Apparently you never primed a SBC/BBC with a heavy duty drill.
Redline Oil Compromises Mileage & HP??
- Thread starter Ron AKA
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Thats a power loss chart.. That has nothing to do
with wear and protection. Reducing power loss
does not mean an oil is protecting better.
with wear and protection. Reducing power loss
does not mean an oil is protecting better.
quote:
Originally posted by Ron AKA:
I see some discussion about pumping loss. That factor did not seem to even make the list of significant loss items. See this table of where losses were estimated in a Mercedes engine and how they were affected by the different viscosity oils. The big hitters are the valve train, main bearings, and the piston assembly. You will note that thinner oil reduces friction and I would presume wear potential in the bearings and piston assembly. However, friction and I presume wear potential increases in the valve train.
I would beg to differ. I would suggest wear requires energy to occur. These are areas where energy is being lost to friction. Increased power loss means energy is being converted to increased heat in the area where the loss is occuring. This in turn would increase the chance of wear in the same areas.
Ideally you would want to feed a higher HTHS oil to the valve train than to the rest of the engine. In that way you would minimize power loss in the overall engine and optimize the oil to the specific requirements of the different engine parts.
Just because you have heat energy produced doesn't necessarily mean it's due to frictional wear, especially with hydrodynamic bearings and rollerized valvetrains. The shearing of the oil in these areas is producing virtually all of the heat. A run through some of the basic bearing design equations will give you some idea of just how much heat is generated in the bearings alone from the oil shearing.
http://www.bearings.machinedesign.com/guiEdits/Content/BDE_6_1/bdemech6_22.aspx
[ August 15, 2006, 01:48 AM: Message edited by: 427Z06 ]
I agree with the last post...for example, it takes more energy to stir a glass of honey vs one filled with water. Inside the engine it's the shearing/deformation of the viscous fluid that requires a certain amount of energy.
It is true that the thicker the fluid, the hotter it will tend to run, due to "intrafluid" friction. In extreme cases, this can mean shorter seal/gasket life, but it doesn't necessarily equate to reduced engine life for wearing parts.
Oil viscosity selection is a trade off of numerous parameters,including engine life, fuel efficiency, oil consumption, deposit formation, cold starting characteristics, etc. It's not as simple as some folks would like to think.
TS
It is true that the thicker the fluid, the hotter it will tend to run, due to "intrafluid" friction. In extreme cases, this can mean shorter seal/gasket life, but it doesn't necessarily equate to reduced engine life for wearing parts.
Oil viscosity selection is a trade off of numerous parameters,including engine life, fuel efficiency, oil consumption, deposit formation, cold starting characteristics, etc. It's not as simple as some folks would like to think.
TS
Here's another model based on the EPA cycle. Oil pump uses 2.2% of indicated horsepower. See page 4
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/hvso_2006/07_fenske.pdf
Note: Most of this paper is in reference to a diesel engine.
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/hvso_2006/07_fenske.pdf
Note: Most of this paper is in reference to a diesel engine.
Just wanted to comment on one thing. GC (0W30) is thicker than almost every 5W30 or even 10W30 oil, except at below zero temperatures.
wow, just came back to this thread....
And to add to Busters pos from personal experience. Circa '93, Using Neo 0w-5 in a small capacity race engine increased power and torque significantly throughout the rev range and increased bearing and bore wear exponentially.(over the xW-30,40,50' we were using, although revised cylinder finish virtually overcame this)
Pumping losses are significant. We would use the absolutely lowest oil pressure we could get away with (30psi @ 6500 RPM). All for the sake of increasing HP and proved beyond doubt on the dyno. Engines were lifed on cylinder leakdown.
[ August 15, 2006, 05:37 PM: Message edited by: tdi-rick ]
Good article but I'm seeing 0.5% for the oil pump on page 4, and it seems to be a passenger car model.
Methinks Dave speaks with forked tongue! Gain 3% on one grade reduction? Not a chance in this world. Perhaps 0.3% or 1/10th of what he claims. Gain 3-5% for the same grade compared to other brands? Not a chance in this universe! It is more likely to lose 1% based on a 3.3 HTHS Redline compared to a 2.6 HTHS "other oil". Have you asked Dave why Redline is not certified to GF-4/SM?
I agree that there is a tradeoff, not only for the engine as a whole, but also for each specific area of the engine. Lubrication of the piston and rings is a different game than journal bearings, different for rolling element bearings, and different again for valve followers. So a single oil is going to be a compromise.
However, I would suggest each of these areas have a sweet spot where the viscosity is not too high or not too low. Too high and there may not be enough oil to form a film - startup situation and startup wear. Too low and the oil film breaks down again causing wear. The trick is to find the sweet spot for most of the components without compromising any. It is probably important to note that GF-4 allows for more valve train wear. Having 4 valves per cylinder and roller cams helps. I only have the 4 valves and hope the cams are up to the job with my Pennzoil Platinum 0w20. Fully agree that is the downside risk of HTHS going lower.
Not exactly answered yet. This was my question in post #1:quote:
Originally posted by buster:
Exactly.
"So my question is why would one use those expensive oils like Redline that have such high HTHS?"
While there is a risk of engine wear by going too thin there is no evidence of us pushing the limits yet. Automakers and reputable oil companies have stuck their necks out big time with GF-4/SM Xw20 oil, and cars are not falling appart.
If I was to answer my own question it would be more like this:
"Because many make the common mistake of equating cost with quality. They think if they spend more $$ on a oil then it will magically buy them something. In the case of Redline all it buys is a higher HTHS and costs them HP and fuel. They could do the same thing by just going to a good conventional 10w40 oil like the Europeans do, and spend 1/4 the $$ or less on their oil."
Apparently your technical reading and math skills need improvement. 0.5% translates into 2.2% of indicated horsepower. Gee, and you call yourself an engineer?
And I said most, not all of the paper is related to diesel engines.
Can't say I'm interested enough to go through the math to the .0001% decimal point. It is quite obvious from the chart that piston, bearing, and valve train loss is far more significant than oil pump loss.
My rough math if you want to play games with the numbers rather than just read them off the chart is that the oil pump loss is about 2.2% of the Brake HP, and 1.4% of the Indicated HP.
Using the same rough math and numbers game, valve, piston, and bearing loss is 22% of
Brake HP and 15% of Indicated HP. This is an order of magnitude higher than the oil pump loss.
Which brings us back to the point that simple viscosity and resulting oil pump HP requirements is not a significant factor when determining optimum oil to use for maximum HP and fuel mileage.
My rough math if you want to play games with the numbers rather than just read them off the chart is that the oil pump loss is about 2.2% of the Brake HP, and 1.4% of the Indicated HP.
Using the same rough math and numbers game, valve, piston, and bearing loss is 22% of
Brake HP and 15% of Indicated HP. This is an order of magnitude higher than the oil pump loss.
Which brings us back to the point that simple viscosity and resulting oil pump HP requirements is not a significant factor when determining optimum oil to use for maximum HP and fuel mileage.
Wrong. Try again.
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