RazorV3

you have to factor in the condition of the whole drivetrain as well (from the transmission to the diff and everything in between).

xviper

Like I already said, oil temp is linked to coolant temp. Honda knows this and most people who have or have had oil temp gauges in other cars already know this. Honda didn't have to calculate this (although I'll bet they have confirmed this in some way). I don't have an oil temp gauge because I don't need to know what the oil temp is. It has nothing to do with Honda being "cheap" (although they are). When the coolant temp has reached 140 degrees, the oil temp will be xxx degrees. If it's cold out, it will take "Y+a" minutes for the coolant to get to 140 degrees. Because the engine is encased in coolant passages and the oil runs through the engine and even the oil filter base has a coolant jacket, the oil temp will be xxx degrees in "Y+a" minutes. If it's hot out when you first start the car, it will take much less time for the coolant to reach 140 degrees, say "Y" minutes. In "Y" minutes, the oil temp will still be xxx degrees since it too, started out at the same temp as the coolant at the time of engine start. I believe that Honda has determined that when the oil reaches xxx degrees, it will flow quite adequately enough to do its job to 9000 rpm.

If Honda went to the trouble of putting in a cold rev limiter, why did they decide on 140 degrees of coolant if they didn't think the corresponding oil temp was adequate? Why not set the limit for when the coolant temp is 160 degrees? 170 degrees? It would have been simple enough.

Worst case scenario: Let's say that oil temp lagged behind quite a bit (and I doubt it lags more than 20 degrees behind) and at 140* coolant temp, the oil temp is only 100*. That's just over body temp. I think oil of the recommended viscosity for this car at body temp will flow and protect quite well. But nevermind. Forget about my "goofy" logic as depicted in this paragraph. Just consider the logic of my first two paragraphs.

As for the tranny and diff fluid, assuming you're not just sitting there idling, these too, will increase in temp. I can tell you that in a warmish day, the diff temp will climb about 10*C in the first 10 to 15 minutes. Since the diff fluid is not pumped and the tranny fluid is pumped at very low pressure, these don't have to be very warm to work properly.

ps. I've never had to think so much and type so much over something that is so trivial and uncomplicated.

xviper

And again, you don't think Honda engineers thought of this? They're not just engine engineers. They are also "mechanical" engineers, fluid dynamics engineers, thermodynamics engineers. Please see my previous post.

BTW, IMO, transmissions and rear diffs, by virtue of the fact that oil is either not pumped or pumped at very low pressures, they can operate quite comfortable at temperatures extremes both cold and hot. Really, all you need is for the "bathed" parts to grab onto the fluid and move it around for the fluid to begin lubricating and protecting. Crankcase oil has a temperature limiting factor by virtue of some of the immense pressures attained during highly viscous pumping. As high as 95 to 100 psi on cold start on a -25*C day. This pressure comes down fairly quickly after about 10 minutes running - about the same time that we get 3 bars.