When to switch to synthetic?

[fenderwrx]

Hey guys, I want to switch to synthetic ASAP. I have an 07 wrx with 4000 miles, and I'm not sure when to switch to synth...is it 10k miles or less? let me know. Also, what type do you recommend? My friend has an 06 STI and switched to Royal Purple. He said it made a little difference.

[sekretskwirl02]

Now. German Castrol 0-30 synthetic if you can find it or Amsoil 5-30. Redline 5-30/40. I love the Casrol. AND I'm not big on Royal Purple Synthetic either. Go to 'Bob the Oil Man's' website and you'll learn all you'll ever need to know about 'fluids' and which brands are the real deal.

[rr1911]

you can switch when ever pretty much

[SD_GR]

Here's mine; this oil is now sold as Mobil1 TurboDiesel 5W-40 or Mobil Delvac1, and I've since switched to Mobil1 0W-40 European Car formula instead:
Synthetic oil data: Mobil 1 used in 2.0L stock motor
either of those M1s will protect your motor but neither will meet your warranty requirements, as one is the wrong API class and the other is the wrong viscosity. I'm past that stage so I don't care, but you're under warranty so follow the book Subaru gave you religiously. Seriously.

Here is older, SL formula M1 5W-30 (they've now moved to several varieties of SM formula):
Another Blackstone Oil Analysis
and another:
OIL Analysis Results - I'm so happy now !!!

Here's Motul 5W-40:
Motul 300V 5W40 oil analysis

... and so on.

[sekretskwirl02]

^+1 to someone who knows good oils.