I am sure this has been talked about but figured a discussion of current choice for oil would be good. My car is due for service and I am not sure what oil to use. So far, shops have recommended motul 8100 xcess 5w-40, motul 8100 xmax 0w-40, castrol edge 5w-40. I know oem is mobil 1 0w-40. What have you guys been using? Am i pulling hairs with choosing an oil? The shop I am going with recommended the xmax however I can request a different one if i want. let me know your thoughts. Thx guys!

Zac

 

Following. I have a service appointment scheduled at my Indie on 4/21.

 

I run Mobil 5W-50, Napa always has a sale and it coincides with my oil change interval-not easily found in other parts stores, but they always have it.
The Castrol version of the 5W-50 viscosity is not on the Porsche Approved list
Many people like Motul, Liqui Moly and others and use 5W-40 viscosity-

JB

 

I have been using Motul 8100 x-cess 5W-40 for my past 10 oil changes, about 40K miles. Before 30K miles, I would change oil whenever it dropped one bar down from full, usually 3K to 4K miles. You may not believe this, but it seems to take longer to reach a liter low and I cannot rely on oil level to tell me when I have reached 4K miles on the oil. I am very careful to not overfill and usually add 1/2 liter until full, with checks after each full temp drive. I am puzzled over this. Could my valves have become fully seated after 25K to 30K miles? The last oil change was 75K miles.

 

Motul's ester based oils do not like to sit, so if you don't change your oil at least yearly I opt for something like Shell T6.

 

has anyone used motul's xmax? seems like the X-cess is the more popular one around here. interesting that one shop likes xmax the other likes xcess

 

deleted.

 

I'm running Liqui Moly 5W-40 and have been using this in all my 911s for years. I do my own oil changes so I can measure exactly how much comes out, relative to how much I put in. So far, my GT3 has not burned any oil.

 

I've run Motul Xcess for as long as I can remember. Then when the X Max came out I switched and I usually never switch oils on a car.

 

These anecodes are an absolutely ridiculous ways to choose an oil. None of us are doing any real durability or wear testing to qualify the oils we "like", and much of it is confirmation bias. Not many GT3s covering hundreds of thousands of miles, so the best we can say is that we didn't have a catastrophe in 60k miles, so our oil must be good. If you have an engine that was professionaly built by someone offering a warranty, you shoud certainly run the oil they require. Otherwise you're kind of on your own, and can definitely use Porsche A40 spec as a guide. At the time when I last picked oil brands Amsoil had a LOT of testing data that they had made public, and you could see how their products stacked up. I was impressed with the transparency, and have been running their oils since. Unfortunately this has become a little anecodotal as well, because they seem to show less testing data on their website. I recently called them because I have been using the full SAPS european oil in my GT3, and I wanted to know if any of their more expensive oils would offer better protection. I don't personally care about porsche spec compliance because my car isnt under warranty... The tech staff was adamant that I shouldn't "upgrade" to the signature oil because their opinion is that the spec is very improtation. I have no idea how much of this is CYA on their end, or how the tech staff are motivated, but I was somewhat surprised at the advice.

Without doing much research, if I had to move away from Amsoil, I would certainly consider the Mobil1. They publish their zinc data, and that oil has historically been very good on paper. I used to run it in a 911 SC, and it seemed like the detergent package worked really well. When I popped the valve covers off the engine was nearly perfectly clean with 100k miles and shot valve guides.

 

Motul 300V Trophy 0-40, because it is reassuringly expensive

A relevant quote from some of the marketing blurb:

Motul tested its 300V Trophy 0W40 on a circa-400 hp 3.6 litre Porsche Cup racing engine and found an increase of up to 7.2 hp over its competitors’ products

https://azupim01.motul.com/media/mot...n_fr_motul.pdf

 

Realistically, none of us have access to that type of dataset. The best we can do is lean on averages collected from lab OCAs like Blackstone. There are plenty of threads on oil, I've posted numerous OCAs as well but didn't feel like retyping everything that's already been thoroughly discussed.

 

For tracking, I'd use Mobil racing 0W-50, it has the highest zddp
It could do damage to the cats, and not meant for long life
Oil change should be done in 12 month intervals regardless of mileage.
The danger is corrosion from water if the car isn't driven, and thinning if the car never comes up to operating temperature(short drives or just quick starts)
Hot and humid conditions are also a problem, as extreme cold start ups-
There are a lot of extreme oil comparisons at the youtube channel Project Farm for those who like to see, from very low temperature freezing to extreme high temperature cooking of the oils

The worst thing someone can do is use the wrong viscosity for the engine-for instance, new oils with 0W-16 viscosity exist for new engines built specifically for using it. Put that in your GT3 and your engine would fail going around the block.
For my 2 stroke, I've been using castor bean vegetable oil for decades-the protection is unequaled and it smells great
JB

 

What is your process or what do you use to measure the exact amount that comes out during oil changes? I want to do this to avoid incrementally topping off after going for drives using the electronic dipstick.

 

I use a clean oil pan which has a spout on it. I let the oil drain until it stops dripping. I then transfer the oil into a 1 gallon "lemonade" container which has measurement marks on it. Fill one gallon, transfer to my used oil recycling container, fill remainder from pan, add the measurements.
Now that I wrote this out, I realize just how deeply ill I've become. OCD has completely taken over.