What is considered a respectable HTHS?

[Carlostrece]

What is a respectable HTHS for 5w20 & 5w30 oils?

Do thicker grade oils have better HTHS or just a higher starting viscosity?

My understanding of HTHS is it tells us how much viscosity loss will occur due to shear. Is that correct?

 

[Brian123]

What is a respectable HTHS for 5w20 & 5w30 oils?

Do thicker grade oils have better HTHS or just a higher starting viscosity?

My understanding of HTHS is it tells us how much viscosity loss will occur due to shear. Is that correct?

Do you want better gas mileage or better engine protection?
How are you driving this car?
What oil are you using?
What are your OCI's?
What are your Oil temperatures like under your driving conditions?

If you drive like a normal person and obey the speed limit and drive the car like Grandma, the HTHS thing or thicker grade does not matter. If you drive your car hard, that is when we need to look at the HTHS Number or maybe going to a different oil viscosity.

 

[SubieRubyRoo]

>3.5 and never worry about it for any stock vehicle sold today in the US.

 

[Glenda W.]

3.5+ Available at Wally for around $27

 

[Klutch9]

3.5+ Available at Wally for around $27

I’m on the same bandwagon now. Been using 3.5+ HTHS oils in my turbo Explorer for a few OCIs now. Today I’ll also be putting ESP 0w30 into the Carnival. It’s not turbocharged, but it’s very high compression and loafs along at low RPMs. Also runs pretty hot by design. I’ve used 20 grades for years (~2.6 HTHS), but as engines become more power-dense and also lug constantly, I’m not sure a 20 grade is optimal anymore.

 

[Carlostrece]

Do you want better gas mileage or better engine protection?
How are you driving this car?
What oil are you using?
What are your OCI's?
What are your Oil temperatures like under your driving conditions?

If you drive like a normal person and obey the speed limit and drive the car like Grandma, the HTHS thing or thicker grade does not matter. If you drive your car hard, that is when we need to look at the HTHS Number or maybe going to a different oil viscosity.

Engine protection is more important to me than gas mileage.

My 97 Buick is driven easy. Mix of city & highway. I'm currently using Maxlife Blend 5w30. I'll likely switch to Quaker State Ultimate Protection Full Syn 5w30 in future.

Mostly, I just want to make sure I understand the HTHS topic and understand why people at BITOG often talk about it.

 

[Carlostrece]

Is HTHS stated in an oil's datasheet or calculated from VOA & UOA? How do you know what the HTHS of an oil is?

 

[ripcord]

What is a respectable HTHS for 5w20 & 5w30 oils?

Do thicker grade oils have better HTHS or just a higher starting viscosity?

My understanding of HTHS is it tells us how much viscosity loss will occur due to shear. Is that correct?

I'm way over simplifying but you can think about HTHS ("High Temperature, High Shear") as the film strength of oil at high temperatures and pressures. Basically, it measure the ability of oil to keep bearings from touching when the oil is really hot (150c). Most 0w-20 oils have at least 2.3cSt at 150c. Some studies seem to suggest that 2.6cSt seems to be a threshold for minimizing wear in some test engines.

 

[Pablo]

3-3.5 for XW-30

 

[Jetronic]

3.5 cP as a starting point, which can only drop from there when in use and preferably stays well over 3.0 cP. Grade is not important, except the cold start viscosity needs to low enough for your climate.

 

[Brian123]

Engine protection is more important to me than gas mileage.

My 97 Buick is driven easy. Mix of city & highway. I'm currently using Maxlife Blend 5w30. I'll likely switch to Quaker State Ultimate Protection Full Syn 5w30 in future.

Mostly, I just want to make sure I understand the HTHS topic and understand why people at BITOG often talk about it.

I am hung up on the HTHS Number, my oil is Mobil 1 ESP 5W-30 with a HTHS Number of 3.5
The oil you are looking at from Quaker State, I am not sure about the HTHS Number. I have good news for you, and I should be jumping on this, but I do not need any oil at this time.

Quaker State Euro 5W-40 with a HTHS Number of like 3.8 and here is the Link

https://business.walmart.com/ip/Quaker-State-Euro-Full-Synthetic-5W-40-Motor-Oil-5-Quart/5213099247

The above oil is Awesome!

 

[Carlostrece]

I am hung up on the HTHS Number, my oil is Mobil 1 ESP 5W-30 with a HTHS Number of 3.5
The oil you are looking at from Quaker State, I am not sure about the HTHS Number. I have good news for you, and I should be jumping on this, but I do not need any oil at this time.

Quaker State Euro 5W-40 with a HTHS Number of like 3.8 and here is the Link

https://business.walmart.com/ip/Quaker-State-Euro-Full-Synthetic-5W-40-Motor-Oil-5-Quart/5213099247

The above oil is Awesome!

I can believe QS Euro 5w40 is good, but I want to stay at thick end of 5w30 and no thicker. A thick Euro 40 is thicker than I want. Also, the QS UP FS is a very good price at Wallyworld. I'm not poor anymore, but pinching pennies is still a habit and a fun hobby, even though not a necessity anymore.

 

[wlk]

Nothing wrong with the 5w30 Maxlife Blend you have been running. I ran that for many years in my gm 3.1s, 4.2, 5.0 and 5.7s. Any Xw30s will run fine, if you want a very good one M1 ESP 0w30 or PP Euro L 5w30 would work very well and easily available at wallyworld

 

[Cujet]

As mentioned above. 3.5 mpas at 150ºc (302ºF) is considered good, and is about the dividing line between low and high HTHS. Mobil 1 5W-30EP has an HTHS of about 3.1. While that might at first seem "low", it is way above the 0W-20 that my tuned Jaguar's engine calls for.

For racing engines, ultra hot running engines (air cooled) or very highly stressed race engines, it is a smart move to choose an HTHS above 3.8 and often well above that could be necessary. But very few engines are in that category. We would all like to think our engines are ultra high output monsters. But the reality is otherwise.

 

[Carlostrece]

Nothing wrong with the 5w30 Maxlife Blend you have been running. I ran that for many years in my gm 3.1s, 4.2, 5.0 and 5.7s. Any Xw30s will run fine, if you want a very good one M1 ESP 0w30 or PP Euro L 5w30 would work very well and easily available at wallyworld

I like nice oils, or at least the idea of them, but only if they're affordably priced. If it's available at Wallyworld, I'm willing to consider it.

 

[JAG]

My understanding of HTHS is it tells us how much viscosity loss will occur due to shear. Is that correct?

No. It is the viscosity at 150 C temperature and 10^6/sec shear rate or similar shear rate, depending on the test method. It is not measured in high pressure conditions, as I saw someone say. A very viscous oil at low shear rates like Lucas Oil Stabilizer would have a lot of temporary viscosity loss (TVL) at high shear rates and high HTHS viscosity. On the other hand, a typical 0W-8 oil will have very little TVL and very low HTHS. TVL affects HTHS, but the most important factor is the dynamic viscosity at 150 C and zero shear rate.

 

[ChrisD46]

3.5+ Available at Wally for around $27

M1 0W30 / 5W30 ESP meet this. Valvoline R&P 5W30 comes in at a respectable 3.2

 

[facility1]

Royal Purple 5w-30 hths is 3.2 and Schaeffer's 9000 is 3.32,,,many brands premium brands are around these figures,,so think outside of the box.....

 

[TiGeo]

4.0 centipoise or sell the car/RIP/leave BITOG.

 

[I<3oil]

4.0 centipoise or sell the car/RIP/leave BITOG.

Only a 4.0? How pedestrian.