Junkyard Dog said:

The S650 7h322 external transmission fluid thermostat opens from XXX° Fahrenheit.

It looks like this:

View attachment 112420


I wonder if we can just swap it out with one of the improved racing designs and set that temperature to send up to the cooler in front of the radiator (and behind the ac condenser) to start cooling at whatever temperature we want.

It would be helpful if we knew what the original temperature rating of this external thermostat is. Probably the same 190°, but I have no way of knowing.

Click to expand...

Good find!

Keep in mind just swapping the thermostat still leaves the radiator heat exchanger as part of the 10r80 cooling loop, so some of that heat and load will still be put in the 10r80 fluid/cooling system. Not a bad thing for warm up on a street driven car, potentially not a great thing for track/performance cooling.

Few thoughts:
1. How to deal with hard lines going to and from the OEM thermostat?
2. Need dimensions and threads/connectors in/out of OEM thermostat for fitment?
3. Full size improved racing thermostat or compact model?

Might be an few hundred dollar experiment, but you could buy a spare OEM thermostat and buy the improved racing thermostat(compact version?) and compare measured dimensions to see if the fit is close enough. This is including finding out the proper threads, or adapters needed.

You are more likely to be better off cutting the OEM hard lines on one or both directions towards the thermostat, and using a hard line to AN adapter. I used a hard line to AN adapter, and then an AN to push lock adapter, then I put a rubber hose over the push lock and clamped down with constant tension spring clamp. I used push lock and constant tension spring clamps at each end of my custom rubber lines, especially since my trans cooler used push lock already. This allowed me the flexibility to have whatever size improved racing thermostat and to mount it where/how I wanted.

Depending on the length of the replacement AN lines, going with AN fittings may not make sense or allow the flexibility you would need. You can reference my 10r80 custom cooling thread to see how I cut the hard lines and converted to AN and push lock to rubber lines. For how short my custom cooler lines were going to be, it didn't make sense to use AN fittings and PTFE/nylon tubing.

Here are more reference links:
OEM S650 10r80 thermostat BT4Z-7H322-B: https://parts.levittownfordparts.co...67qwvo6HK8NyPbHbj1og6Hck9-nqQJbGpTD2jZBIKupEC

Full size Improved racing trans thermostat I used: https://www.improvedracing.com/high-flow-engine-transmission-oil-cooler-thermostat.html

Compact size improved racing trans thermostat: https://www.improvedracing.com/compact-high-flow-engine-transmission-oil-cooler-thermostat.html

Well here goes my first post and I wanted to thank those who are contributing as I plan on beating this Horse to Death!!

That being said, I want to clear up what I read on the first page about the radiator size compared to the Mishimoto (MM) radiator as it is definitely larger than the OEM Dark Horse unit and the GT Premium. The MM radiator is 40mm thick compared to the DH radiator at 31mm and the GT premium at 25mm. Considering the full aluminum construction, the dissipation of radiant plus core thermal exchange is far greater than just the plastic end tanks which over time and pressure are known to fail.

As we got this RTR EcoBoost Mustang specifically for Time-Attack style track events, the cooling system is one part of my intense focus. I have already started the base development for the cooling systems to be divorced, engine, oil, transmission and rear axle. The production build of this car has been fun tracing which parts come from which platform... so essentially this is a Dark Horse Mustang but powered by the 2.3L engine and the 10R80 transmission. Everything under the body work is Dark Horse; cooling, fan, rear subframe, suspension and brakes (6-piston Brembo up front, radial mounted 4-piston Brembo rear).

So far I am planning to mount the Mishimoto dual bypass oil cooler in the driver's front left, using the OEM ducting to seal it to the front bumper. Removing the OEM liquid to Oil Cooler/Filter adapter makes easy work sending hot oil to a remote Oil Filer adapter pictured in this post... with extra ports to record actual Pressure and Temperature data with the Banks iDash coupled with Analog to CanBus conversion to have real numbers, not "inferred numerical" guess-work.

The transmission receives the same program, removing all the OEM lines connecting the engine's coolant loop to the water-to-ATF heat exchanger... also removing something that could potentially get whacked by track debris or driving over track curbing like Allen Patten!! Here I will use the passenger side area inside the bumper, feeding air from the "Faux-Grill" which on the EcoBoost is not encumbered by the Engine's ECU being in the way. Once again, a Mishimoto heat exchanger that has an integral fan will allow paddock cooling of the transmission during idle and temperature control of the fan for street use.

I kinda "borrowed" the hood from the RTR Spec5 prototype as the OEM EB hood has no ventilation at all... this made an amazing difference at speeds as low as 80mph in road feel.