Originally Posted By: Guitarman200806
I have the engine you are talking about that is spec'd for the 30w oil. I have the k20z3 in my 07 si and just posted a UOA thread using amsoil ss 0w30. My car seems to do fine on a 30 weight. I did 8k street miles and 20+ drag strip passes along with 8200 rpm shifting and my wear metals are low compared to yours. I think the wear in your report is a little high for a k series, but not troubling. I'd stick with a 0w30 in the k24. Check out my report in this section if you want to compare.
Thanks guitarman for your input. I looked at your results and it looks like you have had pretty good results with the 0w30 you run. I think two factors make a comparison of your UOA vs mine different. First, I saw that you have ~90k miles on your engine, whereas my engine is around ~20k miles. I would imagine that this difference will play a part in how much metal is being thrown off each OCI. Second, I noticed that you added 1.25qts of makeup oil, which could be substantially helping your UOA as this oil is newer than the original oil that was used at the time of your oil change (that's around 25% of your total motor oil capacity).
Overall, I do agree that 0w30 is a great choice for these motors. In my particular instance, I was using 0w30 M1 AFE and noticed that it sheared a bit too much for my taste. This might be a specific issue to the larger 2.4L engine vs the 2.0 liter in your Si. It could also just be that the M1 AFE is light to begin with.. The Amsoil stuff looks pretty stout..