Lower octane lower HCs?

[are_one]

Just thinking, not that I have the guts to try it, but won't 87 octane fuel produce less unburned gas thus lowering the HCs?

[gofstbuick]

Since your vehicle has to go through I/M240, I would think you would create more problems by using a lower octane fuel to try to pass. The main concern is with NOx and what might happen as the vehicle is accelerated to 58mph (under a load). But i just don't know.

[kidrick]

As long as the tune is good, you should pass with any unleaded fuel. I finally passed(on the third try) for emissions in IL. Had a full tank of 100 unleaded and the wastegate was unhooked so the car was not making any boost during the test. The joys of a Speed-Pro