Thick is better
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Well said JTantare, you're exactly right. We've discussed this idea here before, there is some degree of what we call "viscosity seeking behaviour" in car engines but the phenomena is more prevelant in more closed off systems (isolated sealed bearing with grease lube) where the oil does not return to a sump through a long systems and get cooled!!!!!!
This can easily be proved by checking oil sump temperatures after the same drive run at the same ambient temperatures with different viscosity lubricants. In reality, I don't think you'll see much higher temps with the higher vis lubes....anyone here done this test????? Although there is some truth to what has been proposed by Brother Paolo, the thicker oil will be thicker and you are the man with the plan JTANTARE!!
I switched from M1 10W-30 to Delvac 15W-40 for two oil changes in a 96 Corvette. I expected moderately higher oil temps but didn't get them. The test wasn't real scientific, but with two oil temp readouts in the car and being in the habit of checking oil temp, I think I would have noticed anything over a 5 degree F change. Since it takes about a 15F temperature increase to drop kinematic oil viscosity the equivilant of one SAE grade at constant temp, the oil in my car wasn't achieving some mystical constant viscosity.
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John, he also uses his Ferrari for short commuter drives across town and not in any manner that resembles anything for which this engine was built. He'll probably get away a long time with using 0W-20.
PS: Did you ever follow the lead on Pentosynth, and did you get it?
TallPaul, you are my hero!
From a few weeks back:
My (575 Maranello) 3,000 mile UOA had 3% fuel dilution but I burned it off with a one hour 95 MPH run. Oil temp was 180 F the whole time.
Oil analysis: compare 2003 Ferrari 575 Maranello and 2000 550 Maranello
My neighbor and I have have Maranellos. He own the 550 but has the new SuperAmerica on order. He always runs what the book says. His last oil change was with 9,100 miles on the car. It was 9 or 10 months ago. Last week I sampled the oil with 1,800 miles on this oil.
These cars are nearly exactly the same but for a slightly bored out engine in the newer 575 model. His has 475 BHP and mine has 515. His drive to work is 10 - 15 minutes and mine is 15 - 20 minutes and we drive about the same way, spirited. My car has 6,300 miles on it. I run the 20 wt oil while he has always run the Shell Helix Ultra 5W-40, the factory recommended oil.
One has said that since I get good numbers with the 20 wt oil that I should get better numbers on the 40 wt oil. You be the judge:
__________New _______Ferrari 550_______575
______0W-20 Mobil 1 ___With 1,800 Mi __With 4,100 Mi on the oil
................................................................................................................
Iron__________ Chromium _____ Nickel ________ Aluminum ______3___________8__________9
lead __________ Copper ________ Tin ___________ Silver ________ Titanium ______ Silicon ________4___________6__________8
Boron ________247_________40_________178
Sodium _______15__________8__________15
Potassium ____ Molybdenum __ 164_________18_________86
Phosphorus __1375________ 1203________1243
Zinc ________ 1328________1191________1169
Calcium _____ 3456________1669________2742
Barium ______ Magnesium ____53_________935_________111
Antimony _____ Vanadium _____ Fuel %Vol _____0__________3.0__________1.0
Abs Oxid ______?__________na__________28
Abs Nitr _______?__________11__________4
Wtr %vol ______0_________ Vis CS 100C ___9.0________11.0 _________8.3
SAE Grade ____20_________30 __________20
Gly test ______NEG_______NEG _________NEG
TBN _________9.87_______not done_____not done
I tested my oil using this company, www.youroil.net
Go to this page and download this Excel file to see other peoples results:
http://members.rennlist.com/oil/
He just went to Orlando to purchase an Enzo. It calls for Shell Helix Ultra Racing 10W-60 oil. But my neighbor thinks even he will use a thinner oil for around town. I am guessing the 5W-40 Ultra, probably a good choice.
aehaas
One the arguements for thinner oil is quicker lube to the parts when first starting the motor, makes sense to me. But would a thicker oil leave more oil on the parts your worried about on shut down? leaving a thicker film that may be there for the next start?
Years ago I questioned advisory by suburu NOT to use 5/30 for sustained high speed driving (a 40w was advised). The answer I got from an area service rep was, no worries north americans very rarely ever qualify for this. This advisory was targeted at autoban countries where hours of full throttle is used, Americans think they drive harder than they do. My reply was he never drove to Vegas with me, LOL.
Years ago I questioned advisory by suburu NOT to use 5/30 for sustained high speed driving (a 40w was advised). The answer I got from an area service rep was, no worries north americans very rarely ever qualify for this. This advisory was targeted at autoban countries where hours of full throttle is used, Americans think they drive harder than they do. My reply was he never drove to Vegas with me, LOL.
Really? I've only been here a couple of years. I've never seen this mentioned.
Dear God No! I can't take anymore!
AEHass, My point was that we see a lot of Toyota,Subaru,Ford,GM and DC products. After you have seen a few hundred LS1 UOA etc...you get a really stong idea of what is normal wear patern for the engine. You get an idea of what is unusal as well. Our sample size for Ferari is the smallest we have on this site! I have no idea what is considered good versus what is average. You also have usage cycles that are a lot different then what the average person see's and I am sure the average Ferari owner.
