From reading other threads and from looking at pics of North American RX8, it seems that they have oil coolers on both side of the car (next to fog lights). On the JDM models (on my car anyway), there is only one, on the passenger side.
What is the reason behind this? Shouldn't the warmer countries get higher cooling capacity?

 

It's pretty freakin warm here...

 

Well, our cars are JDM, meaning for the Japanese market. Its much cooler there, so maybe thats why we only get one cooler. Don't think its a problem unless you wanna do some serious trackwork. Mazdaspeed has an additional oil cooler available, as well as other companies like FEED or Autoexe.

 

But then why do they have dual coolers in N. America? It's just as cold there if not colder.

 

I thought the automatic had only one and the manual had two?

 

You're half right, auto get one cooler, but, even the high spec JDM model also get one only.

 

Hmmm, didnt notice that the US had 2! Dat Sux!!!

 

Just speculating but North America has big open roads where speeds of 80 MPH (130 KMH) is common and sustained. That's 4k RPM in sixth gear for maybe an hour or more. Sustained high engine speeds require more cooling.

Might be another reason why the oil pan was changed for the US market. In testing in Japan, they never tested for 1+ hour of sustained high speeds in one direction.

 

Do you know how big North America is??

It includes Mexico too.

There are large cold regions, most of which arent really inhabited (Canada)

And the rest is temperate with desert in the southwest and subtropical regions in the east. In the summertime it gets in the 90's as high as NYC..

 

Thats probably the reason why they have 2 oil coolers for US. Stangely, Australia has huge amounts of desert roads, but I remember them complaining abt getting one oil cooler only.

 

Still doesn't make sense. I wouldn't be surprised if it's got to do with some sort of US regulation/control in the motor industry.
Or, because Americans like to sue left and right, Mazda did not want to take the risk of facing numerous prosecutions for engine failures due to overheating. Dunno!
Americans are a scary bunch.

 

There are already many threads on this topic. So far no one knows for sure, just speculations.

My speculation is that Mazda NA in order to meet the claimed fuel consumption figure needed to spec 5W20 viscosity oil. In order to keep this thin oil from boiling they needed to spec 2 oil coolers.

Unscientifically yours,

Ringer

 

Ringer, that could make sense. But this means that those in hot SE Asia should not use a thin oil like 5w20. If this is true, I reckon even 10w30 would boil over given only one cooler.

 

Hotpot,

I was just joking when I used the word boil.

But seriously, in our tropical climate we can use a broader range say 10W30, 10W40 or even 5W50. For racing Sato san recommended 10W60.

Of course 2 oil coolers are better than one. I was just jealous of the US. Since JDM spec'd just one I reckon it would be sufficient for most users. If you race or max the 8 out much of the time then you should consider after market second cooler.

Ringer

 

from what I understand In japan they dont drive thier cars to several hundred thousand miles like we in america do. This is due to differences in emmisions standards etc. just my guess but many of the recycled engines we in the states get for engine swaps i.e. the b18 honda or the nissan sr20det have been driven for 40-70k miles with nary an oil change.

 

I'm American.. You can expect to be contacted by my attorney for Liabel.