fastegg

Has anyone used 0W-20 oil ?..... Has anyone got any ideas about using this weight to get better fuel economy ? Assuming the motor never gets revved hard... and, the 5W-30 oil in '98 was probably API-SG ?... now where using SN spec which is (I'm guessing) a far better oil on many levels... So is my thinking wrong to think I could use a 0-20 of SN spec ?...
I'm putting a mechanical oil pressure gauge on this weekend and run it for a bit on the 5-30 full syn Nulon (API-SN)..... If the oil pressure is good I might try 0-20....
Does anyone have any thoughts on this ?...
*** A few years back we were racing Honda CBR600's... factory recommended oil was 10W-40.. however on the race track we ran 0-5... that's right. 0W-5... the engines sounded really rattly, like REALLY RATTLY... I, as well as everyone else ran this weight oil as it gave (I can't remember how much) a few more HP (which in a 600 is alot) and they accelerated noticeably 'harder'... The engines seemed to enjoy being 'on the boil' with the lighter oil. My point to all this is that we never heard of an engine failure in anyone's bike (that was oil related).... So I, and everyone else were doing this for the 2 years that I raced them... and there was never a problem.... And the kicker here is my team buddy pulled his motor down after the first year and there was not a single sign of any wear anywhere.... so he just replaced the rings (even though it didn't need them) and put it all back together....
...... This partly leads to my thinking a lighter higher spec oil might be better for my application.
....... I'm interested in anyone's opinions....

dicer

At operating temperature even a very thick oil becomes pretty thin. Single weight 30 pours like water at 200 degrees F. Agreed there is some loss of friction and loss of pumping power with lighter weights. But in places where good protection is needed that would be high pressure areas like ring contact and gear teeth, the gains in hp and or economy may not be worth it. Most strive for longevity of parts in a car. For economy there are other better things to do than possibly shorten the engine life. Number one is to have high pressure tires and smaller tire patches, good alignment, good engine tune. And really if economy is your thing drive a geo metro or a Vw diesel. The use of lower viscosity oil should be more dependent on the temperature of the area you live in.
Lighter weights in the cold areas, and heavier weights in the hotter areas. If your ambient temps are in the 100's I would not use 0-20, I would use 10-30 despite the 5w recommendation, as the 10 will be pretty much better than equivalent at those temps. The 5 is for very cold.

Legender

I'm thinking the mileage difference between a racing bike at a few thousand, maybe a few ten thousand vs the mileage of the LS at well over 300K... I would not even be considering this as you're comparing apples to apples in this case.
Let's just say, I won't be trying this in any of my cars.

fastegg

I would like to use 0W-30 instead of 5W-30. Not because of temperature but the theory that most engine wear occurs on start up. So if you can get oil flow to vital parts quicker like with a 0W-30 is it possible that there will be less wear on start up ?

oldskewel

iTrader: (1)

That makes sense. Were 0W-30 oils even available when these cars were first produced? If not, that might suggest they would have been spec'd if available.

Cool information about the motorcycle engines. Thanks.

PureDrifter

iTrader: (10)

WAY too thin in my opinion.

dicer

The logic is not correct. The thinner oil will run off faster and your starts will be drier. Most all small airplane engines run on 40 weight. Mercedes recommends 5W-40 in some cars. Personally I would not go under 10W-30 unless its winter time in the north east states. Especially with high miles. Brand new then yeah use what the factory says. Hmmm just noticed the VVT that probably needs what the owners manual says, because there are small screens that feed the vvt.

StillLine

Yes, this is the correct thinking on this topic. I'm running Mobil 1 0w-30 in my SC430 for cold start wear protection.
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UNCNOR

iTrader: (1)

I think the Japanese engineers of Toyota are smarter than the "engineers" on Club Lexus.Use the oil specified in the owners manual.

Yamae

Toyota has needed to redesign engines to use 0W-20 in order to keep the durability.
Those Toyota cars specified to use 0W-20 have at least 2 special units in the engine to meet the low viscosity.
1, An improved oil pump.
2, An improved oil cooler.

A LS400/Celsior does not have those and you may damage or shorten the life of your engine if you use 0W-20.

Toyota engineers worked hard to design the new pump, cooler and others in order to improve the fuel economy keeping the engine durability. See the last part of below.

dicer

And most importantly is the running tolerances - clearances of various parts in the engine. What year did they go to
0W -20 oil?