Why is my truck quiter without the tune?

[stng_96]

Guys, I am getting some custom tunes for my SCT X3 today, and read somewhere that I needed to put the truck back to stock before I put in the new tunes, whether that be true or not...whatever. So last night I inputed the stock tunes back into it, and started it and it was much quieter? I had it set on the canned street tune that was in the X3 before, so not really radical, and now on stock the truck as a whole is quieter, can anyone explain to me what that tune changes that makes it soo much louder? Not that I am worried, I am really just curious. Also, it blew out some smoke for about 10 seconds after I started it back in stock mode, what is that about? It was night time, so obviously I couldn't see very well but the smoke appeared white. It has never done that with the tune in??

Thanks!

[jesilvas]

Quiet injectors has to do with timing (SOI) and many other things.
Cold is usually louder, hot is usually quieter because of how the SOI changes depending on conditions fed to the PCM.

[stng_96]

Hmmm, I see, any idea why it smoked a some?

[TheFordman87]

Could have been unburnt fuel and the injectors had to reset to stock and the turbo didn't run as much boost as it would on the street tune. Just a guess. Plus when the truck is cold at an idle it runs less boost then when warm. Well mine does anyway

[stng_96]

Ok cool, I couldn't get it to do it again, so I don't think there is a big problem, I just was curious.

Thanks!