10W-50 oil in BRZ?

[ZDan]

Originally Posted by gen3v8

^^^ So an oil with HTHS of 3.04 will be perfect for track use with an oil cooler keeping OEM reading 106C max?

I wouldn't have any qualms running 3.0 HTHS with 106C/232F oil temps...

[DrinkenBRZ]

Originally Posted by gen3v8

^^^ So an oil with HTHS of 3.04 will be perfect for track use with an oil cooler keeping OEM reading @106C max?

Don’t forget to account for shearing of the oil in use from fuel and mechanical. You can estimate safety at 18-22% operating and half that for HTHS or use a voa and uoas to see how it’s holding up. From what I’ve seen most of the shearing is done before 1000 miles in use.

I too agree that a functional HTHS (after shearing of the oil) is fine for track days with a cooler or with stock power in this application.

[Flarpswitch]

Originally Posted by DrinkenBRZ

Don’t forget to account for shearing of the oil in use from fuel and mechanical. You can estimate safety at 18-22% operating and half that for HTHS or use a voa and uoas to see how it’s holding up. From what I’ve seen most of the shearing is done before 1000 miles in use.

I too agree that a functional HTHS (after shearing of the oil) is fine for track days with a cooler or with stock power in this application.

Before synthetic oil, I used to use Castrol almost exclusively because it was more resistant to shear. At least I bought into the sales pitch and the hype. What I know about synthetic oils is that they are very resistant to shearing and provide reliable lubrication for longer intervals under high load. Something about all the molecules being more uniform in size (smaller) and having stronger bonds. I heard that from someone who claims that he is not on the payroll for the company that makes that claim. I still trust what he says in spite of the fact that he does get free stuff on occasion.

[KillerBMotorsport]

Originally Posted by Flarpswitch

Something about all the molecules being more uniform in size (smaller) and having stronger bonds.

^ That's right. Pretty close to summing it up in a single sentence.

[DrinkenBRZ]

Originally Posted by Flarpswitch

Before synthetic oil, I used to use Castrol almost exclusively because it was more resistant to shear. At least I bought into the sales pitch and the hype. What I know about synthetic oils is that they are very resistant to shearing and provide reliable lubrication for longer intervals under high load. Something about all the molecules being more uniform in size (smaller) and having stronger bonds. I heard that from someone who claims that he is not on the payroll for the company that makes that claim. I still trust what he says in spite of the fact that he does get free stuff on occasion.

Synthetic is generally more resistant to shear in most, but not all cases. However, even the most advanced synthetic that most users will be willing to pay for will shear out of, or close to our of grade. Meaning if you run a synthetic rated as api sp or acea a1/a5 10w, 5w or 0w30 it will shear to a 20 grade or a hths of about 2.6cst. If you want to shoot for 3.04 as the example above you’ll want an api 5w or 0w40 or acea a3/b4 or c3. These will start out at 3.5cst HTHS or there about and shear down to just above 3.04. For reference peruse all the uoas the internet has to offer.

[Bonburner]

Just to remind people of this.



https://www.ft86club.com/forums/show...90&postcount=7

[KillerBMotorsport]

Just to add a datapoint here... dyno plot with oil temp (at sump) and pressure. This was with fresh Amsoil Signature Series (Synthetic) 0w-20. Ambient temps in the lower 50s. Sump temps were ~15 degrees lower than dash indicated temp.

[Compelica]

Originally Posted by KillerBMotorsport

Depends on how far off the scale is on the OEM sender. An aftermarket unit will not only be more accurate but will read changes more rapidly as well (less delay). Every car we've measured both on, the OEM location read higher, by as much as 20 degrees. Worse when on the colder side of the scale.

But is the OEM oil temperature sensor 'wrong' though? I understand different locations could show different numbers, I personally would prefer to see worst case scenarios in my case so that I know the oils have actually hit those temps.

[KillerBMotorsport]

Originally Posted by Compelica

But is the OEM oil temperature sensor 'wrong' though? I understand different locations could show different numbers, I personally would prefer to see worst case scenarios in my case so that I know the oils have actually hit those temps.

This has been debated to death. The problem with wanting to know 'worst case scenario' is that it's a massive rabbit hole. Where do you take those temps at to get the maximum temp? No one knows. Outlet of the pump, before the mains, at the mains, after and before it splits to the left or right head, intake or exhaust cams, or any of the drain-back passages? I'm sure I'm missing some. My bet is on the exhaust cam journals being the hottest.

It's just not practical unless you have an engine on an engine dyno on a test stand. It's likely be done, but that data isn't available, which brings up another point. How do you know if temps at those locations are normal or not? There's no normal operational data out there to go off. What would be the coarse of action if you did see a temperature you felt was too high, but the OEM sensor was within normal? Assume that's OK, or there's an issue?

