2007 Audi RS4, RLI 10W40 PCMO - 1777 mile sample

[JHZR2]

so it doesnt seem like the whole clearance issue is real, compared to specs for other mass-produced engines on the market.

Id agree that it would be interesting to see how a 50wt RLI formulation does in this situation...

JMH

 

[BarkerMan]

I wonder if there is less heat transfer from the pistons to the cylinder walls because of that glass coating in the RS4 engine. Upping rod bearing clearance might have helped combat the increased heat because of the lack of heat transfer.

Fuel dilution most often effects the cylinder lubrication and maybe the Audi is living with higher dilution because of those cylinders. It that's the case then I wonder what effect it will have on the rest of the engine. If RI_RS4 keeps on using this RLI oil we may never find out.

 

[jaj]

Originally Posted By: BarkerMan
I wonder if there is less heat transfer from the pistons to the cylinder walls because of that glass coating in the RS4 engine.


They blend the silica powder (many of us might think of it as sand) into the alloy for the engine block, then polish the bore to flatten the faces of the silica grains to a smooth finish. Then, in the final honing stage they use a soft cloth with a powdered abrasive that eats a little bit of the aluminum away between the grains of silica. This process leaves a glass-hard polished surface inside the bore with stippling for the oil to sit in. It's like the diamond texture from a normal cylinder hone but the cylinder wall is glass.

This process might well cause heat transfer to be reduced compared to a normal cylinder finish, but I'd be really surprised if the designers didn't aim an oil jet at the bottom of each piston to cool it directly.

Originally Posted By: BarkerMan
Upping rod bearing clearance might have helped combat the increased heat because of the lack of heat transfer.



Could you explain this one for me, please?

Thanks!

 

[RI_RS4]

Originally Posted By: Loobed
Originally Posted By: buster
Formulation change? Cu is down.


But so is the length of miles on the oil.

He has 35 copper on 1777 miles, if you multiplied the 35 and 1777 x 5, you would get 175 copper @ 8885 miles. thats more copper in less miles the the 9*** mile sample.





there is no Cu in this oil formulation. The previous formulation had Cu. This is residual from the previous fills.

 

[RI_RS4]

Originally Posted By: BarkerMan
I wonder if there is less heat transfer from the pistons to the cylinder walls because of that glass coating in the RS4 engine. Upping rod bearing clearance might have helped combat the increased heat because of the lack of heat transfer.

Fuel dilution most often effects the cylinder lubrication and maybe the Audi is living with higher dilution because of those cylinders. It that's the case then I wonder what effect it will have on the rest of the engine. If RI_RS4 keeps on using this RLI oil we may never find out.


Actually, heat transfer for Alusil is better than iron. This is how manufacturers like Audi and BMW are able to make such compact engines.

 

[RI_RS4]

Link to Alusil Cylinder Block Process

 

[BarkerMan]

Upping the side and bearing journal clearance will put more oil through the bearing and that will help to keep just a little bit cooler.

 

[BarkerMan]

Thanks for the link. That's quite an engine and the process to cast it is not what you'd expect to find in a mass produced engine.

Just one question. The timing chain. It's at the back of the engine. Is that for weight transfer? To change a timing chain do they first have to extract the credit card from you wallet? I now understand why the science project you're in to determine the best engine oil for your Audi. Your engine is like a Rolex watch inside.

 

[RI_RS4]

Originally Posted By: BarkerMan
Thanks for the link. That's quite an engine and the process to cast it is not what you'd expect to find in a mass produced engine.

Just one question. The timing chain. It's at the back of the engine. Is that for weight transfer? To change a timing chain do they first have to extract the credit card from you wallet? I now understand why the science project you're in to determine the best engine oil for your Audi. Your engine is like a Rolex watch inside.


Yep, the timing chain is placed at the rear for better weight distribution in a car that is nose-heavy to begin with. The intake manifold is magnesium, and the front hood and fenders are aluminum to also reduce weight.

In addition, the timing chain is a simplex sleeve-type chain (without roller bearings) for increased strength.

 

[buster]

RI, do you know of anyone running Amsoil's new SSO oil? Ashless anti-wear package and a tbn of 13.2. I would use this oil as a good benchmark. This oil is supposedly the "best of the best" of that type of oil.

 

[bruce381]

Not ashless with ZDDP in it
bruce

 

[Gary Allan]

Originally Posted By: bruce381
Not ashless with ZDDP in it
bruce


Valvoline appears to get around that notion by just saying it's "ashless AW combine WITH ZDDP". Sorta along the lines of that Castrol "90% of all wear occurs on startup" thing

https://bobistheoilguy.com/forums/threads/valvoline-vr1-racing-oils-ashless-aw.80573/

 

[Pablo]

Originally Posted By: bruce381
Not ashless with ZDDP in it
bruce


That's what I've been saying for the last nine posts. Amsoil says SSO contains ashless additives, not that it is an ashless oil.

We will NEVER see a proper shoot-out comparing SSO 0w30 to RLI 0W-30.

 

[buster]

True Pablo, but it does say "ashless anti-wear system"??

 

[Pablo]

Originally Posted By: buster
True Pablo, but it does say "ashless anti-wear system"??

No, it says "supplemented with ashless anti-wear system" and somehow you took this to mean Amsoil is saying the oil is ashless.

 

[buster]

My mistake. You're correct.

 

[BarkerMan]

RI_RS4 are you going back to 5w-40?

With that RS4 pdf and a rainy day I have some reading to do.