PorscheAddict

Is the oil capacity really roughly half 981?

Syeo86

Yup. See the doc in the link at the bottom of my post, straight out of the owners manual.

I wanted to call that out explicitly. One method to deal with higher temps is to increase capacity. They went from 6 to 4 cylinders so the overall engine size changed, and capacity drops with relation to that. But they put on a turbo charger, which changes the game.

I have a WRX with the 2.0 engine, and I can tell you it is easy for me to take the oil from 208 and push it to 230-240 at the autox. The car is tuned for E85 which technically provides some cooling effect, so on normal 91/93 octane temps would be higher. FYI oil capacity on the WRX engine is 5.1L.

This is why I'm not surprised to see someone take this boxter/cayman engine and see ~250F at the track then subsequently limp mode.

Interestingly enough, they also used liquid to air heat exchangers for the charged air entering the engine. They are using coolant to "cool" the high pressure air being forced into the engine. I tried to dig around to figure out if this is on the same coolant circuit that is being used to cool/warm the engine. If it is, then the coolant would be in the ~170-190F temp range during operation. Not really that cool...

PorscheAddict

Very interesting, thanks for pointing that out. I assumed it had 10-11 liters like the 981. That would certainly at least speed up the time to overheat, all else equal.

JCtx

That one is buffered, so doesn't move from 194ºF until engine is truly overheating, I believe above 240ºF. Maybe with an OBDII device OP could check actual coolant temp, but since oil is heated/cooled by coolant, it's obviously much hotter than 194. Being tied together, they can't deviate much from each other. And yes, these cars have HUGE air pockets from the factory. My car took more than a pint with only 12 miles on the clock. And ended up putting over a quart before it fully stabilized. If OP never added coolant, then it most likely played a role in the overheating. I'd add coolant until system is stable, and see what happens, since nothing else seems wrong.

Me too; really surprised they don't. That's crazy. Yes, engine is smaller, but much more stressed, and with more HP, so oil capacity should be at least what 981s had. Another detraction from this car. Guess since it was actually heavier than 981s, Porsche decided to cut weight and cost at the wrong place. Good luck OP.

ajw45

Thought the 981 is only around 8L?

Pep!RRRR

8 liters is the amount needed to refill after an oil/filter change. But there is still a significant amount of oil that does not drain out.

okie981

I get 9 quarts in my 981 BS every time I change the oil and filter, but I let it drain a loooonnnnnggg time. when I add 30 oz. of the 9th quart, the 3rd green segment in the oil level display is lit but not the 4th. I can drive it 100 miles and occasionally the 4th green segment will illuminate, but only intermittently and mostly see only 3 green segments. I can add the last 2 oz, and see mostly 4 green segments over a few hundred miles of driving.

PorscheAddict

FWIW the press release shows 10.7 liters on the 981S. I realize most oil changes only get 8 liters out, but much of it stays behind (not sure how good that is either ).

JCtx

In ALL engines drain/refill amount is significantly less than total capacity. And by 'significant' I mean 15% or more. In the 981 case, it takes longer to drain than any car I've ever owned. It takes almost 2 hours for oil to start dripping on this car. And THAT is the difference between draining 8 or 9+ qts. I do it the right way, draining it until a slow drip, which usually takes about 3 hours. Last time I drained about 9.25-qts, but only put 9 back, which was enough to trigger the 4th (full) segment. On the first oil change, I put around the same 9.25-qts I drained back last time, but since 9 was enough to register full this time (2nd oil change, at 8K miles total, or 5.5K on the oil), will do that from now on (and yes, I wrote it down to remember). As mentioned above, it's probably just barely above the minimumm for the 4th segment (each segment is 0.45-qt), but that's good enough for me, as overshooting the 4th segment would be a PITA to rectify. But I know I could easily add the extra1/4-qt I drained, meaning I was near full on the last oil change. Since I don't track, that's perfectly fine.

mrjcw

Update from Porsche

Still can't figure out what causes engine to go 'Limp Mode'

Technicians sent all the data logs to Porsche engineers in Germany to find out the problem.

One thing that I notice while looking at the picture is the location of turbo. It sits right next to the oil pan and with a bit of spirit driving the heat traps in the front part of the engine, causing sudden increase in Engine oil temperature.

Hope they resolve the issue....

81911

Have you relayed this information to the engineers?

FlamsteadHill

Syeo86

This is very very normal. The oil pan sits around the bottom of the engine, the headers general sit right on the side. If the engine has one turbo, then the turbo is either right in front, behind or below. This is done to keep header length the same. If the header lengths are kept short, to reduce spool time, the turbo can be even closer to the oil pan. At the end of the day the turbo is always in very close proximity to the oil pan.

Bonus, your turbo utilizes engine oil to keep from blowing up. The oil is needed to make sure the bearings are well lubricated. These howling puppies can spin in excess of 100,000 to 200,000 RPM. Some turbos have a water jacket used to help cool them. I'm not certain the turbo in the 982 has this.

Some guys will use turbo blankets to help keep heat away from the rest of the nearby components. This could be one solution for you. However, if there is nothing wrong with the engine and cooling system, my suggestion would be a dedicated oil cooler.

Keep us posted!

mrjcw

Thank you for the input. However, I do not think this is normal.

I have looked into the other turbo cars. The most similar engine would be the Subaru WRX STi, if you look at the location of turbo it sits on the 10o clock position if you look from the front of the car. Nowhere near the oil pan. Also, 911 turbos has their turbos located faraway from the engine block.


If you look from 3:30, you can see the both exhaust manifold literally runs right next to the oil pan from either side. AND from what I can see there is NO HEATSHIELD like the ones next to the turbo and catalytic converter.

Normal street and highway drive would be okay, however little bit of sprit driving the heat will be generated and it will heat up the oil in the oil pan, and cause sudden increase in oil temp which eventually lead computer to put engine into the 'Limp mode'

Based on my past experience of owning turbo cars, exhaust manifold can easily reach very high temperature that you can even see the manifold glowing red in the dark setting.

I guess mechanics never going to find out this problem by just looking at the data. This is something that they need to research the thermodynamics of the entire engine.

Maybe I am wrong, but this is my guess on why they can't figure out the problem.

Pep!RRRR

Others have stated that similar 718s have not had this problem under high performance driving conditions. The problem clearly has nothing to do with turbo location or heat shielding.