no idea, i use the new pennzoil ultra. apparently it's the new good stuff

 

Not really true. Some additives are controlled by the API, others up to the blender. But basestock plays a large roll as well.

Most synthetics on the market today use a highly hydroprocessed mineral oil classified as Group III basestock by the API and allowed to be labeled as "synthetic" by the NAD. AMSOIL's SAE Synthetics use a Group IV basestock (polyalphaolefins or PAO) but nothing prevents any oil company from using them. AMSOIL's lower cost synthetics (OE and XL lines) use a Group III synthetic basestock similar to what most others use. Royal Purple doesn't state what they use. Red Line uses a Group V polyol ester basestock.

The additives primarly consist of anti-wear additives, detergents and disperspants. The detergents and dispersants are not limited by the API and this is where you see a large difference between oils, generally with those recommended for longer drain intervals with more. The primary anti-wear additive is ZDDP, or Zinc dialkyl dithio phosphate. Due to the phosphorus' impact on catalytic conveters, the API limits the maximum phosphorus to 800 ppm in API SM and SN 30 grade oils. It also limits the minimum to 600 ppm, essentially putting both a floor and a cap on the most common anti-wear additives. For comparison, API SL, the spec in existance when the C5 was made, allowed 1000 ppm phosphorus. What the oil companies due to offset the loss of ZDDP is a closely held secret.

For those will to stray from API SM/SN oils, higher levels of ZDDP can be found.

For example, many use diesel oils to get around this limit. AMSOIL has a 30 grade diesel oil with high levels of ZDDP:
AMSOIL Series 3000 Synthetic 5w30 Heavy Duty Diesel Oil
(Product Code HDDQT)
(zinc – 1379 ppm, phosphorus 1266 ppm)

I personally use AMSOIL's racing oil, which has no detergents or dispersants, but very high levels of ZDDP:
AMSOIL Dominator Synthetic 10w30 Racing Motor Oil
(Product Code RD30QT)
(zinc – 1575 ppm, phosphorus 1474 ppm)

All in all, there is a large variance in oils, both in the basestock and the additive levels. Some by choice, some by regulation.

 

I only use Mobil 1 in all my cars. Then again I have stock in Exxon Mobil.

 

I've used Edge for the last 2 oil changes.
Their claims of 8x better wear protection are probably pretty much B.S.,but hey, if it's really only 2x,I figure it couldn't hurt...
And the price is pretty right at Wallyworld

 

Thank you for the heads up. I will switch to Castro Edge on my next oil change.

 

I have considered changing to Castrol Edge (hate that thinking with your dipstick ad). You apparently had an oil analysis to determine the improvement in the lead ppm ratio.

What I would like to know is what criteria does Castrol use in determining their claims of 8X better wear protection? If this is fact then the other companies will need to get on the stick or risk losing many customers.

 

Mobil 1 at 3K I consider is on the edge of cheap insurance, anything over that I figure is overkill, I suppose, heh, heh. Really, when you change as often as I do I don't feel the need for an oil that's 8X better. I'm just **** about oil. I use really good oil filters, too. There's a lot of things this old man does that don't make a hell of a lot of sense.

 

I used it on my last oil change a few weeks ago .
I like royal purple too .

 

Subdriver, do you use that racing oil in your DD also?

-Alex

 

I switched to Edge 5/30W last two changes. Engine has 109K on it and I think I'll try 10/40W on my next change just to see if it makes any difference.

 

i used it for awhile but then just went back to mobile 1 since thats what the cars says so you cant go wrong there. didnt notice any differance between the 2 oils

 

There is a test that uses a car engine, they run it for so many hours and measure wear on the cam. Now, as with any test, you can have a unusual single data point, not saying that they did, but it is possible.

 

No - my last real daily driver was an 06 CTS-V (LS2 engine) and I ran AMSOIL's best API SM (now SN) oil, the Signature Series 0w30 which complies with the API limits on phosphorus. But, I never tracked that car and I drove it relatively sanely. I sold that car after three years when I moved to DC and with two daughters now in their driving years and with college looming, I haven't replaced it. I'm currently driving our SUV, an 03 Chevy Trailblazer with the 5.3L V-8 for my DC commute. For that, I've been using the same 0w30 has I had a few extra cases after I sold the V.

If I had a Corvette daily driver and didn't track it, I'd probably use the same Signature Series 0w30 I did in my V.

 

Sounds good. But why 0w30?

-Alex

 

I've been a loyal Castrol user for as long as I can remember. I used to use Castrol Syntec which did meet the GM spec. Then they came out with Edge at a higher price. At the same time the Syntec no longer carried the GM spec on the label. So I figured it was a marketing ploy to force Syntec users to the Edge brand. This ticked me off and I switched to Penzsoil Synthetic for a couple oil changes. After awhile Walmart dropped the price of Edge and that's when I went back to Castrol. It didn't do anything but I know it's in there.

 

I use Mobil 1 in all 3 cars and change it once a year or 6K which ever comes first.

 

This is the oil I used:
AMSOIL Signature Series Synthetic 0w30 (Product Code SSOQT)

This is AMSOIL's best API spec 30 grade oil and it only comes in 0w30.

As to why it is a 0w vice a 5w I don't know, but suspect that the 0w comes for free given its high quality synthetic basestock. There really isn't that much difference between a 0wX and a 5wX other than the kinematic viscosity at really cold temps (-30 to -35C). How this is achieved is another matter. Lower quality oils need to use large amounts of viscosity improvers to increase the spread in rating between cold and hot ratings, but that isn't so for the better synthetics. The problem with viscosity improvers is that they can rapidly shear down resulting in a loss of viscosity of the fluid.

As examples of how minor the difference is between AMSOIL's Sig Series 0w30 and AMSOIL's very similar SAE Synthetic 5w30:

100F viscosity
0w30: 56.5 cSt
5w30: 60.7 cSt

212F vicosity (the 30 grade rating)
0w30: 10.3 cSt
5w30: 10.8 cSt

300F viscosity (High Temp High Shear rating)
0w30: 3.2 cSt
5w30: 3.2 cSt

Cold Pour Point
0w30: -60F
5w30: -58F

I think the practical benefit of the 0w30 is that it has a flatter viscosity curve (if you plotted viscosity vs. temp) and thus it is going to flow better when the oil is cold, minimizing wear during engine and oil warmup, but provides the same high temp protection.

FYI, the specification to achieve a 0w rating is a maximum cold cranking viscosity of 6200 at -35C. For 5w it is 6600 at -30C.

 

Man and I thought I was doing perfect with their 5w30 LOL. I think for my stock LS1 I'll stick with that. Maybe once the swap build begins I will switch to their 0w30. Thanks Sub

-Alex

 

I would not lose any sleep over using the 5w30. I get asked that question a lot (e.g. which of these two oils to use) and they are so close it almost comes down the personal preference. I chose the 0w30 because it is just a little bit better... and well, that was enough for me.

 

I changed my oil to Castrol Edge a month before the whole BP thing in the Gulf.

I wanted to try Amsoil and things were going from bad to worse for BP so for my next oil change I switched to Amsoil and I like it so far.