Motul Recommends different oils for different market FDs
 

This sounds strange, I found that motul reccommends 4000 motion 10W30 (which is mineral) for FD's 13B engine, but then i found that for Mazda AUS (australian mazda), motul says: better 4000 motion 10W30 but best 8100 eco-nergy 5W30 which is synthetic. below is the link to the page:

http://www.motul-lubricantes.com/

what can you say about this?

I'd say it doesn't matter. The viscosity ranges are pretty much the same and thats the important part. IMO, the differences of dino and synthetics are starting to blur as oils become more advanced.

synthetic should not be run in a rotary.

Oh my...

Mahjik, the light weight oils wouldn't cause a problem? Please explain. I have no idea what the weight difference even means, but I'd like to know :)

Thank you for ingoring the post of a well respected veteran member of this forum and posting this nonsense. We needed another 30+ long flame fest about oil...

Mazda recommends 10w30. IMO, I don't think the cold vicosity of 5 or 10 will make a difference. I'll have to look it up, but IIRC they recommend an even lighter oil for the RX8. Granted, the RX8 isn't FI though. The problem with the heavier weights is that if you aren't getting them up to a good temperature, then its worse on the car. The lubricating properties work best at certain temperatures, similar to tires (too cold no good, too hot no good... in the middle, just right). So if your oil never gets to that "good temp", you aren't getting the oil's full lubricating benefits, thus causing more wear on your engine components. Also, when heavy oils are that cold, its much harder for your system to push it around (the FD oil pump is mechanical so it can cause more resistance if the oil is not flowing well). That not only steals power but also causes worse gas mileage. This is why I don't recommend the 50 weights for street purposes.

Extremely wrong.

I recommend synthetic in all the motors I build (that are under warranty) after the 1500 mile breakin period.

That link is to the Motul SA (South America) site. Each distributor is going to "recommend" a product that is more suited to the driving habits and needs of their particular region. That includes the buying habits of each region's general public. It's not like the 4000 Motion 10W30 is some bargain-basement oil.

It should be noted that the newer manufacturer recommendations are based on oils they use to meet the federal CAFE (Corporate Average Fuel Economy) standards. This means they're using the lightest viscosity oil possible to reduce drag to the absolute minimum in order to squeeze out absolute maximum fuel economy during the CAFE testing. This is the main reason for the move toward "0W" oils with newer automobiles.

This is not to say that the manufacturers don't know what they're doing, or that ultra-light weight viscosity oils are dangerous. It's just that the "recommended oil" in the owner's manual is based upon a bone-stock car being driven by Joe Average (who usually starts his car, almost immediately puts it into gear and takes off while the oil is still bone cold, and rarely runs his engine up to redline)...not a modified car pushing higher boost and higher overall temps.

Not trying to be sarcastic, but is there an automobile engine oil pump that isn't mechanical?

IMO, that's rubbish. Any "performance" car, they are going to recommend fluids which perform at a high level for the "factory" performance level of the car. Many review put the cars through their paces at levels that the Average Joe will never see. The cars have to perform there just as they do for the Average Joe.

However, simply pushing more boost shouldn't dictate oil weights. Most manufactures select oil weights base on bearing tolerances, and then adjust the cooling system to handle the performance of the car. It should be no different on this car. If you increase the level of performance to where the oil temps are rising, you need better oil cooling, not a heavier weight oil.

shouldn't one increase to a higher weight when oil pressure begins to drop due to higher boost 25+ psi

