Hi all.

I need info about driving RX8 at 45 degree centigrade with AC on.

RX8 radiator supports that kind of heat especially when AC is on?

How many fans are there in RX8 Radiator and they start at what temperatures?

Last summer my thermostat needle stayed idle and didnt move but i need your suggestions on how to avoid engine warming... thanks

 

Driving with the AC on at that temp is asking for engine damage.

You need to seriously overhaul your cooling setup if you want to be able to use the AC still. You need a high capacity high efficiency radiator (and not a crap ebay one), probably a fan upgrade, and almost definitely better shrouding to make sure you are flowing air properly.

Basically what you are going for is the ability to shed a lot of heat quickly, and a fan/airflow setup that can move a lot of air at low vehicle speeds to ensure that you are actually shedding it.

I'd recommend contacting BHR for their advice on it, since they have dealt with solutions for similar heat in Arizona.


Also, you need a PROPER temperature gauge. The stock temperature gauge needle won't move until 112C, which is already 8C past the point where you can get engine damage from (104C). You can't trust it, you can't rely on it. Get a proper gauge. If you have OBD2, the correct temp is reported through OBD2 so you could get a gauge powered through that.

 

It can get that hot here, but it is rare. we do get 100 days a year or so over 100F. A properly working stock cooling system will work fine. But 118F is another story, but at speed it should not be a problem.

In traffic however, the system would get overloaded and heat soak would be unavoidable. But yes a large dual pass radiator and a dual FAL 440 fan (2500CFM) setup would do wonders to help FAL also makes a 3,000CFM unit that will fit, the 490.

 

If it were me.... And moving were not an option.....

I would get an ultra gauge to monitor temps, then do the cooling mods in the Congrats thread below, specifically foam around radiator and fans on low (like $15 total). You could open up the oil cooler back plates a bit as well. Then you know what is going on, and have done the inexpensive things to address heat. After that, the options above.

 

Well, last summer , it did fine with the AC on with stock radiator. i don't have the luxury here in my country to do special mods. i talked to the most expert guy in my country in Asia and he told me to put the fan direct in summer and flush out radiator and fill it with BMW coolant. is he right? He also mentioned that we can increase the speed of the fan

i can do what my guy told me but what if i let the fan work directly ( Not automatically) , will it effect the performance of the car in summer as it will not reach its optimal temperature?

 

kindly suggest on the comment which i made in response to 9krpmrx8

 

You can direct control the fans. That is the fans on low mod in the Congrats thread below. You can also use a tools like mazda edit to adjust when they come on. I have a Cobb Access Port that lets me control that. The factory temp is, well, stupid. It is over 200 degrees. Mine are set for around 185 or so. Running the fans at all times will not over cool the engine, the thermostat will take care of that for you. I run between 183 and 185 summer or winter, AC on or off. I do not see 100 degrees outside, but I do see high 90s. Sorry, you need to do the C conversion. The other mod I suggested is filling the gaps in the radiator mount and front end with pipe insulation or some kind of foam. This keeps the fans from blowing hot air back in front of the radiator. If you think 115 degree air will not cool, try 160 degree air. Seal up the openings that let air get from one side of the radiator to the other EXCEPT the radiator itself, then get the fans running on low.

Also, get something that will read the temp in degrees. I like the ultra gauge, it is about $65 US, there is likely something in your area that will do the same thing. It plugs into the ODBII port. You need to know temps to work on temps, or you will not know if you were successful.

An additional thing is to fill the radiator with distilled water and only add a little coolant or even better, something like (again in the US) water wetter or some other coolant enhancer. I do not think you are in an area that has to worry about freezing temps. However, this will just help dump heat from the radiator, if the fans are not on, or the heat does not get forced out of the engine compartment, it does not help. That is why I recommended the fans and foam first.

