Skyline Rb20 Recommended API Oil rating

[Supraclean]

Hey guys,

Im looking at running some amsoil 10-40 Full synthetic this year and a local dealer figured I should find out what the recommended API stock rating for the engine would be. I thought Skym said 10-60 is from factory but obvously a lil much for Canada climate/ summer driving for me.

What wondering if anyone had those specs or run 10-40 atm. I had 5-30 Royal purple last year but wanted to step up to a thicker weight.

Thankyou ahead of time.

[M13]

read this entire thing:

http://my350z.com/forum/engine-and-drivetrain/258663-vq-oil-analysis-and-info.html

0-40 and 5-40.


/thread

[Supraclean]

Damn good post Mike. Thankyou for sharing, my workplace will be happy I was getn paid to read up on oil

[Skym]

Factory is meant to be 7.5W30. But it says 5W30 on sticker from factory (side of centre console) on my car. I guess the 5W or 10W is close to 7.5W and why they are used for cold start.

I ran the recommended 10W60 and found out it was wrong for my cars engine and even 15W50 (other recommended oil) was wrong (both are too thick). Supposedly 10W60 is the old way of thinking with high oil temps and can actually damage your engine if driven hard (oil fails to get to bearings at higher rpm because it's too thick with cst rating).

I learnt you need to look at oil temperature, cst rating (cst rating at 100 degrees) for your cars engine. This will vary depending on level of mods. Intake, exhaust on RB20DET is around 93 degrees in oiltemp after a drive, so W40 is more than enough. Factory car is alot less with oiltemps, so W30 suits.

Opie Oil guys (oil experts) explain it in a easy to understand way in their 10W60 PDF with cst rating -

http://www.opieoils.co.uk/pdfs/tech-articles/10w-60-oil.pdf

The way I worked it out is I looked at the cst rating for factory W30 in above PDF at 100 degrees and aim for that with the cst rating at oil temps my car was reaching. The 10W40 suited my cars RB20DET and changed it to that. Result was engine ran smoother at idle, better throttle response (first thing I noticed), better cold start, etc. Bingo.

Without a oiltemp gauge your only guessing what your engine wants. Normally RB20DET engine on racetrack is around 100-120 degree range, so W50 suits.

Also that's in degree celcius. From what I understand, most oil guys use cst rating as it's universal.

[DreadedFist]

I'm running german castrol 0w30 right now and love it. For summer I'll be going to 5w40. First thing I noticed when switching to a 0w oil is that cold startups are much, much easier. The OEM oil press. gauge also registers quickly. The engine used to stumble and require a blip of the gas to get started when I had 10w40. Someone who's opinion I trust is why I'm running a 0W oil, and couldn't be happier. Feels good knowing the engine is getting fast lubrication on startup.

Didn't notice any excessive noise or anything like that with the 0W either, once the engine is up to operating temp the 0 doesn't matter anymore anyway, it's running at whatever the second number is.

Forever a 0W fanboy.

[esh]

I went from Royal Purple 5w30 to Amsoil Dominator 15w50 last summer....the engine felt kind of sluggish with the change. So this spring so far its been royal purple 10w40 (partly cuz it was on sale lol). So far so good, but I still want to try others