Engine oil AMSOIL or IDEMITSU

0W-20 Amsoil Signature Series 100% synthetic oil changed every 5k miles. Wix 57173XP filter.

As an avid user of AMSOIL, it’s a noticeable difference, amsoil is the king

With Amsoil even if it's not signature series I trust it more than any other 0w8.

I run Amsoil and my oil change interval is 25k so the answer is it depends.

I only use Amsoil Signature Series in my B58.

I changed to that and really happy with it so far, shifting is butter smooth.

Based on my own tests, I found the AmsOil to be the best at reducing heat a few degrees. It's not cheap, but it's still cheap insurance, all things considered.

I use Amsoil 20w50 in all 3. You don’t need a different oil for the trans. Amsoil is not cheap but I’ve been using it on my 03 FatBoy since new and have had no problems.

i use amsoil saber when i have it but not at 100:1 I don't really care if the engineer says its fine.

im actually running that oil right now... I hate it tbh. 3,100 on the oil and it has allowed excess engine noise since day one, SUPER harsh cold starts, and now its burning through faster than the catrol I ran when I first got the car. a WHOLE QUART over 750 miles. the oil is thinner than piss going in, and it just doesnt stand up to what my engine can put out like Shell Rotella T6 has been doing...