How to improve PB cooling???

[SALEEN961]

Something else that may be of interest to some people is how our fans are commanded to run from the factory. On my 2021 3.5EB, the desired coolant temp is 210°F and the fans aren't commanded to run at 100% until my ECT hits 226°F or my TFT hits 240°. Even with an ECT of 212°F or a TFT of 220°F my fans were only commanded to run at 20%.

Stock Fan Settings for factory 195°F thermostat:

Modified Fan Settings for my 180°F thermostat:

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[Samson16]

Modified Fan Settings for my 180°F thermostat:

But they are worse slightly at 230/240 or am I reading it wrong?

 

[amschind]

The Mishimoto radiator will not fit the PB per Mishimoto.

 

[Samson16]

It seems to me Ford wants the temps up around 220. Unfortunately, the transmission fluid temperature just keeps climbing during heavy load scenarios because the plate heat exchanger is tied to engine coolant.

 

[SALEEN961]

But they are worse slightly at 230/240 or am I reading it wrong?

For the TFT table, I raised the fan speed from 70/77% to 100% at 237°F and I slightly increased the fan speeds at 234°F. I didn't make any adjustments at 220°F and below.

The ECT table was rescaled so the starting and ending temps are not the same. The factory ECT table had my fan running at 65% at 220°F, I have it set to run at 84% at the same temp. At 202°F, the factory ECT table is set to 9% fan speed, I have mine set to 9% at 180°F and it's up to 32% by 200°F.

 

[Samson16]

Interesting. Very cool so to speak lol

 

[Samson16]

The Mishimoto radiator will not fit the PB per Mishimoto.

Would that have been for ATF to air cooling?

 

[SALEEN961]

Interesting. Very cool so to speak lol

Today wasn't the best day for testing as it was only 55°F, but after a quick drive to get things warmed up, I did several back to back WOT pulls to see how high my coolant temps would get and there was a noticeable difference. In my short test today I couldn't get my cylinder head temp over 211°F, compared to easily hitting 230°F after a single WOT pull with the stock tune and thermostat, I'm very happy with this improvement.

 

[Samson16]

Is there any way to pipe trans fluid to the front without major remodeling? Perhaps Saleen is showing the way. Perhaps with a manual misting switch setup for severe conditions?

 

[Samson16]

Today wasn't the best day for testing as it was only 55°F, but after a quick drive to get things warmed up, I did several back to back WOT pulls to see how high my coolant temps would get and there was a noticeable difference. In my short test today I couldn't get my cylinder head temp over 211°F, compared to easily hitting 230°F after a single WOT pull with the stock tune and thermostat, I'm very happy with this improvement.

Awesome now hook up 10,000lbs and go screaming up the nearest mountain. Full report please video evidence preferred

 

[SALEEN961]

Is there any way to pipe trans fluid to the front without major remodeling? Perhaps Saleen is showing the way. Perhaps with a manual misting switch setup for severe conditions?

People have removed the factory oil/water cooler and installed a new oil/air trans cooler in front of their radiator in the past, but it looks more involved on the 2021+ trucks with how the factory cooler mounts to the trans.

A simpler approach might be to separate the trans cooler coolant loop from the main cooling system and install a small secondary reservoir and radiator that isn't heated up to 210°F+ by the engine, similar to what you would have with a water cooled supercharger kit.

Awesome now hook up 10,000lbs and go screaming up the nearest mountain. Full report please video evidence preferred

I would love to do something like that, but I don't even own a trailer or something heavy enough to get one up to 10,000lbs. I also wouldn't want to do a before test on my own truck, Ford runs these things way to hot from the factory.

 

[Snakebitten]

Upon close scrutiny of the 2021+ transmission cooler, VS the previous 10r80 cooler that was mounted below the bell housing, HammaMan pointed out the actual in/out transmission fluid ports appear to be the same.

So theoretically, you could remove the 2021+ cooler and plumb it with the previous generation modification parts, or convert to the Raptor transmission cooling components?

 

[HammaMan]

Upon close inspection of parts / diagrams, the trans setup is like previous years. The only caveat for running air/oil up front is that you'd want a thermostat where the trans fluid recycles in the trans until 150 degrees roughly. In winter if you're just straight flowing the oil to a front air/oil rad, you're going to have rougher shifts with cold fluid.

One of the theories I floated for a possible trans cooling is to hijack its coolant run to pipe the coolant into another rad up front lowering the temps before it heads back. I don't believe that to really be worth the trouble as you'd maybe get at best around 10c pickup with it (likely less). A dedicated air/oil setup would drop you a solid 18-20c, but you still need a winter remedy. A winter remedy may be as simple as just covering that rad by means of a plastic cover with zip ties.

In my searching it appears that the 3.3L 20 and under rad cooling parts fit. These are the same coolers that come on the XL police unit and raptor for 21+. Even w/ all of the parts you're still left where custom mounting the rad itself.

 

[amschind]

It seems to me Ford wants the temps up around 220. Unfortunately, the transmission fluid temperature just keeps climbing during heavy load scenarios because the plate heat exchanger is tied to engine coolant.

Two things:
1) The overheat seen in the initial TFL trucks PB tow torture test was an engine (hot coolant loop) overheat with a modest rise in transmission temperature.
2) I believe that the truck can regulate how much coolant is passing through the trans fluid/coolant exchanger so that it can prevent heat flow out of the transmission.

Based upon that, my assumption is that if we can improve heat rejection from the hot loop radiator, the increased max heat rejection capacity for the engine AND transmission will increase. In other words, the limiting factor for transmission temperature is not the size of the transmission heat exchanger but the radiator itself. I'm NOT certain of this, but two factors support it as a practical place to start:
1) if the engine overheats, you're stopped even if the transmission is still at 220F
2) the likelihood of a drop in radiator for the PB is far greater than a larger transmission heat exchanger.

Finally, the four cats are right next to the transmission: heat is getting transferred to the transmission from the exhaust pipes. Wrapping cats is a high risk/high reward proposition (they tend to do fine, but if they fail, they "fail fiery"), but wrapping the rest of the pipe is pretty straightforward. The exact circumstances where transmission overheat are those where the engine is burning a lot of gas, i.e. there's a LOT more heat moving through the exhaust pipes vs 70 MPH unladen on flat ground. To that end, turbo blankets, exhaust wraps (excluding the cats) and maybe some day Full-Race ceramic coated stainless exhaust manifolds might be the big solution to transmission overheats.

The I Do Cars youtube channel is a really great watch. It's fun to see the different designs and failure modes, but the three big recurring themes are that lack of oil flow, heat, and water in the intake are the major killers of engines. To his credit the channel owner really hammers home maintenance as a point to everyone. This forum is on the extreme end of oil changes, where we argue about oil testing vs halving the recommended maintenance intervals, but we are at a uniquely high risk for overheat conditions due to towing, particularly under high hot and heavy conditions. I don't have heavy stuff to tow YET, so I'm okay with waiting to do this stuff right, but globally my truck's lifespan will be defined by avoiding overheat conditions, deer and Houston drivers.

One helpful bit in that regard: Texas is ending the inspection requirement in 2025, so if the exhaust temp sensors throw codes it won't matter as I can simply ignore them.

 

[amschind]

Would that have been for ATF to air cooling?

Mishimoto Radiator

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