davidc1

OK, I stand corrected. And while I do know that S2k's run hotter oil temps than many cars, from what the experts tell me, 270degrees is nothing to worry about in a typical session. Even 290, for 20 minutes, 4 times in a day, is not a big deal.

They said (mostly Lake Speed, Jr., on of the foremost racing lubrication specialists in the country), that these temps are not a problem unless you are racing, or constantly tracking your car. You then might want to lower them for increased engine longevity. Again, the average syn oil and engine can handle 300degrees for short periods.

Driven

Recently added an oil cooler (28 Row) and did a track day yesterday. New data:

Car: F22C
Mods: Stock oil pan, custom baffle, Mishimoto radiator, 28 row oil cooler mounted in front of radiator...removed OEM oil cooler
Oil: 10w40 Synthetic
Water: Distilled with a bottle of water wetter

Oil Pressure (about 5psi drop across the board)
@Idle; Start up: 50-60psi
@Idle; At Temp (180'): 10-15psi
@3000RPM, Stable Throttle: 80-90psi
@WOT: 80-90psi, with a noticeable dip at VTEC engagement

Oil Temp (55' avg):
@Idle: 110'
@3000RPM, Stable Throttle: 150'
@WOT: 210'
* Oil temp never peaked above 210'; 80mph speeds cruising kept oil temps at 170 or under.

Water Temp (55' Vegas weather):
@Idle: 190-195'
@3000RPM, Stable Throttle: 200-210'
@WOT: 215'-220'
* water temp hasn't shifted whatsoever. Whether it's freezing outside or hot as balls... temp stays exactly the same.


My sensor locations:
Oil pressure - sandwich adapter at oil filter
Oil temp - sandwich adapter at oil filter
Water temp - freeze plug on exhaust side of block

az3ar

If you value your S2000 engine install an oil cooler. Take it from someone who has over 15K of track miles on his S2000 and still running with excellent Compression and leak down test.

Ideal Oil temps are in the 230/240. It does not matter what kind of oil you use, this is miss information that I keep hearing.

spdracerut

I'll add to this a bit with my thoughts. I think it is true that some oils will not have significant break-down when operating at 300F; some oils will still maintain its properties better than others when exposed to those temperatures.

HOWEVER, that's not to say that even the good oils won't become super thin loosing their viscosity at higher temperatures.

I found this chart online. In everyday conditions, the oil is between 90C-100C on the S2000. So 194F-212F. Standard fill is 10w-30 looks to have a viscosity of 12 cSt at 210F. This should be our baseline for ideal operation. At 280F, the viscosity of 10W-30 drops to about 7 cSt and that is an easily reached temperature for S2000s without oil coolers. Not good. The oil pressure drops quite a bit with the oil that hot with that low of viscosity. That's why before I installed an oil cooler, I only used 15W-50 at the track as the viscosity and oil pressure stays higher at almost 10.

So regardless of the quality of the oil in the engine, if it's cooking at over 280F and only 10W-30 then the viscosity could be too low for proper protection against metal-on-metal contact.

Unbr3akable

Interesting discussion. I would log oil temps and go from there, no point in needlessly adding an oil cooler with wishful thinking. Murphy's law works overtime, I'd rather keep everything as simple as possible.
Like someone already pointed out, the dips in my oil pressure are from VTEC engagement. My engine has 100k and has been tracked frequently since 40k with R-compounds. Engine health is spot on.

I'm a bit rusty on my hydrodynamics for thin films but I'll give it a shot:
Journal bearings work on the basis of a thin, high-pressure, film for metal-to-metal separation. The pressure of this film is what keeps the journal "floating". The hydrodynamic pressure of this film decreases with decreasing viscosity (decreasing velocity gradient). So as the temperature of our oil increases, the viscosity decreases, the film's pressure decreases, and the chances of metal-to-metal contact increase.
Finding the "critical" viscosity/temperature - for a given oil and condition - would not be a trivial calculation... but the brains at Honda surely know.

az3ar

You hit the nail on the head... simplicity what we look for . However, I have owned many track/race cars over the years and the S2000 simply runs hot. Anything over 260 for extended period and you asking for trouble. Even if modern synthetic oils can withstand high temperatures does not mean your engine components will. The S2000 is designed well however just like any mass production car has its flaws. Not to veer of subject but brakes are one of them.

An Oil cooler is indeed an add on but one cannot say it will complicate your engine operation. There are many write ups on how to install one and build a kit from scratch.

c32b

Tracking a car with 50 weight oil when the standard fill is a 30 weight is not a band aid for viscosity drop. It's much more advisable to spend some money on a proper oil cooler. Not to scare you but I think putting in 50 weight oil may hold some unintended risk.

spdracerut

Notice I said "before I installed an oil cooler" However, I took the risk of running 15W-50 in non-track conditions over the risk of running 10W-30 in track conditions.

davidc1

This is correct. This is what happened when I rebuilt my engine. I worked with Lake Speed, Jr., of Joe Gibbs Racing, to figure out what weight oil to use. I gave him my bearing clearances, my oil pressure at various rpms, and the length of time I'm on the track. The ideal oil would have been about a 25W, which of course does not exist. So, his suggestion was a 5W-30. He said I could also use a 5W-40 to increase pressure at very low rpms, but it wouldn't really be necessary.

berny2435

My fill, currently in the car, for next track session = 3qt m1 0-30, 1qt 0-40, 1qt 15w-50. Magic potion.

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