rx8 temps & cooling / mods

[rx7ali]

My temps seem to sit between 95-105c, wondered what
other people\'s experience was?

Options to improve things could be:

FAN MOD
Make a switch inside the car that forces the fan relay on to force cooling fans to be on constantly? I\'ve seen this done on the FD, although i would always just switch the AC on which did the same job. Thoughts?

Thermostat mod
You can often buy alternative thermostat\'s that open at lower temps. e.g 85c instead of 95c which helps bring the temp down. Thoughts? Available for the RX8?

Radiator
Again, on teh FD i whacked a nice thick radiator to replace the stock one and this made a world of difference. Thoughts?

[clive]

An RX-8 is designed to turn the fans on at over 100c deliberately as they found  that at these temperatures the engine gives it\'s optimum power

A few years ago I too worried about this and changed the fan switch that doubles up as the temp gauge sender but this made no difference, l even took temperature readings from different parts of the cooling system with an Autometer gauge, then I did some research and found the above.

I found that the best way to keep the temperature consistent was to vent the bonnet.

Hope this helps

[Casey]

I wouldn\'t worry. My experience with RX-8 coolant temps is as follows;

1. Hot day, stop-start in traffic, temp 95-105 (I have alarm set at 108 and it has never gone off in these conditions as the fans will cope).
2. Steady driving, temp 80-95, depending on ambient and traffic conditions.
3. Trackday, 15 mins, boiling hot day (28-30 ambient), towards the end of the day, after about 7 track sessions, the alarm will go off occasionally at 108. Just ease off throttle for half a lap or so and then carry on. Temps drops very fast when off throttle and air flowing (plus fans running).

Most advice I\'ve received is 110-112 is the max you want to see, and that should be rare, but 105 isn\'t a problem.

The RX-8\'s two radiator fans
- START to run at LOW speed at 97 degrees
- INCREASE to MIDDLE speed at 101 degrees
- INCREASE to HIGH speed at 108 degrees

I think you can conclude that Mazda must have decided it is OK for the temps to run marginally above 108 if the fan only STARTS to run flat out at 108 to aid cooling.

[Casey]

This might help (from the RX-8 service manual); click to enlarge pic

[rx7ali]

An RX-8 is designed to turn the fans on at over 100c deliberately as they found  that at these temperatures the engine gives it\'s optimum power

A few years ago I too worried about this and changed the fan switch that doubles up as the temp gauge sender but this made no difference, l even took temperature readings from different parts of the cooling system with an Autometer gauge, then I did some research and found the above.

I found that the best way to keep the temperature consistent was to vent the bonnet.

Hope this helps

Cheers Clive, helpfull but i still worry

From drifting the FD I have always been of the mindset that teh cooler the temps are at standstill.. the longer you can rag the crap out of the engine before the temps reach a critical value.

I guess the ideal for me would be the manual fan switch mod, so i can switch on the fans full blast if and when i want the temps to drop a little.


What about ally rads? I had great success with the old eBay £80 job on teh FD, any throughts on the the same for the 8?

While we are on teh topic, any other reliability mods that are worth doing?

[rx7ali]

I wouldn\'t worry. My experience with RX-8 coolant temps is as follows;

1. Hot day, stop-start in traffic, temp 95-105 (I have alarm set at 108 and it has never gone off in these conditions as the fans will cope).
2. Steady driving, temp 80-95, depending on ambient and traffic conditions.
3. Trackday, 15 mins, boiling hot day (28-30 ambient), towards the end of the day, after about 7 track sessions, the alarm will go off occasionally at 108. Just ease off throttle for half a lap or so and then carry on. Temps drops very fast when off throttle and air flowing (plus fans running).

Most advice I\'ve received is 110-112 is the max you want to see, and that should be rare, but 105 isn\'t a problem.

The RX-8\'s two radiator fans
- START to run at LOW speed at 97 degrees
- INCREASE to MIDDLE speed at 101 degrees
- INCREASE to HIGH speed at 108 degrees

I think you can conclude that Mazda must have decided it is OK for the temps to run marginally above 108 if the fan only STARTS to run flat out at 108 to aid cooling.

This might help (from the RX-8 service manual); click to enlarge pic

Cheers Casey

It put\'s my mind at ease.

When i do decide to have a cheeky sideways bit of fun the temps are likely to soar due to poor airflow and constant high rpm. I\'ll keep an eye on it and see if i can setup an alarm on the OBD2 digi dash thing :-)

[Casey]

If you do try to over-ride the fan temps, the best way is to get someone to change the trigger points in the ECU. A few guys now have "Mazda Edit" kit that I believe can do this. If you try to over-ride the ECU with a switch to the relays you might (not sure) find you trigger CELS as the ECU senses the fan is running when it shouldn\'t be.

Reliability mods - lots of debate on that one, as you can imagine. Personally, my top items are;

1. Use a thicker oil than the 5w30 specified by Mazda, and change it MUCH more frequently then the 12k service schedule.
2. Ensure the ignition is top-notch. Check you are not running the 100(A) coils, but 100B or 100C variant. Personally, I\'ve gone for a D585 coil upgrade, as there is evidence the 100(A) coils fail before 30k miles and there isn\'t enough data on how much better the B and C variants are yet.
3. If using OEM plug leads, change them for decent Magnecor or other good brand.
4. Service interval for spark plugs is 36k/3years. I wouldn\'t run them that long, changing mine at ~15k.

[Arnie_O]

The RX8 map triggers the fans at 97deg and 101deg

[Casey]

^^

Aston, as posted above, I thought it was 97=low fan, 101=middle, 108=high, so 3 triggers?

Out of curiousity, can "Mazda Edit" be used to alter those trigger points in the ECU to lower values?

[Arnie_O]

yes Malcolm we did this on your Stage 1 Flash.
we can change them to whatever you wish however its best keeping the two first stage fans at the same trigger temp as thats what Mazda have done for some reason.
i think my own map i lowered them to 87 and 92

[Casey]

yes Malcolm we did this on your Stage 1 Flash

:confused::confused::confused:

i think my own map i lowered them to 87 and 92

Good to hear they can be re-programmed! Sounds like it could be a good idea for a track-oriented car?