I just pumped 112 Octane LEADED gas into my car by mistake, (idiot i know), I was at the race track and instead of unleaded i pumped the other one by mistake. ANYWAY i had about half a tank of 92octane in the tank already, and I added 5 gallons of 112octane LEADED, noticed it was leaded after I put the 5 gallons so I then finished it off with 5 more gallons of 100octane UNLEADED. As I drove my car through the night I heard a mild knocking, crackling coming from the engine, what damage can be done to my car because of this mistake? How can I fix it? What can I do??

shouldn't have started it at all. . .drain it and put new fuel in. . .

It won't hurt the engine at all, your cats are, most likely, toast. They will melt inside and get covered will goo. Time for some nice HF cats!

I agree with nismo, should have drained it right then and put in all unleaded.

I tried to cyphen it out but I guess our cars have an anti-cyphen valve in the tank to where we can't do it. I tried, and like 4 other people tried and we couldn't get the gas out. Plus I heard I had to take the back seat out in order to get to the drain of the gas tank. I ran it about 30miles after I put the gas in it. But remember I already had Half a tank of 92octane unleaded. Should I try to drain it now that I'm home and have more tools to mess with it, or would it be a waste of time since I drove it a lot?

Also does anyone know if infiniti will still warranty the car if the cats are fried?

Not if you fvcked it up, which you just admitted was your fault. Like was said before, your engine will be fine, but the emissions system will have taken a slight beating. Get some aftermarket HF cats or something, and throw them in there (once you've drained the gas, of course, or you'll just ruin another set of cats).

I did that once with my first car when I was 16... I siphoned as much out as I could, filled with unleaded and never had issues...

That was a 72 mustang (no I wasn’t 16 in 72)... siphoning wasn’t a problem... I wasn’t aware that the G could not be siphoned.

Tetraethyl lead just contaminates the platnium in cats. Half a tank won't do much and the contamination will burn off eventually. Now repeated use will permanently destroy the cats after a few tanksful.

Since mid 90's the thickness of the EXPENSIVE materials has gotten thinner and thinner so don't compare old cats to new as far a robustness is concerned...........todays cats may only have a few grams of platnium dusted on the honeycomb core.

ull be fine, I ran 110 leaded in my car regularly with my vortech. half a tank wont hurt you

yea won't hurt if you did it once (won't hurt motor at all).
May want to change plugs depending on what plugs you are running, they will just get a coating. And yes if you ran it a bunch you can ruin your cats, and 02 sensors.....
Just think, you get that nice race-gas smell for 100 miles or soo.

Tom