If you’re looking for ZDDP 5w30 is going to have the lowest as it’s regulated by law to only have x amount in the U S of A. CAFE standards.

 

I was told that oils high in ZDDP can lead to additional deposits inside the catalyst causing them to clog sooner and that those oils were primarily used on engines with flat tappet cams to protect the lobes from premature wear.

 

That's what she said!!!

 

ZDDP is hard on cats for sure. It’s also not friendly with the ozone, which is why it’s gone from oils designed for street use. You can find ZDDP in most oils listed as a race oil such as Valvoline VR and most all Driven oils. I personally run Driven LS30 in the 434.

 

I bet ZDDP isn’t all that hard on catalytic converters really. Maybe some, but I never had, nor did anyone in my family have any cat failures back in the 90’s when 10w30 was the mainstream OEM and 10w40 was still kind of still a thing.
Is ZDDP totally gone from “non racing oil” or has it just been regulated to how much it can have in order to receive the CAFE seal stamp of approval? If it has been replaced I imagine surely there's a substitute that has been added in to take its place.

 

Scott, what's your take on 0w-30? Think it's too thin at 210° oil temps, or? Don't mean to hijack, but this is pertinent to the OP, too. It would flow better cold than 5w-30/0w-40, and get to critical surfaces sooner during first start of the day. My question is more about if you think it is viscous enough for adequate film strength at 210°-220°+ oil temps at 6,500rpm-7,000rpm. I realize this is Gen III, and I have the 4th gen. Thank you.....

 

Dexos from GM’s standpoint. I have no idea how it compares to ZDDP…I’m far from an oil expert.

 

Polyalphaolefin

 

I run 0w30 in my fleet vans when I can’t get 5w30…Mobil1 exclusively for me in the vans. They get ran pretty hard and haul a lot of weight. Def flows better on a cold morning at startup. As far as the film strength question Mike, it’s very good for an Oem engine or a very mild build. Film strength is dictated by additive packages and base stocks, and it has to be chosen for the particular build and its power level/usage. For instance, NHRA Pro Stocks run 0w3 oil…yes three weight oil…but the additives are selectively chosen and the best base stocks are used in the 1500hp 10k rpm engines. So there is no one-size-fits-all oil for builds per say. I’ll see if I can get our in-house oil expert to chime in here. He’s forgotten more than I’ll ever know about oils.

 

He is the guy!
…edit….he hasn’t been on since May of last year unfortunately.

 

I bet it’s too thin for sustained high temps like I’d one was on a road course. If it wasn’t I don’t think the auto manufactures would recommend using XW40 and 50 weights when road course racing cars that normally call for Xw-20 & 30 for everyday use. I bet a w-30 would probably suffice for drag racing unless you were hot lapping all day. All that being said I don’t think a 0w-40 is too think to run year round most places in a motor that the mfg recommends 0w-20. Look how wide some of (probably a lot of) auto mfg’s spread is when it comes to accepted oil weights. The manuals read something like, “0w20 is recommend but 5w30, etc is acceptable if 0w20 is not available. Surely the 20 is recommended to meet the mpg requirements and not because it’s better for your engine.

 

Thank you......

 

Really enjoyed reading his posts too.

 

diesel oils are the worst thing you can use in gas engines.....the needs of either engine are best suited with using oils for specd for those engines

our resident oil guy who has not been here in awhile does recommend euro M 0-40 as a good oil to use.....i use it exclusively ,,,,,and its dirt cheap a wally world in the big jug

 

Have you noticed any lower mpg’s with the 40? I switched from a 0-20 to M1 euro 0w40 on Friday before going out town on Saturday. Going down it was raining cats and dogs so I didn’t get a good gauge on mpg’s then, and just now going home there was a 20+ mph headwind most of the way so it got two less mpg’s than usual. I was hoping to see if I could tell any difference in MPG’s between the thick vs the thin oil during a long hwy run but the weather didn’t corporate. Its next long highway run will be pulling a trailer towing an F-Body I think, so no good highway MPG test there either ha.

 

the resident oil guy said that the M 0-40 actually wears down to a 0-30....and I have not noticed any lesser MPG from using it

 

went to wally world today.....noticed the M euro 0-40 is now 5-40 !!!

 

I bought m1 Euro 0w40 at Walmart last Friday. I had to go to two different ones though. The first one I went to didn’t have it in the 5qt jug.

 

I've had my Audi S4 2.7t for 22 years now and when I got it around 26k I used Mobile 0w40 as many owners did (still think it's decent). The oil had decent oil analysis from forum members(they sent them often), but from time to time we would see a exhaust cam bucket get eaten when running it (not saying it was for sure the oil or lack of maintenance, but in the early years guys wee nice to the cars), these engines are hydraulic cam on bucket type lower springs pressure etc. Lots of guys switched to Rotella t6 back then as it was easily available and Audi called for 0w40/5w40 and in all these years I've never found a post of a lifter bucket having failed and pretty much perfect Blackstone lab reports that others sent in on many high mile engines (some 300k) over the popular years of ownership. I ran t6 in that car from about 2005 till I hurt the stock engine from power around 2020. I removed the cats and kept them around 2015 as they are high quality and in perfect condition with 100k+ miles of t6 ran through them. Lifters and cams were perfect as were bearings etc I just pushed the stock rods too far.

I ended up using t6 it in my 383 C5Z when it was NA around 500whp. Oil saw 302F on the road course a few times and with about 15k on the engine I pulled the camshaft when going turbo (which was an xer 238 242 605/610 lift) out and the lobs and lifters were perfect easy to sell that cam. Continued to use the same shortblock into my turbo build that made 1000whp with no oil issues. I'm not recommending anything, Rotella t6 zinc has dropped from around 1400ppm to 1200mmp or a bit less, but for all the examples out there, turbo cars, millions of motorcycles, etc running this crap it's doing ok from my personal experience.

As for the OP's question those oils get use a lot in the German car crowd and I've not seen or heard of any issues. They probably meet the Audi/VW standard on the 5w40 stuff. give it a go and see how pressures sit etc.

 

Looks like legit testimony for T6 to me....