oilman

iTrader: (9)

John was talking about a power gain from using a 0w-20, rather than as an economy oil as Honda use them. A lot of new American and Jap cars and 4x4s also use 0w-20 and 5w-20 oils for economy. If you have a top end oil pump, 0w-20 is fine for performance use as it has such a small viscosity gap, making it very stable as long as the oil is pumped at a high enough rate. A little while ago, Cosworth engined F1 cars were using Silkolene Pro R 0w-20.

5w-50s are not great oils as there is a such a large viscosity gap, meaning a lot of polymers are required to maintain that viscosity range. Those are sheared fairly quickly by the engines action, breaking the oil down to a 5w-40 or 10w-40 in a short time. You're better off going for a good 5w-40 to start with.

Cheers

Tim

trogg

In what way does the 0W oil affect the engine?

I have seen "noise" mentioned, but also read here that the noise has no negative technical affect.

Setright

I can see some good advice around this thread.

But if you're serious about chosing an oil, and don't have an engineering degree, or understanding of physics and chemistry, and don't like reading technical documents, then ask a proper expert. Like some of the oil-retailers on this website.

I always read the technical spec sheets on the oils I consider. You will be surprised to find how much difference there is between the same grade of oils. 5W-40 oils, from two different companies, or even the same company, but a different range will have varying viscosities. the 5 and the 40 are both short-hand for an interval of viscosities. Shell Ultra for example...their 5W-40 is ALMOST an 5W-30.....whereas Mobil Delvac 1 5W-40 is almost in the 50 group.

ZEN Performance

Yes but you put that info out there and forget that people will take it at face value. It says in not so many words that you'll get 5% more power from running 0w-20 oil. Now if that was the only change, who wouldn't want 5% more power?! But I wonder if anyone at Silkolene has actually run a Subaru on a track day with 0W-20 or did they just think it would be a good idea for someone else to try? What John sort of eluded to, but didn't go as far as saying, was "0W-20 migh make more power but might cause an engine failure".

No amount of oil pump size is going to make 0W-20 work reliably in a high powered Subaru on track unless it had a substantial oil cooler and dry sump system, even then I would only use if it the person recommending it was prepared to pay for the engine rebuild if a bearing went!

There is a place for such oils on track, I have tested some and found some gains in power on restricted cars (engine, gearbox and diff oils) but the gains were probably in the order of 4% with all three oils changed, and only on engine making 118hp, suffice to say it wasn't a subaru!

oilman

iTrader: (9)

To be honest, I thought what John said was pretty clear. No, I wouldn't suggest using a 0w-20 in an Impreza, but you could if you are prepared to run the engine to destruction for a small increase in power

ZEN Performance

Clearly you haven't dealt with the sort of Scoobynet inspired technical enquiries that I have!

simpsons !

He's classed as a full weighter

polishingbooth