They are going to recommend an oil that is sufficient to achieve their goals of fuel economy and performance, without additional testing of other oils that will cost more R&D funds.
Sure they do, but they don't drive the cars day in and day out for years. At the most, it's 8 months or so for a long-term test.
Everything you've stated here is true, but it's not possible to always control oil temps at every stage of their use in the engine. There is also the aspect of additional blow-by dilution, higher load shearing by the stationary gears, etc., with modified cars that will break down the viscosity quicker.
Yes, very frequent oil changing can help ward off these problems. And while I use synthetic oil, I don't look at those who use quality dino oils as foolish, nor am I saying that 20W50 is the only way to go (I use a 15W-50). My only point in all this is that with older cars like the FD, viewing the manufacturer recommendations as gospel without researching alternatives is a bit short-sighted, especially when the car has been moderate to heavily modified, and/or its usage is far beyond its design intentions.
And using the manufacturer oil recommendations of a much more recent car like the RX-8 as an implied justification for using ultra-light oils in the FD-- even if the engines are basically the same for the most part-- is a dangerous assumption. The camtrain galling in older V-8 engines resulting from usage of the newer API SL standard multi-viscosity oils with their lower levels of ZDDP additive is one example.

I've seen many documentaries of car manufacturers who use basically a dyno to run the cars for extended periods of time to simulate wear (and then do an inspection). Whether Mazda did this or not, I don't know but I would wager they did at least something similar rather than pulling straws to see which oil weight was going to be used.

I'm not going to debate this back and forth, as there isn't much point. However, I don't see even higher powered cars causing enough stress the shear the oil that badly "on the street" or overheat a lower weight oil. Highway/drag pulls are not for a prolonged time that its going to really matter, verses a 20-30 minute session on a road course.

I do think the heavier oils should be used for those who road races their cars, however I'm not convinced that the heavier weight oils serve any real purpose on public streets other than to extend oil changes for the lazy people (i.e. help with dillution). ;)

You're over-reacting here. I never implied that manufacturers simply arrive at their recommended oil by dumb luck, and I'm not saying that the recommended oil isn't fine for average street use.

I feel there's nothing wrong with using a slightly heavier viscosity oil as insurance against the aforementioned stresses that our oil must endure. It doesn't cost me any more, and I'm not worried about the flow rates of a 15W at cold temps, because those rates increase exponentially once above the 0-degree F threshold at which the winter viscosity rating is measured; and I'm not going to be pushing any boost at cold engine temps anyway, nor even driving my FD when it's 0 degrees F outside. Much of my car's use is driving through canyon roads near my home or track days (not "highway/drag pulls"), so I'd rather have that insurance against shearing and blow-by dilution, even if...hmm, I do change the oil at much more frequent intervals than the manufacturer's recommendation.;)

Basically, this all got started because I do feel that going to lighter viscosity oil such as 5W or 0W in an engine not designed for it is a risky proposition. I've seen oil analysis results from 5W oils in motorcycles (which share the oil with the transmission gears, similar to how the rotary shares its oil with the stationary gears) show a considerable amount of viscosity breakdown after only 1000 miles of average usage. Did they spin a bearing or freeze solid? Nope, but I'd rather not take that chance.

i think motul is the only thing french that i buy.lol

i'll ask the question again as you guys went off topic. My car is 95 JDM model with 40K miles on it. i will not put more than 10-15 miles per day in avarige and sometimes autoX it on weekends. which of these 2 oils is better in my situation?

Kento and I are both splitting hairs... ;)

IMO, if you car has run regular mineral oil up to this point, don't switch to synthetic now. Run the mineral oil.

well i dont know what oil was it runing.
Can mineral oil handle engine temperatures during autocrossing?

Yep, you really aren't stressing the engine that much over a 60-90 second time frame. ;) It quite a bit different than a 20-30 minute session on the track when the entire time you are flogging the car. :)

what about 2-3 laps on a 4 kilometer track?

Do you have a single or double oil coolers? If you are running a single oil cooler, your oil temps are going to really climb on a road course (track). I would recommend running something heavier than a 10w30 (as the conversation between myself and Kento referred to).

The problem is, its hard to make a car dual purpose.

my car is 95 Type R japanese model. i dont know exactly if it has dual oil coolers or not.

go to the front of the car and look into the openings at the 2 sides of the front bumper.. and see if there are 1 or 2 oil coolers

FD3S2005
:) i know where they are and i would have known their number already if my car was not on a ship, floating somewhere in the ocean :)

I found out that Type R's have dual oil coolers. that should be good :)