20W-50 is just a HUGE leap from OEM recommendation. And I agree, it'll rarely get 0°F in Texas (and if it did I would not be driving my rotary) but are there any risks besides worse gas mileage for adopting such a heavy oil for regular use? I'm not going on the track with this, btw.

… how dare some guy you despise from the bottom of your worldly heart express an opinion about anything, as hypocritical as it is to state your own in another attempt to make it about him again.

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for everyone else the answers to all the things being discussed here in this thread are all before you on this forum and on your RX8, yet are not the things you’re doing in error as stated here or in many other threads.

it’s very simple, you first need to fully understand what it is you have; that which exists from the factory, then know and perceive what it takes to correct them. Swapping out the factory oil cooler t-stats and dancing with the OEM factory fan strategy devil are not the answer. Neither is an additional radiator.

Because their goals were not the same as your goals. Those are all bandaids, not solutions. The factory radiator and oil coolers are quite adequate when the system is correctly configured for them.

The path to that worldly and hence ultimately meaningless revelation begins here:


https://www.rx8club.com/series-i-tec...3/#post3432330

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it’s very simple, you first need to fully understand what it is you have; that which exists from the factory, then know and perceive what it takes to correct them.
Swapping out the factory oil cooler t-stats and dancing with the OEM factory fan strategy devil are not the answer. Neither is an additional radiator.

To answer teamrx8's comment:

Auto makers have to deal with a lot of government requirements. One of those is the average mileage for all the models the maker markets.
(NHTSA's Corporate Average Fuel Economy (CAFE)) So when a car is put onto production this is a big item on the "to do" list.
Having thin oil "suggested" in the owners manual helps the over all increase in mileage of each particular model. (yes it's small but still important at least to them.)
They also think about warranty issues when the decision is made on the choice of oil viscosity.
They calculate that most engines will last just past the warranty period.
That's why these guys get the big money.
As owners of these cars, we want them to last as long as possible. (in most cases, I would guess)
Using heaver oil will lower your mileage but cause other possible problems. One is lack of lubrication when cold.
We all know all about how you should not "stomp on it" until the engine is warm. Given what owners see in movies
letting the engine warm up is not "macho". That's just how the younger generation is, (in my opinion) .
That temperature gauge on the dash is not to be believed. I've always suspected that the gauge goes to the middle
a bit before the engine is really warmed up. I wonder if you guys with OBD monitoring can confirm this??
The same goes for the lowering of the thermostats on the fans and the oil coolers. A hotter engine will get better
mileage every time.

I don't want to loose my readers so I will cut this here.
Comments???

..

On my Series 2 the warmed up rev limit disappears at between 125° and 133° F as displayed by my Prosport gauge (dummy gauge shows warm). Not really warmed up for another 5 km and the oil remains below 100° F. Typically it’s at least another 10 minutes of sensible driving after the car says it’s warm before I believe it based on the gauges (water and oil temp). I don’t sit and idle to warm up the car, just start out granny shifting - about 15 minutes total time.

Thanks for making me think about this. Winter maintenance will be a Koyo rad and replacement for the leaking AC condenser. Probably a new tank as well. So many threads to weed through in replacing the rad and best application of the foam for airflow.

"Configured properly." Oh boy.

Hopefully that doesn't just mean rerouting the hot loops.

Can you answer this: Why this type of thermostat?

I don't think you can...

As was stated before and as proven again, you just can’t or won’t stop.

You only possess bits and pieces, yet believe yourself informed while lacking the whole. Again, the heat exchanger capacity is well sufficient unless there are other problems not perceived occurring.

Of course you’re going to disallow such a thing never having experienced it yourself. That’s what all unbelievers do, just as the book you blaspheme to get a dig in reveals over and over again. The very same that occurred 2000 years ago as well, directly demonstrating the statement that the pupil is not greater than the teacher who was also mocked in the same manner.

therefore I thank you for another blessing.

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I'm getting a little confused here guys...
I'm not sure the "Good book" has any info on the cooling needs of the RX8...
Or did I miss something???? (been a long time)
Can anyone lead us out of the wilderness here ???

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You might also want to look at Fal420 or whatever is the modern equivalent fan model.

https://www.rx8club.com/new-member-f...r-fans-258677/

I copied a link to one of the threads to send you down another rabbit hole. I didn’t go this route since I don’t deal with the hotter temperatures that you encounter. There's stuff in these threads about fans along with other cooling strategies.

