5W30 vs 0W40
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Instructor
Joined: Apr 2014
Posts: 176
Likes: 3
From: Princeton NJ
Corvette Magazine's opinion
A 2008 LS3 owner asked the 5w30 vs. 0w40 question in the Tech Nerd section of the latest issue (June 2017) of Corvette Mag. Here's the answer: He basically said that if you live in a cold climate and run the car in winter "the engine would likely benefit from 0w40." Also "if you autocross the car, do occasional track days in hot weather, the engine would benefit from a switch (to 0w40). If you don't drive it in super cold weather or drive it very hard in super hot weather, then practically speaking, the answer is no, there is no significant difference if you switch to 0w40 oil. In that case, I'd recommend sticking with the factory spec 5w30."
I was interested in this topic because I live in New Jersey and I drive my '08 all year long.
I was interested in this topic because I live in New Jersey and I drive my '08 all year long.
Advanced
Joined: Jul 2014
Posts: 53
Likes: 17
From: Shreveport Louisiana
Betty's teenage son might think there are big hp gains using Tony's motor oil, though! I can see the post now. "My buddy said I will gain 25 hp using this official NASCAR oil. And more mpg!"
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
Teenage?! Hell I've known grown men who've made similar claims with their daily drivers.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Sorry for the brief humor, but we know age doesn't automatically include all knowledge.
Drifting
Joined: May 2015
Posts: 1,525
Likes: 391
From: Martinez CA
A lot of stuff keeps changing, too.
Much of the "pressure" on EOM car makers comes from the EPA and CARB. As cars last longer & longer, they are determining what kills the catalyst and trying to get that stuff out. Small changes times many millions of daily drivers adds up.
In CA, CARB (Ca Air Resource Board) dictate our "special" gasoline specs, as we here in smog free CA
*get* to use. And it costs well OVER $1.00 a gallon MORE, LOL. Only a few out of state refiners can make all of the blend components, too (read $$$$$$$). Less sulfur, lower benzene, aromatics, lower olefins, Lower RVP, distillation curve changes, etc.
SO, with oil recco's, MUCH of this is based on emissions IMV, NOT what serves the engine the best.
Perhaps Canada does NOT pressure GM to recco 3w-30 M1 due to zinc, phos, etc. But is more relaxed - so GM has more latitude? to really state what they want Vette's to use? MMT is an octane booster. Legal in Canada, NOT legal in US (mixed in MOGAS blends).
Complicated by Gov emission std & politics, not whats best for our engines, LOL.
PLUS, GM ships Vettes from Alaska to AZ (not to mention places like the Caymens, LOL). SO, their advice most be general and generic enough to be mostly safe for *everyone*. Even LS3's on small islands, LOL
Much of the "pressure" on EOM car makers comes from the EPA and CARB. As cars last longer & longer, they are determining what kills the catalyst and trying to get that stuff out. Small changes times many millions of daily drivers adds up.
In CA, CARB (Ca Air Resource Board) dictate our "special" gasoline specs, as we here in smog free CA
*get* to use. And it costs well OVER $1.00 a gallon MORE, LOL. Only a few out of state refiners can make all of the blend components, too (read $$$$$$$). Less sulfur, lower benzene, aromatics, lower olefins, Lower RVP, distillation curve changes, etc.SO, with oil recco's, MUCH of this is based on emissions IMV, NOT what serves the engine the best.
Perhaps Canada does NOT pressure GM to recco 3w-30 M1 due to zinc, phos, etc. But is more relaxed - so GM has more latitude? to really state what they want Vette's to use? MMT is an octane booster. Legal in Canada, NOT legal in US (mixed in MOGAS blends).
Complicated by Gov emission std & politics, not whats best for our engines, LOL.
PLUS, GM ships Vettes from Alaska to AZ (not to mention places like the Caymens, LOL). SO, their advice most be general and generic enough to be mostly safe for *everyone*. Even LS3's on small islands, LOL
Last edited by Chiselchst; Apr 29, 2017 at 04:07 PM.
