10W-50 oil in BRZ?
 

So I dropped my BRZ for regular service after 10k km which is fairly low interval but I'm hammering my BRZ fairly hard and tracking it quite often, so guys at Subaru recommended to check in every 10k or even less instead of 15k which is recommended by manufacturer. Since they know how hard I'm hammering and tracking it like it's stolen, and since summer is coming, they asked me if I want some more track ready oil, to which I replied "sure bud". I thought they'll pour some 0w-40 or something but they put Rockoil 10W-50 competition.

And now I'm like holy f*ck that sounds extreme. Does anyone have any experience with such oil? To put it in some context - I do indeed hammer my BRZ daily on my way to work (which unfortunately is really nice and engaging :D). On average when I'm arriving to my work parking lot I need to make few cooldown laps around building because I'm arriving with like 120 degrees oil. In fact I rarely see my oil to sit below 110 deg apart from rare occasions when I'm driving with family and have to pretend I'm responsible person.

But still difference between 0w-20 and 10w-50 sounds like entire universe of difference at least according to my (probably not so good) understanding of engine oils.

I am no expert on this, but from all the digging Ive done on oil for this chassis, 10w50 is ok to run in this car. Many have gone the 5w30 route for daily driving. Some even 5w40 or 0w40, especially when boosted. In one make races, or GT endurance cars, Toyota had them running 10w60 racing oil. If you beat on the car as much as you say, 10w50 seems just fine. DO NOT keep running it in cold weather. Youre in Poland so 5 degrees Celsius or less. If you are often driving when its below 5*C, you may want to switch to a 5w40. And do not beat on it when the engine is cold. Get 40*C in the oil first.

I know, that's something I'm really strict about. 80 deg, not less before real hammering. It's better safe than sorry.

Ok I guess I feel reassured. I'll most likely get different oil for winter anyways but good to know that it shouldn't damage anything in summer. Luckily I keep car in underground garage so it never actually drops below 0 where I keep it. Always around 8 deg here.

10-50 seems excessive. I don't think it will be a big deal, maybe be a bit careful to get some temp into it before being hard on it.

On a stock engine, this is a bad idea. Will your oil pressure go up, heck yes! But your oil flow will absolutely go down. To run heavy weight oil, the engine needs to be properly built for it. There is a stark difference in the flow dynamics of 0w-20 vs 10w-50. Hot temp characteristics are going to be poor, but the base going from 0-to-10 is worse.

The right thing to do here is send your oil out for analysis. Know what is going on with internal wear, then bump the viscosity up one step, then check again. Don't be surprised if the best results are obtained by the factory recommendation. Many, many times we hear of tech giving outlandish recommendations all the time with no clue, and definitely no thought to actually testing results from the recommendations they give. Tread lightly!

The only time I would consider swapping oils is if you're observing severe temperature swings between your daily driving and track time. The right thing to do there, is use the best oil for each job. Change the oil before a track day and bump a step up (not double). Based on temperature/flow profiles a decent bump in normal temperature (say +25-50 degrees f) with a one-step higher grade of oil, will give you very similar flow rates to the thinner spec during daily driving temps.

Ideally, you right the proper oil for the conditions your car will see 90% of the time.

I’ve run 50wt with UOAs in these engines off and on since 2016 with never an issue. You’ll be fine and it’s probably wise to step up to that weight for summer tracking if you’re experienced enough to push the car hard on track and aren’t running and oil cooler. I’d reduce your oil change interval though. Maybe down to 6000km. Tracking dumps a lot of nasty in the oil and is worse with how rich direct injection platforms run.

Unnecessary in my experience.

I have tracked with 0W20 oil the entire time (both without and with oil cooler). I don't use special race oil either. Have not seen any issues with oil pressure since I added a means to monitor it.

My oil analysis from multiple tracking scenarios over a variety of climate conditions (very hot to cold). Based on the results, the oil is good for at least 2 track days and a full mileage interval (7500 mi/12000 km). This will vary based on your car's setup and the demands of your local road courses.

