tadpole1969

ok got a question i have the 7015 sct x4 tuner it has the preloaded tune file that my dyno tech edited for my 2001 gt, from what he told me i can use 93 octane in it with no ill effects by simply picking 93 octane from within the tune before programing it to my car ,have any of guys and gals used 93 octane in the 4.6 motor? it calls for 87 octane from factory so i do not wanna screw something up! i want to make sure its safe , the preloaded tune has options for 87 octane all the way to 93 octane in the user editable options, so its my guess that it will correct everything needed for 93 octane dureing the programming process

yourmom6990

As long as the car is tuned for a specific octane, you will be fine. You can always run a higher octane with a lower octane tune, but NEVER visa versa. A higher octane fuel ensures that more fuel is burned within the cylinder resulting in better performance. It is not going to hurt the engine. Just be sure never to run a lower octane w a higher octane tune.

tadpole1969

ah ok! yeah dyno tech had said that also not to run anything lower if i used 93 octane in tune options which i kinda thougth that before hand , but never hurts to get a 2nd opinion thx for the input ,also i got about a quater tank left think i should run it lower or am i good to go to fuel it up on 93

yourmom6990

Before I tune mine for a different octane, I usually run it down a few miles even after the light comes on. Then fill it with 93. Just to be safe, I would wait until the light comes on at least.

tadpole1969

k will do thx again

school boy

Actually, higher octane is harder to combust resulting in a more advanced timing. If you run 87 octane on a 93 tune, you are more likely to create detonation. It is given that in most cases, more fuel is needed when a higher octane is used.

tadpole1969

yeah i kinda figured it migth use more gas with 93 octane, but can always return to stock and use 87 again for long trips

school boy

It wouldn't be that much of a noticeable difference

tadpole1969

performance wize there should be a small increase in hp so dyno tech said anyhow by useing 93 and nothing at all useing 87 with custom tune he put on it

school boy

Either tune is going to gain hp, especially under the hp curve. Lets say as an example the tuner claims 35rwhp and we will say a bone stock GT is 225rwhp. You may only gain 5-8 rwhp at peak but 33-37rwhp at say the 4250rpm mark.