0w20 Synthetic instead of 5W30?

[Shannow]

Originally Posted By: TiredTrucker
Just curious, as I have no dog in this hunt, but wonder how then that Ford specifies a XXw20 oil for their Ecoboost V6 with turbocharger if there is no turbo designed with using 20w oil in mind.[/quote

Just interested in what the Ford engineers were doing deisigning Mitsubishis and why they didn't advise them to use Motorcraft 5W20 in their Ford/Mitsubishi engines...

Unless Ford had nothing to do with said Mitsubishi engine, and the Mitsubishi engineers have their own designs and performance parameters...

And since a lighter fluid sheds heat faster than a heavier fluid, why wouldn't the 20w be a good choice over a 30w, as long as the film strength meets the demands of the application?


How does a lighter fluid "shed heat" faster than a heavier...just in technical terms, specific heats, flow rates, stuff like that...so that we can quantify the percieved and much vaunted
(on BITOG) improved heat transfer capacities of 20s.

As to your films strength aassertion, you are falling into the one armed bandit mindset

Hydrodayanim lubrication has parts separated by a film/wedge of oil, the film stiffness and strength determined by surface speeed, bearing size, and viscosity...viscosity up, film thickness up, parts move further away from each other

When the oil wedge is gone, through too low a viscosity, or abnormal operation, you get into the realms of films strength that is determined by additives...this part has not much to do with viscosiy, however if you look up the liner scuffing paper that I posted a couple days ago,you'll see that a straight 40 could pass the scuff test, while a 10W-40 couldn't.

 

[CATERHAM]

Originally Posted By: 901Memphis
As long as you can maintain sufficient hot oil pressure most engines will tolerate a lower grade well. DR Hass was using Redline 5w20 in his Lamborghini which is basically a 5w30 but the engine was specified for 10w60 iirc and his uoas were fine.

What is the specific application before we go further?

Actually Ali Haas is now running MotorCraft semi-syn 5W-20 (HTHSV 2.65cP) in his wife's Lambo'.
BTW 5W-40 is spec'd for the Lambo; the 10W-60 is spec'd for his Enzo Ferrari and he's running RLI 0W-30 in that.

 

[CATERHAM]

Originally Posted By: Kuato
Originally Posted By: Bandito440
That's an expensive turbo that's going to heat up the oil. I sure wouldn't.


Yep; I haven't seen a turbo yet that is specified for 0w20. Best to stick with the heavier oil in this one.

A 0W-20 is approved for the BMW 4 cyl turbo:
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3394810/Re:_BMW_approved_0W-20_for_N20#Post3394810

But it isn't spec'd for the OP's Evo but that doesn't mean he couldn't possibly use the 0W-20 grade if he can maintain sufficient oil pressure when the oil is up to temperature. Unfortunately from the sound of things his car isn't equipped with an oil pressure gauge which would have told him conclusively whether or not the dealer did install the 0W-20 or 5W-30 grade. If the high VI Idemitsu made Mitsibushi 0W-20 was what the dealer used the oil pressure would have been noticeably lower the moment the engine was fired up.