M1 0W-30 vs. 0W-20/40 Mix (S2000)

[ludiferino]

Is there any benefit to using Mobil 1 0W-30 versus a mixture of 0W-20 and 0W-40 in a Honda S2000? I am thinking about switching from the 0W-30 to a 60%/40% (3/2 qt) mix of 0W-40/0W-20, respectively. M1 0W-20 and 0W-40 are used in other vehicles within the household, see list below, so I can simplify oil purchases/stocking with a mix.

Also, it seems I can gain some performan...ed information. Although, I don't intend to perform oil analyses to verify.

Thanks.

'00 Honda S2000 [M1 0W-30; summer driver/autocross]
'94 Mazda Miata [M1 0W-40; autocross]
'06 BMW 330i [M1 0W-40; daily]
'06 Honda CR-V [M1 0W-20; daily]

 

[dparm]

I'd just run the off-the-shelf M1 0w30 or 0w40. The car was spec'd for 10w30 when it was introduced in the US, and in other countries they actually spec a 5w40. Either of those M1 weights can be had for $5/qt or less.

You certainly can mix the 0w20 and 0w40 though. It's not optimal but it will work.

 

[ludiferino]

Originally Posted By: dparm
I'd just run the off-the-shelf M1 0w30 or 0w40. The car was spec'd for 10w30 when it was introduced in the US, and in other countries they actually spec a 5w40. Either of those M1 weights can be had for $5/qt or less.

You certainly can mix the 0w20 and 0w40 though. It's not optimal but it will work.


I have been using the 0W-30, but I'm looking to simplify. Two oils in the household rather than three, and AAP has stopped carrying M1 0W-30.

I was under the impression the 40 is a bit thick for the S2000; something about building oil pressure quickly and bypassing early (old internet recollection). Also, I thought 40s were only recommended by Honda in hot climates (Australia, etc

Thanks.

 

[demarpaint]

I'd make it simple if I were you, I'd buy Mobil 1 0w30 from another supplier. Walmart comes to mind as does PB and Auto Zone. You'll find that Auto Zone and PB run it on sale, and Walmart prices are usually pretty good.

 

[TrevorS]

I agree that 0w40 straight is likely too thick as it is a Euro oil.

I would just run your favorite 30 weight. It's more work to figure out the proportions when mixing and oil has been designed to work as that oil.

 

[Ramblejam]

Originally Posted By: TrevorS
I agree that 0w40 straight is likely too thick as it is a Euro oil


False.

Originally Posted By: ludiferino
I was under the impression the 40 is a bit thick for the S2000; something about building oil pressure quickly and bypassing early (old internet recollection). Also, I thought 40s were only recommended by Honda in hot climates (Australia, etc


No. See below:

This is from the 2000 S2000 Owners Manual (USA).

 

[jrustles]

M1 0w40 is a light 40 either way, so why not?

 

[TrevorS]

Min HTHSV of a 5w40 oil is 2.9.

M1 0w40 has a HTHSV way above that.

In the US, any oil marked Euro typically has an HTHSV above 3.5 including Euro oils in the SAE xw30 grade.

This will be heavier than both the 10w30 and 5w40 oils that Honda allows by a good margin.

 

[Ramblejam]

Originally Posted By: TrevorS
This will be heavier than both the 10w30 and 5w40 oils that Honda allows by a good margin.


Ok, I'll play.

Could you please provide us with a document from Honda stipulating a maximum HTHS viscosity for the S2000?

I'll wait...

P.S. -- You might want to research Honda HFS.

 

[jrustles]

Indeed. Also the manual was written pre-Y2K.

OTOH I doubt Honda Motor is implying an HTHS restriction with what's printed in the manual, just that they couldn't see and predict the future of motor oils. Plenty of 5w40s out there currently exceeding 3.5

 

[TrevorS]

The important thing is that you provide the min HTHSV that Honda spec.

I would imagine it is 2.9. Why would you go to 3.8?

Remember, I said 0w40 is way thicker than required.

I never said that it was not allowed. So you asking me to prove a maximum HTHSV is a ridiculous argument.

 

[TrevorS]

Originally Posted By: jrustles
Indeed. Also the manual was written pre-Y2K.

OTOH I doubt Honda Motor is implying an HTHS restriction with what's printed in the manual, just that they couldn't see and predict the future of motor oils. Plenty of 5w40s out there currently exceeding 3.5


Yikes! They recommend 10w30 which is pretty much always going to have a HTHS from 2.9 to 3.3.

The 5w40 is for COLDER ambient situations!

Repeat, they are happy with HTHSV of 2.9 in all ambient temps, and you are arguing that I am saying HTHSV of 3.8 is higher than required?

Repeat, I never claimed there was a max restriction, I said there is a big difference between the suggested 3.8 and the min required in all ambient conditions of 2.9!!!!!

 

[Ramblejam]

Originally Posted By: TrevorS
I never said that it was not allowed. So you asking me to prove a maximum HTHSV is a ridiculous argument.


and I quote...

Originally Posted By: TrevorS
In the US, any oil marked Euro typically has an HTHSV above 3.5 including Euro oils in the SAE xw30 grade.

This will be heavier than both the 10w30 and 5w40 oils that Honda allows by a good margin.

 

[TrevorS]

I think you are having an interpretation problem!

