I am tired of everybody saying 20 wt oils exist only for gas mileage

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quote:

Originally posted by 427Z06:

quote:

Originally posted by TallPaul:
Yeah, guess you're right. It was a dumb idea.
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No, on the contrary, I thought it was a great idea.
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And my last post was somewhat tongue-in-cheek. Now if we only had a tongue-in-cheek icon. Hmmm, wheres the Boss? We need him get that icon for us.
 
Thought this quote was interesting - it is from discussion at the recent SAE Fuel & Lubricant meeting.

Link to ILMA Article on April SAE Conference

quote:

The GF-5 Fuel Economy Panel identified technical issues and concerns with low viscosity engine oils, including oil film thickness, oil pressure, piston and valve train wear, and customer acceptance of "thinner" oils. The panel noted that although there was some computer modeling evidence that suggests that significant fuel economy benefits could be secured by using lower viscosity oils, this could be at the expense of engine oil durability. The panel explored the topic of how fuel economy could be improved through a balance of performance additives, such as antioxidants.

 
quote:

Don't forget to test your engine under high load.
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If it will help, I'll flog my minivan. It has 5w-20 in it.
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I'll slam it up to the rev limiter for ya!! Heck, I can probably hit the hp peak (if it's still there) of 5000 rpm ..and maybe more.


Then you'll have it! A comprehensive evaluation of thin oil in a "world class" (well, 3rd world anyway) engine.
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quote:

Originally posted by 427Z06:

Remember, this is just data to show that a large percentage of 5w30 dinos will end up as SAE 20 at 100C. I'm not claiming this data is the definitive proof of anything else. Further, we'll never know how many sheared down a grade and then rose back up a grade due to oxidative thickening.


Just because "for years we've been running 5w30 conventional oils that sheared to a 5w20" doesn't mean that it was a good thing for our engines.
 
quote:

Originally posted by darkdan:

quote:

Originally posted by 427Z06:

Remember, this is just data to show that a large percentage of 5w30 dinos will end up as SAE 20 at 100C. I'm not claiming this data is the definitive proof of anything else. Further, we'll never know how many sheared down a grade and then rose back up a grade due to oxidative thickening.


Just because "for years we've been running 5w30 conventional oils that sheared to a 5w20" doesn't mean that it was a good thing for our engines.


True. And the contrapositive is also true.
 
quote:

Originally posted by moribundman:

quote:

YES! Please show us where VW specifies 5w20 for all temp ranges especially high speed driving. Obviously 5w20 is available in Europe for low temps. But for fuel economy at 120kph on a 30C day? I don't think so.

"Obviously"? The repeatedly made claim that 5W-20 wasn't and isn't available in Europe says the opposite of what you claim to be obvious. As I pointed out in an earlier post in this thread, 5W-20 was listed already in my '89 VW's case as an option for temperatures under 10 degree F. I was just trying to show that the claim that 5W-20 was not specified in Europe was erroneous. I think I've also made it clear on more than enough occasions that I would never use that stuff.
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Please excuse my negative tone. I was trying to be funny but in hind sight I realize it sounded harsh. I was tired.
The whole 5w20 think sounds silly to me. I think at this point we have firmly established that the only reason Ford and Honda recomend 5w20 for all temps is CAFE. Im sure I'm sure a large engine (3.0 V6 for example) pulling a mid size sedan at highway speeds will be fine for a couple 100k miles. But for the average European driver it would be a desaster. Think 1.6 litre pulling 3600 lb at 130kph at 4000rpm. No thanks. That was the situation with our VW Touran.
 
quote:

Originally posted by jtantare:
I'm sure a large engine (3.0 V6 for example

Surely I must live in a different world as I always considered the 3.0 a small engine. I have three vehicles and they are 3.0, 4.9, and 7.5 liters. But by todays standards, perhaps 3.0 is large?
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the morbid one wwrote:
quote:

quote:Don't forget to test your engine under high load. [Big Grin]

Gary wrote:
quote:

If it will help, I'll flog my minivan. It has 5w-20 in it. [Big Grin] I'll slam it up to the rev limiter for ya!! Heck, I can probably hit the hp peak (if it's still there) of 5000 rpm ..and maybe more.