1)Small sample size
2)Non approved off aplication oil
3) Very low production almost hand built car and power train
4) Usage nontypical
So it is the above that makes it diffacult to make any meaningful extrapolation from your results. It is not the results. We just do not have enough simalar examples to look at. So while we can say that 5W20 did appear to work well in your application that is a far cry from useing your results to rubberstamp anything!
1)Small sample size
2)Non approved off aplication oil
3) Very low production almost hand built car and power train
4) Usage nontypical
So it is the above that makes it diffacult to make any meaningful extrapolation from your results. It is not the results. We just do not have enough simalar examples to look at. So while we can say that 5W20 did appear to work well in your application that is a far cry from useing your results to rubberstamp anything!
It seems to be pretty low mileage driving and I'll guess at lower load levels for the vast majority of the time, so oil requirements won't be as critical. What oil would you use in Germany or Italy, or even for a season of 'club racing' in the US ?
His 40wt seems to be measuring as a 30w now, due to the higher fuel dilution ?
If you're going to use UOAS to compare viscosity effects maybe a better comparison would be the same type of oil at different viscosity levels, ideally in the same engine. If it's different engines then do at least one interval with the engine/oil combos swapped for comparison. How does the Shell compare with Delvac 1 / M1 T&S ?
His 40wt seems to be measuring as a 30w now, due to the higher fuel dilution ?
If you're going to use UOAS to compare viscosity effects maybe a better comparison would be the same type of oil at different viscosity levels, ideally in the same engine. If it's different engines then do at least one interval with the engine/oil combos swapped for comparison. How does the Shell compare with Delvac 1 / M1 T&S ?
The answer to the "thicker/thinner is better" debate is that it depends.
My Vue with the Honda 3.5L V6 works great on 20wt oil and provides good UOAs from me and others with the same engine. Thinner is better for this vehicle.
Conversely, the 20wt oils on my older Saturn 4cyl with 130K miles, don't look good at all in a UOA. Thicker is better for this vehicle. No consumption at all with either ride.
I would like to find a one-size fit's all viscosity, but there isn't one. GC just isn't thick enough in my older car and just seems like it's too thick on the newer one.
[ May 21, 2005, 09:31 PM: Message edited by: ToyotaNSaturn ]
My Vue with the Honda 3.5L V6 works great on 20wt oil and provides good UOAs from me and others with the same engine. Thinner is better for this vehicle.
Conversely, the 20wt oils on my older Saturn 4cyl with 130K miles, don't look good at all in a UOA. Thicker is better for this vehicle. No consumption at all with either ride.
I would like to find a one-size fit's all viscosity, but there isn't one. GC just isn't thick enough in my older car and just seems like it's too thick on the newer one.
[ May 21, 2005, 09:31 PM: Message edited by: ToyotaNSaturn ]
What is quoted here is part of the very fundamentals of lubrication theory (and practice). I hope nobody here is trying to say that this quote is untrue because that's tantamount to saying that the credibility of Newtons first, second, and third laws are up for debate. Well, maybe they are up for debate by BITOG psuedo "be an expert today" types but they're not up for debate for scinetisits and engineers. We use Newtons laws as a basis for many physical and engieneering principles. Lubrication engineers/scientists understand and use the concept that higher viscosity leads to higher film thicknesses and more distance between metals generally means less wear. If they don't debate this, why do you???? This aspect of lubrication theory is not rocket science folks and can be easily and repeatably demonstrated in a lab with either a journal or anti-friction bearing. In fact, this is the primary consideration when the designers look at the main and rod bearings in your auto engine. They determine the minimum "operating" (viscosity at bearing inlet temperature) viscosity needed to form a stable oil wedge. They know and do not debate that higher viscosities (especially the type measured at high shear rates) lead to increased oil film thicknesses here.
What is complicated is dealing with the understanding of mixed type lubrication; boundary lubrication; and the action of surface active anti-wear agents and EP agents like sulfur and phosphorous compounds. But, lets get back to basics, these types of lubrication can theoretically be avoided or lessened if you have enough viscosity such that a thick film can be generated.
However, a real world compromise must indeed be made between start-up pumpability, fuel economy, the "doesn't need to be designed for over 200,000 miles or even maybe 100,000 as the warranty will be up and you can buy another one from them" factor, etc!!!! We can sensibly debate how much weight to give to these various factors (including lubricant cost too) but please don't be so foolish as to pick a fight with the basic and well known principles of lubrication. It's like picking a fight with the law of gravity......the law is simply correct and easily provable and so is basic hydrodynamic lube theory.
Lately, it appears the automakers in the US have more heavily weighed in teh factor of fuel economy than they used to and maybe are taking more risks on way past warranty reliability. Way past warranty reliability is your concern, and perhaps not theirs.
1911
No one is saying NOT to use what works best, that is what this site is about, instead we're trying to determine what does work best without the influence of CAFE requirements on US OEM recommedations. As has been said over and over in this forum, Ford and Honda both appear to often recommend thicker oils outside of the US.
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