Both of these motor oils are 5 grade when cold, however, 5w30 oil is 30 grade, and 5w40 oil.

EJ25: 5w40.

FIRST IMPRESSIONS: Feels different than my other synthetics, especially different than the royal purple i use on the Fiances toyota. Rotella T6 5w-40 is the proven oil.

5w40 oil is not thicker as it has a higher viscosity.

5w40 with higher temperatures in summer has a higher viscosity.

. And based on the fuel economy, 5w30 wins the race in terms of performance. Just pick a spec like Porsche A40 (Motul X cess, Mobil 1 0W40, or Castrol 0W40).

Both oils are 5 grade when cold, but 5w30 is 30 grade and 5w40 40 grade when at operating temperatures.

2. 5mPas. 5w40 ensures higher pressure, but less flow.

5w30 vs 5w40. Amsoil European Car Formula 5W-30 Improved ESP Synthetic Motor Oil.

however, I use 5w-40 Amsoil because oil in turbo cars goes through alot of abuse and deteriorates.

Jul 5, 2019 · In terms of motor oil, correct me if im wrong but I believe it's 5w-30.

. I recognize that the car calls for 5W-30 but it seems like WRX/STI owners tend to prefer a higher-viscosity oil, even if they do not.

But I heard about some old timers running 5w40 instead. 8 TBN remaining I'm not sure I buy this oil being.

The shear rate viscosity of both the oils is different.
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5 to 16. Low-Shear-Rate Viscosity for 5w30 and 5w40. Fuel Economy.

2. As with 5W30, 5W40 motor oil has a cold viscosity of 5. Car is (and will remain) bone stock aside from having the noise pipe removed. -2022 Lexus IS500 Launch Edition. .

Amazon Basics Full Synthetic Motor Oil 5W-40 With Euro Formula: Best Oil For Subaru WRX 2002-2010.

But I heard about some old timers running 5w40 instead. 5 to 16.

In most inhabited regions a synth 5W-40 will be OK, since it will behave at least adequately from -10 to +45 or so.



On the other hand, 5w40 will not be as great as 5w30 regarding fuel consumption.

Using the OEM oil and filter will make sure you're meeting Subaru's specifications, should any warranty work ever be required.