Study on Engine Noise Level vs Oil Formulation

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Thought this was somewhat interesting, especially the engine noise level vs oil formulation used data. We've all seen various threads where people say they can hear an engine noise level difference with different oils, and some say it's "all in their head" or "their ears aren't sensitive enough to tell a difference". Guess I go with science on this one.

 
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Just to make sure we are comparing apples to apples, I read on page 1:
Vehicle tests show that the consumption of fuel oil for vehicles using research and development engine oil will drop by 12%, and noise will drop by an average of 7dB.

Now what is "research and development engine oil"? Is this a special lube they came up with for the purpose? I know they talked of getting the best selling 20 & 30 grade oils for use in their testing later on in the paper. But what type of oil did this--the best selling 20 grade, or something one of them concocted?

EDIT: OK I see this R&D oil is what they call their "debugging oil." that is what did better on their test. What exactly is that?

For the record, I don't doubt that an oil that reduces friction to the point of a 12% increase in fuel consumption will be quieter. I was just wondering what is being compared to what, that's all.
 

ZeeOSix

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EDIT: OK I see this R&D oil is what they call their "debugging oil." that is what did better on their test. What exactly is that?

For the record, I don't doubt that an oil that reduces friction to the point of a 12% increase in fuel consumption will be quieter. I was just wondering what is being compared to what, that's all.
Must be the new unicorn tears oil formulation. But yeah, it would be interesting to see what the exact formulation is.
 
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Perhaps! I am just wondering what they had to do to the oil to get that 12% increase in MPG--run an 0w8 or 0w12 or something? That's what I'm trying to get at.

Must be the new unicorn tears oil formulation. But yeah, it would be interesting to see what the exact formulation is.
 

SR5

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The noise difference between their reference oil and their special oil was 5 to 7 dB.

But even the two reference oils, a 5W20 and a 5W30 measured a 1 dB difference.

Shannow also gave a chart from another paper which also showed different oils giving a few dB difference in noise.

People who say “you can’t hear the difference between oils”, well I believe that they can’t hear the difference (because of their hearing) but I certainly believe that some people can hear the difference and that the noise effect of oils is real.
 
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Great thread. I do believe some oils are quieter.

If I recall correctly, in a similar thread some time back someone mentioned that it is not just about decibels but also frequency levels. Certain frequencies are picked up easier by the human ear.
 
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Funny that this oil vs engine noise came up. I have run my '08 RAV4 V-6 on 5W30 Amalie for the last 3 years since that's what the shop I use has. The engine has always had a tiny bit of start up noise for just a second or two. I'm tuned to my car so I hear it, others might not.

After the last oil & filter change the cold start was quiet, notably quiet. Was I losing it? Nope, further cold starts were the same. The new owners of the shop had changed to Chevron Supreme which they put in my car. I don't know if it's the synth blend or not but will find out when the weather & roads clear up here. The price was the same as dino Amalie, no upcharge. This proved to me without a doubt that a different oil can make an audible difference. Prior to this I always thought that was pure crappola. I was wrong.
 
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There’s a whole bunch of guys on a Toyota Tundra forum I frequent that talk about different oils making noticeable differences In the 5.7

there’s even a few videos on YouTube where they show comparisons.

scientific...no.
do they have a point...maybe
 
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There’s a whole bunch of guys on a Toyota Tundra forum I frequent that talk about different oils making noticeable differences In the 5.7

there’s even a few videos on YouTube where they show comparisons.

scientific...no.
do they have a point...maybe
This!

Of the engines I service, the 5.7l noise level appears to be related to the grade of oil. 20 grade being much louder than a 30 grade.

Other engines I don’t notice a difference
 
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The noise difference between their reference oil and their special oil was 5 to 7 dB.

But even the two reference oils, a 5W20 and a 5W30 measured a 1 dB difference.

Shannow also gave a chart from another paper which also showed different oils giving a few dB difference in noise.

People who say “you can’t hear the difference between oils”, well I believe that they can’t hear the difference (because of their hearing) but I certainly believe that some people can hear the difference and that the noise effect of oils is real.
Keep in mind, the Decibel scale is logarithmic - near silence is 0 while 10 is 10 ten times the intensity. 100 times more intense is 20. So, 5 to 7 on the decibel scale can be significant.
 

