iam beginning to wonder if using 100% synthetic oils cause more or increased engine noise (slap etc.) the more i read alot of people on here have more noise with synthetics and conventional oils eliminates the noise...we explain?
100% synthetic oils = increased engine noise?
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Seems like it follows GM's.
My cars have always seemed quieter on synthetics, except my beater Volvo turbo was quite noisy back in the day when I ran Mobil 1 5w30. One reason I started using Amsoil is how much quieter it was than M1.
My theory is the fact that synthetic oils have a much lower viscosity at all but high temps relative to conventional oils.
The real question could be: does noise = more engine wear (less engine life)?
My cars have always seemed quieter on synthetics, except my beater Volvo turbo was quite noisy back in the day when I ran Mobil 1 5w30. One reason I started using Amsoil is how much quieter it was than M1.
My theory is the fact that synthetic oils have a much lower viscosity at all but high temps relative to conventional oils.
The real question could be: does noise = more engine wear (less engine life)?
There is one brand of synthetic oil commonly discussed on the board that has been referred to as causing (possible) valve train noise. As a whole, I would say most synthetic oils are excellent products and keep engines running quietly.
DISCLAIMER: Notice I used the word "possible" and did not mention any Brand Names in this post.
DISCLAIMER: Notice I used the word "possible" and did not mention any Brand Names in this post.
Well...subjective observation or scientific fact? I would not make any conclusions withhout objective data. Decibel meter perhaps? I have read a lot about perceived differences, but I have a hard time believing.
Subjective observation is good enough for me when it's MY dollars paying for the stuff to be used in MY vehicle.
So, does more (subjective) noise = more engine wear (less engine life)?
I recently went back to dinos from synthetics due to all the noise in my 1999 3100 V6. it was horrible. The ones the caused all the noise though were PAOs. Mobil 1 and Amsoil seems to be the worst on my car. I will soon experiment with EOPs and see if they have the same effect.
I want to say that conventional oil could be better matched with the piston-cylinder clearence change from cold start up to temp than an "engineered" synthetic, but unless temperatures are approaching extremes, I could only think that weights are just about equal.
IIRC, the utilization of VII's to create an equal weight of say a synthethic, might not equate to like film strengths. Base oil aside, addititves also factor in.
I also wonder about the piston to crank arrangement, and the exteme angles that the connecting rod reaches off-verticle as things move about. A larger angle translates to greater percentage of force to the horizontal upon the compression up-stroke and combustion down-stroke...all of which could force the piston against the cylinder wall. Perhaps in trying to make the engine more sompact and/or maintain a desired redline, connecting rods have been kept relatively short, only adding to the lateral force potential.
Honda uses pistons with short skirts I think, but how short compared with these engines that slap? I can't recall hearing any slap issues with a honda, you?
IIRC, the utilization of VII's to create an equal weight of say a synthethic, might not equate to like film strengths. Base oil aside, addititves also factor in.
I also wonder about the piston to crank arrangement, and the exteme angles that the connecting rod reaches off-verticle as things move about. A larger angle translates to greater percentage of force to the horizontal upon the compression up-stroke and combustion down-stroke...all of which could force the piston against the cylinder wall. Perhaps in trying to make the engine more sompact and/or maintain a desired redline, connecting rods have been kept relatively short, only adding to the lateral force potential.
Honda uses pistons with short skirts I think, but how short compared with these engines that slap? I can't recall hearing any slap issues with a honda, you?
While I don't have any "hard data" to prove this, at least subjectively, the synthetic GC makes my VQ35 run slightly quieter than the couple of dinos I've tried in it (Havo and MC5).
And even a simple dB meter wouldn't tell you everything, as you want to see the whole spectrum. Even inaudible harmonics can modulate or affect lower frequencies, making them sound different. A louder noise at a pleasing frequency (or 'sonic signature') will seem smoother and quieter than a softer annoying noise. Temperature affects sound by changing the size and stiffness of materials. And your own hearing changes in frequency response depending on how loud a sound is (and with age and from person to person). How can you reconcile all these factors out in your garage? It must be measured under extremely controlled conditions, and even then...?
Moderators Please delete. Somehow my reply ended up in the wrong thread.
On all the engines I've used it with, synthetic oil seems to make things run quieter or at least the same. That includes an '87 Toyota 1.6L, a '99 Honda 1.6L, a '00 GM 3800 and an '05 GM 3500. My two GM's (both current vehicles) are whisper quiet, anyway, despite which oil I run.
THe thicker the synthetic the quiter the engine. THe more ZDDP and moly the quiter the engine. Redline oil is always quiter then any of it's competition in any like viscosity. Mobil 1 is rather noisy and it is usualy the thinest synthetic for it's given viscosity. Amsoil is right in between the two extremes listed above!
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