toyota 86 oil question

Status
Not open for further replies.
If you have a vehicle programmed to thermally castrate when the oil reaches a certain temperature, and the programming assumption behind that is that the oil in the sump is xw20, and you are of the opinion that that temperature is set lower for an xw20 than a heavier oil, isn't it counterproductive to use heavier oil even if you're racing?

Firstly, friction losses from heavier oil generate more heat, so the heavier oil will reach the higher temperature sooner. So you'll be thermally castrated sooner with a heavier oil than a thinner oil.

Secondly, the friction losses mean you're getting less performance from the heavier oil.

I'm not saying it wouldn't be desirable to have a thicker oil in conjunction with a higher point at which the engine is thermally castrated. What I am saying is if you are presented with a vehicle that was designed and programmed for an xw20 oil and you decide to track it then your only reason for using a thicker oil has to be that you don't trust the temperature at which the engineers set the thermal castration.
 
Originally Posted By: aa1986
If you have a vehicle programmed to thermally castrate when the oil reaches a certain temperature, and the programming assumption behind that is that the oil in the sump is xw20, and you are of the opinion that that temperature is set lower for an xw20 than a heavier oil, isn't it counterproductive to use heavier oil even if you're racing?

Firstly, friction losses from heavier oil generate more heat, so the heavier oil will reach the higher temperature sooner. So you'll be thermally castrated sooner with a heavier oil than a thinner oil.

Secondly, the friction losses mean you're getting less performance from the heavier oil.

I'm not saying it wouldn't be desirable to have a thicker oil in conjunction with a higher point at which the engine is thermally castrated. What I am saying is if you are presented with a vehicle that was designed and programmed for an xw20 oil and you decide to track it then your only reason for using a thicker oil has to be that you don't trust the temperature at which the engineers set the thermal castration.


Reasonable thinking , but as I mentioned in my previous post even Subaru suggest using a 5w30 in higway and heavy load/use. Using a tad thicker oil do not raise oil temp. by much.
I found this information (about using 5w30) on another forum where owner of a BRZ posted this info from his handbook.
 
Last edited:
aa1986, I agree with what you are saying completely, and have said similar on a number of occasions.

It depends on what the thermal castration is supposed to achieve, and whether it's being misinterpreted in the track context, same as manufacturer's minimum oil pressure is being used (by some) to prove that thinner is safe/better.

If the thermal castration is designed to get you home safely in the event of a failure of something (e.g. cooling system and the way that same is marketted by Ford in Australia), then it's reasonable to anticipate that the people designing it meant that at that point, the driver would be buttonned off simply to get home...they would be unlikely to expect that the driver would thrash the engine all the way home using every rev/hp available to them...I think that's the difference.

If the castration system were designed to keep the vehicle on the track, they wouldn't do it. They'd thicken the oil up to take the heat, and sacrifice a couple of HP to do it...hmmm, like a track pack...not much point having a track car that randomly pulls power...

...and the tuners have found that 5 15 second pulls on a dyno with a minute between them triggers the nannies, scarcely a robust system designed to keep them under power/revs for tens of minutes at a time.

If it's a system designed to reduce the risk of failure in an overheat or similar, a "limp home", then I see reason to run a thicker oil...less chance of wiping a bearing if you decide to keep using every one of the reduced number of ponies.

Personally, I think it's laughable that a manufacturer has to protect an engine from their chosen viscosity while being operated entirely in the performance envelope of a stock standard package...why buy a 200(most of the time on a cold day)hp car ?
 
Originally Posted By: chrisri
Oil pressure and temperature gauge will NOT tell you the whole story of how an engine is lubricated. This is not a 1931. You can put SN 5W30 in a BMW and maintain good oil pressure, but will you provide good lubrication to your engine? Don't think so.


Why would't the BMW be properly lubricated by a 5W30 SN oil? Manufacturer's specific specs aren't about lubrication or lack of it, but about extreme conditions, that makese these engines unique from the standard. Like extended drain interval, or high heat deposit control, something that is not part of SN standard.

So, if those extreme limits are not reached, the engine will be fine, unless you can prove to me that the 5w30 SN oil lacks the oil film strength for normal driving around town or will sludge up the engine in few thousand miles. If that doesn't happen, the engine will be lubricated the same as on A3 oil.
 
Originally Posted By: KrisZ
Originally Posted By: chrisri
Oil pressure and temperature gauge will NOT tell you the whole story of how an engine is lubricated. This is not a 1931.


Why would't the BMW be properly lubricated by a 5W30 SN oil? Manufacturer's specific specs aren't about lubrication or lack of it, but about extreme conditions, that makese these engines unique from the standard. Like extended drain interval, or high heat deposit control, something that is not part of SN standard.

