i want to know more about this new dexos 2 0-40w that is goin in the new vettes......any opinions?

 

1. It is what it is. GM went to a crank driven oil pump instead of a cam driven pump like in the past. This doubled the speed of the pump causing cavitation at an rpm it wouldn't normally happen. A few companies have solutions for the issue.

2. I'm not going to say there's no benefit as the detergent package of the D1G2 / SN+ oils are superior to the previous "high calcium" formulas. You just won't notice as much of a benefit as the newer direct injected engines. The main concern with Dexos is combating low speed pre-ignition (LSPI) and reducing carbon deposits around the pistons. The secondary purpose is reducing chain wear. Also note that some oils contain the formula for a D1G2 or higher oil, but just aren't certified for it. A good example is Mobil 1 High Mileage 10w-30 which has the Dexos style formula, but isn't certified. This is most likely because it was cheaper for Mobil 1 to change the formula across the line, but only the standard M1 needed certifying since not many GDI engines are running high mileage oil yet.

While Dexos oil tends to be less susceptible to aeration, the main issue with aeration comes from oil dwell time in the pan. All oil picks up air as it's tossed around the engine. Much of it is soluble air which becomes insoluble when pressure is relieved off the oil such as when it's draining and sitting in the pan. The longer the oil sits in the pan, the more those insoluble air pockets or bubbles can rise to the surface of the oil and evaporate out. This problem usually arises when people use a high volume oil pump with a stock oil pan as the oil pump is grabbing more oil with each rotation, reducing the dwell time of the oil in the pan, and thus worsening aeration. This is why I don't recommend using a high volume or high pressure pump unless it is absolutely necessary and you're running a larger oil pan to allow for longer oil dwell time.

3. If your engine is healthy, there's no reason it couldn't go at least 7,500 miles with frequent spirited driving and 10,000 miles with "normal" daily driving. Mobil 1 guarantees their oil to 10,000 miles.

https://mobiloil.com/en/article/warr...1-oil-warranty

Having said that, properly filtering the oil is key to making it last that long. Fram Ultra, Mobil 1 EP, and K&N filters will be sufficient for 10,000 miles. I normally would add Wix, but I've been weary of them lately since Mann+Hummel bought the company. Quality is starting to suffer as production cost is being slashed, including some production being farmed out overseas.

4. That depends on which Amsoil line you're referring to. Amsoil OE is fine to 7,500 miles. The XL line can easily go 10,000 miles or possibly more. The Signature Series can go 15,000 miles or more. Many people have gone to 25,000 miles that Amsoil claims, but that's pushing it too far for my taste without better filtration. If you do almost all highway driving with a high efficiency filter like Amsoil Ea or Fram Ultra, combined with a high efficiency air filter, and rarely ever go WOT or high rpm, then you could go 25,000 miles. For the usual mix of city/hwy, I wouldn't go past 15,000. I did a change of Amsoil SS 5w-30 in my 2002 Tahoe with the 5.3L and the TBN was 1.8 at 16,800 miles with 50/50 city/hwy and a Fram Ultra XG9837 filter. I've considered adding a bypass filtration system on the truck.

 

I really dont buy your cavitation point. Especially when the georotor and now vane style are completely different to the sbc gear style. And the oil gallery design as well. They arent a direct comparison like you are trying to make them plus they recycle the bypassed oil also.

 

Polyalphaolefin,

Thank you for the detailed reply.

Next engine build gets a stock volume & stock pressure oil pump. It makes more sense to me now why cavitation can occur at ~ 6,200 rpm in an LS with a crank driven oil pump but doesn't at 6,200 rpm in a traditional small block Chevy with a cam driven oil pump. The SBC would have to be spinning at ~12,400 rpm for the cam drive oil pump to see the same rpm level as the LS pump at 6,200.

 

One other detail,, the new breeds of late model engines, with lightweight piston rings,,
don't handle heavy oil, they will actually over flex just due to the oil on the cylinder walls.

Sure fire way to screw up a new BMW or Honda is to try 20w50..
Ever noticed that Hondas ,, reliable they may be,, you often see them smoking oil out the tail pipe.. ??
I started just asking folks if they were running the stock 0-20 or 0-30 or what,,
MANY of them are running 10-w40 M1 because it was "cheaper" than the synthetic 0-20 Honda or other brand oils..

I've also seen some of the new Formula Ford/Sports racers and bikes that have issues with the thin rings when run with heavy grade oils..

This post is totally non scientific,, undocumented and unproven, likely from scientifically insignificant samples and worth what ya paid for it..

 

Yeah but it sure makes a LOT of sense!

 

How about I pay you double?

 

Yea, General Motors finally admitted the supercharged motor needs a forty. I guess it became impossible for the motor to avoid the gas guzzler tax, so the general finally caved in and recommended the correct oil.