[Outtopasture]

Hmm. I don't understand the recommendation for 5w20 at the track. 0w30 makes more sense. You want better retention of viscosity specs at sustained high temperatures. My oil temp is typically 248 - 252 on the track (90 degrees ambient temp). This is quite a bit better than the sustained 270 degree temps on my Camaro 1le with all of its cooling devices.

 

[TRU-BOOST]

I would not recommend 5w20 for legit track duty either. Short little autocross runs and basic\hard street driving it will hold up well all while retaining factory MPG. A 5w30 or better yet 10w30 is a better option for dedicated track duty. Any oil with a 0 cold rating is a bad choice every time unless you live in the arctic circle.

 

[s2mikey]

I would not recommend 5w20 for legit track duty either. Short little autocross runs and basic\hard street driving it will hold up well all while retaining factory MPG. A 5w30 or better yet 10w30 is a better option for dedicated track duty. Any oil with a 0 cold rating is a bad choice every time unless you live in the arctic circle.

Back to this again - so the owners manual is wrong? I can see upping to a 5w20 or 5w30 for track use but my day to day driving.... 0w20 which is what they specifically call for is bad?

 

[TRU-BOOST]

Not "bad" but not "as good".
0w oils are nothing more than to keep the EPA whiners happy. Their protection and durability is absolutely without any doubt inferior to an oil with a 5w or 10w rating. I literally manufacture, sell , and test the viscosity modifiers that are used to make those oils change their cold ratings. I can tell you the less of them in your oil, the better. For a prius or little civic that just puts along... Sure whatever, they offer versatility in all weather and good fuel economy. For a high revving application that sees high temps and gets driven "spiritedly" you are doing your vehicle a disservice. Owners manuals are not bibles, and most people think engineers know more than they do, or that they actually try every oil weight under the sun. They dont. Subaru uses 2 weights of oil. Therefore everything they build will get 1 of the 2. Not because its the best, or even good, but because its what they have and what the EPA likes.

 

[chrisz5z]

Back to this again - so the owners manual is wrong?

Depends on which owners manual you read...

Combining both GR86/BRZ owners manuals in US/Canada/Japan, the oil weights that are shown as OK to use are: 0w20, 0w30, 5w20, & 5w30

 

[BobGPL]

Not "bad" but not "as good".
0w oils are nothing more than to keep the EPA whiners happy. Their protection and durability is absolutely without any doubt inferior to an oil with a 5w or 10w rating. I literally manufacture, sell , and test the viscosity modifiers that are used to make those oils change their cold ratings. I can tell you the less of them in your oil, the better. For a prius or little civic that just puts along... Sure whatever, they offer versatility in all weather and good fuel economy. For a high revving application that sees high temps and gets driven "spiritedly" you are doing your vehicle a disservice. Owners manuals are not bibles, and most people think engineers know more than they do, or that they actually try every oil weight under the sun. They dont. Subaru uses 2 weights of oil. Therefore everything they build will get 1 of the 2. Not because its the best, or even good, but because its what they have and what the EPA likes.

I have a hard time believing that the oil industry would come out with 0W oils just to satisfy whiners. Your biases are getting the better of you

 

[Mario0617]

I have a hard time believing that the oil industry would come out with 0W oils just to satisfy whiners. Your biases are getting the better of you

It’s big money to supply to OEMs a zero weight oil to help them meet EPA standards. If I’m an auto manufacturer, and I can get slightly less emissions on startup with a 0w oil instead of the 5w or 10w - that’s worth a lot of money. It would be a lot costlier to try and engineer a system to make the engine burn cleaner at startup or something similar.

He isn’t arguing that 0w oils will grenade your engine. If you want your car to meet the OEM specifications for lubricity, emissions, efficiency and detergency- use the dealer 0w-20. If you want a different blend of benefits (let’s say greater protection, better long term stability, shear characteristics and so on) and are willing to accept a trade off (minuscule changes to emissions etc) then a 0w oil isn’t the best choice.

I can personally attest to the concept the multi weight oils are not necessarily the best for your engine. I live in a VERY hot climate, and I use legit straight weight (SAE 50) in my V twin motorcycle engines. The engines run cooler and the top ends are objectively quieter - despite being cammed fairly aggressively and using hydraulic lifters. With 20w-50 Mobil 1, the bikes ran hotter and noisier and the oil broke down noticeably faster.

The concept here is that the farther away the two numbers are (XXw-XX), the less stable they are. They can protect better in cold climates - but unless you live somewhere very, very cold a 5w is more than sufficient.

 

[jdmchris]

I would not go higher in viscosity than 5w30. the 86 has extremely tight tolerances, and going anything higher than 5w30 may not lubricate properly. 0w20 is absolutely fine as long as it is a good quality oil. If you are FI and tracking, 5w30 is recommended. And as ALWAYS.... run an oil cooler!

 

[chrisz5z]

I run 5w30 on the street, it keeps me sane while I look at my oil pressure gauge lol.

Did swapping to 5w30 change the behavior of the engine at all? quieter, smoother, etc

 

[BlyatRZ]

Did swapping to 5w30 change the behavior of the engine at all? quieter, smoother, etc

I bought the car used with 1200 miles on it, I changed the oil the next day. I have no idea what the car was like on 0w20, but 0w oils have always been iffy in my opinion.