Then you'll have it! A comprehensive evaluation of thin oil in a "world class" (well, 3rd world anyway) engine. [Big Grin]

Gary, when I said "high load" I meant load and not high RPM! Put your car in second gear and do some rolling starts with full throttle. That's high load! Let's see what your rod and crank bearings will "say." Go high speed and let drag and air resistence cause high load on the engine. Sure, high RPM and high load can occur together, but not likely at the local street-legal speeds.

PS: jtantare, no offense taken.
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Ok here's the other reason for 5W-20.
THE ENGINE HEATS UP FASTER!!

Why do they care? Because all the pollution controls on a
new car do NOT work until the engine is completly to
temp. Not just the water gettng warm and the heater working
but also the oil.

At least here in Michigan, we always had/have oxygenated fuel in the winter. This provides for less air pollution.
The typical short runs to the store in the winter do not get the engine warm enough for the anti pollution stuff to work producing more air pollution.

Simply 5W-20 oil warms up faster than any 30 or heavier oil.

Craig
 
quote:

Originally posted by Craig:
Ok here's the other reason for 5W-20.
THE ENGINE HEATS UP FASTER!!


Not in my experience. The brief time I ran 10w30 back in the winter that was the first thing I noticed. The automatic climate control on my Chrysler won't let the fan start up on the heater until the coolant reaches 40C. With 10w30 the fan would start blowing warm air much sooner than when I'm running 5w20.
 
quote:

Originally posted by Craig:
Ok here's the other reason for 5W-20.
THE ENGINE HEATS UP FASTER!!


I think you have it backwards. Thick oil generetes more heat than thin oil. So the engine will heat up faster with thick oil.
 
Thicker oils have more internal friction and therefor heat up faster. However, it assumes all else is constant. A thicker, synthetic with more lubricity may have less friction than a poorly formulated dino 20 wt oil.

aehaas
 
It's hard to compare thin & thick with quality synthetic oil because they are thinner to begin with than dino. They flow faster. It runs cooler. Less heat better for the engine longevity.

Given the choice, I would want an oil as with synthetic that cools the engine down far quicker than dino oil. The thinner the fluid, the quicker it cools it down. Now the question remains, how much thinner can you go in wear protection.
 
When testing a non-friction modified 15w40 HDEO and a friction modified dino 5w20 in particular engines, my experience has been that when they have non-friction modified 15w40 HDEO in them, they reached operating temperature is less time. My guess is, they were burning more fuel to maintain the same idle and moderate acceleration levels, thus the engines were generating more heat.
 
quote:

Originally posted by jtantare:

quote:

Originally posted by Craig:
Ok here's the other reason for 5W-20.
THE ENGINE HEATS UP FASTER!!


I think you have it backwards. Thick oil generetes more heat than thin oil. So the engine will heat up faster with thick oil.


I think thinner oils are able to absorb/transfer heat faster due to the advantage in surface area(I could be visuallizing viscosity wrong but I think of thicker viscosities as having larger molecules or longer chains of them while lighter viscosity would have smaller molecules/shorter chains). Would that not allow the motor oil to warm up faster?
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quote:

It's hard to compare thin & thick with quality synthetic oil because they are thinner to begin with than dino. They flow faster. It runs cooler. Less heat better for the engine longevity.

Given the choice, I would want an oil as with synthetic that cools the engine down far quicker than dino oil. The thinner the fluid, the quicker it cools it down. Now the question remains, how much thinner can you go in wear protection.

In theory a thinner oil will cool your engine down quicker. But in real world application, wear protection I would assume is the first priority.
 
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