Drifting
Joined: Mar 2003
Posts: 1,771
Likes: 141
From: Kaukauna WI
A 2008 LS3 owner asked the 5w30 vs. 0w40 question in the Tech Nerd section of the latest issue (June 2017) of Corvette Mag. Here's the answer: He basically said that if you live in a cold climate and run the car in winter "the engine would likely benefit from 0w40." Also "if you autocross the car, do occasional track days in hot weather, the engine would benefit from a switch (to 0w40). If you don't drive it in super cold weather or drive it very hard in super hot weather, then practically speaking, the answer is no, there is no significant difference if you switch to 0w40 oil. In that case, I'd recommend sticking with the factory spec 5w30."
OP's quote that pertains to this:
"The 5W30 flows better/quicker during cold start-up, to reach critical engine components quicker to prevent wear. And since cold start-up is where 90% of engine wear takes place, the thinner the oil is when cold, the better."
Last edited by Must_Have_Z; Apr 29, 2017 at 05:29 PM.
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Instructor
Joined: Apr 2014
Posts: 176
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From: Princeton NJ
This totally goes against the OP's post. I'll take the OP's research as more valid than what you've posted here (some other guy's off the cuff comments). He proved through testing that 5W-30 actually flows BETTER, much better, at colder temps and warmer temps than 0W-40. So it's very clear cut - if you live in colder temps and don't constantly track your car, run the 5W-30. He proved that the labeling of 0W-40 is totally misleading when it comes to flow and temperatures.
OP's quote that pertains to this:
"The 5W30 flows better/quicker during cold start-up, to reach critical engine components quicker to prevent wear. And since cold start-up is where 90% of engine wear takes place, the thinner the oil is when cold, the better."
OP's quote that pertains to this:
"The 5W30 flows better/quicker during cold start-up, to reach critical engine components quicker to prevent wear. And since cold start-up is where 90% of engine wear takes place, the thinner the oil is when cold, the better."
Drifting
Joined: May 2015
Posts: 1,525
Likes: 391
From: Martinez CA
To meet desired specs/classification, all of the oil companies have to have many tests ran. However, often they are normally EXTREMELY reluctant to make them public. I'd love to see some comparisons of the specs below, LOL...
Burning Brakes
Joined: Oct 2013
Posts: 1,061
Likes: 130
FYI: This question cam up in "Ask Tadge" and his answer does provide some insight into why the GM engineers recommend the oils that they do:
https://www.corvetteforum.com/forums...-road-use.html
https://www.corvetteforum.com/forums...-road-use.html
descartesfool asked:
What is the effect of changing from Dexos compliant 5W30 to Mobil1 15W50 for the track and back for road use? Some cars which are used on track a lot such as Porsches and GT-Rs recommend Mobil 1 0W40 for all uses, with no changes required when driving on track. Would this oil be fine for track and street use in the C7? What are the negative effects of leaving the 15W50 after track days and driving on the road, and at what temperatures is it an issue, hot or cold?
What is the effect of changing from Dexos compliant 5W30 to Mobil1 15W50 for the track and back for road use? Some cars which are used on track a lot such as Porsches and GT-Rs recommend Mobil 1 0W40 for all uses, with no changes required when driving on track. Would this oil be fine for track and street use in the C7? What are the negative effects of leaving the 15W50 after track days and driving on the road, and at what temperatures is it an issue, hot or cold?
Tadge answered:
GM Propulsion Systems has validated all Corvette engines to operate with the DEXOS 5W30 for all but the most extreme track conditions. We recommend the use of Mobil 1 15W50 when the vehicle is going to be used for high temperature track operation as the higher viscosity range provides a greater degree of protection under the extreme stresses of that duty cycle. We like the extra lube performance in those conditions because, unlike some other manufacturers, driving on the track does not automatically void the warranty. However, daily driving use of the Mobil 1 15W50 on the street has not been validated, and as such we do not recommend its use where the operating temperatures can run lower. Some contributors to the thread correctly point out that few Corvette drivers operate their vehicles at extremely low temperatures, but as the manufacturer, we have to protect for that possibility. Another issue is that the 15w50 oil has higher phosphorous and ash content than we specify for factory fill. That is ok for track usage, but in long term street usage, those chemicals can compromise catalyst performance. As the manufacturer, we are expected to meet EPA emissions for a very long time. Lastly, the higher viscosity will also result in a small loss of fuel efficiency.
