jchapura

The flush oil I used before the DT40 was the JGR break-in oil BR30. Yes, multiple changes (well, maybe 1 change only) with the final oil in relatively quick succession would do the same thing, I think.

Lahainabry

Thanks for the information. Not trying to cause a "Hot Topic" about oil.
Just looking for some advice on changing brands and compatibility.

I read an article Mr Raby wrote about the Joe Gibbs oil. I am due for an oil change so I was interested in that brand.

Lahainabry

Thanks John, that is great information, I appreciate it.
I need to call in the am. I have a warranty and don't want to void it over oil.


B

LexVan

Mobil's additive package really fights with Joe Gibbs. That's why you need to run in a few hundred miles with the BR30. To reduce the cross pollination.

Or, if you want to use a better oil than Mobil 0W40, just switch to Mobil 5W50 and be done with it. Porsche A40 approved too.

jchapura

I'm not a lubricant expert but does the Mobil 5W50 have a sufficiently similar "zinc" content - I understand that's one of ingredients that really differentiates a better oil for the M97.

And with regard to climate...when compared to the DT40 (with maybe 20% DT50), for the summertime here in Texas, especially for a daily driver (in fairly regular stop-n-go traffic), does the Mobil 5W50 have a better viscosity over a 5000 mile life span, on the unkind hottest of days?

golfnutintib

i predict this thread will see 75 posts before it dies its natural death

ADias

There are plenty of A40 oils for your car. I like:

Motul 8100 X-cess 5W40 - great high temp shearing properties and higher Zn/P than Mobil 1.

vrnkc

I switched to Joe Gibbs. No problem

Petza914

I've had my BR30 and DT40 in the garage for a few months now and am likely doing the changeover this weekend. Changing oil & filter with a BR30 fill and will put 100-150 miles on the car, then change oil and filter again, filling with the DT40. I'm changing because I'm both my C2S cars (one RUF supercharged and one not) I've seen breakdown of the additive package in the Motul xcess in the UOA reports with a change interval of both 4,500 and 5,000 miles. Changing the SC car first and will use up the rest of the Motul I have on hand in the other car with a 4,000 mile change interval.

As others have said already, the reason for running the BR oil as an intermediate step is to prevent conflicts in the additive packages between the two oils and there has proven to be a conflict with both Mobil 1 and Motul xcess when switching from either to the JGR DT40.

With the DT40 not being A40 approved, I would likely not change to it until after my warranty expired (if I had one). I'd use the Motul and a 4,000 mile change interval, then change later.

LexVan

According to Mobil's data sheets 0W40 and 5W50 have the same zinc and phosphorus levels. Right at 1,100 ppm, IIRC. DT40 is also very-very similar.

According to my Blackstone UOAs, there is always more zinc and phosphorus left in the 5W50 after my 5,000 drain interval. That speaks to the better and more robust additive package in the 5W50. As compared to 0W40. About 200 ppm better.

With regards to viscosity, the 5W50 exhibits a much improved SUS 210 viscosity and cSt 100 viscosity over the 0W40. Mobil 0W40 has the classic high shear breakdown that I find unacceptable.

You should not be using DT50 in a water cooled 911. Maybe you're getting away with it because you are mixing a cocktail with DT40.

dgjks6

I think I remember the concensus decision from the 996 forum. It was olive oil mixed with unicorn semen that gives the best protection. I will double check to be sure, but I think I am right.

Carmichael

The documentation on my FSI/Raby car says DT40 is strongly recommended, but that Royal Purple or Motul X-Cess are also acceptible substitutes. Mobil products are apparently never to be used in the engine.

Do with that information what you will.

I just miss the days of ~5 quart oil changes with $9/quart Royal Purple and a $8 filter from the dealership, with my old Cooper S.

golfnutintib

Really???

semicycler

Jake Raby and Flat 6 Innovations rebuild engines for a living. They are highly regarded in the Porsche community. They also developed their own motor oil that they recommend over other brands, especially Mobil 1 0W40. FSI requires you to use their developed oil with their engine rebuilds if you want their engine warranty. Reach out to Jake directly for his opinion on the topic. Carmichael is just reposting what FSI recommends, their DT40 motor oil with their engine rebuilds.

My own used oil analysis with Mobil 1 0W40 shows early viscosity sheer, turning the 0W40 into something lower like 0W35 or even worse 0W30. This is something you definitely do not want to see with UOA. It's not a very good oil for high mileage changes or track usage because of this. But if you change your oil frequently, before it sheers completely, it's works just fine. I use Mobil 5W50 often mixed with 0W40 depending upon the time of year and change out at 5000 miles. UOA come back perfect every time with this scheme. Again, my opinion, some guy on the Internet, definitely not an expert Porsche motor rebuilder. And I'm not trying to start the oil brand debate. Just putting some context around FSI's requirement to use their oil over other Porsche specified A40 oils.

Lvt19672

This^^^