Fuchs Race Pro S 5W-30/5W-40 ester..

[mojocvh]

First post here we go...

Just what is the actual difference between these oils once up to full working temperature?

The reason being, sigh, in Europe we are recommended a -40 weight oil.

I'd rather run with the -30 weight oil due to the usage the vehicle has [city driving but also some 60/70mph longish runs. I have seen oil temps of 120C [248F] on runs [85k mile AJL 4 pot engine with 3.5 ltr oil capacity] and I am trying to judge whether this ester based -30 weight oil will provide sufficient cover for this turbocharged engine in terms of heat capacity around the turbo bearings.

thanks for reading,

Mo.

 

[EddieCairns]

Car and mileage are you expecting the posters here to guess it.

The 40 grade oil will be thicker at normal running temperatures than the 30 grade oil and it will also work at higher temperatures without degrading.

A 50grade being probably better again at thicker temperatures.

In the UK, Subaru Impreza STI drivers tend to go for the higher viscosity oils as they assume it will protect the engine better but none of this is based on a UOA.

eddie

 

[mojocvh]

"Car and mileage are you expecting the posters here to guess it."

Yeah, I was asking specifically what the difference between the two oils quoted...never mind...

 

[dparm]

Here are the HTHS values for both, which should approximate their viscosity in service (at operating temperature):

Pro S 5w30 = 3.22
Pro S 5w40 = 4.07


As you can see, the 5w40 is some 20% thicker. Their 5w30 is not a "thick 30" like some oils. It is a mid-30.

I would stick with the 5w40.

 

[supercity]

If you want to use a 30 grade I would use something A3 rated.

 

[mojocvh]

Originally Posted By: dparm
Here are the HTHS values for both, which should approximate their viscosity in service (at operating temperature):

Pro S 5w30 = 3.22
Pro S 5w40 = 4.07


As you can see, the 5w40 is some 20% thicker. Their 5w30 is not a "thick 30" like some oils. It is a mid-30.

I would stick with the 5w40.


Brilliant! Just what I have been looking for.

I have tried to find a tech spec sheet for comparison for these oils for ages, Google throws nothing up and I resorted to mailing a query from the Titan race mini site.

thanks very much indeed. Oh do you have a link/source for those stats please.

thanks again

mo.

 

[dparm]

No problem. Their spec sheets are not complete so I emailed them last year to get the extra information. They're slow to reply, but very nice people.