Another Oil question (0w20)

Another Oil question (0w20)

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Richyvrlimited

Original Poster:

1,824 posts

162 months

Thursday 11th February 2016
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I've recently purchased a GT86, and was rather surprised that the recommended spec of oil for the engine was 0w20 (or 5w30 - but if you use 5w30, it should be changed to 0w20 at the next service).

AIUI the number after the w indicates the viscosicy under load / at higher temps, and generally the higher the better, (as long as it's not a large distance from the 1st number as that indicates lots of additives which will degrade).

I also was under the impression that if it's a boosted or high revving engine you should have a higher right hand number i.e.40 or 50.

The GT86 is relatively high revving, 7.5k redline and I'm someone who likes to rev a car, I also like to track the car.

So should I stick with the manufacturer specification oil, or change to something else?

Cheers

HJG

461 posts

106 months

Thursday 11th February 2016
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All the development and validation on that engine would have been completed with the specified oil. For road use it would be pointless to deviate from the manufacture specifications. Some people like to run a slightly thicker oil for track use, but this is engine dependent and you can run into issues with variable cam timing actuation if oil controlled.

HustleRussell

24,602 posts

159 months

Thursday 11th February 2016
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Richyvrlimited said:

I also was under the impression that if it's a boosted or high revving engine you should have a higher right hand number i.e.40 or 50.

The GT86 is relatively high revving, 7.5k redline and I'm someone who likes to rev a car, I also like to track the car.

So should I stick with the manufacturer specification oil, or change to something else?
Yeah, put whatever right hand number sounds nice to you, so long as it's not too far from the left hand number !!!1!

Silly Toyota telling us to put little right hand number oil in when 40 or 50 right hand number definitely sounds more familiar and also bigger?

AW111

9,455 posts

132 months

Friday 12th February 2016
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One reason manufacturers spec very thin oil is to help get better fuel consumption.

Richyvrlimited

Original Poster:

1,824 posts

162 months

Friday 12th February 2016
quotequote all
HustleRussell said:
Yeah, put whatever right hand number sounds nice to you, so long as it's not too far from the left hand number !!!1!

Silly Toyota telling us to put little right hand number oil in when 40 or 50 right hand number definitely sounds more familiar and also bigger?
Did you get out of the wrong side of bed this morning or something?

A larger difference between the cold and hot viscocities requires more, (long chain I think), additives which when the oil is subjected to extreme temps/pressures break down.

My old car (MX5 obviously), had an OEM spec of 10w30, but the engine performed much better with a 0w40. This is why I'm asking about possibly defiating from the manufactures recommendation.

PaulKemp

979 posts

144 months

Friday 12th February 2016
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Hey it's your car, if you want to gamble with an expensive engine, carry on.
Just let us know when it goes wrong so we can learn by your mistake
If it doesn't strip it down and measure the wear so we can compare your engine to one with servicing to the manufacturers specification.

Richyvrlimited

Original Poster:

1,824 posts

162 months

Friday 12th February 2016
quotequote all
PaulKemp said:
Hey it's your car, if you want to gamble with an expensive engine, carry on.
Just let us know when it goes wrong so we can learn by your mistake
If it doesn't strip it down and measure the wear so we can compare your engine to one with servicing to the manufacturers specification.
Jesus wept,

I don't want to gamble, that's why I'm asking.

nsa

1,682 posts

227 months

Friday 12th February 2016
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I thought it was a reasonable question, but agree that if the manufacturer recommends that grade, you should probably go with it. I'd never have thought 0W20 would work in the GT86 engine. Somebody sensible will be along soon to explain why it does.

alolympic

700 posts

196 months

Friday 12th February 2016
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I questioned a similar thing as my 5 cylinder Volvo engine is recommended 0w 30.
After some deliberation I kind of thought, they know better than I, so go with it. The low viscosity at cold temperatures will presumably flow better on start up. My engine has a high Rev auto choke on cold start up, and in reality, 1500rpm for the 1st 30 seconds probably benefits from the better flow rate of a 0w grade. With the Volvo, I wondered if it was related to Swedens cold climate too. Dunno.
Less risk in following manufacturers advice I feel. It could cause problems if you did have any engine problems and had a warranty claim if they traced the wrong grade of oil?

Pumaracing

2,089 posts

206 months

Friday 12th February 2016
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I could have sworn I covered all this not long ago but can't remember which thread. In a perfect world engine oil would have the same viscosity at any temperature - the one single viscosity that produces the ideal oil pressure for the pump system and bearing clearances in a given engine.

In the real world fluids get less viscous as temperature increases and no amount of long chain polymer additives can compensate for this. EVERY multigrade oil ever made is too thick when it's cold - end of. Even a 0-30 is far too thick when it's cold. So forget the first number in a multigrade other than it can never be too small. Something like a -30 would be nice.

