I've been reading thru older posts on this board, looking for information about use of 50+ weight oils in racing application. As you can imagine, there is an abundance of posts that cover alot of the details, but getting a good summary is often difficult.
Here is my situation, and I would love to hear your guys feedback. I have a 2002 Subaru WRX, with relativly heavy modifications (about 480crank hp, 377 wheel hp from 2.0Ls at 24psi).
[see www.wrxworld.com for videos, etc]
I'm looking for a good oil to run, given then constraints of the car use. I drive the car on the street occasionally, but not every day. I race the car quite a bit in the summer months, and usually have 10-20 days of track time in by the end of the season. (road track racing, 20-30 min full throttle sessions). Oil Temps at on the track are right at 110-112 deg C, and crusing around town they are about 95C.
My primary concerns are good protection of the internals during hard use. I'm running a pretty large turbo, with 24+psi of boost, plus 100 octane race gas. I'm not really concerned too much about wear, as I will rebuild the motor within 30-40k miles. I don't mind waiting for the car to warm up before driving it, and the temperature here doesn't go below 32 except for a few days of the year. Change interval is not a big deal, as I usually change the oil once every 3-4 track days, which is usually about 3k miles or every 2 months.
With all of this in mind, it would seem like I would get better protection from a 15w50 or 20w50 synthetic oil. Most stock WRX guys run Mobil 1 10w30. The oil is also a factor for the turbo, since the engine oil is the primary lubricant for the turbine.
Any opinions on this kind of application? I would still be interested in doing some oil analysis after a race to see how things are looking of course.
Jeff Sponaugle