So, if those extreme limits are not reached, the engine will be fine, unless you can prove to me that the 5w30 SN oil lacks the oil film strength for normal driving around town or will sludge up the engine in few thousand miles. If that doesn't happen, the engine will be lubricated the same as on A3 oil.


I think his statement was meant to say the oil pressure and temp gauges don't tell the whole story and engine damage can still occur even with good readings from both gauges.

IIRC it was Shannow or Trav that said this a few times and maybe if one of them sees this post they can elaborate better. Or chrisri can elaborate. Happy Thanksgiving.
 
Originally Posted By: KrisZ
Originally Posted By: chrisri
Oil pressure and temperature gauge will NOT tell you the whole story of how an engine is lubricated. This is not a 1931. You can put SN 5W30 in a BMW and maintain good oil pressure, but will you provide good lubrication to your engine? Don't think so.


Why would't the BMW be properly lubricated by a 5W30 SN oil? Manufacturer's specific specs aren't about lubrication or lack of it, but about extreme conditions, that makese these engines unique from the standard. Like extended drain interval, or high heat deposit control, something that is not part of SN standard.

So, if those extreme limits are not reached, the engine will be fine, unless you can prove to me that the 5w30 SN oil lacks the oil film strength for normal driving around town or will sludge up the engine in few thousand miles. If that doesn't happen, the engine will be lubricated the same as on A3 oil.


An OCI (Oil Change Interval) is the period between when new oil is put in the engine, and it's taken out having done its job. It's got to take into account everything that the manufacturer reasonably expects to happen. And You've raised in your post what a lot of the things that "could" happen in an OCI.

So what's the option that you are suggesting ?

"In a perfect world, this will do the job forever...all worlds are perfect, so this oil is perfect ?"

Has anyone ever used the OEM's roadside assist during warranty ?...the world isn't perfect.

Oil pressure is a general proxy for High Shear viscosity, I agree. Minimum Oil Film Thickness is poorly but generally correlated to HTHS...

But maintaining that the manufacturer's minimum maintenance oil pressure enables you to choose viscosity is two or three steps removed from agreement, through poorly correlated, onto poor science.
 
Originally Posted By: KrisZ
Originally Posted By: chrisri
Oil pressure and temperature gauge will NOT tell you the whole story of how an engine is lubricated. This is not a 1931. You can put SN 5W30 in a BMW and maintain good oil pressure, but will you provide good lubrication to your engine? Don't think so.


Why would't the BMW be properly lubricated by a 5W30 SN oil? Manufacturer's specific specs aren't about lubrication or lack of it, but about extreme conditions, that makese these engines unique from the standard. Like extended drain interval, or high heat deposit control, something that is not part of SN standard.

So, if those extreme limits are not reached, the engine will be fine, unless you can prove to me that the 5w30 SN oil lacks the oil film strength for normal driving around town or will sludge up the engine in few thousand miles. If that doesn't happen, the engine will be lubricated the same as on A3 oil.


From what I understand, there are other parts of the engine to take into consideration: Bearings see high temperatures and in these engines, tolerances seem to require a high HTHS characteristic.

Bobbydavro wrote that modern BMW engines require at least a HTHS of 3, therefore the recommendation of a minimum of 3.5 for a fresh oil.

That is why I won't try a light SN SAE30 oil in my BMW: some other characteristics from the oil are needed than just the oil classification.

But if you find a 0w-20 oil with a HTHS of 3.5 minimum, I will glady use it ;-). Time for Christmas wishes, right?
 
Trav, I'm not proposing anything and I mostly agree that oil pressure is not the sole attribute for choosing oil viscosity.

Perhaps I read too much into "You can put SN 5W30 in a BMW and maintain good oil pressure, but will you provide good lubrication to your engine?”. I think you could, but you would have to tread very carefully doing so.
 
SN synthetic do not work well in a Euro cars for multiple reasons, HT-HS value difference being biggest. There is also better sludge prevention, piston ring cooking, lesser evaporation losses in A3 or C3 specifications.
There is a thread or post on BITOG) made about people going with their Euro cars to quick lube and changing oils using SN synth on normal OCI out of ignorance or because of price. Lots of sludged engines.
But this is not important for this thread.

What I was trying to explain earlier is that OP and temp gouge are indeed good starting point to determine oil grade, but there are other factors involved. Temporary oil shearing under high load. 20 weight oil will work at his limits under heavy load.
Today's engines have oil jets for cooling piston tops. I wonder how would 20 grade oil working at its thermal limit prevent living deposits when hitting hot piston crown. Excessive oil evaporation would come into play as well leading to possible deposit buildup on intake valves.
 
