Hello,

I am new to this forum and I am doing research on 2 different Pontiac cars. I like of these models the 2006 GTO and 2009 G8. Both come with the 6.0 LS2 engines and I am wondering why the 2009 G8 GT has a reduced horsepower rated at 355 compared to the older GTO rated at 400. I can only assume for fuel economy but looking to see if anyone really knows why. Maybe the GTO has a manual trans and the G8 has an automatic trans?? I don't know.

Also I am not sure if both of these vehicles require premium fuel or not. Do they??

There is a low mile G8 out in my area that has the color scheme I like. If I were to pick this one up can it be easily brought up to 400hp with a PCM tune?
Thanks

Horsepower could be an emission thing or the way its programmed for that platform.

Horsepower isn't based on whether it has auto or manual trans. It'* actually estimated from an engineering standpoint.

If they are high compression engines or boosted, then I suggest using high octane. Or use whatever is recommended in the owners manual.

Most of the time, tuning can increase the power output.

Thanks Mike. I appreciate the input.