Originally Posted By: CATERHAM
Garak a nicely summed up and correct history lesson but it has nothing do do with this thread. That's why Shannow off topic remarks are confusing;
I think the lack of the historical content is the only thing that could have been confusing in the least. Shannow's point was clear. Your point about the HTHS 3.5 oils was clear. The point about HTHS versus operational viscosity is clear.
Of course, the real query is what HTHS would be sufficient for this vehicle, and significant differences can be found within the 30 grade, for instance.
Shannow: As odd as it may seem to be concerned with adding oil cooling at this point in the game, it may be a very reasonable point. In my G, for example, most performance upgrades also strongly suggest additional oil cooling (of which there are many, many direct fit options), since high oil temperatures will result in limp mode, so just going thicker in isolation won't do the trick. Of course, the G37 and 370Z have some very high oil temperatures with even conservative driving, so it's "easier" to trip the limp mode. That may not be the case with the BRZ; there could be sufficient reserve cooling from the factory. But, I think that from now on, when improving performance of a vehicle, oil cooling is going to have to be considered as much as oil grade. Many professionals consider this, but there are plenty of people who don't, and at their own peril, from a performance and longevity perspective.
As for ElastoHydro's and jrustles' arguments on oil coolers, do recall that some on the market are thermostatically controlled and others are not.
