Why all the fuss over NOACK?

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43
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South Carolina
Im not an expert by any means, but whats the big deal over NOACK? Unless you drive a car that runs really hot or a performance vehicle is it really that important? I would think just by looking at the stats... TEOST would be something to be more concerned over? Or even TBN? I see all this down talk of the new PUP because of the NOACK readings... but what about other aspects of the new oil? Thoughts?
 
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'Stralia
If you've got a car with an engine that has piston rings, a cylinder wall, and a catalyst, then NOACK has meaning for you...wehich is why it's specified and has upper limits. It CAN be an indicator of better basestocks for a given viscosity grade. But for a correctly labelled lubricant (SN/GF?) It's not on my radar as far as selecting on oil...probably on par with VI.
 
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North Carolina
I think NOACK is more important now if you have a direct injection engine. Less vaporizing of the oil = less going through the pvc system and condensing as it cools as varnish or deposits on unwashed intake valves.
 
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10,146
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Burlington, Ontario, Canada
I agree from a practical point of view Noack has zero importance. It's a footnote spec' that's nice to know but as long as it's reasonable, and most are, it plays no further role in my oil selection. But since a low Noack is associated with higher quality and heavier base oils many incorrectly assume the finished oil is automatically better and incorrectly attribute certain characteristics to justify this view. Then it just bragging rights for some. "Hey look this oil only has a Noack is 5% or 6%! It's one reason some people think that a 10W-30 synthetic is not an obsolete product because it has a lower Noack vs a 5W-30 of the same brand. No at the top of my list are a low KV40 value for it's HTHSV, a high AW additive level and reasonable shear stability.
 
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I think (personally) that the NOACK reducing the amount going through the PCV is a BITOG myth perpetuated by those trying to justify why their brew of choice is superior in spite of NOACK. Your sump doesn't get anywhere near those temperatures, it's ring belt and liner, where the temperature IS 250C, and the oil hangs around there for 10s of seconds...NOACK is to similate the oil volatility (and in particular the phosphorus volatility) in that area, which has straight access then to the catalyst. Anything that is boiled off at these temperatures isn't going to make it back through the crankcase/rocker area to the PCV, it's exposed to large areas of cooled metal,and a rain of comparatively cool oil...it will condense rather than head to the PCV.
 
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Burlington, Ontario, Canada
Originally Posted By: spasm3
I think NOACK is more important now if you have a direct injection engine. Less vaporizing of the oil = less going through the pvc system and condensing as it cools as varnish or deposits on unwashed intake valves.
And what difference does a couple of percentage points make in Noack when most of what gets past the PCV is actually atomized oil? In which case choosing an oil with a very low TEOST deposit score or a low SAPS oil would make more sense. That's assuming the particular DI engine design is prone to the problem in the first place.
 
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What happens when that atomized oil hits the intake valve? I know the intake valve is cooled by the incoming charge of air ( air and fuel in a non DI). But how hot does the intake valve get? will the oil vaporize off leaving deposits behind underneath the valve head? The noack test is at what 300 deg fahrenheit? But does that mean there is no vaporization at all at lower temps say 200- 250 f?
 
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Originally Posted By: CATERHAM
Originally Posted By: spasm3
I think NOACK is more important now if you have a direct injection engine. Less vaporizing of the oil = less going through the pvc system and condensing as it cools as varnish or deposits on unwashed intake valves.
And what difference does a couple of percentage points make in Noack when most of what gets past the PCV is actually atomized oil? In which case choosing an oil with a very low TEOST deposit score or a low SAPS oil would make more sense. That's assuming the particular DI engine design is prone to the problem in the first place.
Well, Lubrizol does say: "Two key parameters for TGDI use are oxidation stability at higher temperatures and volatility.". So at least they think it's relevant.
 
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Kendall, FL
If this is the article you site, it seems to be aimed more towards the challenges TGDi face in developing nations due more to poor quality fuels and out dated oil specs than Noack. Again, if this is the one you site. http://gf-6.com/sites/default/files/Turb...ig%20Hurdle.pdf
Originally Posted By: Danh
Well, Lubrizol does say: "Two key parameters for TGDI use are oxidation stability at higher temperatures and volatility.". So at least they think it's relevant.
 
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43,676
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'Stralia
Originally Posted By: Danh
Well, Lubrizol does say: "Two key parameters for TGDI use are oxidation stability at higher temperatures and volatility.". So at least they think it's relevant.
Given that one of the emerging problems with GDI is auto-ignition around the top ring land, and the only ignitable product in that area is oil vapors/fumes, I can see volatility control becoming more important for GDI engines into the future.
 
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726
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NoVA
Originally Posted By: Skid
For me, I don't particularly care for VII. Low Noack means you don't have some ultralight base oil mixed in with a heavy dose of VII.
Yup - Unless you enjoy a big wad of plastic slime in your oil. NOACK will be even more important with the new HCCI engine technology.
 
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Burlington, Ontario, Canada
Originally Posted By: Skid
For me, I don't particularly care for VII. Low Noack means you don't have some ultralight base oil mixed in with a heavy dose of VII.
So you don't like 5W-XX mineral multigrade oils and presumably you also don't like most 0W oils, particularly the heavier 0W-40 and 0W-50 grades.
 
