I was looking at an old post on one of the Honda Civic forums recently. The conversation pertained to Japanese engines which can run 30 wt oils. Many of the members were explaining why thinner oils such as Mobil 1 were preferred in their engines over Castrol Syntec 0W30. Basically the argument goes as followed:
"Most German engines generally utilize a unique, low friction piston; which results in better performance, fuel mileage and higher efficiency. Their engines have larger piston ring gaps (clearances), and consequently, more engine blowby. So a thicker oil is needed to retain a lower visosity at higher temperatures.
Most Japanese engines have tighter specifications and clearances. The engines are economy green based. So thicker 30wt oils like GC does not work as well. The engines are not as "rev happy" in the upper rpm zones as thinner oils like Mobil 1. GC, makes these engines sluggish and lose fuel economy. GC should be used only if you have one of the few Hondas with a turbo."
My questions to anyone with a Japanese engine who has run both:
1) What is this "economy green based" design mean?
2) Any truth to the low friction piston statement?
3) Any truth to the less "rev happy" statement?
4) In general, have you had a better UAO with GC than thinner oils like Mobil 1?
"Most German engines generally utilize a unique, low friction piston; which results in better performance, fuel mileage and higher efficiency. Their engines have larger piston ring gaps (clearances), and consequently, more engine blowby. So a thicker oil is needed to retain a lower visosity at higher temperatures.
Most Japanese engines have tighter specifications and clearances. The engines are economy green based. So thicker 30wt oils like GC does not work as well. The engines are not as "rev happy" in the upper rpm zones as thinner oils like Mobil 1. GC, makes these engines sluggish and lose fuel economy. GC should be used only if you have one of the few Hondas with a turbo."
My questions to anyone with a Japanese engine who has run both:
1) What is this "economy green based" design mean?
2) Any truth to the low friction piston statement?
3) Any truth to the less "rev happy" statement?
4) In general, have you had a better UAO with GC than thinner oils like Mobil 1?