I did not say "heavier than allowed", I said "heavier than Honda allows".

There is a subtle difference!

 

[OVERKILL]

Originally Posted By: TrevorS
Originally Posted By: jrustles
Indeed. Also the manual was written pre-Y2K.

OTOH I doubt Honda Motor is implying an HTHS restriction with what's printed in the manual, just that they couldn't see and predict the future of motor oils. Plenty of 5w40s out there currently exceeding 3.5


Yikes! They recommend 10w30 which is pretty much always going to have a HTHS from 2.9 to 3.3.

The 5w40 is for COLDER ambient situations!

Repeat, they are happy with HTHSV of 2.9 in all ambient temps, and you are arguing that I am saying HTHSV of 3.8 is higher than required?

Wow!


They don't spec an HTHS, your interpretation that they are "happy" with an HTHS of 2.9 is something you've simply inferred from the 10w-30 recommendation. I don't see any data that supports it

Honda spec's a 5w-40 because it has better low temperature performance. What we CAN infer from THAT is that they did NOT recommend a 5w-30 because they did not consider it shear stable enough to provide enough protection. That would seem to support that they certainly are aware as to a safe minimum HTHS for the engine and that a 5w-30 wasn't able to provide it at the time of testing.

A non-Euro or HDEO 5w-40 with an HTHS below 3.5cP is not going to be easy to find. It is unlikely that Honda had that in mind when they made their recommendation. And in that vein, the 5w-40 was likely to shear, bringing the HTHS down a bit anyway. Something Honda was certainly aware of and likely why that was their recommendation.

 

[147_Grain]

Suggest you run a 0W-30 in the winter and 0W-40 in the summer for this high-revving engine.

Personally, I like the blend of 0W-20 / 0W-40 year around and would use the Widman Calculator to thicken or lighten up the oil (a little) using HTHS ratios as the #1 value.

 

[TrevorS]

If a 5w40 is only required for cold temp, then the relevant minimum HTHSV interpretation is for the SAE 10w30 grade.

As I said, they will range from 2.9 to 3.3. Easy to find a 10w30 with HTHSV less than 3.5 right?

So 3.8 is quite a bit thicker than necessary.

Bringing up HTHSv for 5w40 is just confusing the issue. Clearly the objective there was to provide 5w performance. Yes they may have felt a 5w30 would not be shear stable in which case it just reaffirms they wanted to stay above the 2.9 minimum.

 

[TrevorS]

M1 10w30 has HTHSV of 3.0. Honda says it is suitable for all hot ambient conditions.

And people are arguing that I said M1 0w40 is thicker than necessary?

Priceless!

 

[OVERKILL]

Originally Posted By: TrevorS
If a 5w40 is only required for cold temp, then the relevant minimum HTHSV interpretation is for the SAE 10w30 grade.


Yes, MINIMUM HTHS, note there is no maximum. Perhaps the engine operates properly with an HTHS between 3.0 and 4.0? We don't know, because Honda doesn't provide a spec, all they provide are two oil recommendations.

Quote:
As I said, they will range from 2.9 to 3.3. Easy to find a 10w30 with HTHSV less than 3.5 right?


Yes, and those oils will be conventional. Honda doesn't spec a synthetic, nor did they create a specific oil requirement (like they did with HTO-06) for this car. They obviously observed that a conventional 10w-30 was stable enough to meet the minimum requirements of the car.

That said, the 5w-40 recommendation implies a synthetic. It is also recommended for all temperatures. Honda obviously factored in shear to that recommendation. And as I said, they would know that the 5w-40 would shear, whilst still exceeding the minimum necessary HTHS requirements of the engine.

Quote:

So 3.8 is quite a bit thicker than necessary.


Thicker than the minimum allowed maybe. Not sure why you assume this is such a bad thing. Oil temperatures have a major effect on viscosity, so even with the 10w-30 in the pan, the HS visc observed by the engine with cooler oil temperatures is going to be greater than necessary.

.6-.8cP isn't much in the context as to how much temperature has a role on visc.


Quote:
Bringing up HTHSv for 5w40 is just confusing the issue.


Ummm, you brought it up

Originally Posted By: TrevorS
Min HTHSV of a 5w40 oil is 2.9.

M1 0w40 has a HTHSV way above that.

In the US, any oil marked Euro typically has an HTHSV above 3.5 including Euro oils in the SAE xw30 grade.

This will be heavier than both the 10w30 and 5w40 oils that Honda allows by a good margin.


Quote:
Clearly the objective there was to provide 5w performance. Yes they may have felt a 5w30 would not be shear stable in which case it just reaffirms they wanted to stay above the 2.9 minimum.


That's what I said. Which means that they were not concerned with the HTHS of the 5w-40 being higher than the 10w-30. They wanted 5w-xx performance and wanted to ensure that the oil exceeded the minimum HTHS requirements of the engine.

 

[A_Harman]

60% of 3.8 HTHS + 40% of 2.7 HTHS will give a final HTHS of about 3.3 or 3.4, so I think you're in a good space to keep the final sheared HTHS above 2.9. If your car has been running fine on M1 0w30, it should continue to do fine on the 0w40/0w20 blend.

Other oils I would consider would be M1 HM 10w30 or GC 0w30, but I realize this defeats your idea of only keeping two types of oil in the house.