Thin higher grade (5w30 Moylgen) vs thick lower grade (5w20 Redline)

[altaylar]

I was part of a discussion that I thought I should bring here as it would be good to have everyone`s opinons, and I am sure it will be useful in the future for other members too.


There is a turbo vehicle that calls 5w20 and the owner is looking for some extra protection when he is pushing his turbo vehicle and now that he got ECU tune, so considering bumping it up to 5w30 Molygen, but he is also feeling uncomfortable to be going thicker than OEM spec. Then his friend tells him that Molygen 5w30 has a HTHS of 2.9, whereas Redline 5w20 posts an even higher HTHS right at 3.1, so he could rather go even "thicker" while going lower on viscosity grade.

Please share your opinion, either spesific to these two oil, or more general about 2 oil that are close to eachother but on different sides of viscosity cutoff for grades

 

[Hohn]

Additive pack differences trumps small changes in viscometrics. For example, the 300ppm Moly in a Havoline 5w-30 will have less startup wear than an Mobil 1 Advanced Fuel Economy 0w-20 with 80ppm of moly. Especially at startup, where a robust EP/AW additive package trumps a half second or so faster oil pressure arrival.


It seems ridiculous to ignore the factory tune and then honor the factory oil recommendation. Either factory knows best or it doesn't, right?

For a tuned TGDI engine I'd suggest never being lighter than 40 grade. But the reason to go 40 grade has less to do with thicker being better (although it is), but rather it has to do with getting away from ILSAC and Energy Conserving certs that constrain the add packs. You want a bit more phosphorus and some Moly.

Any group III or better Euro 0w-40 will work well in this case, with of course Mobil 1 FS Euro and Castrol Edge getting the nod for common shelf oils. Don't overlook the Havoline Pro DS Euro if you happen to find some.

And even though it's an API SPI D1G3 additive package, even the lowest grade of HPL PCMO will run circles around shelf oils because their blend is *chef's kiss* harmony of Esters, Moly, and good modest VII. HPL's group III formulas are more robust than most other's PAO bases. And then as you go up their line in VII upgrade and ultimately to PAO base, it only gets better.

I'm running HPL 15w-40 in my Honda 2.0T that specs 0w-20. The car loves it anecdotally and soon the UOA will show what's going on. I'll be expecting total wear metals around 2ppm/1k miles. TDGI engines IMO need thicker oils to combat fuel dilution and oil volatility/aerosolization.


Spend some time on the virgin oil analysis database. Pick an oil that's known to be solid performer (Mobil 1 ESP, Castrol Edge, etc) in the highest viscosity that works for your local area.

When in doubt, 0w-40 the whole world.

 

[kschachn]

I was part of a discussion that I thought I should bring here as it would be good to have everyone`s opinons, and I am sure it will be useful in the future for other members too.


There is a turbo vehicle that calls 5w20 and the owner is looking for some extra protection when he is pushing his turbo vehicle and now that he got ECU tune, so considering bumping it up to 5w30 Molygen, but he is also feeling uncomfortable to be going thicker than OEM spec. Then his friend tells him that Molygen 5w30 has a HTHS of 2.9, whereas Redline 5w20 posts an even higher HTHS right at 3.1, so he could rather go even "thicker" while going lower on viscosity grade.

Please share your opinion, either spesific to these two oil, or more general about 2 oil that are close to eachother but on different sides of viscosity cutoff for grades

Is this a variation on "I know this subject has been beaten to death already, but..."?

I'll post some previous threads if that's a help. Perhaps not the same brands, but in reality that isn't relevant.

 

[MolaKule]

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