 

[patsimca]

@BlyatRZ Any chance you have a DIY written up or a tutorial you followed to install an oil pressure gauge?

 

[chrisz5z]

I bought the car used with 1200 miles on it, I changed the oil the next day. I have no idea what the car was like on 0w20, but 0w oils have always been iffy in my opinion.

I see. I've went from 0w20 to 5w20 in other cars & it resulted in a noticeably quieter/smoother engine...this car, didn't change much. I might go for 5w30 next time I change my oil.

 

[BlyatRZ]

@BlyatRZ Any chance you have a DIY written up or a tutorial you followed to install an oil pressure gauge?

I used a DIY for the first gen cars, its all basically the same except for mounting it. I initially used a Print3d pod from Import Image Racing, but have since switched to a custom made vent pod.

 

[TRU-BOOST]

I have a hard time believing that the oil industry would come out with 0W oils just to satisfy whiners. Your biases are getting the better of you

My biases...? Its very literally what I do for a career. I manufacture the viscosity modifiers that get sold to the big oil companies. If I were bias I would support the use of more modification to oil like what is seen in 0w oils. That afterall is what pays my bills. I am telling you that you want less modification to your oil always. You can listen to whatever you want. But dont make assumptions about things you know nothing about. I have worked with many engineers from many manufacturers and watched more engines explode on a bench than most people. If there is 1 thing I consider myself to be an expert in its oil. Not gloating or bragging. Just trying to get a message across and people dont like to listen because "thats not what the manual says".

 

[BlitzPig]

The 0 viscosity rated oils are not so much about emissions, per se, but about getting a good CAFE rating for the manufacturer. That tiny bit of extra MPG that you get with 0w oils may not seem like much, but when taken as an average of a manufacturer's total vehicle fleet it keeps them from having to pay gas guzzler taxes, and helps avoid other legislative BS. That fact that it increases wear is unimportant to the maker, they do want to sell you another car after all, and the more in your lifetime the better for them.

 

[s2mikey]

Depends on which owners manual you read...

Combining both GR86/BRZ owners manuals in US/Canada/Japan, the oil weights that are shown as OK to use are: 0w20, 0w30, 5w20, & 5w30

Got it, lol. Ok, next change I’m going with 5w20. But, one has to ask….for those of us that will be parking our cars for the winter or never drive in temps under 30 degrees, why can’t we run straight 20w oil?

 

[Mcgiiver]

🧞Did somebody summon me?🧞
I know its been discussed in great length, but yes 5w20 will offer the best overall protection. There are less viscosity modifiers that break down over time. You will see greater film strength, less viscosity break down and better fuel dilution resistance. What you will "lose" is fuel economy for the 1st 2 minutes of engine warm up when compared to 0w20.
Thats all I have to say about that. 😁

Fully agree. 0w20 or 5w20 are both 20 weight at normal operating temperatures. Something about reading 0w, tells me the oil has zero viscosity at low temps, doesn't sound right. I would rather to see the oil labeled 1w20. I will run 5w20, just to avoid the viscosity break down Tru-Boost mentions.

 

[boxkita]

toyota owners manual says higher weight oil is recommended for severe duty or high performance. When done, 0w20 should be used again.

Redline sells "straight weight" oil that tends to last longer in severe duty applications. 20WT Race Oil (5W20)
I ran 30 weight in my spec miata. Other than the extreme cost, I'd run it in my 86 if I get back into track days.

 

[LateOnTheBrakes]

My understanding has always been you can go lower on the first number and higher on the second number safely. The first number is the viscosity at cold start. The second number is what viscosity oil it behaves like as far as film thickness at high temperature. I would think a 0w-30 or 0w-40 would be ideal if they make it.

The best way I've heard it described is 0W-20 flows like a 0 weight oil but has the same protection as a 20 weight oil.

 

[TRU-BOOST]

That is only somewhat true. In almost all cases you can safely go up in the 1st number as well. The exception being winter months in extremely cold climates. Dont pay attention to silly "scientific" oil tests you see on YouTube with guys tipping over tubes of oil and watching them race down a platform. Keep in mind the oil feed system is pressurized. It isnt just drizzling into the engine. It will get where it needs to be just fine in most cases even in the cold. I would highly recommend anyone avoid oils like the germans use. Things like 0w40 oil. In theory it sounds great. An oil that is super thin in the cold and has great high heat resistance from the added viscosity on the top end. In practice they just arent very good at protecting. It takes an immense amount of chemicals like viscocity modifiers and additives to make a fluid that can cover that wide of a spectrum. Problem with that is that you end up with more chemicals and less actual oil in your blend. Those chemicals break down much faster than the base oil itself. Oils made this way tend to lose lubricity and film strength very fast. No matter what oil change interval is recommended, you just cant run those oils that long, especially if the car will see any kind of severe use. Ideally what you want is to have the 2 numbers as close together as possible. For example a 5w20 will require less alteration to the base oil than a 0w20. A 10w30 will require less alteration than a 5w30 etc. I think 5w20 for street use with plenty of hard driving is fine all year round anywhere in the USA. For track I would use 10w30. No sense running anything too thick for street use. It does not protect any better if you are not getting it hot enough to matter.