RX-8 ECU (PCM) Inbuilt Temp Sensor for After Cooling... S2 Only...
 

For Series II RX-8 owners interested Mazda newly introduced an ECU (PCM) 'Inbuilt Temperature Sensor' for After Cooling when your Engine Bay Compartment Temperature is HIGH.

If the ECU gets too hot after you stop your car and exit the Cooling Fans will turn on at Medium Speed.

The Series 2 PCM is a new design with a totally new mounting cradle.
Instead of being enclosed in a vented box like S1 RX-8's, the S2's have the ECU separated by clear space (air) top and bottom. (About 60 mm each side)

The reason for the ECU Sensor is to protect the ECU from extreme (still) engine heat when you stop and or garage your car.

Fans circulating air helps to move heat away and around the ECU.

It also works in conjunction with your Engine Coolant Temperature for After Cooling at similar temps...on High speed at 230F (110c).

https://www.rx8club.com/attachment.p...1&d=1257832400

https://www.rx8club.com/attachment.p...1&d=1257832400

REPORT: My Oil Cooler Rear MESH Grille Air Holes..
 

This week we have been having an "extreme" heat wave around 38c (100F), with my newly made Oil cooler Mesh Grilles recently fitted, today was the day to test their effectiveness as it reached 103F, the same temperature last year when I tested my Coolant Temps with my First DIY Mod of cutting the rear Black Plastic Vent Holes to a larger size.

This time my data was collected with the new rear Mesh Grilles, and same OBD-II Reader..

Todays trip was 40 minutes at 100 KMH (60MPH) in 103 F heat, and I am very happy to report that I am seeing Cooler engine temps by 6 degrees C or 12F!!.

Today my fans were cycling from 85 lows to 91c Max, with longer periods of fan off and shorter periods of fans on.

Same temps last year with Vent Shield Modification number 1, min temps were still 85c , but max were going up to 96C!..

NO Air Conditioner ON in both exercises, just the window down and lots of sweating.

Sorry I don't have an Oil Temp Guage data, but it is obvious my Oil is cooler which is helping keep Coolant Temperatures Lower....so I am happy..:smoker:

I can recommend Opening up the rear of your Oil Cooler Ducts and "Let the Air Flow Through!"

https://www.rx8club.com/showthread.php?t=181658

https://www.rx8club.com/attachment.p...3&d=1251872423

I might have to open that area as well ~ but its getting cold now and I will be away from town the coming weeks ... so ...

will open the "Extra" space after the winter I guess.

Good one, yes, I would definitely recommend this mod, the mesh I used gives a 55% Opening or Air Flow, so you could put a bigger Hole or Diamond and make the opening even larger, IMO would be even better.

It is a bit of a trade off wanting to protect the coolers too.

I have noticed, the odd very small piece of road tar and or bit of leaf attaching to the mesh, but you only have to touch them with a finger and they fall off, so there appears not to be a problem there.

As I said in the other DIY thread anything has to be better than the originals for Summer..
In Winter the OEM's are fine, I definitely would not open them up any more.

IMO when you have 2 Oil coolers their efficiency in cooling your oil is better than you think....BUT!

However, I have always thought that the rear black splash shields and the small slits are air flow restrictive, lets face it if you can't pull the air through the Oil Coolers fast enough they are not going to be efficient in reducing oil temps, and you can have a HUGE front opening like the S2's, but if Hot Air can't escape easily at the back it is pointless..you have to have quick flow through air. :)

Sorry to revive an old thread but it's better than creating a new one.

ASH8 you said the "Engine compartment temp sensor" is only in new S2s. I found a fan control diagram for the S1 and that too has a "high engine compartment temp" setting for After cooling.

Is it really new for the S2 or is my diagram wrong?