Best way to measure engine noise before and after oil change?

[Owen Lucas]

It's YouTube time again and I will be recording a video searching for and measuring the elusive post oil change sound reduction. Is it a myth or is there something to it?

This will be on a 2021 Honda pilot with 10% left on the MM and likely 9k on the oil itself.

My planned setup involves a rope across 2 work lamp posts and a decibel meter hanging in the middle over the engine. This is to isolate the meter from any vehicle vibrations and to listen to the engine from the same position before and after the oil change with the hood open.

Any advice?

 

[Passport1]

Make it simpler.

Measure the pre-oil-change radio volume necessary to mask the engine sound. Then change the oil and take another radio reading.

Compare the two values.

Done.

 

[cptbarkey]

Laptop with Audacity and record it. Would be interesting to see before/after wav or mp3 files.

 

[Jetronic]

Laptop with Audacity and record it. Would be interesting to see before/after wav or mp3 files.

Yes, run it through a spectrum analyzer (a function in audacity) to see if the pitch changed

 

[JavierH19]

Decibel meter and spectrum analyzer as other's have said on the valve cover same position on both with the hood closed at idle rpm is what I'd do. The oil needs to be the same temp on both. Run both for at least a half hour. You can't listen to a hot engine with thinned oil right before doing a change then with fresh cold thick oil at startup right after and come to a reasonable conclusion.

 

[M1Accord]

If you are that retentive about oil change and its impact on vehicle at this level, just spring for the Pennzoil Ultra Platinum in desired grade and know that you are doing much more than necessary. And don’t forget that good filter is just as important as good oil, that is why filter cost so much for such simple technology, especially when it is just the element instead of the entire canister.

For me, a happy medium is Kirkland 0W20 or 5W20 for 10k or around whenever I am free. I used to be that M1 only guy until Project Farm video clearly showed Warren oil, which is Kirkland and Wally, are pretty tough too. At over 200k miles and 180k miles, both vehicles run great. Other drivers and state inspection are my only risks and I can’t oil change those dangers.

 

[SHOZ]

See if you can access the OBDII knock sensors in real time.

 

[RooflessVW]

Yes, run it through a spectrum analyzer (a function in audacity) to see if the pitch changed

Yep.

Was able to use this method to send a recording of an engine whine to P&WC, where they used the recording to determine which bearing was making the noise. I also recorded it with Microvib, but the intial sound analysis was spot-on.

 

[SHOZ]

I have an app on my phone that can audibly measure high speed bearing speed. It picks up everything, basically a decibel meter. Dental RPM plus it's called but no longer on the store.

 

[kschachn]

Meaningful sound pressure measurements are extremely difficult to obtain. And then correlating the measurements to human perception of loudness is even more difficult.

How is your Fourier analysis? And your understanding of human hearing and frequency analysis? What’s the response of your microphone? And have you analyzed the reflections in your garage? Environmental changes also have an impact on sound perception. Are you controlling this?

 

[4WD]

Meaningful sound pressure measurements are extremely difficult to obtain. And then correlating the measurements to human perception of loudness is even more difficult.

How is your Fourier analysis? And your understanding of human hearing and frequency analysis? What’s the response of your microphone? And have you analyzed the reflections in your garage? Environmental changes also have an impact on sound perception. Are you controlling this?

Having done Company hearing tests and tests with a real Audiologist - IMO, this would take far more than a PF budget …
Even after my own crude dB tests - I think it was more to do with sound pitches vs ears - the dB spread was not as wide as perceived … Background noise and reverb is also tough - think of a sound studio …
Of course there needs to be goals & objectives …

 

[ripcord]

Be sure to park in an anechoic chamber before taking any measurements.

 

[kschachn]

Be sure to park in an anechoic chamber before taking any measurements.

That would be a start.

 

[4WD]

That would be a start.

Yeah - this done properly would be in a custom test “dog house” - motor not even in a vehicle …

 

[ripcord]

I don't understand the obsession with oil change related noisiness. Oh, well. I guess it's just not my particular brand of OCD.

 

[Astro14]

Someone explained it once - there is likely a noise reduction.

You take a warm engine, with all the clearances tightened up, and put cold, thick oil in it.

Of course it sounds quieter. It is quieter.

But that doesn’t last. You’ve created an anomaly - warm engine/cold oil.

Next time that you listen to the engine while it is warm, the oil will be, too, and the sound will return to normal

 

[Owen Lucas]

Meaningful sound pressure measurements are extremely difficult to obtain. And then correlating the measurements to human perception of loudness is even more difficult.

How is your Fourier analysis? And your understanding of human hearing and frequency analysis? What’s the response of your microphone? And have you analyzed the reflections in your garage? Environmental changes also have an impact on sound perception. Are you controlling this?

Thank you for the input everyone! There are too many variables here for me to get even close to the ballpark of any respectable result. I realize this is the equivalent of trying to measure windspeed with a wet thumb.

I'll pass on making a serious video for this subject for now, or ever. For this level of accuracy, an automotive lab would be needed with a scientist behind the equipment.

 

[nomas]

I don't understand the obsession with oil change related noisiness. Oh, well. I guess it's just not my particular brand of OCD.

I'm not OCD about it but I once commented that my Tundra's engine was noisier after changing my oil and using NAPA synthetic . Some folks just wasn't having it .