Well, I've had a chance to conduct some testing on the modified Lil' Tex over the past couple of days and the results are inconclusive....
Bottom Line Up Front: I have not been able to repeat reaching a set temperature of 500º but I've come close. Reaching 450º is a sure thing unless the controller starts acting up.
Maybe I did dream it, but I remember waking up to the Traeger bellowing smoke as it burned all the residual drippings at such a high heat so I got up to turn it off and noticed it had reached 500º. This is what I was alluding to in my initial post. To test this again I thought I would walk it through two steps of 450º and 475º before trying to reach 500º. In an attempt to verify the temperature I placed the two meat probes on the grate inside while running this test. The first set point of 450º was reached in 47 minutes as shown by the app screen shots below.
[ Invalid Attachment ]
The strange part is that the probes measured much higher temperatures of 482º and 507º. Noting this anomaly but pressing ahead, I then adjusted the set point to 475º which was reached in another 14 minutes.
[ Invalid Attachment ]
Again with the probes at much higher temperatures of 505º and 530º. Still undaunted, I adjusted the set point to 500º for the final step of the test. This is where things became a little strange. After continuing an initial ramp up to the next set point the Rec Tec controller began to struggle. It reached a high temperature of 488º but then began to drop down in temperature. Around this time the app began to display an error code when selecting the Temperature Chart display. The last charts I could capture are shown before the error occurred after which I terminated the test without reaching 500º.
[ Invalid Attachment ]
Two puzzling results from this first test are 1) Why do the meat probes measure a much higher temperature? and 2) What conditions cause the controller to no longer display the Temperature Chart? I sent a message to Rec Tec about the error state of the app through a "Comments/Recommendations" messaging system on their web site (they don't have a way to reach them for support help, at least without calling, which I haven't done yet mainly because I don't want to tiptoe around the fact that I'm using their controller on a Traeger) but haven't received a reply yet. Therefore, I thought I would address problem 1) the next day by re-calibrating the temp probes again. As shown below I went through the ice water calibration and hung the meat probes from the top of the grill. The Rec Tec Controller has a calibration mode that displays all three temps and you can set offsets +/- 25 to calibrate. After the ice water cal I let the meat probes stabilize to ambient and then I adjusted the "Actual" pit probe to the same temperature of 77º. Another oddity is that the pit probe doesn't display the adjusted temp while in the calibration screen but does correctly display once the pit is turned on. However, at the same time the meat probes display a higher temperature as soon as the grill is turned on. At this point I'm beginning to suspect that the new Rec Tec controller still needs some fine tuning and maybe my query will provide some enlightenment on their perceived state of the controller software. Regardless, I let it run to see if it could reach 500º today but to no avail, it basically leveled off at about 366º and wouldn't progress any higher while the meat probes leveled off at 501º and 504º
[ Invalid Attachment ]
Now I began wondering if the Rec Tec controller used the meat probes as additional feedback in the PID algorithm to keep the pit stable if the food is already above the set temperature. Therefore I tried pulling out the probe lines at the controller to see if it would continue ramping up the pit temp without that feedback but the temp remained around 366º. Maybe once that trigger threshold is met it doesn't reset if the meat probes drop out, so I decided to shut it down and let it cool off. After a few hours I started the grill again with a set point of 500º but this time without the meat probes connected. It reached about 429º before it began to falter and the app error began occurring again.
[ Invalid Attachment ]
The next day I was smoking some burgers so I set it for 450º which it reach in 54 minutes, a little longer than the previous time but it was a little windy that day.
[ Invalid Attachment ]
After the burgers were done I thought I would let it try to reach 500º again but the app began faulting and the temperature was erratic, almost as if there is some problem in the feedback loop parameters of the PID algorithm.
At this point I think I need to give up on the claim that it can achieve 500º but 450º seems pretty repeatable or even higher as long as the controller doesn't act up. This product is pretty new so maybe Rec Tec will come out with a software update that will correct these issues.
I will say that for most normal cooks it works very well. Since I've made this upgrade to the Traeger I've cooked pulled pork twice, brisket, whole chicken, hamburgers multiple times, steaks a couple times, a bacon weave fatty, and currently cooking beef short ribs, low and slow at 225º and it is working like a champ. The WiFi remote control is so convenient! I still am very happy with the mod and believe the cost of the new Rec Tec controller is well worth it.