Yes it does. A custom tune changes the fuel & Spark mapping, or curves. The OBC will still pull the modified curve back and forth in the same way.

 

5w-50?also wondering

 

The temps around MD where I live are freaky, we never get this hot, so we're used to cars producing much more power. The humidiy is also a killer, solid water is great for an engine, ie spray, but once it turns into a gas it removes lots of the oxygen from the same volume of air. Furthermore it's not even going to cool the engine as there is no evaporation to soak the heat up so humidity is terrible.

 

I would be concerned that the oil is not the specified weight..

 

did you have tcs on?

and +1 about the oil. the heat/temp would make somewhat of a difference, but not kill half your power. maybe if it used to be like 65 and then shot up to 98

 

that is what the gt500 and ford GT call for 5w-50 i kno i was shocked 2 and mad cuz no mobile 1...

 

Yep 5w-50 is definitly what the engine takes, the weather is just very unusual around here.

 

Yeap for sure. Why dont you just take a drive at night, if heat is the problem your car should run a lot better in the cooler night air. BTW I drove my friends 08 GT500 this past weekend after I installed some springs for him. The car makes 567rwhp and it is an absolute beast and sounds like a NASCAR. I love it and must get one!

 

It is just possible that your computer reverted back to "break in" settings which detune the engine for the first 100 miles or so to 350 hp or there abouts. My Ford Tech told me about it when they got a new GT500 that was totally lame on its first test drive, they found out about this when they called Ford. Worth a trip to the dealer to run a diagnostic.

 

As was stated 5-w50 full synthetic is the correct oil for the motor.

Zporta, we have been dealing with some rather hot and humid weather here in Houston already. However, I upgraded my heat exchanger to the Afco and added the Pfab tank. The Afco is a huge element compared to the stock heat exchanger and the Pfab ice box is double the size of the stock one. It has helped considerably with keeping the Eaton cooler. I also changed the thermostat.

The stock GT500 heat exchanger is tiny!

Check it out I got the stage 1.

http://www.lethalperformance.com/pag...-packages.html