CT4-V Anyone actually try 0W-40 when tracking 4BW?

[motormatt]

So has anyone actually tried using 0W-40 in a CT4-V Blackwing or use it regularly? There was a rumor that an engineer at GM made a statement that all V cars now should use it and I have also heard that the only reason it may not be approved for the 4BW is due to emissions. I am going to a 2 day track event and in the past day 2 my oil starts running much hotter, in the 240-250. Wondering if it makes sense to use the 0W-40 just for track events. Looking for someone who has actually done this and if it causes any problems. - M@

 

[Stiletto]

Been using Amsoil 0W-40 for two years. I'm not stock and daily on E85. Zero issues. No track days yet, but plenty of spirited driving.

 

[Melon]

I use Mobil 1 Supercar 0w-40 for the same reason you listed.
I see 240-250 oil temps. There is a little headroom even at those temperatures, but the 40w holds up better in hotter climates.

 

[BigShark]

Been running Mobil 1 0W-40 in my track car for a while now and haven't had any issues, so I'd say go for it especially if you're seeing those higher temps on day 2.

 

[Kawman]

I understand the change form the W-30 to W-40 and agree with it. What I don't understand is why you folks are going from the 5 to 0. This seems like going in the wrong direction. I'm now using 5W-40. I was seeing 280-285 oil temps running in 90+ degrees at WG a couple of weeks ago.

 

[Melon]

Sticking with Mobil 1 brand oils.
I've considered Motul or Liqui Moly, but trying to stay in the realm of OEM and more importantly, more affordable oils, although Dexos R oils aren't exactly cheap.

I ran Motul 5w40 8100 in the 1LE. That would be a good 5w40.

Going to a 0w-X won't hurt anything other than provide better flow at startup going to a 10w-X wouldn't be ideal.

 

[Kawman]

Sticking with Mobil 1 brand oils.
I've considered Motul or Liqui Moly, but trying to stay in the realm of OEM and more importantly, more affordable oils, although Dexos R oils aren't exactly cheap.

I ran Motul 5w40 8100 in the 1LE. That would be a good 5w40.

Going to a 0w-X won't hurt anything other than provide better flow at startup going to a 10w-X wouldn't be ideal.

I wouldn't run 10w40 in the winter with 0 temps, but I'd consider it during the summer months when the ambient temp is never below 60 degrees.

With the wholesale contact I've provided, the Motul is the same price as Dexros R.

I called Motul and spoke with them. I told them my car, what I was doing with it and that I did not want to discuss price. The only variable I wanted to know about is what is the VERY best oil you make for my application. I was told the 300V is their best oil.

As for Motul 8100 versus the 300V, the 8100 is their street car oil, while the 300V is their race car oil. Here's an AI answer on the topic.

Neither is objectively "better" overall; it depends strictly on your usage. Motul 300V is the better racing oil for track use, extreme heat, and maximum horsepower. Motul 8100 is a far better street and daily driving oil, offering longer service intervals and better engine cleaning additives. [1, 2, 3, 4]
Understanding the specific differences will help you decide which fits your needs:

• • Motul 300V (Racing): Uses a specialized Ester Core technology designed for competition. It provides superior shear resistance, film strength, and power output. However, because it is formulated purely for performance, it lacks the standard detergent packages found in street oils and must be changed frequently (typically every 3,000 miles or immediately after track events). [1, 2, 3, 4, 5]
  • Motul 8100 (Street/Daily): Formulated for everyday passenger and sports cars. It meets strict manufacturer approvals (like BMW, Mercedes-Benz, Porsche, and VW) and features long-life additive packages designed to clean the engine and handle extended oil drain intervals (often up to 10,000+ miles, depending on your vehicle's manual). [1, 2, 3, 4, 5]

The OP's question was specifically about track use, so I stand firm on the Motul 300V. Mobil 1 simply is not in the same league as the Motul. Like not even close for track purposes.

I previously used Mobil 1 and changed my oil every 2 days. With the Motul, I've gone to 3 days between oil changes.

 

[Melon]

Right, for my needs Mobil 1 Supercar or Motul 8100 fits the bill.

300v is top tier oil.

AmsOil is also a great oil, just not Dexos 1, Gen 3 certified.

 

[motormatt]

I understand the change form the W-30 to W-40 and agree with it. What I don't understand is why you folks are going from the 5 to 0. This seems like going in the wrong direction. I'm now using 5W-40. I was seeing 280-285 oil temps running in 90+ degrees at WG a couple of weeks ago.

My understanding is that the first number is how the oil reacts in the cold and the second number is how it reacts in the heat. I am also thinking of the formulation in the Supercar product which meets and exceeds the Dexos standards supposedly required by the CT4-V Blackwing.

 

[Melon]

Correct, the higher the first number, the more viscosity at cold temps. you can go down, but don't go up.

Mobil 1 and GM's relationship makes my confident in using their products. There are oils that will protect more, sure, but I'm also not running the car that hard.

 

[piranha971]

The bigger the gap between the two numbers, the quicker the second number will shear down to a lower value.

 

[Kawman]

See what I mean, every piece of knowledge one gains leads to 4 more doors to be explored.

Based upon what you just said, dropping from a 5w40 to a 0w40 is absolutely the wrong way to go. Additionally, we would now have a possible argument for moving to a 10W40.

