Shell tests fuel-saving 0W-10 synthetic motor oil
 

Interesting and quick read. Looks like they saw a 6.5% increase in FE in the city and 4.6% on the combined cycle. Note though that they don't really tell you if they compaired that to 5W-20 or 5W-30. In any case, thinner oil is better as long as it can still protect the engine!

Shell pushes lubrication boundaries with fuel-saving 0W-10 synthetic motor oil — Autoblog Green

I wonder who's going to approve it first, as there are no approvals today (AFAIK).

"The testing undertaken compares the concept lubricant to a 10W-30 oil which is a widely used viscosity in European markets."

Daox -

In a new engine from today I would try this, but I think my old engine would leak. The Saturn S-Series engine block is a late 1980's design.

CarloSW2

...GM is heading that direction with their current 5W-30 dexos1™ "global" specification.

Some guy over on Bobistheoilguy ran a custom-crafted 0w-10 in his Jeep's 2.5l 4-cylinder for a few oil changes with no changes in his normal driving habits. There was no measurable increase in wear per used oil analyses.

That being said, I still can't get over running a 20-weight in my car's engine that specs 30-weight.

Its all about the main and rod bearing clearances and the pressure/volume ratio of the oil pump.

When you rebuild an engine for racing you use the tightest clearances, and run a 0w10 for qualifying. (Faster) then switch to a "heavier" oil for the race.(Better durability) Joe Gibbs Racing sells a bunch of special synthetics some with extra zinc for breaking engines in, some that are for higher RPM's, etc. Good page to look around at...

Typically you want a high pressure NOT a high volume pump because the pressure on the oil is what keeps the clearances where they should be. A high volume pump usually will cause over-oiling to the top end and cause leaks at the valve cover gaskets.

Just a couple opinions... Probably worth what ya paid for em... :)

Dave

the mans right zinc is used to help break in engines.

i ran 5-50 full synthetic in my starlet once, the oil was so thin the valve train noise was ridiculous and tappets were horrible. it also leaked out of alot of places.

as for acceleration though the thing couldn't wait to jump off the tacho

i switched to a full synthetic 15-50 and its alot happier. it doesnt leak anymore either :)