Join Date: Mar 2008
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2 cycle oil sound test results!!!!
OK boys and girls.........the results are in-
Here is the setup:
Does 2 cycle oil actually quiet the engine, or is it all in our warped minds??
For the test:
>I parked my truck in it's usual spot on the driveway
>Placed a tape measure on the ground perpendicular to the left front wheel
>Placed a digital sound meter on an 8" high photo tripod with the sound pickup at 36" from the wheel.
>Recorded sound measurements on fast response, "c" weighting and adjusted scale for decibel range.
>Sound measurements were taken with truck at operating temperature, no accessories on (a/c, htr., lights, etc.)
>Measurements recorded for truck at idle and 2000 rpm in park, auto trans.
>Setup was duplicated for straight ULSD and 128:1 2 cycle oil mix, both tests conducted at approximately 6:30 pm PDT., several days apart.
Test #1- 128:1 2 cycle oil (I already had the mix on board, so I ran this test first):
>Reading at idle- 79 db
>Reading at 2000 rpm- 89 db
Test #2- Fuel tank run as low as I dared, then filled with straight ULSD, driven for 125 mi., then tested:
>Reading at idle- 84 db
>Reading at 2000 rpm- 92 db
The addition of 2 cycle oil at a ratio of 128:1 (or 1 oz/gallon) attenuates or reduces the sound generated by the diesel engine at idle 5 db, and 3 db at 2000 rpm.
Subjectively, the tester felt that the truck ran more smoothly overall and displayed less perceived vibration in-cab with the addition of 2 cycle oil, and also the 5 db sound attenuated recorded was easily noticed both in-cab and standing outside.