When is it time to change to synthetic oil?

[88fivepointoh]

well using 3 months 3000 miles, I would change it.. I like that royal purple that just came out... It seems to quiet noisy lifters on some cars, its pretty neat, purple oil, all synthetic. if your hard on the motor change it often, i mean they say sythetic you can go to 5000miles, I would never do that.. i used to change mine every 1500 as well. if you race it on the track 10W40 or 20W50 is best.. I would go 20W50 just becuase Synthetic oils are generaly thinner then conventinal oils so a 20w50 synthetic is more or less, a 10w40 weight oil. I used 20w50 and it works great.