (assuming the fans work fine and there is nothing leaking on the car), i would get a mazmart t-stat and waterpump, a new radiator cap and new coolant. Evans npg-r or just regular coolant for 1/3 the price. Drain the system (drain out the block), replace the pump and t-stat. Fill it up, make sure the air is out and the system is full and go from there.

olddragger

iTrader: (3)

you need a secondary radiator installed AFTER your primary system is working properly.
That helps everything including the a/c
OD

Mazurfer

Wait........let's make that more clear Denny.

"AFTER your primary system is working properly".

Razz1

Well if it's not this thread it was anotherone and I believe it was in the DIY section too.

I tested this with a thermometer and compared it to other RX8 memeber on the same day same time during a club run.

My system was consistantly cooler from 2 to 4 degree's.

Remember you need to use the fire retardant material from a race shop. The other crap doesn't work.

Since it's a 2004, its time to flush your A/C sytem and replace it.

In the early days.. many members reported having the AC system only 80% filled from the factory.

And yes... once you get over 90 degrees the system begins to degrade. There is nothing you can do about that. The car runs 2.5 times hotter than a piston engine.

You can raise the back of your hood with a couple of washers. Look for the DIY on that.

laythor

2 to 4 degrees? someone fetch me a coat!

TeamRX8

iTrader: (25)

I heard the same thing about having an index finger shoved up your butt. Let us know what you find out ....

HiFlite999

iTrader: (2)

Talk about thread crapping.

I've found insulating that pipe useful (though don't use water pipe foam unless you like the smell of melting urethane). However it won't have any positive effect on your engine cooling. I think the Mazmart water pump is a more effective water mover which seems to help, since I've had none of the issues I had last year with the stock. But I doubt if minor fiddles like that are going to help much in those extreme circumstances. There are many threads on the subject - and not that many successful fixes.

longpath

iTrader: (1)

I'm not convinced that both my fans are working properly, so I will be investigating that. For one thing, the only time I run into trouble is when the car is not moving, and the same car, two Summers back, had no issues with being stuck in traffic and going nowhere. Also, the fans seem quieter than I remember (though maybe I'm losing my hearing since my toddler loves to scream out of the blue). I'll verify that the airway for the radiators are not blocked, that the fans aren't jammed, that I don't have a blown fuse (G_d, that would be embarrassing), and that I can make the fans run when connecting them directly to the battery.

After I get everything working properly, then I'll look into these and report my findings, before and after. I apologise for the unintentional thread-jack.

laythor

it's not crapping when it's true