Most things i read say it should be harmless to the cat, in fact it will will help to keep things in the fuel system clean. a lot of people think 1-3 oz per 10 gal will increase mpg. My first tank (2oz mix) gave me 35.5MPG in mixed driving (about 50/50 highway and city) which is a couple of mpg better than i usually do . I have a couple of 300 mile highway trips this week and will report back on the results.
about 285 miles with a little local driving at each end and about 15 min of bumper to bumper at the tappen zee bridge. used 2 oz of acetone but only got 39.15 MPG outbound leg was in the dark and it was below freezing for most of the trip - tomorrow should be a little better - we'll see how that goes-
From what I have found, via Google, adding Acetone is bogus. From lower BTU values, to it's more common use of paint stripper eating away an engine's gaskets and seals creates enough doubt for myself to avoid using it.
trip 2. used 2 tanks of gas, first had a lot of traffic and some city driving - 37.68 mpg. for the second tank, i tried to drive the car for the best gas mileage. (held it to 55, almost all highway, slow acceleration,) got 44.24mpg (my all time best for this car). My car is the late model, so it weighs more and has a 16valve 4cyl. My guess is that the early 3 cyl car driven carefully, might really get better than 45mpg- by the way the last two tanks were without acetone so i really didn't see any real difference in mpg with the stuff.
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