 

If you change the fans to turn on 100% of the time, you will still reach operating temperature. That's what your thermostat is for. No coolant will get to the radiator until the coolant temp reaches the thermostat opening point, so if the coolant temp is below this point, your fans will just be blowing air through the cold coolant sitting in the radiator. So this also means that there isn't a point in having your fans run when the coolant temp is lower than the thermostat opening temp. Keep that in mind if you adjust the ECU to change the starting temperature for the fans to come on. You can also change that target temp with a different thermostat.

A 172F (78C) thermostat might actually help you here, since if your temps start climbing from sitting in traffic or at a light, you will have a bit more buffer before you hit critical temp points.

 

Got it, thanks all

 

Great points..other things that may be of help;

Move the battery to the trunk,
Get a vented hood or fabricate your oem hood
Get your front bumper fabricated for bigger wider openings, Since labour is super cheap there. in my opinion all of this should allow better airflow under the hood.

 

Well, apart from ordering cooling kit , My electrician told me that he can speed up the fan which turns on first ( As normally first thrust of fan is low and then if engine gets warm the fan speeds up). In my case, electrician told me that he can make the first fan thrust quicker so that engine don't get warm at all in summer while AC is on..

will that work? Chris from BHR told me that there are two fans and this idea WILL work as it is same as cooling kit idea

 

Can you please guide me on what to do when my gear lever and console gets warm. i mean, while driving a little, the whole gear lever panel and silver console gets pretty warm. My mechanic checked under the car whether a shielding is there which don't let the exhaust heat come up to the front cabin and it is still there. Any ideas about how to avoid it or is it normal?

 

2 things..
Before fans, do the radiator foam. Really, it can make a huge difference. And, if you do need it, any fan mod you make will not work.

second, check the CAT if you have one. It sits the other side of the cup warmer. If it is getting too hot, hit can damage engine. If you have an ODBIi reader like an ultra gauge, you can get the cat temp. Mine used to run above 1600 degrees (measured by rear 02 sensor until I removed it. The exhaust temps are not much lower most of the time. It is not good for the transmission either.

 

thanks, a picture or diagram would really help to show my radiator guy how to properly insulate it with foam

 

Will do foaming on radiator tomorrow, after that i will install the cooling kit that i ordered from rx8performance.com. that will turn on the fan at full speed on 180 degrees, so i think that will pretty much cover all the heating issues that im gonna face in upcoming summer here. Will also look for a gauge that can connect to ODB2 port. that port is just above brake pedal... right?

 

Sounds like a good plan.

And, yes, that is where it plugs in.

Let us know.

 

Got the foaming done around the radiator. Now waiting for the shipment for Cooling Kit Mod

 

you can force the fans on low to test, follow the DIY.

Posted From RX8Club.com Android App

 

Make sure your thermos switch and thermostat is working properly. Replace if needed also change the rad cap regularly.

 

they are all working fine

 

MY RIDE 2007 5 FORWARD MANUAL.. 87K Mileage but still going strong

 

Damn, my radiator plastic tank leaks from a very small area.. its hard to find a new one here. any one have any idea what to do or just use some sticky thing on it.. its a very very small one inch point where it is leaking.. the rest of the radiator is in perfect condition
HELP!!!!

 

Bummer,

That tank is pressurized. Not my favorite thing to make out of plastic. If you have a crack, it will likely propagate. If it were my car, I would undo the cap one notch, to take off pressure, and have one shipped in.

Your problem is that the temps in your area will drive you wanting a pressurized cooling system to raise the boiling point of the coolant. I suggest making sure you have the highest boiling point possible (water and coolant mix) in the interim check the water level often. Also, the little spill and vent tube should be routed someplace where it will not dump on the power steering. I would just add some hose and sent it anyplace but where the factory sends it.

Just my opinion.

 

hmmm, well i am not driving my 8 until my new radiator arrive tomorrow. i will make sure that it will run on coolant and water mix, also will add pipe on the water reservoir bottle to dump water somewhere else.. thanks brother

 

No worries.