Two heavy duty case scenarios both returned just fine for oil and engine health:

• 2 track days /w 8600 mile interval (no oil cooler, winter only tracking): normal wear characteristics, normal oil & filtering characteristics, remaining total base number (TBN) 2.5
• 3 track days /w 7500 mile interval (oil cooler, e85, summer and winter tracking): normal wear characteristics, normal oil & filtering characteristics, remaining TBN 4.6

I've done some digging around the oil-club.de forum.

It seems this is an excellent Group IV and Group V synthetic engine oil (Ester and PAO based) with a lot of ZDDP and Molybdenum (really good for reducing friction between 2 metal surfaces). Mind you, it does contain a higher amount of "ash" and it might affect (clogging possibility) the stock catalytic converter:

https://oil-club.de/index.php?thread...carbon-10w-50/

https://oil-club.de/wcf/index.php?at...on-10w-50-pdf/

As @Westen86 already mentioned, avoid regular usage in sub-zero ambient temperatures (°C) and ensure proper warm-up is achieved.

I personally use Ravenol RRS 5W_50 (it's also used by Gazoo in their 86 cup cars) or RCS 5W_40 (is more viscous than Motul 300V 5W_40).
Here's also a post I made, why I use the aformentioned engine oil (mind you, my engine is no longer stock):

https://www.ft86club.com/forums/show...99#post3502099
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TL : DR - ensure proper warmup before putting the foot down. The oil you have in your engine is excellent :)

50 is for non stock motors that are in a 100% racing environment. Any less and it’s not the correct oil.

Doesn't a thicker oil make the motor run hotter than a thin oil?

Summer weather in Poland seems to average at 70-80*F. Are you sure you need anything above a 0w30?

Isn't it right that most oil viscosities thin out to the same degree when at operating temperature?

Aren't the VTC's designed to operate with a specific viscosity of oil, otherwise might not work properly? Have seen this claim made a couple times.

Probably better off buying a more affordable off-the-shelf oil and changing it often, rather than running it 10-15,000 miles.

"For a dual-purpose car, engine oil needs to be at least 220 degrees F to burn off all the deposits and accumulated water vapor. For every pound of fuel burned in an engine, the combustion process also generates a pound of water! If engine sump temperatures rarely exceed 212 degrees (water's boiling point), the water will mix with sulfur (another combustion by-product) and create acids that can eventually damage bearings."

-Motor Trend acticle

Heat kills oil. Not time, not friction. Whats happening is a trade-off between heat deterioration and oil life. What you want is maximum protection for the amount of time between oil changes. Is 0w20 just fine for a race car? Yes, but for how long? Is 10w50 just fine for a race car? Yes, but for how long?

I dont think you are ever reaching a point with 10w50 where you are maximizing its capabilities. A thinner oil would protect your engine better GIVEN A STANDARD OIL CHANGE INTERVAL. Is 10w50 just fine for your car? Yes, but...

Yeah well I kinda noticed that it does indeed seem to run a little bit hotter, maybe due to a bit lower oil flow mentioned above, but the idea is that such oil should protect engine better at such temps and degrade less right?

I meant 10k km interval which is 6200 miles. Actually this time I changed oil after 5500 precisely.

So I should change oil more frequently when using 10w50 or less frequently?... "standard" interval was never considered but I don't have anything against reducing this interval below 10km / 6k miles like idk, change every 5k/3k sounds acceptable to me if it'd be recommended.

Standard Mustang GT 5W-20. Track pack? 5W-50. Exact same engine.

The higher weight provides a higher load capacity, but an engine really needs to be properly built for that, with increased bearing clearances. Otherwise, you are restricting oil flow (which is why oil pressure increases with heavier weight oil).

If you think it's all about power, think again, Nascar runs 0w-5 weight oil under some VERY harsh conditions, and also at much higher temperatures than we're seeing. It's not about what someone says is the better oil to run, it's about what oil the engine was designed to run with.

If you're going to experiment with it, one step at a time. It safest. Not only that, if you had an issue and brought your car in for warranty and they figured out you were running the wrong weight, you will very likely be denied warranty.