We don't KNOW it's purely CAFE, just because it is mentioned on the internet by several people......

Maybe the fuel saving is a side effect, and not just "cause & effect".

S

 

So you're saying 5w20 is so awesome and new that only us in the united states get to use it? Poor poor rx-8's living in backwards Japan

 

What he's saying is that its not as redily available in some of the lesser devloped markets that the RX-8 is sold in.

 

I have attached data from 88RX7 W/S Manual and 2005 RX8 W/S Manual which clearly show that there is no design technical requirement for 5W20 oil.

It has been previously claimed by some that the Renesis engine has finer bearing clearances,oil pump clearances that earlier rotary engines(RG and others).THIS IS NOT THE CASE.

The RX7 data is attached.RX8 data will follow

 

The RX8 engine data is below.

Lubricant recommendations for both engines are also attached.

If you examine the data you will find:
1 Bearing clearances are a little tighter for RX7 engines.

2 Oil pump clearances are the same.

3 Oil seals are the same.

4 Rotor clearances are tighter in the Renesis which means a smaller apex seal (lighter) which helps with high rpm.These clearances do not create an issue with oil weight.


The above data demonstrates that there is no mechanical issue with 5W30,10W30,5W40 or even thicker oils.

 

^^, I could not agree more, I have always said the US oil weights are too light and IMO over use (mileage) would be a "thin" as water... and don't offer the protection in high ambient temps.

In Australia Engines have been replaced with brand new factory units...I posted this in another thread, but, at a dealer I once worked for I talked to their head mechanic (25 years there), they have replaced 5 RENESIS's, ALL, I repeat ALL were done because the OWNERS did not bother to EVER top up the oil.!!!!
To use his words "went to drain the sump...next to nothing came out!"

The Factory Recommendation here is 5w30, you can use IMO 10 or even 15W40
depending on your climate.

I am sure the "plastic" oil experts here will flame me down...over to you..

 

I am not sure how the US government conducts fuel mileage tests,but in Canada,as I understand it, they are done on an engine dynamometer,ie they test the engine only.Obviously the operating conditons of the engine are controlled to optimum conditions.
I have not detected any difference in mileage due to heavier oil---I use 10W40 and 23mpg on the highway at 75-80mph is normal.

 

Would you mind sharing with me... there is only one option here in the US.

 

An 0-50 wt oil would be perfect.............acts real thin on startup when cold...and protects like a 50 wt when hot.

Funny thing...can't be done with Dino oil....wonder why

 

I just went down to check the manual - I was mistaken - I must have been recalling the manual from my 3.

 

I use 10W-30 just as it recommends in the manual.

 

Does it matter?If the container has the appropriate trademark symbol you can use any oil you want (according to my Owners Manual)

 

FYI...Castrol Syntec makes a 5w-40 and 5w-50 if you are looking for a wide range of thermal coverage with a good cold flow rate.

 

IMO, those CAFE standard are here NOT to increase MPG, they're here to get some *big* cash outa Auto companies.

 

I've used Castrol Syntec 5W-50 year round in my 1991 Toyota Previa since it was new. It's got 226,000 miles on it with no problems whatsoever. Starting is fine summer and winter. No leaks or burning. In addition, I only change the oil every 7,500 miles - just when the "change oil" light says to. Not telling you to use it in a RX, but if you're looking for a wide viscosity range, this seems to work.

 

i saw your lips move when you were talking out of your ***... practice..


beers

 

Because all our cars are made in the same place (Hiroshima) and to the same spec, there is no question that some might require other oil grades than others. The weight of the oil is only dictated by average temperatures. And a 5W-50 is not required unless you commute between Alaska and Florida on the same oil change ;o)
A US owner can use oils that are SL or SM certified, because anything else will void your warranty.
As for a general grade versus temperature recommendations, the guys in Australia posted their manual page, so take your pick based on temps where you live.

The concern I have - Renesis has larger gasoline dilution in the oil than piston engines and a thicker oil might help with holding the viscosity, I hope... I run 5W30 for 3 seasons and 10W40 in summer.

 

To me your attachment shows exactly the ambiguity and confusion with NA owners on what grade to use, the diagram shows a 5w20 oil is OK between -30C and +50C, this is plainly wrong from my side of the world, a 5w20 oil is exactly what it says, offers protection down to 5 degree C and up to 20 degrees C, so if you live in Florida or Nevada IMO this is the wrong oil to use.

According to the temp graph the this oil really is a -30W50 oil!

 

Yea ,sorry about that---I was just commenting about dino oil /synthetic oil.

As far as proper lubricant I prefer the information from my 88 RX7 manual,it is clear what you need to do.Some of the wizards however seem to think there is some big difference between the Renesis and 13B/13BT engines(other than the obvious ones which have dick all to do with lubrication).

 

In the US, testing is done on a chassis dyno. The test cycle replicates an urban drive through Los Angeles, and is really intended to measure emissions. Everything is monitored, including fuel use, so mileage is obtained as a byproduct.

FWIW, it was not EPA's intention to generate mpg numbers from the test. But Congress, with a "Any data, however irrelevant, is better than no data" attitude, ordered them to publish the numbers.

Ken

 

Are you kidding around and forgot to include a smiley, or do you really believe that?

Ken

 

Interesting read so far....

I ran across this in my search which distorted the issue alittle more.

http://www.performanceoiltechnology.com/ford5w20.htm

excerpt:

One of the main reasons 5W-20 and 0W-20 was specified for your engine is to increase the CAFE (Corporate Average Fuel Economy) reported to the Federal Government. CAFE is the combined average fuel economy of all of a vehicle manufacturers product line. Minimum CAFE levels are specified by the Federal Government. In order for a vehicle manufacturer to continue selling profitable large trucks and SUV's, which typically have poor fuel mileage ratings, as compared to smaller cars, and still meet mandated CAFE requirements, they must also sell enough of the smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles. The change to a 5W-20 or 0W-20 oil will allow and an auto companies overall CAFE to increase by a very small amount, typically in the tenths of a mile per gallon range. 5W-20 or 0W-20 oil is a lighter viscosity than a 5W-30 oil and therefore has less internal engine frictional losses, or less drag on the crankshaft, pistons and valvetrain, which in turn promotes increased fuel economy. This increased fuel economy is virtually undetectable to the average motorist without the use of specialized engine monitoring and testing equipment under strictly controlled test track driving when compared to a 5W-30, 10W-30 or a 0W-30 viscosity motor oil.

Can anyone elaborate on using a pure synthetic motor oil in their RX8.

 

Original poster... Where do you get your information?

AFAIK, Mazda did not decrease the warranty from 5 years to 3, they increased it on ALL RX-8s ever made, from 3 years to 4!

As for oil, up here in the frozen hinterlands of upstate NY, I run 5w20 year round for oil changes, and then sometimes top-off with 5w30 for a couple months in the summer when it gets into the 80s.

 

they did decrease it - all their cars now have a shorter standard warranty, but a longer powertrain warranty.

 

sounds like i need to stop using 5w20, which i've used for the last 47,000 miles here in texas.. with no issues..