HTHS Q's

[Bryanccfshr]

HTHS is simply a viscosity measurement under specific conditions. Higher viscosity numbers always require more energy to overcome so technicly higher HTHS robs power unless the HTHS is required to prevent boundary lubrication (that is really a power robber))

 

[427Z06]

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HTHS is simply a viscosity measurement under specific conditions. Higher viscosity numbers always require more energy to overcome so technicly higher HTHS robs power unless the HTHS is required to prevent boundary lubrication (that is really a power robber))

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I'm glad someone else understands this point. Some engines, like a full boogie SBC/BBC with flat tappet cams might actually see a horsepower increase with an increase in HTHS value. Especially if you can increase the HTHS without substantially increasing the absolute viscosity.

 

[Bryanccfshr]

Absolutely, if high prifile agressive cams and heavy spring pressures are part of the engine design you need an oil that can maintain seperation between the moving parts of these extreme pressure situations, if that film is broken thedrag from mixed or boundary lubrication is exponential compared to good fluid seperation.
The issue comes when Joe Honda thinks that a high HTHS oil will benefit him and reduce wear in his Honda engine because it does in his buddy's crate motor powered mustang.

The Honda with its low friction valvetrain will not stress a low HTHS lubricant and he will not gain any additional wear protection, but he will lose energy (power and economy) to the parasitic drag from increased viscosity being pumped, having to overcome viscosity (viscosity=friction) in moving parts and windage of thicker oil taking longer to get off the crank and rods. So many times I read post that high viscosities only parasitic effect is on pumping losses. Although that is a big loss percentage wise every moving part that has to be lubricated by the oil is directly affected by the fluids viscosity, be it bearings or the pisons having to overcome more viscosity between the cylinders.

 

[Ron AKA]

This table gives you a good idea where the power losses are and how they are affected by HT/HS. Note that this is on a "high HT/HS loving" German engine.

 

[bruce381]

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I thought a high mileage oil would have higher HTHS. I would think friction reduction is not the main goal of high mileage oil, but filling in the larger gaps from wear. Thus HM oil should be thicker overall or, better yet, use a thicker base oil, which (all else equal) should give a higher HTHS.

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Tall paul correct I ment to say a low friction FUEL saving type oil would be at the low end.
bruce

 

[427Z06]

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This table gives you a good idea where the power losses are and how they are affected by HT/HS. Note that this is on a "high HT/HS loving" German engine.

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You really are clueless. That Mercedes Benz M111 2.0 litre is a DOHC engine.

 

[Ron AKA]

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This table gives you a good idea where the power losses are and how they are affected by HT/HS. Note that this is on a "high HT/HS loving" German engine.

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You really are clueless. That Mercedes Benz M111 2.0 litre is a DOHC engine.

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[427Z06]

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Absolutely, if high prifile agressive cams and heavy spring pressures are part of the engine design you need an oil that can maintain seperation between the moving parts of these extreme pressure situations, if that film is broken thedrag from mixed or boundary lubrication is exponential compared to good fluid seperation.
The issue comes when Joe Honda thinks that a high HTHS oil will benefit him and reduce wear in his Honda engine because it does in his buddy's crate motor powered mustang.

The Honda with its low friction valvetrain will not stress a low HTHS lubricant and he will not gain any additional wear protection, but he will lose energy (power and economy) to the parasitic drag from increased viscosity being pumped, having to overcome viscosity (viscosity=friction) in moving parts and windage of thicker oil taking longer to get off the crank and rods. So many times I read post that high viscosities only parasitic effect is on pumping losses. Although that is a big loss percentage wise every moving part that has to be lubricated by the oil is directly affected by the fluids viscosity, be it bearings or the pisons having to overcome more viscosity between the cylinders.

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Exactly, Bryanccfshr. Too bad some people don't have your depth of knowledge.

 

[427Z06]

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This table gives you a good idea where the power losses are and how they are affected by HT/HS. Note that this is on a "high HT/HS loving" German engine.

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You really are clueless. That Mercedes Benz M111 2.0 litre is a DOHC engine.

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And you are your usual ignorant self

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No, more like you are nimrod. You even know the difference between a crate SBC with a high lift flat tappet cam and a stock Mercedes Benz M111 2.0 litre?

 

[Ron AKA]

If you had an ounce of perception you would understand it was a joke about Germans (Europeans), insisting on high HT/HS oils - in fact they used to write it in their spec. I don't pretend to be an engine expert, and I also do not appreciate people who use every opportunity to fire insults at others just for the sake of doing it. Appears that is your main purpose in participating in this forum.

 

[buster]

Ron, you consistantly use broad sweeping generalizations to try and prove your particular point. You've done nothing but cause problems on this board by ignoring what others have said. It seems all you like to do is pick fights. Your conclusions about HT/HS and product data sheet specifications can not be used as the "end all" in telling how well an oil can perform. Get over it and use some common sense.

 

[buster]

Oh BTW, Bryan and 427, GREAT posts! I just learned something.

 

[TallPaul]

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I thought a high mileage oil would have higher HTHS. I would think friction reduction is not the main goal of high mileage oil, but filling in the larger gaps from wear. Thus HM oil should be thicker overall or, better yet, use a thicker base oil, which (all else equal) should give a higher HTHS.

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Tall paul correct I ment to say a low friction FUEL saving type oil would be at the low end.
bruce

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Which is one reason I avoid oils with "Energy Conserving" on the label.

 

[Bryanccfshr]

TallPaul, I am not debating your choice but for the benefit of the lurkers who are trying to figure things out can you explain your equipment and your reasoning more clearly. (I believe you have a Motorhome but I don't trust my memory that much on that and your other engines).

 

[TallPaul]

I have a 15,000 pound (loaded for trip) motorhome ('97)with a gas 7.5L V8 that calls for a heavy duty engine oil, so I used Maxlife with a zddp boost to 1600 ppm.

I have a '95 F150 with a 4.9L inline six and a '92 Aerostar with a 3.0 V6. I am running a boosted Durablend at 2100 ppm zinc in the F150 and currently have the Aerostar loaded with Redline 10w30.

The reason I like non energy conserving oil is that I prefer a more robust oil for any vehicle and I don't like the idea of my oil being modified for the purposes of auto manufacturers reducing their fleet average fuel economy. I just feel that the non energy conserving oils are truer to the most important goal of engine lubrication and protection. Likely the difference is insignificant as I know the energy conserving oils have to pass all the tough tests, so really it is more my own personal issue and desire to have it my way I guess. And while the corporation will see significant savings in fuel economy over the whole fleet of vehicles it sells, I sure won't see it on one vehicle. This is the same reason I don't like 5w20.

Okay, hope that answers it, but if not, ask me more.

 

[TallPaul]

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...and I don't like the idea of my oil being modified for the purposes of auto manufacturers reducing their fleet average fuel economy.

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Oops, that should read "increasing" their fleet average fuel economy (so they can reduce or avoid the $$ penalties).

Oh yeah, the F150 runs 10w40 which automatically is not energy conserving (only 30 weights and below can pass that test).

 

[Toy4x4runner]

So Engine design and HTHS go hand & hand.

 

[Ron AKA]

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Ron, you consistantly use broad sweeping generalizations to try and prove your particular point. You've done nothing but cause problems on this board by ignoring what others have said. It seems all you like to do is pick fights. Your conclusions about HT/HS and product data sheet specifications can not be used as the "end all" in telling how well an oil can perform. Get over it and use some common sense.

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I don't pick fights, I state facts. Problem is that some here have trouble with facts, and respond with personal insults when their belief in myths is questioned. I'll always stand corrected on facts.