H Ken..you are right on the new Mobil-1 site the cst @100*C is 17.7. M-1 15W-50 is 18.

I think some reformultaing has been done. Too bad.

That's why bike racers are moving on to Motul 15W-50 as they say M-1 V-Twin is shearing in endurance racing.

Some are also going to Amsoil 20W-50 V-Twin which has a cst of 20 @100*C.

Redline 20W-50 or 15W-50 is a great choice too.

Noting stays the same forever I guess...

I've been using synthetic in my 525 but it seems to be burning through a lot of oil...any idea what would be causing that?

I run it hard in spurts, but I'm not sitting on it at WOT all the time.

First things first, what are you using? How much are you burning, how often?

Using Mobil 1 Synthetic 15W 50. I went through 2+ qrts in about 20 hrs

Try Amsoil V-Twin 20W-50 I think your consumption will go down. It has a tendency to seal around pistons very well.

http://www.amsoil.com/storefront/mcv.aspx

I went that route myself on my other boat.
It will help somewhat with consumption.
My big blocks have always had this thing where you check oil level even after blasting and things are OK.
Then a fews days later it will have taken a drink.
Nature of the beast.......
d

Yea, I think Bob likes Amsoil.

He uses the new 15w-50 Dominator Racing Oil and the SVT 75w-110 Gear Lube

He does now........
Damn I could use a free T-shirt

Amsoil is making it's way to the very top of synthetics..they are taking things very seriously.

They have an outstanding line. I would use any of their products with confidence.