NOAK

[buster]

Mobil sent me the NOAK numbers for 5w-30 M1 and it was 12.9% They used the (ASTM D 5800) I noticed Amsoil uses (DIN 51581). Does anyone know the difference? 12.9% is not good at all and I either think it's an old number or Dennis at Mobil tech support gave me the wrong number which wouldn't surprise me.

[ October 23, 2003, 09:42 AM: Message edited by: buster ]

 

[Chris B.]

Can you explain NOAK to me in lame man's ters? Why is 9% better then 12% and what does this mean? Thank you!

 

[F1Crazy]

quote:

---

Originally posted by Chris B.:
Can you explain NOAK to me in lame man's ters? Why is 9% better then 12% and what does this mean? Thank you!

---

Noack number tells us what percentage of the weight is lost under this high temperature test condition. The bigger the number the higher weight loss and you may expect higher oil consumption from the oil that has bigger Noack number.

 

[williar]

By weight loss it means that's the percentage of the oil, by weight, that evaporated during the test.

 

[RavenTai]

quote:

---

Originally posted by TooSlick:
then held @ 250C/482F for one hour.

---

M1 5w30 has a 224c flash point acordign to M1's website, if it is releasing enough vapors to start a fire at 224c I would guess it is loosing quite a bit at 250c

I would assume the m1 10-30 would do a bit better it has a 244c flash point

does oil get even close to these tempratures in a normal passenger car engine?

 

[buster]

We know the NOAK should at least be 9% for 5w-30 based on Amsoil's comparison test. 12.9% would be a good reason for me NOT too use this oil.

 

[TooSlick]

Buster,

The Noack test was developed in Europe and DIN 51581 is the original designation. Now that the test has been adopted in the US, the American Society for Testing and Materials has written a test protocol for it and given it a test number of ASTM D-5800. If you look at a recently updated amsoil spec sheet, the test is called ASTM D-5800.

The DIN and ASTM tests are the same ....The oil sample is first weighted, then held @ 250C/482F for one hour. A slight vacuum is held on the sample to draw off any oil vapors. The sample is weighted after the test and the weight loss expressed in terms of a percentage is the Noack score for the formulation.

I find that Noack volatility relates pretty well to oil consumption, as long as you are comparing the same SAE grade. All things being equal, a heavier oil will generally reduce consumption.

TS