Not claiming to be an expert, but I imagine a sports car with inefficient fuel burning abilities and extra hot cat converters won't perform well in 100+°F weather. I figured in the winter this will be much less of an issue as the air intake temps will be much lower and the car will be much better at cooling itself when the rest of the world isn't on fire.

I purchased the fan control kit and the oil thermostats because they made logical sense for addressing the rapidly climbing heat sooner, rather than waiting until peak engine temps to begin the cooling process using ambient air that is 120°F (per my OBDII). I won't deny there could be some other problem with the car, but the first step was determining what is normal, and the car seems to find cooling past 230°F normal, which does not work well enough in this current climate. So oil can be a culprit, fans not turning on could have been a culprit. But Team, to your point, what are common issues that you know of that would lead to this overheating if you feel the car should be perfectly capable of performing stock?

You wont notice any gas mileage penalty. There are 0 risks.

People have lost touch with what worked well in these engines over the years. It sounds radical now, but this was common not that long ago.

Team,

You are insane. Period.

Toward the effort of getting this back on track and contributing useful content rather than word salads-


My view on the cooling system:

Street use:
The radiator in the RX8 is too small for the application.

There is no cooling system margin built in like there are designed in on other vehicles.

The fan temps are silly as delivered by the factory

The radiator is compromised by poor airflow in addition to its small size (smaller than that of the 2500lb 105HP FB rx-7).

The oil coolers are fine but benefit from a lower thermostat temp.

In Arizona, with low humidity, and elevation, the stock cooling system in normal, good condition, can't maintain thermostat temp when above about 90 degrees, when going down the highway, and producing about 60-70HP.

Add greater power demands and the problem gets worse and the system loses ground. So your engine temp becomes a factor of power demand and ambient, not designed temperature.

If you live in an area where you see your temps not develop a runaway pattern consistently, you are likely in the zone where the designed capacity of the cooling system is not overtaxed.

I chose to add a large second radiator here in AZ, and it proved to be effective. I did this on both my RX-8s, and they used different second radiators, but the results were similar.

I chose not to reroute factory cooling paths, because I know from other experience with other engines that the methods Mazda used here should not be altered.

Even rudimentary math will tell you the radiator is too small to support the engine. This is the path I chose to take.

Many have chased inadequate cooling here for many years, with big fans, upgraded stock radiators, removing junk from engine compartment, etc, and these cars still overheat in short order on the track.

The problem remains, the radiator is too small for the application.

Extra heat and heating/cooling cycling is not the best for any engine, and especially this one. The metal never forgets.

If you are not seeing more than 10-15 degrees above thermostat temp at times of stress, your stock cooling system is fine for you and your car.


Also, the AC makes a big difference in heat load the cooling system must deal with. Some seem to not have that factored in...

And all this is referring to the S2, right? I was under the impression that the S2 shipped with a larger radiator to address the issues the S1 had with the older, smaller radiator?

I'm looking for 20W-50 but don't see much of it readily available like others like 15W-50. And you're talking about synthetic oil, or conventional? I've heard synthetic has come a long way and now it's less advised against for the rotary like once before.

I cannot speak for track use as my RX-8 is 100% street but I haven't been in a situation where the cooling system has failed me yet. I have stock S1 radiator and fans (I think they have 150k miles on them), thermostats, oil coolers, and FL22 coolant at 70/30 ratio (70% water). I run AC in 97*F days (per dash themometer cruising) in stop and go traffic, highways, etc. The only difference is I have both fans turn on sooner and increased the KPH when the fans turn off. I guess you could say my vented hood helps but even with the stock hood I didn't run into issues.

AZ heat is probably 10-20*F more than what I experience in FL, but in my case I think the stock cooling system works for most street driving. When cruising in mid/high 90s *F my coolant temps go down to 170-180s*F, i figured that was just the thermostat equalizing to ambient airflow and engine demand. Did you not encounter the same in AZ summers?

Walmart has Castrol GTX 20w-50 everywhere cheap. Use the SP rated stuff, not the Classic.

I don't want to get into the synthetic/mineral debate at the moment. GTX is as "mineral" as you can get today.

No, in AZ, above about 90 degrees the thermostat temp starts to lose ground with the stock system, and the AC running.

Koyo, Dual row s2 radiator, stock s1 radiator, no appreciable difference. I have tried all 3. FAL fans, etc.

The single biggest change was a big second radiator plumbed in parallel with the stock. Immediately dropped temps 20-25 degrees from peak temp, and enabled the thermostat to maintain temp at 110+ degrees ambient with ac running.