I'm all for more data, but it's a tricky rabbit hole. The sump is a standard location for measuring oil temps (what going into the engine) in motorsports. Not that measuring in the pump is bad; it's certainly better than nothing.

As another note, there is speculation that Subaru skews this temp through the ECU to project higher temps on purpose. Some have speculated to be on the conservative side of safety? Maybe it's a cheap sensor? Ours are lab grade and get calibrated at each use. Whatever the reason, we'll continue to monitor this over time. Maybe with higher ambient temps that delta decreases? IDK, we're just here to share information

[Compelica]

Originally Posted by KillerBMotorsport

This has been debated to death. The problem with wanting to know 'worst case scenario' is that it's a massive rabbit hole. Where do you take those temps at to get the maximum temp? No one knows. Outlet of the pump, before the mains, at the mains, after and before it splits to the left or right head, intake or exhaust cams, or any of the drain-back passages? I'm sure I'm missing some. My bet is on the exhaust cam journals being the hottest.

It's just not practical unless you have an engine on an engine dyno on a test stand. It's likely be done, but that data isn't available, which brings up another point. How do you know if temps at those locations are normal or not? There's no normal operational data out there to go off. What would be the coarse of action if you did see a temperature you felt was too high, but the OEM sensor was within normal? Assume that's OK, or there's an issue?

I'm all for more data, but it's a tricky rabbit hole. The sump is a standard location for measuring oil temps (what going into the engine) in motorsports. Not that measuring in the pump is bad; it's certainly better than nothing.

As another note, there is speculation that Subaru skews this temp through the ECU to project higher temps on purpose. Some have speculated to be on the conservative side of safety? Maybe it's a cheap sensor? Ours are lab grade and get calibrated at each use. Whatever the reason, we'll continue to monitor this over time. Maybe with higher ambient temps that delta decreases? IDK, we're just here to share information

I would certainly understand if OEM sensors project values on the safer side, but from an ECU calibration standpoint it probably wouldn't make much sense as all aspects for that calibration related to that sensor would similarly be skewed. You would have a coolant temperature showing at 90C when it is actually at 80C, with the tables based on 80C which it is actually 90C. Probably would make warranty claims based on freeze-frame data a lot more difficult as well if everything else was similarly skewed... but I see what you mean.

As a person who entirely relies on OEM sensors - thinking through I would not expect the sensor to be accurate but rather be consistent, at the very least there is a point of reference to work with.

[lapsio]

So I *finally* managed to get 5w30 rock oil competition (major distributor in poland screwed me over by claiming they have 20L in stock while in reality they only had 1L and I had to wait until last friday for remaining 5L bottle). My initial observation is that idle and low load temps are better (similar to 0w20 I had before) while high load temps seem to be about the same as that 10w50. "On paper" it looks fine. Though OEM gauge still shows about 118 deg C on my way to work (245 F) but this oil advertises 3.7 HSTS in 5w30 variant so I believe it should be fine even for daily use at those temps. Especially if OEM shows higher temps as KillerBMotorsport mentioned, it sounds safe.

Though what was quite interesting to me - engine is noticeably louder and sounds harsher than with 10w50. I already noticed that when changing from 0w20 to 10w50 (back then I noticed it feels softer) but now changing back to 5w30 just confirmed my initial impressions. I don't think it's good or bad but I was just a bit surprised by fact that such minor thing as oil may affect engine vibrations and sound. But since oil directly affects resistance of parts movement it kinda makes sense I guess.

Well... at least due to this hardcore delay in delivery I managed to make 3k km already (1800 miles) on that 10w50 oil so it wasn't entirely wasted purchase xD

[lapsio]

Originally Posted by Compelica

I would certainly understand if OEM sensors project values on the safer side, but from an ECU calibration standpoint it probably wouldn't make much sense

All those correction can be takien into account by ECU. Just like speed governor and other things. If OEM shows reliably 20 deg diff it's not rocket science to factor it in. Knowing what manufacturers tend to do for user "safety" I'm really likely to believe it's true that OEM shows too high readings to scare driver so that he doesn't damage engine even if he isn't really aware what temps are safe.

[tomm.brz]

Our ecu with oem calibration doesn t even take any kind of action against oil temperaturr, you could have 160 celsius and the ecu wouldn t care and keep providing the timings as if it were at 80 celsius

[KillerBMotorsport]

Originally Posted by lapsio

Though what was quite interesting to me - engine is noticeably louder and sounds harsher than with 10w50.

Not uncommon. In fact, of a few crusades for the 'perfect oil' I've come across oils that run louder and quieter than the factory fill, all within the same viscosity. The impression I always got was that quiet was good, but this wasn't true at all. The quietest oil on one test actually had the worst UOA results, by a lot. Since then, I take sounds as just interesting observational note, since it seems to have no bearing on performance/wear. It's counter intuitive, but that's the way life works sometimes.

Might be worth trying a couple of different brands. High quality brands of course.