pslewis

Mine has a 10Gallon tank ............... hasn't it??

Pete

Trout

iTrader: (1)

I can almost agree with you here.

However how do you know how many people who read your posts drive their cars like you do?

Many Scooby owners take their cars on track with unfortunately no clue as to what they are doing.

So being clear on your advice is very important as you repeatedly point out to others

I have never suggested that you should use Motul - I am suggesting that it has more to it than just a higher price tag and good marketing. I have also suggested that there are real issues that should also be considered when choosing an oil - not just the ones that fit within your view of the world

pslewis

Indeed I do .... as a Work Area Safety Panel member (WASP)

http://www.nerc.ac.uk/healthsafety/h...ndlowering.jpg

Pete

Trout

iTrader: (1)

Go on then - I am looking at the bait - put us out of our misery?

Why have you only got a ten gallon tank?

pslewis

Quantify 'many' ............

I would state here and now, that MOST ..... ie, MORE THAN 90% of Subaru owners do NOT track their cars!!

Pete

pslewis

I HAVE a 10 Gallon tank ...........................

I am sure of it?????

45 Litres??

Pete

oilman

iTrader: (9)

It's to do with NOACK Volatility (do a search on google) which is an API volatility test. The oil is heated to 250degC and the amount of evapouration is measured as a percentage.

To meet API SL or ACEA A1, a standard pass for a 5w-40 for example must not exceed 13% evaporation. This is not a tough target to meet. A proper pao/ester synthetic for example will have a NOACK volatility of far less, in the case of decent synthetics in the region of 5% to 7%.

The difference is down to basestock quality, synthetics are far more heat resistant.

Hope this helps
Simon (Yes I wrote that )

Trout

iTrader: (1)

Do you drive an Evo?

Trout

iTrader: (1)

Simon,

I knew that you knew - I was wondering if our learned colleague was aware of both this fact and the consequences. And just feedback from my experience Motul is by far the best performing oil I have used in this area. Indeed Mobil 1 Motorsport as an example comes out pretty much as fast as you can put it in a track day.

Rannoch

GrahamG

Mines 60 Pete.

Pete, also. Do you work on the T5 project?

G.

Trout

iTrader: (1)

I was referring to the subset that take their cars on track - not the set that describes the Subaru universe, thank you for resolving that ambuigity

Of the track subset, a significant subset of that do not understand the consequences of which oil they are using on a hot track day.

oilman

iTrader: (9)

I should explain as you clearly don't understand.

The lower the viscosity of an oil at say 0degC the better it flows when you turn the key which means less friction, heat and wear. 90% of engine wear occurs at cold start.

Take any sae 40 multigrade (0w-40, 5w-40, 10w-40 or 15w-40) and compare the viscosity figures at different temperatures, the lower the "w" number the better it flows at lower temperatures. However to be rated as an sae 40 they are all around 14cst at 100degC.

Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid.

As viscosity varies with temperature, the value is meaningless unless accompanied by the temperature at which it is measured. In the case of oils, viscosity is generally reported in centistokes (cst) and usually measured at 40degC and 100degC.

So, compare these figures and you'll understand what I'm talking about:

Visc/Temp:.........0degC...................10degC...... ...........40degC.............100degC

0w-40................350cst....................200cst ...................60cst...................14cst
5w-40................800cst....................400cst ...................90cst...................14cst
10w-40..............1100cst..................550cst... ................120cst.................14cst
15w-40..............1400cst..................700cst... ................130cst.................14cst

So, it's not just down to arctic temps although 0w would be the least viscous, it's down to flow and rate of flow!

Cheers
Simon (Yes I wrote this too )

oilman

iTrader: (9)

Mobil1 actually has good quality synthetic basestocks but you will always find a 0w-40 less stable than a 5w-40 as it requires more VI improvers due to the larger viscosity gap. I have never considered Mobil1 as a race oil and the HTHS & Noack figures bear me out on this.

Mobil 1 is still built to a spec, the likes of Motul & Silkolene exceed the specs by a wide margin as they are built as out and out competition oils.

Here are some comparisons:

.....................................HTHS......... .....................NOACK%

Mobil1 0w-40....................3.7......................... ..........13%
Motul 300V 5w-40.............4.51............................... ...7%
Silkolene Pro S 5w-40........4.27...................................6 %

Cheers
Simon (oh and yes, I wrote this )

GrahamG

Trout

iTrader: (1)

Simon,

do you have the figures for the 15/50 as that is the grade I am referring to in these comparisons.

Rannoch

jaytc2003

iTrader: (1)

Castrol doesnt always come in 4 litres, in fact many of their oils are boxed in 4 x 5 ltrs

oilman

iTrader: (9)

Yes indeed but bear in mind that HTHS numbers will always be higher on an sae 50 than an sae 40. Noack remains a comparative figure across all viscosities as it indicates basestock quality.

............................HTHS.................. ..........Noack%

Mobil1 15w-50.........5.11..............................11%
300V 15w-50...........5.33..............................6%
Pro R 15w-50...........5.23..............................5%

They are all shear stable oils but then again 15w-50 is a small viscosity gap like 5w-40. The noack % tells the story here.

Cheers
Simon (I wrote this )

oilman

iTrader: (9)

Not the performance grades. Only the semis and mineral oils

Cheers
Simon

Trout

iTrader: (1)

C'mon Pete - explain to us why you have a 45 litre tank?

My Classic Scoob had a 60l tank and my current one has a 50l tank which is non-standard.

I am really looking forward to your explaination

ZEN Performance

I'm fed up with this article being posted time and time again.

AC-scoobie

It’s just another inconsistency to add to the list. How in the space of one month Mr Lewis managed to age 4 years? Why his car has been stuck on 65k miles for the last two years? For answers to these and other not so interesting questions tune in to the next oil/knocklink/fuel consumption/brake pad thread.

GrahamG

MPG figures might be going out the window here... lol

GrahamG

agreed... but who is going to shut them up....?

Trout

iTrader: (1)

Paul,

and you got as far as post #79

Rannoch

16vmarc

I was waiting for this, but no one picked up on it!!! I do alot of short journeys during the week, well i use to. So a thinner grade of oil is more sympathetic. But, as ive already said, look at the grades. Theyre both 40's so when up to temperature theyre both the same consstancy. If my driving requirements were differant i would indeed use a thick grade of oil such as 10w.

New_scooby_04

iTrader: (4)

Only cause people keeep asking the same questions!

Conclusions, on which we can all hopefully agree:

-Subaru reccomend certain brands of oil; they know what they are talking about- they built the car. If your car is not modified and you don't track it, i.e. you use it as Subaru no doubt intended you to, use these and you'll be fine.

-There are, however, demonstrably superior brands of oil - at least superior with respect to the empirical benchmarks against which oils are assessed- to those which Subaru recommend. These are of benefit to any high performance car, especially those that are modified, or are tracked.

-These oils cost more than the one's Subaru recommend and can be harder to get hold of.

-The cost amounts to less than £20 every 6 months or 7.5k miles (based on a classic service schedule). That's less than half a tank of optimax.

There it is in black and white. You pays your money you takes your choice.

NS04.

flynnstudio

New_scooby_04

iTrader: (4)

GrahamG

PMSL!

GrahamG

you did foeget Oilman though......

G.