For occasional track use , which oil viscosity to use? Using oil data sheet for guidance

[julianobl]

0W-20? 5W-20? 0W-30? 5W-30? 10W-30?

I've done 2 HPDEs and oil temps have reached temporarily 275F which is quite high but not sustained. I live in a very hot tropical climate with 90+F ambient temperature on track days. I've been researching into which oil viscosity to use but there's so much conflicting information out there that I don't know which way is up. I'm currently using AMSOIL signature series oil 0W-20.

For example, some of the technical data is counterintuitive on this AMSOIL data sheet, such as:

• Some lower weight oils having higher viscosity indexes than heavier weights (0W-20 higher than 5W-20), although my understanding is that 5W-20 is actually somewhat better in high temps than 0W-20 (although same high temperature 20 rating).
• Same issue with NOACK volatility % weight loss (5W-20 having less volatility than 0W-30)

I would assume Hight-Temperature/High-Shear Viscosity is one of the most important data points but then again, I'm not entirely sure, this data point follows what one would expect in terms of having higher value in direct proportion to higher weight.

According to these data in the table, which would you chose? Which property is more significant or important for our K20C1 for occasional heavy track use and high temps?

Thanks in advance

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[Jester04]

I use 5W-30 in mine but will bump it up to 10w-30 since I live in a hot climate.

 

[CTRifecta]

Given your climate, and how high you run your oil temps to, I would run a higher viscosity, Mobil 1 0w40 supercar would be a great choice. It's more like a 0w30 viscosity wise and is a med-low SAPS oil, which helps with build up on DI engines. It's also got HTHS of around 3.5.

Personally I run 0w20 Amsoil but I live in new England and primarily use it as a DD. Even when I track the car, I back off once oil temps reach 250. This is my DD and also a brand new car, I'm not gonna risk it all just for a few extra seconds on a lap...

 

[Jester04]

Given your climate, and how high you run your oil temps to, I would run a higher viscosity, Mobil 1 0w40 supercar would be a great choice. It's more like a 0w30 viscosity wise and is a med-low SAPS oil, which helps with build up on DI engines. It's also got HTHS of around 3.5.

Personally I run 0w20 Amsoil but I live in new England and primarily use it as a DD. Even when I track the car, I back off once oil temps reach 250. This is my DD and also a brand new car, I'm not gonna risk it all just for a few extra seconds on a lap...

With his climate he would be better off with a heavier oil. That way he can do what he wants with it and not have any issues and does not have to limit himself. Those 0w-20 oils are for fuel economy but are basically water.

 

[tezzasaurusrex]

I am currently running 0W30 Motul 8100 and have done lab tests on this against Honda LEO 0W20 with no discernable differences in engine wear (used both oils on track). I would say either is fine, the Honda LEO oil has a better additive package than the Motul.

 

[Jester04]

Given your climate, and how high you run your oil temps to, I would run a higher viscosity, Mobil 1 0w40 supercar would be a great choice. It's more like a 0w30 viscosity wise and is a med-low SAPS oil, which helps with build up on DI engines. It's also got HTHS of around 3.5.

Personally I run 0w20 Amsoil but I live in new England and primarily use it as a DD. Even when I track the car, I back off once oil temps reach 250. This is my DD and also a brand new car, I'm not gonna risk it all just for a few extra seconds on a lap...

Just in case I did not mean in a bad way lol . Just that the guy is from PR island climate is 80’s-90’s year round so he does not really get any benefit from a 0 weight oil since it never really gets cold there.

 

[CTRifecta]

Ahh okay, if he's in PR, agree a 5w30 or 5w40 would work. I think the 0w40 is great regardless but understand.

 

[Jester04]

Ahh okay, if he's in PR, agree a 5w30 or 5w40 would work. I think the 0w40 is great regardless but understand.

Oh for sure! If you live in a colder climate that 0w30 or 0w40 will work great.

 

[julianobl]

Thanks everyone for your answers, appreciate you!
I should have added that I use it as daily driver with the occasional heavy track use.
I'm also running PRL I/C & P700 turbo, Hondata tune, DP, FP, K&N drop in filter.

Would a 40 weight heavy oil (regardless of the W rating) affect fuel economy significantly? Is it really safe to use such a high weight oil seeing as the engine was designed for 0W-20?

 

[Jester04]

Thanks everyone for your answers, appreciate you!
I should have added that I use it as daily driver with the occasional heavy track use.
I'm also running PRL P700 turbo, Hondata tune, DP, FP, K&N drop in filter.

Would a 40 weight heavy oil (regardless of the W rating) affect fuel economy significantly? Is it really safe to use such a high weight oil seeing as the engine was designed for 0W-20?

You can use a 40 weight no problem. But it you want to keep it closer to spec. Just do 5w-30 which is what I’m doing and tracking the car also.

 

[CTRifecta]

I think you can't go wrong with a 30 or 40w, what's more important is to monitor your oil levels and make sure to change your oil more frequently.

 

[Jester04]

I think you can't go wrong with a 30 or 40w, what's more important is to monitor your oil levels and make sure to change your oil more frequently.

This!^ oil levels should be monitored regularly. Especially on turbo cars. Great suggestion @CTRifecta

 

[julianobl]

I use 5W-30 in mine but will bump it up to 10w-30 since I live in a hot climate.

Why the change if you don't mind me asking

 

[Jester04]

Why the change if you don't mind me asking

Cause I’m in Florida where its super hot and the less spread between the weights the less shearing there is. I will use 5w-30 for winter and 10w-30 for summer.

 

[Rhorn]

Cause I’m in Florida where its super hot and the less spread between the weights the less shearing there is. I will use 5w-30 for winter and 10w-30 for summer.

Any issues if you were to use 5W-30 year round?

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