As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorous and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use.
Like all aspects of the auto industry, lubricants continue to improve over time. We work with Mobil and others to elevate the performance of their products and hence ours. We will continue to do that and when we have a better oil to ship in our engines or recommend for use on the track, we will do so.
GM Propulsion Systems has validated all Corvette engines to operate with the DEXOS 5W30 for all but the most extreme track conditions. We recommend the use of Mobil 1 15W50 when the vehicle is going to be used for high temperature track operation as the higher viscosity range provides a greater degree of protection under the extreme stresses of that duty cycle. We like the extra lube performance in those conditions because, unlike some other manufacturers, driving on the track does not automatically void the warranty. However, daily driving use of the Mobil 1 15W50 on the street has not been validated, and as such we do not recommend its use where the operating temperatures can run lower. Some contributors to the thread correctly point out that few Corvette drivers operate their vehicles at extremely low temperatures, but as the manufacturer, we have to protect for that possibility. Another issue is that the 15w50 oil has higher phosphorous and ash content than we specify for factory fill. That is ok for track usage, but in long term street usage, those chemicals can compromise catalyst performance. As the manufacturer, we are expected to meet EPA emissions for a very long time. Lastly, the higher viscosity will also result in a small loss of fuel efficiency.
As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorous and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use.
Like all aspects of the auto industry, lubricants continue to improve over time. We work with Mobil and others to elevate the performance of their products and hence ours. We will continue to do that and when we have a better oil to ship in our engines or recommend for use on the track, we will do so.
Le Mans Master
Joined: May 2016
Posts: 7,098
Likes: 1,546
From: Florida
This a very informative post. Many thanks to the OP for this. I have been an avid reader of his blog for some time now. I've always found it amazing that the advertised viscosity ratings on motor oils really don't accurately indicate the viscosity of the oil in the bottle. I don't think that most folks appreciate this. In a way, it's a form of false advertising, in my humble opinion.
One thing of interest that I've recently noted from the OPs testing of Mobil 1 5W30 vs. Mobil 1 0W-40 (Euro spec) oil is that the latter is much more resistant to thermal breakdown at elevated temperatures (~275*). Therefore, it may be a better oil for those of us who do road course/autocross racing where temps can get up into that temperature range.
For me, I'll stick with the 5W-30 with my stock bottom end and high volume oil pump, because I have more than enough pressure and I think that's what these engines were built for.
As far as why the 0W-40 oil is specified for the European market, I've been puzzled by that too. I wonder if this could be because the engines are built with different clearances for the euro market, if that us even possible? Or is it just a marketing ploy, because I've noted that manufacturers like BMW likes to specify thicker grade oil for their performance cars?
We have been having another discussion on another thread on this forum about a member who has a built engine with looser clearances and, consequently, lower oil pressures, and it clear that some folks thinks that whatever the factory recommends is the what should always be used.
This all reminds me that what folks need to know to decide on what viscosity oil they need to run is in fact the clearances of their engine. That's not to say that I agree with the old school train of thought that looser is better and you should just run a 40-50wt oil to keep pressure in the oil galley sufficiently high to keep an oil film on the bearing surfaces.
In the end, you need to know what your engine needs. No doubt GM has done a fair bit of research on this, because the liability from a factory warranty would dictate that's necessary.
But I'm still curious as to why they recommend the 0W-40 for the European market, if that's in fact the case?
Thanks again to the OP for sharing the benefits of his expertise on here.
One thing of interest that I've recently noted from the OPs testing of Mobil 1 5W30 vs. Mobil 1 0W-40 (Euro spec) oil is that the latter is much more resistant to thermal breakdown at elevated temperatures (~275*). Therefore, it may be a better oil for those of us who do road course/autocross racing where temps can get up into that temperature range.
For me, I'll stick with the 5W-30 with my stock bottom end and high volume oil pump, because I have more than enough pressure and I think that's what these engines were built for.
As far as why the 0W-40 oil is specified for the European market, I've been puzzled by that too. I wonder if this could be because the engines are built with different clearances for the euro market, if that us even possible? Or is it just a marketing ploy, because I've noted that manufacturers like BMW likes to specify thicker grade oil for their performance cars?
