I currently run my 2007 GT on unleaded regular pump gas, but i was wondering if switching to unleaded premium pump gas is worth it. Is there a significant increase in performance and HP/Torque output or is it not worth it due to the inflation of gas prices?

 

Unless you have an '08 Bullitt (or was it '09?), the PCM on the 4.6L S197's won't adjust to provide any gains on octane higher than 87. You need a custom tune which will provide power gains, even with 87 octane compared to the stock tune, and even more so on higher octanes. Toss a tune-required CAI in with that and you're adding more power.

BTW, a no-tune-required CAI won't gain you much either since the PCM also cannot adjust for the additional air; again needing a tune to make power from the added airflow.

 

What Nuke said. Dont bother unless you have the tune for it. I run premium only at $4.89 a gallon.......with a smile too!!

 

Just to elaborate on what the fellas have said,

A higher octane rated fuel allows you to run more timing in your tunes. When tuned properly, the gains are nice.

I've watched my SCT datalog and when I jump on mine, the timing will get as high as 40 degrees.

 

If tuned for premium, you get a nice HP boost, but you MUST ALWAYS run premium.

If not tuned for premium, then putting it in your tank is a waste of $$.