dadnpony

I just picked-up my new 2010 GT yesterday ! When I was reading the mannual, It said it can run on Reg 87 Octane, but for best performance they recomend 91 or higher (93). Does that mean you can run on High-test gas
with out a tune ? I'm still on the dealers gas but I would go to 93 octane when I fill-up. Thanks for advice.

Adam

93 is overkill without a tune, IMO.

Nuke

The 2010 GT's have the FRPP tune that the prior years Bullitts had which can make minor timing adjustments for higher octanes. But don't be misled. Even a good custom 87 octane tune will kick azz over your stock tune on 93 octane.

Art161

I'm wondering if, in stock tune, you would notice a difference between regular and premium gas. If you fuel the car yourself, it's somewhat likely you will favor the premium gas, just for psychological reasons. Unless you are using instrumentation to gauge any performance difference, the best thing would be to have someone else put fuel in the car and not tell you what grade it was. Do that a few times and see how often you choose the correct answer.

Nuke

I've heard that the change in HP going from 87 octane to 93 with the stock '10 GT tune is about 5 HP which is more like ~4 RWHP. Not everyone's butt dyno is as sensitive as other's but it takes an astute driver to feel a 4 RWHP change on these cars. Some will notice; others will not.

GrayGhost01GT

I run my Brenspeed 93 octane tune! And my butt feels all tingley lol I kno i kno TMI! But hey its what my seat of the pants dyno tells me! Oh Well HA !