https://revmaxconverters.com/product...ypass-upgrade/

 

Engine oil needs to be over 170º to prevent nitration, and over 190º to control moisture and fuel buildup.

 

Would you happen to have a link or anything for this data? We control 150 degree engine oil temps on our large compressor engines at work, but I've never looked for passenger car specific requirements.

And would this still apply to transmission fluid that shouldn't see combustion effects and fuel?

 

For those with external coolers, the ECU will turn the fans on at 20% to assist transmission cooling when it hits 249ºF. It's not until 265ºF that it has stepped to 100%. The truck doesn't care about the transmission temp until it gets to 249ºF, I wouldn't bother changing my speed until it gets above 250º. The few pieces of information about LV transmission fluids I've found seem to indicate it's good until about 285-295ºF, depending upon the specific makeup of each mfg's fluid.

 

My fans come on pretty early with my tune, I cant imagine getting up to 300 degrees on transmission temp. boiling Temp is around 600 i think depending on the fluid, but it just seems so high. I would think that would lead to premature wear on clutches etc, but i would think too cold of fluid will do the same.

 

This was my thoughts. Being a sealed transmission you shouldn't have to worry about moisture, correct?

 

I know internally the transmission cooler won't even have flow going to it unless it's a certain temperature, but i think it's around 190 because once mine hits 190 it will not go higher than that and goes back down with the 170tstat i got.

Mine has a small cooler mounted in the grill (2017 was the year before they put the oil to water cooler)

 

Nitration is the result of reacting with NOx in blowby, which may not apply with your compressor engines.

Moisture buildup occurs in all engines not regularly reaching 200ºF+ temps regularly.

"Good until 285-295ºF" does mean nominal operating temperature. That's the absolute upper limit of operating range of the fluid. Stay at that temp for long, your transmission won't last. At 265ºF, the PCM is putting everything it's got at bringing the temp down, fan is running 100% regardless of the temp of the coolant.

Transmissions have breathers as the fluid, especially LV, expands and contracts with temperatures. They do not, however, get a constant supply of fresh atmosphere like crankcases do through the PCV circuit. You should still get transmissions up to temp regularly to drive off moisture they ingest via the breather since we go so long between oil changes.

 

What would you consider up to temp? I suppose I could always mock up some sort of cover plate to block off some airflow to the trans cooler while daily driving. That may allow it to heat up a bit more.

For racing though, every performance/transmission shop I've talked to said these 10R80's burn up fluid and clutches once you start throwing big power at them and trans coolers are basically a requirement to keep them alive longer.

I'm definitely far from a transmission expert though so I take everything I hear with a grain of salt.

 

Oh man, I feel like you're spying on me! We operate 2,000hp - 4,000hp natural gas-fired engines, most of which are two-strokes. This article discusses Mobil Serv analysis which we use, as well as, "Maintaining an oil temperature of over 65.5ºC can also limit this chemical process, with even better results for oil temperatures over 71ºC." which is 150-160 degrees F. I guess that's why we control oil inlet temp at 150, outlet temp is usually 8-10 degrees higher. Anywho, thanks for taking the time to look up both articles and share. Getting the engine oil temps up to cook off moisture seems to make sense for long intervals.

Sorry to thread-jack... my stuff above doesn't provide anything meaningful to the trans cooler question. w00t's observation about an internal bypass is intriguing. Makes me wonder how Ecks' temps stayed so low with just a cooler swap. Are there multiple locations to measure fluid temp? I feel like I remember seeing two different temps when scrolling through the Ngauge but I can't look right now.