2023 BRZ (FA24); Redline 0W-40 vs Mobil 1 0W-40

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Been using M1 Euro 0W-40 since it meets A40 and 229.5. It seems to have a viscosity of hardly a 40 weight (13.8 cSt). While a Redline 0W40 is at (15.7 cSt), they also have a 5W30 which is (11.9 cSt).

I’m wondering for my use case, autocross and a few track days. Temps range from 190-250F. Then in the winter I swap back to 0W20 for cold starts (under 0F) usually Pennzoil Ultra Plat, Motul Specific, etc.

Would trying the Redline be an issue due to the viscosity being much higher than the M1 Euro? I can get the Redline for cheaper via the FCP Euro program. Also the M1 is AP rated and the RedLine is not, but these are naturally aspirated engines. Non turbo if that helps influence the decision. However, both are A40 and 229.5.

Reason I ask is I saw an oil analysis for Redline and the SAPS looked much better than M1 for the same price due to the exchange program. Aka send old oil back in, get new one for free via gift card.
 
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Both oils are very good. You can not go wrong with either.
Use these year round without worry.
Now I understand that there are viscosity modifiers which allow this oil (40W) to step down to a (0W).

But wouldn’t it make more sense if the car sees down to 0F to run 0W20 (e.g., overall less viscosity, less modifiers since it’s a smaller gap between 0 and 20) to reduce engine wear on cold starts?
 
Now I understand that there are viscosity modifiers which allow this oil (40W) to step down to a (0W).

But wouldn’t it make more sense if the car sees down to 0F to run 0W20 (e.g., overall less viscosity, less modifiers since it’s a smaller gap between 0 and 20) to reduce engine wear on cold starts?
No, that's not how viscosity modifiers work. They INCREASE the viscosity of the base oil as the temperature rises, by uncoiling (they are coiled polymers, a type of plastic basically). When the temperature is reduced, they contract, reducing their impact on viscosity.

The Winter grade (the number in FRONT of the W) is completely separate from the SAE grade (the number after the W) and are derived through very different processes.

There's a sticky thread on this, you would benefit from reading it:
 
No, that's not how viscosity modifiers work. They INCREASE the viscosity of the base oil as the temperature rises, by uncoiling (they are coiled polymers, a type of plastic basically). When the temperature is reduced, they contract, reducing their impact on viscosity.

The Winter grade (the number in FRONT of the W) is completely separate from the SAE grade (the number after the W) and are derived through very different processes.
Got it. I appreciate the clarification! Not an expert at all (on my end). Lol
 
For whatever reason, RL 0w40 is not one of their best grades. I've read some posts on different forums that does show it kind of behaves like most of the other 0w40's on the market. I think I'd opt for RL 5w40 if you want more shear stability.
 
@Auditorjazz

Been using M1 Euro 0W-40 since it meets A40 and 229.5. It seems to have a viscosity of hardly a 40 weight (13.8 cSt). While a Redline 0W40 is at (15.7 cSt), they also have a 5W30 which is (11.9 cSt).
For your purposes, you need two things:
1. KV100 is not important. On track you pass that immediately and around piston rings temperature is far higher. What matters is HTHS. Considering M1 0W40 is basically half GTL and half PAO from that KV100 HTHS is probably 3.7-3.8. That is more than sufficient. Redline will have higher HTHS bcs. ester based and higher KV100, but the question is: do you need it? Bcs. when you increase HTHS you also increase resistance and heat. SO your performance will drop (maybe you won't notice it. But with such jump in HTHS you might).
2. In that engine you absolutely want W40, even if it is lighter W40. The reason is for you obvious, drop in pressure in those engines during high G turns. I would stick to W40 (maybe some 5W30, I will come to that later)..

I’m wondering for my use case, autocross and a few track days. Temps range from 190-250F. Then in the winter I swap back to 0W20 for cold starts (under 0F) usually Pennzoil Ultra Plat, Motul Specific, etc
1. I ran Mobil1 0W40 to 300f on track and still did 5k OCI. You are good!
2. 0W is 0W. Whether it is 0W8 or 0W50 (Mobil1 racing). They all use standardized testing. The difference is in the flow after the start. 0W20 will obviously have lower viscosity and have less resistance. So at, let's say KV40, it will flow better and create less resistance, save a bit of fuel, and if you push it hard, flow, again, better. These oils are better if you cannot reach operating temperature or need long time to reach it.

