[arpad_m]

Originally Posted by radz28

MMT is the additive that gives the fuel it's knock resistance (very simply). If the product has enough MMT to be effective (i.e. Race-gas, Boostane, Torco), then you'll likely be getting the orange soot. If it doesn't have MMT, it probably is not really going to effect your octane much, if anything. MMT, apparently, also is what kills sensors and emissions devices. The products I listed above all have higher MMT-content than most other products claiming to increase octane, and there are other product lines, within these brands, which have even higher MMT-content, allowing more resistance. This additional MMT-is also why you won't find (not that I've seen anyways) statements saying these products are guaranteed not to impact emissions devices or anything. I'm fine with that. O2 sensors and even cats', are too big a deal to have to deal with replacing, IMO.

Well, Race-gas at least claims zero harm to cats, O2 sensors and plugs. I am not qualified to judge whether this can be true, but their statements are unequivocal.