10w30 oil on a BPU

[RB-GTE]

My mechanic which owns a 750bhp Supra. Claims he runs 10w30 synthetic oil, and for my new oil change he said he can just use 10w30... and I'll be BPU next week with full decat and everything. I know that 10w30 is the stock engine oil, I thought if I'm running a lot more power I need to run a thinner oil? Anyone have some insight on this? This is just a daily driven street car.

 

I do spirited hard driving once in a while but no track or anything too competitive.

Edited September 20, 2012 by RB-GTE (see edit history)

[jimojameso]

I'd recommend a 5w-50 oil for bpu matey.

 

Read this thread:

http://www.mkivsupra.net/vbb/showthread.php?56684-FAQ-Oil-Fluid-Interval-Capacity-Steering-Brake-Coolant-Diff-Engine

Edited September 20, 2012 by jimojameso (see edit history)

[Lee P]

I put millers 10w60 in all supras now. Only oil I would use, 10w50 would be minimum.

[mark newman]

10w60

[Alex]

Thin-ness. The 0-10w rating is more to do with cold start protection, getting the oil in the right places fast. Lots of short journey's look at thinner oil than 10w.. Other wise stick to it.

Edited September 21, 2012 by Alex (see edit history)

[Tricky-Ricky]

Thin-ness. The 0-10w rating is more to do with cold start protection, getting the oil in the right places fast. Lots of short journy's look at thinner oil than 10w.. Other wise stick to it.

 

The 2nd number is the sheer resistance, effectively the strength of the oil to resist breaking down over time. 30 would need changing quite often in a high HP engine.... 60 should give you a much larger service window and peace of mind that it won't breakdown even with track work.

 

The actual choice of oil has been discussed to death. I stick to Fuchs Pro S others Millers etc up to you.

 

 

Really!? i was always under the apparent misconception that the second figure referred to the hot viscosity rather than the first cold viscosity figure?

Now i know that the shear factor is an important one, but i didn't think the actual figure as in 10W40 reflected this alone.

 

 

I put millers 10w60 in all supras now. Only oil I would use, 10w50 would be minimum.

 

Can you tell me why? i see the use of what i thought was the hot viscosity ( see above) more and more, and to my mind if you increase the hot viscosity of an oil yes its likely to have higher sheer, but it also increases the pumping (hydraulic force) side of things too, so the oil pump works harder, and the oil pressure increase's as well which is not always a good thing as if std oil pressure relief valves are used they will be trying to bleed off a lot of the over pressure at certain RPMs and temperatures,

The other thing that comes to mind is the fact that a higher viscosity oil will also add more resistance to moving / reciprocating parts, and if you are raising the RPM limit in a tuned engine thicker oil is the last thing you want as it add to the overall dynamic stress.

 

I see a lot of people over on the Skyline forum advocating 10W50-60 oils and the RBs suffer from oil pump problems with the crank nose being too small and so failing, just why you would use a higher viscosity oil which increases the hydraulic force is beyond me.

[Alex]

Really!? i was always under the apparent misconception that the second figure referred to the hot viscosity rather than the first cold viscosity figure?

Now i know that the shear factor is an important one, but i didn't think the actual figure as in 10W40 reflected this alone.

 

It probably reflects a number of factors...but that's one of them - best to ask OilMan for a fuller explaination - infact I think there's one on here...

[bodilx6]

All sorts of BS is going on in this thread. Everything from incorrect references to what ##W-## actually means to unsupported reccomendations.

Correct that 10w-30 is the reccomended viscosity, but remember that is 20 years ago and semi synthentic. Today you would probably use a synthetic. Massive difference. Especially in longevity and "stretch" of the oil.

And where does the fact that "60" mean breakdown resistance come from? The ##W-## is just a stement of viscosity. Thats it. That you might be able to generalize a certain viscosity haveing better resistance to the breakdown of the oil might have some trouth to it though. But still a generalization.

 

As mentioned above, I also remember a very good explanation for most of the above posters to read. Another is this:

10w-60-oil.pdf

Edited September 21, 2012 by bodilx6 (see edit history)

[Alex]

Cheers for the PDF. Think I'll go for a 10w40 Ester if I can find one, based on my state of tune.

 

Edited my post to remove cr@p info...

[Tricky-Ricky]

All sorts of BS is going on in this thread. Everything from incorrect references to what ##W-## actually means to unsupported reccomendations.

Correct that 10w-30 is the reccomended viscosity, but remember that is 20 years ago and semi synthentic. Today you would probably use a synthetic. Massive difference. Especially in longevity and "stretch" of the oil.

And where does the fact that "60" mean breakdown resistance come from? The ##W-## is just a stement of viscosity. Thats it. That you might be able to generalize a certain viscosity haveing better resistance to the breakdown of the oil might have some trouth to it though. But still a generalization.

 

As mentioned above, I also remember a very good explanation for most of the above posters to read. Another is this:

 

Thought i hadn't got it too far wrong! and in theory being his business oilman should know what hes talking about.