Would trying the Redline be an issue due to the viscosity being much higher than the M1 Euro? I can get the Redline for cheaper via the FCP Euro program. Also the M1 is AP rated and the RedLine is not, but these are naturally aspirated engines. Non turbo if that helps influence the decision. However, both are A40 and 229.5.
No it won;t be an issue. But Mobil1 will be better for street usage. Redline is dual street/track oil. Generally, street oils are much better in daily grind in cleaning, preventing deposits etc. than track oils. Street oils are also good on track, especially oils with Porsche A40 approval that must pass track testing. API is irrelevant!

Reason I ask is I saw an oil analysis for Redline and the SAPS looked much better than M1 for the same price due to the exchange program. Aka send old oil back in, get new one for free via gift card.
I know a lot fo people on track who use Redline. You just have to make a decision, is 5W40 right for you or 5W30. HTHS of 5W30 is 3.7cP. Personally, I would go with that if Redline.
 
@Auditorjazz


For your purposes, you need two things:
1. KV100 is not important. On track you pass that immediately and around piston rings temperature is far higher. What matters is HTHS. Considering M1 0W40 is basically half GTL and half PAO from that KV100 HTHS is probably 3.7-3.8. That is more than sufficient. Redline will have higher HTHS bcs. ester based and higher KV100, but the question is: do you need it? Bcs. when you increase HTHS you also increase resistance and heat. SO your performance will drop (maybe you won't notice it. But with such jump in HTHS you might).
2. In that engine you absolutely want W40, even if it is lighter W40. The reason is for you obvious, drop in pressure in those engines during high G turns. I would stick to W40 (maybe some 5W30, I will come to that later)..


1. I ran Mobil1 0W40 to 300f on track and still did 5k OCI. You are good!
2. 0W is 0W. Whether it is 0W8 or 0W50 (Mobil1 racing). They all use standardized testing. The difference is in the flow after the start. 0W20 will obviously have lower viscosity and have less resistance. So at, let's say KV40, it will flow better and create less resistance, save a bit of fuel, and if you push it hard, flow, again, better. These oils are better if you cannot reach operating temperature or need long time to reach it.


No it won;t be an issue. But Mobil1 will be better for street usage. Redline is dual street/track oil. Generally, street oils are much better in daily grind in cleaning, preventing deposits etc. than track oils. Street oils are also good on track, especially oils with Porsche A40 approval that must pass track testing. API is irrelevant!


I know a lot fo people on track who use Redline. You just have to make a decision, is 5W40 right for you or 5W30. HTHS of 5W30 is 3.7cP. Personally, I would go with that if Redline.
Going to stick with Redline 5w-30 or 0w-40 since the FCP program is great.
 
@edyvw
I'm on the same boat. Currently running LM LF High Tech 5w40. With a better understanding of their marketing gimmicks, now I want to switch to something else also from FCP.
It doesnt make sense to put "Group III" and "Premium" together.
Would you recommend RL 0W40 for a 577HP turbo amg v8? Considering a 6m/3k OCI with 80% short city commute
 
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So 5W-30 from redline would be your final choice?
Yep. 0W40 has HTHS of 4.1cP. You really, really do not need that.
The golden rule of lubrication is: "as thin as possible as thick as necessary."

You have two concerns:
1. Pressure drop (I think left corners?) with that engine. So you want a bit thicker oil to help with pressure. I personally would overfill a little bit unless that boxer is sensitive to that. When I track BMW I overfill by 0.5qt at least.
2. It is the track. So, going from 0W20 to "Euro" thick 5W30 is not too much. IMO it is just about right. But if you go HTHS 4.1cP, it will rob you of too much power, and more resistance means more heat (5W30 will do the same, but not that dramatic).

Another thing. 5W30 will be more shear stable. Redline is generally shear-stable oil. But between 5W30 and 0W40, 5W30 will retain its viscosity better. Think about it like this: All things equal or similar (which is the case with Redline Performance series), the less "spread" between the first number (5W) and the second number (30), the more shear stable the oil is. Sometimes 0W40 will be more shear stable than 5W30. But that is usually the case when you have very sophisticated 0W40 (like that Redline, HPL, Motul 300V, etc.) and average off-the-shelf 5W30, like let's say Kirkland from Costco or even just regular Mobil1 5W30. But in this case, you are talking two oils that are VERY similar when it comes to base stocks, additives etc.
 
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