We have been having another discussion on another thread on this forum about a member who has a built engine with looser clearances and, consequently, lower oil pressures, and it clear that some folks thinks that whatever the factory recommends is the what should always be used.
This all reminds me that what folks need to know to decide on what viscosity oil they need to run is in fact the clearances of their engine. That's not to say that I agree with the old school train of thought that looser is better and you should just run a 40-50wt oil to keep pressure in the oil galley sufficiently high to keep an oil film on the bearing surfaces.
In the end, you need to know what your engine needs. No doubt GM has done a fair bit of research on this, because the liability from a factory warranty would dictate that's necessary.
But I'm still curious as to why they recommend the 0W-40 for the European market, if that's in fact the case?
Thanks again to the OP for sharing the benefits of his expertise on here.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
To make sense of the results, you'd first need to know and understand the test methods and it's importance. For instance, the circled one requires ASTM D7563 as the method. You can Google the specs, but be prepared to spend $$$$ for documents, since they aren't free.
Drifting
Joined: May 2015
Posts: 1,525
Likes: 391
From: Martinez CA
True perhaps, unless you worked for an oil company..
Point is, there are a lot of things to consider other than viscosity (resistance to flow). The 0w-40 excels at HT/HS, has better TBN value, and actually flows better when much colder. That viscosity test at 104*F is not exactly what I consider to be a cold test.
Point is, there are a lot of things to consider other than viscosity (resistance to flow). The 0w-40 excels at HT/HS, has better TBN value, and actually flows better when much colder. That viscosity test at 104*F is not exactly what I consider to be a cold test.
Le Mans Master
Joined: Apr 2013
Posts: 5,376
Likes: 1,118
I remember back in the day when 50wt oil and loose clearances were considered mandatory for racing, and then people like David Vizard (IIRC) started publishing dyno tests results with 30wt oil, and I thought, how strange!
But I've since learned that there's a lot more to oil than the viscosity rating.
That's why I think the OPs testing is invaluable. For once someone is actually independently testing the actual film strength of various oils and publishing the results. For that, he deserves some kind of medal, IMV.
Le Mans Master
Joined: May 2016
Posts: 7,098
Likes: 1,546
From: Florida
Thats the way to do it. But, even when you know the clearances and the oil specs, regardless of viscosity ratings, it's hard to know what oil works "best" (i.e. offers the best protection, which is the primary function of engine oil) without some impirical data such as oil tests and bearing inspections after the fact.
I remember back in the day when 50wt oil and loose clearances were considered mandatory for racing, and then people like David Vizard (IIRC) started publishing dyno tests results with 30wt oil, and I thought, how strange!
But I've since learned that there's a lot more to oil than the viscosity rating.
That's why I think the OPs testing is invaluable. For once someone is actually independently testing the actual film strength of various oils and publishing the results. For that, he deserves some kind of medal, IMV.
I remember back in the day when 50wt oil and loose clearances were considered mandatory for racing, and then people like David Vizard (IIRC) started publishing dyno tests results with 30wt oil, and I thought, how strange!
But I've since learned that there's a lot more to oil than the viscosity rating.
That's why I think the OPs testing is invaluable. For once someone is actually independently testing the actual film strength of various oils and publishing the results. For that, he deserves some kind of medal, IMV.
We hot rod engine builders in the day, however, never thought through what it would take to get to 100,000 miles and more. We looked for "simple science" for the moment. We tended to build - rebuild to rebuild which, in a lot of cases, was nothing more than a season or even less.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Yeah, everything you say is true.
We hot rod engine builders in the day, however, never thought through what it would take to get to 100,000 miles and more. We looked for "simple science" for the moment. We tended to build - rebuild to rebuild which, in a lot of cases, was nothing more than a season or even less.
We hot rod engine builders in the day, however, never thought through what it would take to get to 100,000 miles and more. We looked for "simple science" for the moment. We tended to build - rebuild to rebuild which, in a lot of cases, was nothing more than a season or even less.
Big clearances, Teflon buttons, 50 wt oil, high volume pumps, and 10-12 quart pans was the standard fare of the day. I wonder how much quicker I could have been if I would have known todays technology.
