2006 GT broken valve again

[Dino Dino Bambino]

Yeah was crazy cause when the valve broke it fell and “kissed” the piston and went back into guide and got stuck. Both times I was taking a drive went on the highway went WOT as usual and drove fine until I got off the hwy normal cruising speed less than a few miles from my house the valve broke.

That DOES sound heat related. If you were running the engine hard on the highway, as soon as you exit and slow down, there's less airflow through the radiator to cool the engine and it then becomes heat soaked. The IAT also rises because there's less airflow through the intercooler. The exhaust valves are exposed to more heat anyway and that's why the OEM units are inconel.
There are some measures that might mitigate the problem such as:

1. Enrich the WOT air/fuel ratio to closer to 11.0:1.
2. Lower the cooling fan on temperature to 195*F and run a 170* thermostat.
3. GT500 style hood extractor vents.
4. Ease off the throttle after a WOT run, shift into 5th (or 6th if you have a Magnum XL), and cruise the engine at lower rpm on the highway for a few minutes to allow it to cool down before you exit.

 

[Juice]

Sorry Dino, I dont agree.
1 11.0 is too rich.
2 Wont help, will only end up burning the BEC.
3 I dont see this as helping either here.
4 This should never be required.

I didnt recommend a specific afr, Im pretty sure Lito got it pretty good, thats why I said .5 fatter. Since its not boiling over, I dont see 2&3 as needed. And 4 should never be needed.
For AFR, supercharged I shoot for 11.8 or .80 lambda. WOT ignition timing I pull 1*/psi FI. Thats safe and will last without leaving much HP on the table.

 

[lwarrior1016]

Sorry Dino, I dont agree.
1 11.0 is too rich.
2 Wont help, will only end up burning the BEC.
3 I dont see this as helping either here.
4 This should never be required.

I didnt recommend a specific afr, Im pretty sure Lito got it pretty good, thats why I said .5 fatter. Since its not boiling over, I dont see 2&3 as needed. And 4 should never be needed.
For AFR, supercharged I shoot for 11.8 or .80 lambda. WOT ignition timing I pull 1*/psi FI. Thats safe and will last without leaving much HP on the table.

Your 11.8 is only .80 lambda on pure gasoline. Pump gas being e10 puts you at .83 lambda.

My supercharged coyote made best power at .78-.79 lambda on pump gas.

 

[Juice]

Lambda is not affected by E content. And stoic afr is set for E10 in these. So .8*14.08= 11.2

You are right, 'yotes like fuel. (I run mine at .82)Coyote is so easy to wot tune since its closed loop all the time. But I dont want to jack this thread.

 

[JC SSP]

It’s difficult diagnosing over the internet… and there are too many variables to properly assess the real issue.

That being said, OP should have someone locally look at this and figure out the core issue. Heck for all we know it might be Manley has a batch of bad valve stems…