Last edited:
One should have faith that the engineers that designed the engine and made the testing (with 0W-20) did a good job. Otherwise don't buy the product, right?

Now, if there is thermal castration built in (and it is!) using a heavier oil will only make matters worse, making one reach the limit faster and then losing even more hp to stay within the limits.

Lastly, as I read it, Toyota says that 5W-30 is acceptable. It never says "recommended", not even for heavy duty/hot weather usage.

There are two clear options: Do what the design team of the engine calls for and use TGMO 0W-20 or equivalent or do differently and potentially lose the warranty.
Always remember BMW that shifted from 10W-60 to 5W-30 for the NA "M" engines. Thicker is not better. In fact there is no better. There is only proper oil, and the designer knows better.
 
Originally Posted By: nickolas84

Always remember BMW that shifted from 10W-60 to 5W-30 for the NA "M" engines. Thicker is not better. In fact there is no better. There is only proper oil, and the designer knows better.


BMW shifted from TWS to an HTHS >=3.5cP 5w-30/0w-30/0w-40/5w-40 oil for the M cars. Not your regular plain-Jane 5w-30, it is a Euro-spec oil with a much higher HTHS than your typical domestic PCMO 5w-30.

And TWS was never an oil recommended for ALL M-cars, many spec'd other oils through the years, usually an LL-01 product.
 
BMW have a new engine oil spec Longlife-14 FE+.
Its a 0W-20 weight.

Currently only approved for new B38 and B48 (and soon B58)
All new engines will be based on the new spec

Only currently approved manufacturer is FUCHS with their Titan GT1 EVO 0W-20.
Expect Castrol to be approved soon

-bimmerpost.com
 
Last edited:
Designing NEW engines to use a lower viscosity oil does not mean that ALL BMW engines are good with that lubricant as some here would posit (not you wemay).

Rereading the thread, it would appear that the 86 is truly a global collaboration, not just between Toyota and Subaru, but Ford and the Euros as well.
 
Originally Posted By: nickolas84
One should have faith that the engineers that designed the engine and made the testing (with 0W-20) did a good job. Otherwise don't buy the product, right?

Now, if there is thermal castration built in (and it is!) using a heavier oil will only make matters worse, making one reach the limit faster and then losing even more hp to stay within the limits.

Lastly, as I read it, Toyota says that 5W-30 is acceptable. It never says "recommended", not even for heavy duty/hot weather usage.

There are two clear options: Do what the design team of the engine calls for and use TGMO 0W-20 or equivalent or do differently and potentially lose the warranty.
Always remember BMW that shifted from 10W-60 to 5W-30 for the NA "M" engines. Thicker is not better. In fact there is no better. There is only proper oil, and the designer knows better.

As I mentioned much earlier in this discussion, the N. American manual states that thicker viscosity may be better suited under higher loads (Unfortunately without defining the thicker viscosity or high load conditions).

Again specifically:
"The 20 in 0W-20 indicates the viscosity characteristic of the oil when
the oil is at high temperature. An oil with a higher viscosity (one with a
higher value) may be better suited if the vehicle is operated at high
speeds, or under extreme load conditions."

Other countries do list 5W-30 and some list 0W-40. Heck, the Middle East is using 10W-40!

The other thing that seems to have gotten lost in this discussion is what is happening in 86/FR-S/BRZ-'s that are being tracked. We can all sit around and theorize, but I would be guided by what is happening in other 86's that see track time. And I would be concerned about taking proper precautions to mitigate bearing failure that some 86 owners are seeing (oil cooler, proper oil grade for the conditions, etc).

-Dennis
 
Last edited:
Deciphering the owners manual. Nobody should be made to do that but on the same page there is a picture.
15771477437_a20a3917bc_b.jpg


They write:
15957208015_74607b9488_b.jpg


And then they write an explanatory paragraph about oil viscosity, with smaller letters.
15955262511_2a77ce6e36_b.jpg


So there may be some things to gain from 5W-30 in some specific conditions, but still only use it when proper oil is unavailable and for the shortest possible period.
 
They have to say that because they certified its CAFE rating with 0w20. They cant very well come out and say "but really the 5w30 is the better choice'.

If they endorsed 5w30 and the majority if owners used it they would be subjected to the same government thuggery Hyundai went through with this CAFE B$.
 
I wonder what they use as bulk at the dealerships. I would assume 5w30 is less expensive.
 
Status
Not open for further replies.
Back
Top