Oil Recommendation: 2004 Lexus IS300 Turbo

[CATERHAM]

Additional boost (you didn't say how much) usually doesn't increase oil temp's much for street use.
In all likelyhood, a quality 5w30 syn would still be more than fine.
Rotella T6 is without doubt heavier than necessary but it won't do any harm in your climate although you may find the car sluggish when cold.
You really should install an oil pressure gauge in a modified engine as that's the only way to know what you're doing when you start experimenting with different grade oils.

 

[afree]

Thanks for the input. Im currently running relatively low boost (7-8 PSI). For those that don't know, the IS300 has a 2JZ-GE motor (N/A version of the Toyota Supra's 2JZ-GTE engine. Twin turbo, different cylinder head and pistons/rods). Thought this may help a bit. And I hopefully will be installing an oil pressure gauge soon since this seems to be an important factor in choosing oil.

 

[dailydriver]

Originally Posted By: afree
Thanks for the input. Im currently running relatively low boost (7-8 PSI). For those that don't know, the IS300 has a 2JZ-GE motor (N/A version of the Toyota Supra's 2JZ-GTE engine. Twin turbo, different cylinder head and pistons/rods). Thought this may help a bit. And I hopefully will be installing an oil pressure gauge soon since this seems to be an important factor in choosing oil.


What's the max boost anyone has pushed through the GEs, before grenading them, without building the bottom end at least to GTE specs/strengths (including all of the other 'band aids'; meth injection, chilled intercooler, thicker head gasket, etc.) ??