[98jeepxjlimited]

i have an 09 GC hemi. will putting 93 octane gas increase horsepower, or am i wasting my time? does it have a knock sensor to advance the timing to take advantage of higher octane?? anyone know?

[justa4banger]

If its tuned for 87...then probably NOT. reason is, the car won't know if 93 or 87 is in the tank, thus the timing tables only allow so much , end of story.

Get a tune and then you can take advantage of the 93, otherwise, your just wasting money.

[98jeepxjlimited]

well it says 87 can run in it , but 89 is recomended....

[TJJP77]

Remember that higher octane fuel is more resistant to igniting to avoid the possibility of self igniting in a high compression engine. Putting 93 octane fuel in your engine will probably have a negative impact on driveability. Just stick with 89 and you'll be fine.

[justa4banger]

well 89 or 87, thats what it is tuned for... so runing 93 won;t hurt anything, but it won't help either. if you get it retuned for 93, then you'll notice a difference

as for 93 and hurting drivabilty, i highly doubt that. Now drop in some C16 race gas (116 octane) and yea that might affect drivabilty.

[98jeepxjlimited]

doesnt higher octain give it more power? my original question was if the car had a knock sensor, if it does, using 93 will give it more power b/c it adjusts the timing..

[Texas WJ]

Not how it works. It can detune the engine to accept lower octane, but not increase it to accept, and properly use, the higher than designed for stuff. If you go higher than rated it's just wasted money out the exhaust.

[rhusak]

Guy's..
You would have to install a chip that is tuned for 93.. OEM folks only detune for fuel.. Not up tune..
There are some companies who say so and so power on 87 and so and so for 93.. Usually not that much more..
Ron.. Whose CRD doesn't know the difference..