The second number, the hot viscosity, is the one to worry about and IMO you can't really beat a 30. You certainly never need anything thicker in an unworn modern engine and I still believe that anything thinner is more about fuel economy than engine protection.


powerstroke

10,283 posts

159 months

Friday 12th February 2016
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AW111 said:
One reason manufacturers spec very thin oil is to help get better fuel consumption.
This , my toyota recommends in the hand book 0w30 c2 but also 5w30 and thats what oil firms web sites recommend
shell and others the local toyota dealer said they would use 3w30
I'm sure 5w30 will be fine unless you are going to the arctic circle....

one eyed mick

1,189 posts

160 months

Saturday 13th February 2016
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Do you really think that manufacturers and oil companies would specify incorrect oil for millions of cars ? If so get the next bus back to earth asap

steveo3002

10,493 posts

173 months

Saturday 13th February 2016
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chances are they put some thought into what spec oil it needs , i think id trust them over some internet randoms

stick with top quality stuff and change it often if youre driving it hard

Richyvrlimited

Original Poster:

1,824 posts

162 months

Saturday 13th February 2016
quotequote all
one eyed mick said:
Do you really think that manufacturers and oil companies would specify incorrect oil for millions of cars ? If so get the next bus back to earth asap
Get over yourself and read puma's reply.

The OEMs pick an oil type for many reasons, not necessarily to protect the engine to last 200k+

Richyvrlimited

Original Poster:

1,824 posts

162 months

Saturday 13th February 2016
quotequote all
Pumaracing said:
I could have sworn I covered all this not long ago but can't remember which thread. In a perfect world engine oil would have the same viscosity at any temperature - the one single viscosity that produces the ideal oil pressure for the pump system and bearing clearances in a given engine.

In the real world fluids get less viscous as temperature increases and no amount of long chain polymer additives can compensate for this. EVERY multigrade oil ever made is too thick when it's cold - end of. Even a 0-30 is far too thick when it's cold. So forget the first number in a multigrade other than it can never be too small. Something like a -30 would be nice.

The second number, the hot viscosity, is the one to worry about and IMO you can't really beat a 30. You certainly never need anything thicker in an unworn modern engine and I still believe that anything thinner is more about fuel economy than engine protection.
Thanks for the technical response, this was the sort of reply I was after, then I could make some form of informed opinion.

If we all did what the manufacturer though best, no one would modify their cars at all....

stevieturbo

17,229 posts

246 months

Saturday 13th February 2016
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Sort of related, but one extreme application where they use very thin oils

http://www.enginelabs.com/engine-tech/oiling-syste...

Sardonicus

18,928 posts

220 months

Wednesday 17th February 2016
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Pumaracing said:
I could have sworn I covered all this not long ago but can't remember which thread. In a perfect world engine oil would have the same viscosity at any temperature - the one single viscosity that produces the ideal oil pressure for the pump system and bearing clearances in a given engine.

In the real world fluids get less viscous as temperature increases and no amount of long chain polymer additives can compensate for this. EVERY multigrade oil ever made is too thick when it's cold - end of. Even a 0-30 is far too thick when it's cold. So forget the first number in a multigrade other than it can never be too small. Something like a -30 would be nice.

The second number, the hot viscosity, is the one to worry about and IMO you can't really beat a 30. You certainly never need anything thicker in an unworn modern engine and I still believe that anything thinner is more about fuel economy than engine protection.
This^ a properly designed modern engine should not need more than a */30 yes the likes of BMW only quote higher viscosity for their larger M motors etc because they have oil burning issues especially when punished on track etc which they no owners will biggrin all things being equal most modern stuff 0/30 5/30 etc I also highly regard japanese engine design especially Honda & Toyota I would go with what Toyota recommend although I cant see an increase in the upper by 10 making much of a difference quite frankly with VVT etc


Edited by Sardonicus on Wednesday 17th February 11:47

Richyvrlimited

Original Poster:

1,824 posts

162 months

Wednesday 17th February 2016
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Thanks again all, that's really good to know.

That article steveturbo posted was fascinating.

Pumaracing

2,089 posts

206 months

Wednesday 17th February 2016
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Richyvrlimited said:
That article steveturbo posted was fascinating.
Albeit appallingly written with a graph with no axis descriptor so you have no idea what's it's meant to show and gibberish about cavitation in high revving engines. You can gear the pump down to any speed you want - you get more volume flow by making the pump bigger, not making it spin faster.

Anyhoo, the key point is at that level of racing, as in F1 or similar, everyone is trying to gain the last few bhp by using the thinnest possible oils that sap the least amount of power in parasitic drag. Bearing clearances, volume flow, cooling etc are key to making all that work reliably and it should not be used as any sort of guide to the oil you need in a road car.

CABC

5,533 posts

100 months

Wednesday 17th February 2016
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i'm no expert but i've read a lot about oil. sad. It can be confusing and internet experts abound, of course real evidence is thin on the ground as you'll only know after 100k or a lot more what worked or failed and that's assuming you test cars side by side that have had the same oil type throughout their life. Anyway, i would suggest you consider a very high quality 0/20 oil (eg 300V or Millers Nano) or if you want to be a bit more cautious a quality 0/30 or 5/30. Ester oils resist shearing and even if 20 weight will retain their properties for a long time... a lot of 86 users have moved to a 30 weight, especially with track use. Many suspect that the manual is written with CAFE in mind. Interesting that most oil sites themselves propose a 30 for the 86. Stateside oil analyses have shown quality oils lasting way over 7500 miles. Not sure what the UK oci is now, but if it is 15k then you might consider a mid term oil change.
I agree with you that the 86 likes a good thrashing, so few extra £ on oil and changes no more than 10k is easy peace of mind.

just my 2p worth from the armchair.