This year we had a lot of heat, with multiple 115+ days. With the stock system, I would not be able to drive the car during the day for any length of time in those conditions. Temps would creep steadily until I would have to give the car a break.

Like I said, there is no reserve capacity engineered in from the factory. Other cars, sport or performance cars included, do not have this severe of a problem, if any problem at all.

No, in addition to that also being said 2000 years ago, you only deceive yourself again, unable to accept our differences over meaningless worldly garbage that will never amount to anything. So devoted to your worldly ways, worldly thoughts, and the worldly reasoning of men that you didn’t take heed of. It’s one thing to be upset in a moment, it’s another to have such bitterness and hatred for another person so firmly rooted in your hardened heart. May the Lord grant mercy to heal what ails you.

Again, I ran an REW Turbo converted RX8 that had notorious overheating issues before I bought it and never even cracked over 178°F on the dyno making 15 WOT runs in a row between 25-30 psi boost with nothing other than a Koyo S1 radiator and FAL fan-set that were already installed on it in the prior overheating situations with some small crappy blower fans in the front. I both drove and towed my other NA RX8 all over this country since 2005, both street driving and competing in every weather and elevation scenario possible and never had cooling issues. Since before you were even on the forum.

I’m not insane. It’s just the inability of your fleshly mind to see, hear, and comprehend that which your ego is too fragile to accept. You can’t even comprehend such petty and useless worldly matters that are here today and gone tomorrow, it’s no wonder less so of the spiritual ones that matter the most and are for the age of ages.

I’m not without blame either; may He forgive us both for the times when we know not what spirit we’re in.
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Cue the mortal kombat movie intro
Ahura Mazda vs. Yahweh
Round infinite.
Fight!!

0000

That was awesome.

This is from the Rotary Resurrection site:

• Change oil every 2500-3000 miles at most. Rotaries tax their oil supply more heavily than piston engines.
• NEVER run mazda’s recommendation of 5-20 or 5-30 motor oil. I recommend 10-30 for cold climates and 10-40 or 20-50 for hot summer climates.

The oil chart for Mazda rotaries has not changed significantly in the 50+ years of production, when not tampered with by local government intrusion.

The Australian oil chart and the US oil chart are different, but the cars/engines are the same. Only the local regulations are different, that is why the charts are different.

The RX8 makes more power as delivered, than all other 2 rotor rotaries, except the FD turbo. 20w-50 was recommended for the 105 hp 12A I used to drive. The bearing sizes and clearances are the same.

In my opinion there is more need for 20w-50 in the RX8, with higher redline, higher power, bad cooling, and less effective rotor balancing from the factory.

The "less lubrication when cold" gets people scared, but in actual real-world use, it is a non-issue in most US climates , in this and other engines.

Try it, you'll like it. :)

I’m using Valvoline VR1 20w-50 , nothing has changed gas mileage still sucks lol

https://www.rx8club.com/series-ii-di...-15%25-168650/

here’s a diy that I did that was created by one of the Mods on this forum, it’s fairly easy and helps improve the airflow to escape from the oil coolers, I used a dremel but a sharp box cutter works well too since the plastic is not that thick, I also didn’t remove the entire panel but the dremel was part the reason I really didn’t need to.

so just to confirm, there isn't much you can do for a s2's fan control? the fan control kit works or it doesn't? is it even worth bothering with? I hit 218 via obd temps in mild heat on the street

OP here, I can run through the purchases I've made and the results so far.

I ended up going with the Fan Control Kit and the aftermarket Oil Cooler release sensors. The fan kit definitely helped flow more air through the engine bay sooner, rather than letting the motor get super hot and spend the entire drive fighting a losing battle. The oil coolers helped also by opening up sooner and flowing oil through the radiators in the front on either side of the coolant radiator.

Between those two mods, I saw temps drop.

My oil can still get up to 250F, but after much reading I learned that today's oil handles temperatures well, you WANT oil hot enough to boil out any moisture that could damage your vehicle, and since my car's does live in that upper range anymore (closer to 230s) I call that a win.

Coolant temperatures are also better. I haven't really pushed it in 100 degrees weather yet since getting the oil coolers installed, but the fan kit has kept my coolant temps around the 180-190F which, again, is good enough for me, esp if it can maintain that throughout the summer.

I decided to go with 5W-30 oil and I'll opt to just change it often so I never worry about whether it's breaking down too quickly or not. I don't track my car, just drive it through twisty roads on the weekends and run errands from time to time.