Brands of Gasoline = Actual Difference

Jordo!

RE: Shell V-power... uh, okay. Although that is far from a controlled study, if the octane rating is the same, and the results are genuine, then the differences are likely due to the additives. If the engine is tuned for a higher octane, unless it was re-tuned, I call BS on the whole thing.

If tuned for 93 AKI, we wouldn't expect much worse results from another 93 AKI fuel...

In any case, Shell is clearly a sponsor for them, so take that with a pinch of salt. Likewise, Sunnoco sponsors NASCAR, hence all the hype there...

RE: Octane Boosters -- I've seen a few lab test shoot outs of various octane boosters -- I believe there's one by Torco that actually is found to raise it about a full AKI point (RON+MON/2), but most of those additives (104 Octane boost, et al) barely budge it a fraction of a point.

It's hard to say what was wrong with the gas you got (water? lower than claimed AKI?), but if you can find a Sunocco with 100 AKI pump gas (only mentioned because I know they have that at some stations -- another brand of that high an octane would be fine if you can find it), a few gallons of that shouldn't hurt, and will help ensure the fuel in the tank is closer to the octane rating needed.

You can find charts on octane blending if you google it to give you an idea how much you need to add.

If it's water in the fuel, you could try adding some Heet (methanol) or toulene to suck it up.

Anyway, unless you are tuned for it, there's no need to go higher than 93. I know of zero evidence that the ECU will allow more advance without tuning just because of a higher AKI. It might help if you were running on the ragged edge on a hot day on the track to stave off incipient knock, but for DD, don't expect any real improvement.

No idea on Risoline -- never heard of it.

EDIT: Looks like it has some alcohol to absorb water. I'm guessing that also helps provide the "stabilizing" action? The alcohol probably also nudges up the octane.

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