Jump to content
SAU Community

Recommended Posts

Hi Alex,

I'm no expert when it comes to oil but some peoples ideas on this forum (not this thread) can be totally wrong. Remembering oil is a very complex item and in terms of lubrication, there are many tradeoffs from start up lubrication to hot lubrication, and the amount of heat the oil transfers around the car.

In reply to your question Alex the 10w-60 seems ok for Canberra all year round. The manual (for my car and I believe yours) says 7.5-35w oil. So a 5 or 10 weight oil when cold should be fine. The higher number (hot) can generally be as high as you want, if you are racing the 60w is when most people recommend as the oil gets very hot and as you probably know oil thins out the hotter it gets, daily driving 40 is fine as the oil never reaches really high temperatures.

I've been running Shell 5-40w but I will be using the Castrol 10-60w in Summer or for any track days.

I've never changed oil on an RB25 but it can't be as hard as the RB26. Just don't rev the engine to get the last bits of oil out :-)

Link to comment
https://www.sau.com.au/forums/topic/220214-what-oil/#findComment-3884876
Share on other sites

Hi Alex,

I'm no expert when it comes to oil but some peoples ideas on this forum (not this thread) can be totally wrong. Remembering oil is a very complex item and in terms of lubrication, there are many tradeoffs from start up lubrication to hot lubrication, and the amount of heat the oil transfers around the car.

In reply to your question Alex the 10w-60 seems ok for Canberra all year round. The manual (for my car and I believe yours) says 7.5-35w oil. So a 5 or 10 weight oil when cold should be fine. The higher number (hot) can generally be as high as you want, if you are racing the 60w is when most people recommend as the oil gets very hot and as you probably know oil thins out the hotter it gets, daily driving 40 is fine as the oil never reaches really high temperatures.

I've been running Shell 5-40w but I will be using the Castrol 10-60w in Summer or for any track days.

I've never changed oil on an RB25 but it can't be as hard as the RB26. Just don't rev the engine to get the last bits of oil out :-)

an important thing to note, is that while you are definitely correct in using thicker oils in racing, for daily driven purposes using too thick of an oil can be detrimental in the worst cases. certainly with cars like skylines, people want to rev the engine occasionally, however the cars may only be used for 30-40 minutes at a time. if i recall properly the best viscosity for protection at high revs is between 10-15 centistokes. for a 10w-60 oil to reach 15cs it needs to be over 120 degrees C, while 10w40 needs to be over 100degrees C. 10w40 only starts to become too thin over 120degrees.

the problem is at 90 degrees C, 10w60 oil is still 30cs and too thick for revving an engine. high engine speed and high viscosity can lead to foaming and worst of all cavitation

im not an oil expert either, im just saying its important to identify what purpose your oil needs to fulfill, racing protection or daily longevity. for my next oil change ill probably get a synthetic like 5w-40 or 0w40 as the viscosity offers more protection when the car is first started at low temperature. your current shell 5w-40 sounds like a good bet for daily use, perhaps its a good idea to put in thicker oil specifically for a track day, but run the thinner oil when you go back to daily use

Link to comment
https://www.sau.com.au/forums/topic/220214-what-oil/#findComment-3885794
Share on other sites

an important thing to note, is that while you are definitely correct in using thicker oils in racing, for daily driven purposes using too thick of an oil can be detrimental in the worst cases. certainly with cars like skylines, people want to rev the engine occasionally, however the cars may only be used for 30-40 minutes at a time. if i recall properly the best viscosity for protection at high revs is between 10-15 centistokes. for a 10w-60 oil to reach 15cs it needs to be over 120 degrees C, while 10w40 needs to be over 100degrees C. 10w40 only starts to become too thin over 120degrees.

the problem is at 90 degrees C, 10w60 oil is still 30cs and too thick for revving an engine. high engine speed and high viscosity can lead to foaming and worst of all cavitation

im not an oil expert either, im just saying its important to identify what purpose your oil needs to fulfill, racing protection or daily longevity. for my next oil change ill probably get a synthetic like 5w-40 or 0w40 as the viscosity offers more protection when the car is first started at low temperature. your current shell 5w-40 sounds like a good bet for daily use, perhaps its a good idea to put in thicker oil specifically for a track day, but run the thinner oil when you go back to daily use

Hey Zoomzoom sounds like he knows what he's talking about. We had to find someone who could put some science behind it.

Just remember get the oil that is classed as a fully synthetic oil and also remember that different oils of the same rated viscosity can react differently.

I remember a certain mechanic telling me the 5-40 weight oil was too light for the GTR when cold (the 5) and that was why I was having a leakage issue.

Link to comment
https://www.sau.com.au/forums/topic/220214-what-oil/#findComment-3887759
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I'm thinking that this is such a small part of the problem that you could easily forego the vac pump and just achieve 90% of what you need, which is keeping the gate open when off boost. It's not as if there are not already techniques to keep a gate fully closed under boost. After all, you have boost. Just use a wastegate actuator that will allow you to apply the boost on the appropriate side, just like every external gate out there.
    • Heres another fitment photo. redrilled the pattern to 5x112, and threw my audi´s rims on. had to touch the upper control arms with grinder, because the "sharp corner" was sticking about 2-3mm on the tire path. i have the "fender lip" mostly cut off, otherwise these (too) would contact with it. 20x9.5 ET25 rear    265/30 20x8.5 ET20 front    255/30 they are temporary, and look too big for the chassis. searching for 19s to it.
    • From experience, it will come back to bite you haha.
    • Background: my BMW 225i hatchback (rebodied MINI/X1) came with 3x RE003 and 1x Goodyear Asymmetric something. The RE003 roared and slid around, the Goodyear side was quiet and grippy. Definitely my car was thrashed before it got sent to dealers. My brother also got RE003 all round on his old VA WRX STI, I wasn't impressed with them, car was loud so can't comment on noise. Anyway, Hankook stopped making/updating V12 Evo2. So bought S1 Evo3 runflats. Great daily duties tyre and not that harsh ride. Tyre reviews site/youtube rated them as best stopping in the rain and I believe them. Next set, Goodyear Asymmetric 5 non-RFT. It beat PS4 in tests and is like $100 cheaper, so put them on. Great tyre, more grip then S1 Evo3 but a tad noisier as expected, still rocking them. Next set I am looking to go runflats, probably the new Hankook Evo. Although the new Pirelli PZ5 did well in tyrereviews test. Or go Goodyear Asymmetric 6 which was top tyre last year. The V12 Evo2 on my gen5 Liberty GT wagon did great in cold condition (drove to snowy mountains for a day so my husky can feel his ancestor's roots). Super impressive performance for $120 each lol. Never skimp on tyres, brakes, suspension. There's old pics of my R31's crappy random brake pads bending in the caliper at Oran Park track day somewhere around here. Anyway, my 2 cents.
×
×
  • Create New...