ZeeOSix

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I always remembered that a 3 dB increase was basically twice the intensity/power. More detailed info here.

HOW DO DECIBELS RELATE TO SOUND LEVEL?
The human ear's response to sound level is roughly logarithmic (based on powers of 10), and the dB scale reflects that fact. An increase of 3dB doubles the sound intensity but a 10dB increase is required before a sound is perceived to be twice as loud. Therefore a small increase in decibels represents a large increase in intensity. For example - 10dB is 10 times more intense than 1dB, while 20dB is 100 times more intense than 1dB. The sound intensity multiplies by 10 with every 10dB increase.
 
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The human ear (healthy) can sense a 1dB change and 3 dB change is usually fairly apparent. The problem of course with anyone saying they can “tell the difference” is that there simply isn’t a direct reference. You aren’t hearing oil x and then an immediate comparison to oil y. Beyond that - ambient noises can change drastically as well - as sources as innocuous as a garage door opening down the street or a car driving a street over can affect the receptors perception of sound. Using this report - a change between 20 and 30 wt oils gave approximately 1dB of change. Oils of similar weights likely have LESS difference. So we are talking about the very bottom end of what humans can discern and then NOT talking about every other variable in our uncontrolled garage or driveway or whatever.

Simply put - you aren’t hearing a difference between oils. You can’t control the ambient sounds and you don’t have a direct comparison. If there is a difference it likely isn’t discernible by the human ear. And certainly not discernible (at best) 20-30 minutes later in a completely uncontrolled scenario (assuming an oil change).

I’m tired of this nonsense.
Edit: if you’ve actually ever taken noise readings you will know that they aren’t a static number - they have lots of variability. Beyond that, even the distance between you and the source (by as little as a foot) can affect your perceived noise level. Not to mention the hundred other things that can skew noise levels or your perception of them. If a certain oil makes you FEEL better then use it - but trying to stretch this study into some sort of cudgel for your superhuman ears argument is asinine.
 
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So I suppose we can scratch all the comments that say "you can't possibly notice the difference in sound between two oils", and anything similar, that have been posted here for as long as I've been on the site.
 
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Perhaps we are too focused on volume and ignoring "tone". Some people are tone deaf, some obviously are not.

In my old Jeep 4.0 I could without question tell the difference between Pennzoil and Rotella for example.
 
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Perhaps we are too focused on volume and ignoring "tone". Some people are tone deaf, some obviously are not.

In my old Jeep 4.0 I could without question tell the difference between Pennzoil and Rotella for example.
When you say that did you put the Pennzoil in and immediately drain it to change to the Rotella? If you didn't then you were comparing fresh oil against old oil, which is always different. I struggle with the notion that someone's quantitative aural memory is good for 8000 miles or whatever your OCI happened to be.

Even then I question whether the real difference isn't between cold oil and warm.
 
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763
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So I suppose we can scratch all the comments that say "you can't possibly notice the difference in sound between two oils", and anything similar, that have been posted here for as long as I've been on the site.
Read it again - they specifically designed a lubricant that results in reduced fuel consumption by 10%! And only reduced noise by 5dB. Off the shelf lubricants of similar viscosity aren’t going to result in such drastic reductions. This also completely ignores the other inherent issues with the completely qualitative “human ear” assessment.
Your optometrist doesn’t wait twenty or more minutes in between whether “one or two” is better and then another another 30 minutes between “3 and 4” because your body simply isn’t able to differentiate that minor of a difference over that time period. A major change, sure.

it is the same with our ears. Major decibel changes would be easy to tell even over long time frames “this car is much quieter than the rock concert last month.” Something as little as 1dB? Not a chance.

And this STILL doesn’t address the uncontrolled variables.
Laughable.
 
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Perhaps we are too focused on volume and ignoring "tone". Some people are tone deaf, some obviously are not.

In my old Jeep 4.0 I could without question tell the difference between Pennzoil and Rotella for example.

Adding “Tone” or frequency takes an already laughable set of variables and makes it full clownshoes.
 
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