jchapura

Perhaps. I would not have thought that the amount of fuel introduced via the evap system was substantial. But maybe every little bit helps.

Here's one well known company's take on carbon buildup:
https://team.valvolineglobal.com/diy...carbon-buildup

Wayne Smith

From the Valvoline article ...

Ford, for example, has gone from direct injection only on its EcoBoost engines to dual systems of both port and direct injection.

So a bit of vented gas getting into the intake ... that's a good thing.

Meanwhile, that article also mentioned an easy clean technique. Curious.

silver_tt

Buildup on the intake valves is a problem with GDI engines but it's also not that big of a deal if you manage it running a low volatility oil.

jchapura

I know. I'd like to learn the details of that procedure...
​​​​​​
i remember the old Seafoam method whereby one took the brake vacuum booster hose and sucked in the liquid while the engine was running.

bheit1

This was recently discussed in another post. The P car engine authorities that be, have recommended, at least for the 997.2s, to fill
the oil level to one or two segments below the Porsche suggested level on the electronic gauge. The level according to the manual
apparently can overload the air/oil separator. That solved my problem of smoke at start up.

jchapura

EasyGDI.

MrMoose

Nah, there's very little fuel vapor coming from the purge solenoid. Basically when you park the car there's a carbon canister to absorb fuel vapors and prevent leakage to the air. When you're driving the purge solenoid opens up and pulls fresh air through the canister to flush it: it desorbs the gasoline from the carbon and burns it off, but there's not really much gas there

I'm sure the 987.1 has a purge system as well, pretty much every modern car does.

Bruce In Philly

Yea, I kinda doubt that gas evap system would be significant.

I just posted a question on "The Porsche engine gurus" facebook page... fishing for data. Check it out there (my post is waiting to be admin approved there).

Regarding that Valvoline procedure... there are plenty of DIY vids out there showing before and after with similar stuff (I assume) and some show miracles while others just show the carbon turning a bit gooey but still caked on. Who knows?

Peace
Bruce in Philly (now Atlanta)

Wayne Smith

I've always run at the bottom bar for just the above reasons plus concerns over thermal expansion (I've seen 275F on my oil temp gauge). But if I park on a side to side slope, I can still get a smoke screen on start up.

silver_tt

It is the case the for M9x as well. Always ran my oil level down a notch or two from max on this car to help keep the AOS from becoming overwhelmed.

Graufuchs

Yes!

Bruce In Philly

Typical me... doing things differently... I fill to the top line. Never smoked, but I am usually parked on flat ground.

My logic (pretzel type) is that one more quart results in that much less use/stress on the oil. Just like changing the oil earlier. Correct? I dunno.

Peace
Bruce in Philly (now Atlanta)

jchapura

@lnengineering @Lake Speed Jr
Does anyone know what the volatility of the Driven oils are - DT40, DT50, DI40, FR50?

Even qualitatively? And perhaps compare to the Valvoline low volatility oil?

silver_tt

For DI40 the Noack volatility (%M/M) is 9.9 as of 8/2023

8x57IRS

If you look at the criteria for the LongLife calculations of other manufacturers for the dynamic change interval, the following criteria are used:

Oil temperature => thermal load => conversion to section #1

- Engine speed => thermal load + soot load => conversion to section #2

- Engine load => soot load => conversion to section #3

- Distance travelled + section 1-3 = total distance

The only effect that a little more oil has is of course the temperature, which does not rise as quickly. But the calculations don't take the fill level into account. I think the effect is more cosmetic but I wouldn't top up to the maximum -- on any car.