ummm..the rev limiter on the m5 is to protect the engine due to the lack of lubrication from thick oil when it is cold and oil breaking down when it is too hot. thats not a good example of how a car running 240f will make less hp than a car running 200f under the same exact condition. ecu doesnt pull timing or trim fuel directly based on the oil temperature, you can say how it might change the cvtc's function or how it can increase water temp and consequently it might lead to timing being pulled due to higher water temp or different afm reading. i have my own set of data from my car, i still dont see any power drop from the first lap to the last lap. plug a datalogger in your car and see, you will be amazed the difference is not big.

detontation? knock sensor backing timing due to heat?

I don't want to argue about why the m5 does what it does that wasn't the point. The point is that there are many cars that have an ecu that have parameters and limits based on oil temps. Those parameters and their purpose will vary from one vehicle to another. As for your car and your data... Enjoy it, I don't really take it as any worthwhile information. I will rather take the word of industry professionals who have said so, and my own experiences that also prove it.

If you think you have nothing to gain by cooling your oil, than go ahead and run it as hot as you like. There's nothing left to debate. I hear you clearly that you don't wish to believe it, that's just fine with me. Carry on, there isn't anything left to say about it.

+rep

You made your points, I am simply stating the flaw to some of what you said. I would never dare to question experts like you or other professionals at some speedshops. What do I know? I am just a hack who happens to carry a little computer that tells me what is faster and what isn't. I am sure my timing program isn't as good as some guy who works on cars for a living. It's just such a bad idea to collect data at the track, better to keep it on the dyno or in the shop.

I do have a question. Since you are preaching about how wonderful overcooling your oil is, how come M5 has a mode to limit your revs when the oil is too cold?

I have the Setrab 25 Row with thermostat oil sandwich plate. Works great. Got mine from Z1.

I guess it would be easy enough to test on the dyno, just disconnect the oil temp sensor and connect a variable 5V source. You can then dial in any temperature you want to test what the ECU does at a given "fake" oil temp vs a real world temp.

I am not a professional, remember none of my data matters even though it is collected by a computer.

On my logs from May, the car had almost the same acceleration on lap 1 as lap 8 (difference of .32mph on average in the acceleration range). At 250-260F, I was surprised my Prius didn't pass my Z down the straight.

Nobody recommends overcooling the oil. M5 limits rev when oil is too cold because the oil is too cold.

Unless you build a block off plate or live in the south, you can't run too large of an oil cooler without the oil being overcooled in the winter. One of the thermostatic adapter plate is not going to cut it, you need the H type oil thermostat.

agreed, even with just my 25 row and the mocal thermostat, i can wind up with my oil being too cold.

you probably know that the mocal thermostat is not 100% bypass, it just has a passage that opens inside allowing a path of lower resistence for the oil. in turn, it only reduces how much is passing through the cooler rather than diverting it completely.

what i have found works for me, but is not always going to be a realistic option for everyone else... i let my car warm up before i drive it. if i just do what i did before the cooler, which was start driving it as soon as the coolant temp was a few "dots" up, then it ends up taking FOREVER for the oil to get up to operating temp. But if I let the oil temp begin to register on the stock gauge before i begin driving, then it finishs warm up rather quickly as i drive it nice. even on the coldest nights the only time i end up overcooling the oil, once the engine is heat soaked from driving a little bit, is if im cruising at like 70 on the highway in 6th gear for 15-20 straight just practically idling along... but even then i dont recall seeing it ever drop below 170 although it may have.

one of these days i want to research trying to build some sort of setup that uses a second 25 row off another thermostat. i would like to run it parallel to the primary cooler (in terms of plumbing, rather than in a series), but see if i can figure out a way to have it not open pretty much at all until something like 200-220. its been in my head, but i havent looked into what type of components may be available to accomplish this. i wouldnt want to do it if it became as complicated as having to use some sort of solenoid or motor valve and switched by a sensor or anything like that. i want it to use some sort of typical expansion thermostat.

I believe the Mocal can only bypass 90 or 98% of the oil. I have that adapter, that's why I said the oil will probably not come up to temp in cold winter days. 31R or 31R plus is nice, but it's not for everyone who has to drive the car on the street (especially people who lives in the snow belt).

Ya... Since it's just an internal passage that opens and closes, but has nothing that limits flow to the cooler... How much oil that bypasses the cooler is probably a function of resistance through the cooler.. So -10 lines and a -32 row might bypass a lot less than say -8 lines and an 18 row.

I've noticed this too. Funny thing but logical. I always give it 10 to do it's business.

It probably isn't necessary to wait for the oil temps to rise for normal street driving. The Ester oil, or any good synthetic 5W-30 flows well at fairly low temps. 5W refers to winter viscosity for a multi-viscosity oil. According to ehow.com, 5 weight oil will pour properly at -40 deg. F. That means you will get good enough lubrication for road use in most places. The 30 refers to viscosity at 212 deg F (100 deg C).