Noack vs Viscosity Index

Messages
6
Location
Zurich
Hello peeps, could someone please explain whether Noack volatility is more important than Viscosity Index ?

I am comparing three 913D oils, Liqui Moly Special Tec F, Motul Specific 913D and Ravenol FDS, all 5w30 ACEA A5/B5 oils and trying to figure out which one is the best. So far I was with Ravenol because apart from the 913 spec, has also the MB 229.6 which seems extra protective for the engine + a Noack of 8.9. However, it has a VI of "only" 163, where in comparison Liqui Moly has 171 but a Noack of 12%. Please unravel the mystery for me 😜
 

OVERKILL

$100 Site Donor 2021
Messages
46,511
Location
Ontario, Canada
Hello peeps, could someone please explain whether Noack volatility is more important than Viscosity Index ?

I am comparing three 913D oils, Liqui Moly Special Tec F, Motul Specific 913D and Ravenol FDS, all 5w30 ACEA A5/B5 oils and trying to figure out which one is the best. So far I was with Ravenol because apart from the 913 spec, has also the MB 229.6 which seems extra protective for the engine + a Noack of 8.9. However, it has a VI of "only" 163, where in comparison Liqui Moly has 171 but a Noack of 12%. Please unravel the mystery for me 😜

VI is simply a calculated value based on the difference between KV40 and KV100. It's not something to be concerned about. High VI oils are primarily chased for fuel economy, and usually have a higher VII treat rate and use lighter base oils, which in turn drives up Noack.

In your examples, the Ravenol uses less VII, which may be desirable.
 

SchumiGr

Thread starter
Messages
6
Location
Zurich
Thanks ! That is very helpful. Overall it seems that Ravenol is a better oil (other than TBN, but from what I read here, a 10.1 TBN is fine plus higher is not always better), so I think I will go with that. Hopefully the extra MB 229.6 spec make the oil stand out from the rest of 913Ds (although kinematic viscosities seem the same with the rest).
 

SchumiGr

Thread starter
Messages
6
Location
Zurich
Thanks for the hint, but I have got no idea how to translate flashpoint to heavier/fancier base oils and what that actually means. If you could provide a short explanation would be much appreciated.

On another note, someone recommended the Ford-labelled oil which to my surprise had quite good indicators - attached a screenshot. How come that an oil with 25 Euros price tag have the same specs with prestigious oils like Motul/Ravenol etc which cost twice as much ? I mean, where's the catch ?
 

Attachments

  • Screenshot 2020-12-07 at 21.23.40.png
    Screenshot 2020-12-07 at 21.23.40.png
    240.3 KB · Views: 37
Messages
6,005
Location
down in the park
The ravenol is considerably thinner at -30C, lower Noack and slightly higher flashpoint. Due to more use of PAO base oil which leads to better oxidation resistance and less need for high TBN.

From what I see the Ravenol is superior. I don't know if it's superior for your intended use though, as the ford labelled oil might just be good enough
 

SchumiGr

Thread starter
Messages
6
Location
Zurich
It's a car with 187K Kms, drives usually medium distances (60-80 Kms) and every now and then long trips (200-1400 Kms depending on destination). I drive as a family man (lol) but when I go to the track or mountains or meet with friends etc I am stepping on it without hesitation - after all it is a Fiesta ST. Therefore I am looking for something that maintains the Ford specs (relatively low fuel consumption) but offers maximum protection and cleanliness to the engine, which in this car tends to be quite hot.

I used to have Amsoil SS 5w30 but due to oil consumption I decided to switch to something that has the Ford specs (Amsoil didn't). In my mind, the Ford-labelled oil was just a very basic 5w30 just to go through the warranty period, but its numbers seem quite good. Would you still recommend going with Ravenol ?

Also a bit of a stupid question: Is there any chance of an oil having the Ford specs and not operating properly ? Heard from a couple of peeps that Ravenols + Fords do not go along very well, which sounds a bit strange to me
 
Messages
6,005
Location
down in the park
As you found with the Amsoil, some oils are consumed more by some engines. There's no way to know before hand. Some oils also tend to be louder as other, more mechanical noises. You would be hard pressed to notice the difference in fuel consumption by going to an a3/b4 oil. In fact if that oil costs a couple euro less you likely come out ahead... The hotter the engine the more the case can be made for a heavier oil as that's how you damage engines, get the oil hot and thin and then drop the supply (clutching/rpm drop or through G-force) and run out of oil pressure in rod bearings of cylinder 3 or 4...

I have no experience with any of the oils you mentioned though. My choice would be the Ravenol or Motul
 

SchumiGr

Thread starter
Messages
6
Location
Zurich
Yes that is very true about engine damaging. So if I want to stay with A5/B5 Ravenol or Motul, if I want the xtra kick in protection then I should go to A3/B4 class (I guess this is what you mean by the term "heavier" oil). Tbh, I thought about it many times (switching to A3) and the only cons I read were the fuel consumption so I will go have a look for some A3 5w30s and see what I can come up with.

Thank you very much for your help !
 
Messages
2,727
Location
WY
I don't know. With over 100k miles a little oil use may be just the result of some engine wear. I imagine the warranty is gone so I would maybe just experiment a little bit. Moving to a more mainstream and less costly oil for an interval may be interesting. I have no idea what bargain brands are available off the shelf in your country in a 5W30 specification but it may be a direction to look at. Maybe even a diesel oil. The Ravenol is excellent but expensive here.
 

SchumiGr

Thread starter
Messages
6
Location
Zurich
Yes you are right, warranty is gone. Ravenol here is quite okay, around 50 Euros for a 4 Liter can. I am also seeing this as a bit of an "experiment" and I do know that there is probably a bit of engine wear - that is why I want to find the ideal oil for my engine. That is also another reason for deciding to install oil pressure and temp. gauges (under planning to find which ones) so I can see "which oil does what" in my engine.
 
Top