Re: Royal purple = more power???

Ten bucks says Techie is reading this thread through one of the non-Mitsubishi newsgroups. :)

Many dyno tests have proven the horsepower gains from Royal Purple. Whether it's worth it or not, eh.

Oh my.

A multigrade oil has two numbers on it--say 10W30. They mean different things.

The numbers refer to the oil's viscosity, as we all know. "Weight" in this case is slang; if you were to put a quart of 10W30 on a scale next to a quart of 20W50, there might be a few grams difference between the two but nothing to write home about. They measure viscosity with a Saybolt Viscosimeter, which is a bucket with a hole in the bottom of it. Plug up the hole, put in some oil, open the hole and time the oil as it drains. The longer it takes, the higher the viscosity. Compare the time to a table that comes with the viscosimeter and you'll learn the oil's weight.

The "10W" part is the oil's winter (sometimes called "arctic") viscosity. It's measured at 0 degrees celsius. The viscosimeter is different, with a larger hole than the summer viscosimeter, and the table is different--the times are much longer because you're dealing with a fluid the consistency of honey.

The "30" part is the oil's summer viscosity. It's measured at 100 degrees celsius through a viscosimeter with a little hole in it.

(Having said that, all of which is true, the international standards community has gotten involved. Now it's all in metric, and certified by ISO, but the US table's been jiggered around so that 30-weight oil is still 30-weight oil. Europeans always liked their oil spec'd in Saybolt times; I have a Heidelberg press that lists the oil it needs in Saybolt times. Then you call the oil company and ask for some oil with that special rating, and what shows up? Straight 30-weight Shell Rotella T...with an invoice for $425 for a 55-gallon drum. We buy it at Sam's for $257 a drum now.)

You can go to the store, buy a quart of straight-weight oil and run it through the two viscosimeters so you'll have a "multigrade" oil, but it might be 750W30. To solve the problem, everyone's on the right track: take an arctic oil with one viscosity and add polymers to modify the weight/temp curve.

I remember in my misspent youth running into 20W20 Pennzoil. My dad loved 20W20 Pennzoil in his Chrysler for some reason. Now he's into 5W30 Mobil 1.

Oh, the 0W oil? The arctic table does go that low. Why you'd want oil that thin I have no idea.

--jmowreader a fount of useless knowledge

Better quality oil = poorer lubrication? Dude, quit smokin' that stuff!

If you're minimizing your mechanical losses through lubrication, it would follow that you're getting better lubrication than before. Not worse.

--jmowreader