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28,123
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Regina, Saskatchewan, Canada
Obviously, there's some value to a low Noack. It's part of specifications for a reason. However, even in the days of Noack values of 25%, there were vehicles that consumed no measurable oil over an OCI. So, the notion that low Noack oils might be consumed less could be a red herring. On the other hand, while I did have the opportunity to run very high Noack oils on oil burners I had in the past, I didn't have the opportunity to switch them immediately to something with a very low Noack for the sake of comparison. I suppose I could have tried an SAE 40 or something like that, but that was out of the question.
 
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10,146
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Burlington, Ontario, Canada
With the Noack minimum set at 15% the main reason some manufacturers spec' something lower is to minimize phos' shortening cat' life. So it's 13% for GM and with some European OEMs it's as low as 10%. But from an end user point of view it can be ignored. As you know, if an engine doesn't consume much oil one can use a high phos' diesel oil without noticeably shortening the cat' life.
 
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Originally Posted By: wemay
If this is the article you site, it seems to be aimed more towards the challenges TGDi face in developing nations due more to poor quality fuels and out dated oil specs than Noack. Again, if this is the one you site. http://gf-6.com/sites/default/files/Turb...ig%20Hurdle.pdf
Originally Posted By: Danh
Well, Lubrizol does say: "Two key parameters for TGDI use are oxidation stability at higher temperatures and volatility.". So at least they think it's relevant.
That is the article. Interestingly, the article suggests the intake valve deposit issue we obssesives focus on is a bit of a sideshow to the problem of exhaust particulates contaminating the engine oil - a problem that becomes worse with poor quality fuel. So now we have something else to worry about (thanks, Lubrizol). Nonetheless, Lubizol does acknowledge low volatility is real virtue in an oil for DI engines. And, as this is one of the few pieces of objective evidence DI engine owners can get their hands on, Noack volatility seems like a good place to start in the oil selection process. For example, if you have a DI engine specifying 5w/20 and shop at WalMart, two good choices would be Pure Plus Pennzoil Platinum (8.2% Noack) and Mobil1 0w/20 AFE (10.1% Noack). Not coincidentally, both seem to be really great oils overall as well.
 
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Paradise of Florida
Oil catch can is too hard of a hurdle to overcome. Noack is just another spec, no more or less important, than the rest. Combination of specs is important. It's just a way to weed out the weak. Pretty much every modern engine run hots and is a performance tech masterpiece.
 
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17,593
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Upper Midwest
You've seen this big wad of plastic slime in your oil?
Originally Posted By: Lex94
Originally Posted By: Skid
For me, I don't particularly care for VII. Low Noack means you don't have some ultralight base oil mixed in with a heavy dose of VII.
Yup - Unless you enjoy a big wad of plastic slime in your oil.
 
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43,676
Location
'Stralia
Originally Posted By: Danh
That is the article. Interestingly, the article suggests the intake valve deposit issue we obssesives focus on is a bit of a sideshow to the problem of exhaust particulates contaminating the engine oil - a problem that becomes worse with poor quality fuel. So now we have something else to worry about (thanks, Lubrizol).
Another issue is LSPI, and the presence of oils in the hot compressed air in and around the ring belts (the location at which NOACK is modeled). http://energy.gov/sites/prod/files/2014/03/f8/deer11_alger.pdf Have read a couple of articles that say NOACK is a poor indicator of LSPI, and the linked article is about oil reactivity, but if the oil's not there, it doesn't matter if it's reactive...they need a test that does double duty...like NOACK measures one thing, but the stability of the phosphorus compounds partly dictates the phosphorus carry.
 
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2,035
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Ontario, Canada
Originally Posted By: CATERHAM
I agree from a practical point of view Noack has zero importance.
That's probably over-doing it
Quote:
It's one reason some people think that a 10W-30 synthetic is not an obsolete product because it has a lower Noack vs a 5W-30 of the same brand.
Aw yea! thumbsup and less VIM/ varnishing potential and a touch higher HTHSV; in a climate where even the 10W rating will never be challenged, what's not to love about that?!
Quote:
No at the top of my list are a low KV40 value for it's HTHSV, a high AW additive level and reasonable shear stability.
And that is perfectly reasonable. There are times when that's my own priority also, mainly because I still like to micro-optimize for operating conditions and climate and live in a frozen wasteland. To those that like to revel in the one size fits all-ability of new oil technology, 'set-it-and-forget-it', there's nothing wrong with it, I done it. The operating margins of the ECO oils is wide (on the cold side)- not optimal for heavier duty, but very much acceptable for most motoring, thanks to supporting industry changes.
Originally Posted By: Shannow
Another issue is LSPI, and the presence of oils in the hot compressed air in and around the ring belts (the location at which NOACK is modeled). http://energy.gov/sites/prod/files/2014/03/f8/deer11_alger.pdf Have read a couple of articles that say NOACK is a poor indicator of LSPI, and the linked article is about oil reactivity, but if the oil's not there, it doesn't matter if it's reactive...they need a test that does double duty...like NOACK measures one thing, but the stability of the phosphorus compounds partly dictates the phosphorus carry.
How about a consumption test, which measures an oil's predisposition to being consumed Nice paper, very interesting to the tuning mind. Notable sidenote on how ester base oils have the lowest CN, ANs in the middle while PAO has the highest. I can see yet another reason why a blender like Redline sticks with esters.
 
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