Originally Posted by BOOSTTT

The old Mobil 1 was great, but the EPA said that the added ZDTP, which protects for long life engine wear, is now no longer EPA approved saying it will hurt your cats. I have always used synthetics with ZDTP...Zinc/phosphorous. I have never had a cat go bad in any car. To keep the EPA starburst stamp, Mobile 1 had to take out the good stuff. Now the oil does not protect as well. However, They can write, "For off road use only" and keep the ZDTP such as what Royal Purple does and Mobil 1 High Mileage. I use Royal Purple 5-40 in my Cayenne Turbo and it is doing great in the super hot climate in Arizona. I use Mobil 1 High mileage in my collector cars that don't get driven as much because it has a longer life (oil will break down just sitting in a car) and seal conditioners. Cars that are not driven much can get brittle/cracked seals. I have read about 50 articles on oils and all the tests. How the oils performed, and these are the two that stood out in the tests. Amsoil did well in the tests too, but broke down faster with heat, and with age, faster than those others. Royal Purple seemed to be consistently the best in many test. When I tore down my 300ZX Twin Turbo engine, (Hold less than 4 quarts) I had nearly zero measurable wear and the machinist was pretty impressed asking me why I'm doing a rebuild.....To make the internals stronger for upgrades to come... Royal purple did its job. That engine gets HOT. 2 turbos and 4 quarts of oil. It stays fine. I have never had any issues using Royal Purple in any of my Porsches either. Tons of real tests and info out there if you have time to read it all.

Originally Posted by jdubbya

Preach it. What, do you have stock in royal purple or something? You dug up a 4 year old thread to add your info. Just kidding, it seems to be good info and thanks for sharing. I've stuck with Mobil 1 but am always open to learning more.


I was going to a decent oil change place to do mine but the amount they want to charge is silly. I brought the filter because they don't stock it, I brought new crush washers. They still wanted something close to $150. I did my last one at home but realized they stripped out the head on the upper drain plug. Now I have to figure out how to get that out. Already have a new magnetic plug just have to get the old one out. Bastards.


Was it you that mentioned buying Royal purple in 5 gal jugs from Amazon? I haven't been able to find any either 0-40 or 5-40 in 5 gal jugs. Would be nice since it takes about or more than 2 gals for one change. 5 gallons should be enough to do two changes with some left over for topping up in between.

Originally Posted by BOOSTTT

I'm looking on Amazon right now and see 5w-40 in 5 gal. $142.32 and free shipping. I did write a very very long article on here about 8 years ago all about oil. With liks to ea. Independent test. It's been a long time though. That 5 gal of RP at the parts stores cost over $200, so it's a good deal. Ships in 2 days for free with prime. The oil code number is 05540. Look that up on Amazon 5-gal

Originally Posted by BOOSTTT

I'm looking on Amazon right now and see 5w-40 in 5 gal. $142.32 and free shipping. I did write a very very long article on here about 8 years ago all about oil. With liks to ea. Independent test. It's been a long time though. That 5 gal of RP at the parts stores cost over $200, so it's a good deal. Ships in 2 days for free with prime. The oil code number is 05540. Look that up on Amazon 5-gal