The 5W30 GM gave us and has since revised to 5W40 is for all of us everywhere. As one looks at their own situation, one should be considering their own unique environmental factors. A car that lives in Alaska and sees more sub zero days than above 80 days should probably go to the 0W40. Should a car that lives in Arizona and almost never sees a temp under 30 and hasn't seen an overnight low during the past 2 weeks of less than 90 not be thinking about 10W40? Both because the 10 value isn't going to be a problem because the car just doesn't see low temps and to lower the gap between the 2 numbers?

So, for summer driving and track driving is 10W40 more appropriate? Hmmm, another rabbit hole. Time to make more phone calls.

 

[Melon]

The bigger the gap between the two numbers, the quicker the second number will shear down to a lower value.

Yup, that's why you would want to change it right after a track day where it sees heavy use, or more frequently than a 5w30. I believe that's stated in the performance manual that came with my 1LE, I don't recall the BW's getting one, but I might be mistaken.

There's so many variables.

• Ambient Temp
• Driving Style
• Oil Temps

When you get into the weeds, it's not a one-size fits all. Different applications call for different oils.
It's not unreasonable to run a 5w30 normally and then do a fill of 0w40 or 5w40 for a track day, drain that and then run a 5w30 again.

Or, if you're in my shoes, I run a 0w40 all the time, I live in a hot climate, and like to romp on the car.

Honestly a 5w30 Dexos 1, gen 3 will satisfy 98% of buyer's needs, we're talking about the slim variances.

 

[motormatt]

See what I mean, every piece of knowledge one gains leads to 4 more doors to be explored.

Based upon what you just said, dropping from a 5w40 to a 0w40 is absolutely the wrong way to go. Additionally, we would now have a possible argument for moving to a 10W40.

The 5W30 GM gave us and has since revised to 5W40 is for all of us everywhere. As one looks at their own situation, one should be considering their own unique environmental factors. A car that lives in Alaska and sees more sub zero days than above 80 days should probably go to the 0W40. Should a car that lives in Arizona and almost never sees a temp under 30 and hasn't seen an overnight low during the past 2 weeks of less than 90 not be thinking about 10W40? Both because the 10 value isn't going to be a problem because the car just doesn't see low temps and to lower the gap between the 2 numbers?

So, for summer driving and track driving is 10W40 more appropriate? Hmmm, another rabbit hole. Time to make more phone calls.

So after doing some more research it seems that the benefit of the lower weight cold temperature oil (0W) is that it is thinner and getting to rings, bearings, and camshafts faster which is what is needed at start up. The (40) is what then stands up to the additional heat from a track day. 5W takes longer to hit the dry components on initial startup causing the most wear.

 

[Melon]

These engines are designed to run a 5w30, so that's not an issue.
This time of year, the oil temps at my car sit at 90 degrees, I could get away with a 10w, probably without issue.

I just wouldn't run a 15w50 on a -20 degree frozen Midwestern day.

 

[Kawman]

So after doing some more research it seems that the benefit of the lower weight cold temperature oil (0W) is that it is thinner and getting to rings, bearings, and camshafts faster which is what is needed at start up. The (40) is what then stands up to the additional heat from a track day. 5W takes longer to hit the dry components on initial startup causing the most wear.

Correct, but it's not as simple as a lower first number is better. That 0w first number is better for a car that lives in Alaska where it experiences cold temperature starts. A car that lives in Arizona would never see cold temperature start in it's life! My car doesn't see cold temp starts, as it does a Rip Van Winkle during the winter months.

Here's AI's comment on the topic:

The primary difference is their cold-weather flow. Both oils offer the exact same protection at normal engine operating temperatures (the "30" rating), but a 0W-30 flows much better during freezing winter startups than a 5W-30.
The breakdown of how these ratings work:

• • The First Number (0W vs 5W): The 'W' stands for Winter. A 0W-30 oil is thinner at extreme freezing temperatures and reaches critical engine parts faster than a 5W-30 during cold starts, which minimizes early engine wear.
  • The Second Number (30): Both oils have the same viscosity (thickness) at high operating temperatures (around 100°C or 212°F), meaning they provide similar levels of protection when your engine is fully warmed up.

GM first gave us 5W30 and had since revised that to 5W40. If a 0 first number was better, why wouldn't they have given us that? The answer is because 0W is ONLY better in extremely cold conditions. A 0W oil does NOT lubricate your engine better outside of extremely cold conditions. The additives used to make the oil thinner when cold also cause it to breakdown faster in heat.







always

 

[schernov]

M1 Ow40 is good oil and carries various Euro car certifications. I have been running it in our 2009 bmw 135i which is a 3.0L twin turbo for last 12 years with twice a year oil changes (low mile per year car).

 

[ellteefour]

So after doing some more research it seems that the benefit of the lower weight cold temperature oil (0W) is that it is thinner and getting to rings, bearings, and camshafts faster which is what is needed at start up. The (40) is what then stands up to the additional heat from a track day. 5W takes longer to hit the dry components on initial startup causing the most wear.

The magic happens with these so-called viscosity modifiers, which are specially crafted polymers that curl up into a smaller volume when cold and unfurl into longer shapes when hot (think soup thickener). Shear forces will chop these polymers up into shorter segments over time, which lowers the higher viscosity number. This is why the track day regulars get their oil analyzed so they know when to change it based on how hard and how often they're running.

 

[blkout]

The bigger the gap between the two numbers, the quicker the second number will shear down to a lower value.

True.