Acetone increasing MPG. For real or BS?

[cgrey8]

This subject came up on the EECTuning website and there was a number of comments on it but no conclusive evidence either way. So a few of us decided we'd put it to the test. As far as I know, there's 3 of us that were brave enough to attempt it after reading an article on the Internet about the positive benefits of it.

Everything we've found indicates that 2-3oz acetone for every 10gallons of gas seems to be the sweet spot. Any more, and you get diminishing returns and in many cases fuel economy actually starts going back down.

There's another chemical called Xylol (aka Xylene) that is sold in the same area of Lowes and Home Depot that Acetone is that has also shown some improvements by adding 1oz/10gal ratio. One guy claims that the benefits were additive with the acetone. I'm not sure I believe that, but if the acetone continues to yield me gains, I might just have to try the Xylol too at some point.

The 1st argument that was brought up was how much is acetone vs just buying premium? I broke it down like this:

The difference between 93 octane vs 87 is roughly $.20/gal. So for a 10 gallon fill:
$.20 * 10 gallons = $2
That's $2 per 10gal extra that you pay for premium.

Acetone is about $14/gal. 1 gal = 128oz. It takes 2oz per 10 gal of gasoline, so:
128/2= 64
That's 64-10gallon gasoline treatments.

So you divide $14 for a gallon acetone up into 64 treatments which gives you:
14/64 = $.21875 per 10 gallon treatment

So assuming acetone can get you a fuel savings equal to or greater than premium, that's $2 vs ~$.22 per 10gallons of gas. But you do have to consider the extra hassle it is to dump in those couple of oz before filling up at the station. That may be enough to discourage most people from bothering. But it didn't discourage me from at least trying. And this is what I know so far....

First off, with nothing but daily-driving stop-n-go traffic, I average about 16-18mpg depending on how crappy traffic is. If I get a few WOTs on the tank, that number can go down. I think the worst I've gotten since I've moved is 15mpg but that was with lots of WOTs, sitting still and doing tuning stuff, as well as crappy daily commute. Keep in mind, that my commutes consist of nothing above 55MPH and a LOT of sitting and idling.

My last tank did see fuel economy improvements of more than a MPG point. But just 1 tank isn't enough to say whether it was the acetone or just the gas I got that tank, or my driving on that tank especially since that tank did see a trip out of town that included a good 100 miles...which I was datalogging MPGs around 26 on the backroads! The tank ended with me getting dead on 20MPG which is about what I was getting when I drove backroads and Interstate speeds to work. The one negative thing I did find with the last tank was on 93 octane and 2oz acetone/10gal gas, I lost some WOT power, but the engine ran noticeably smoother at idle and while cruising.

Until now, I've only run 92/93 in my truck on a regular basis. Back early on with the swap before I got the tuner, I ran 87 and said never again. It pinged way too much even with the dizzy at base 10°. Even 89 was a little pingy, but better than the 87. So, I've run 92/93 ever since and I've even been able to pick up some spark in some areas.

This 2nd tank I'm working on now is too soon to tell. But I decided to drop down to 87 octane and see if I could get away with that. With still 2oz acetone/10 gal gas, my WOT did improve, but I had to back my timing off. The acetone may be improving things, but I was getting some ping at both cruise and WOT with all the extra timing I'd dumped on things in my tune from running 92/93 for so long. A few tweaks in the Spark tables and WOT spark vs RPM function, and I'm back to no pinging. This tank runs just as smooth as the last tank. Again, it's too early for me to say for sure what's going on and where benefit lies, but I've got almost 100 miles on this tank with nothing but stop-n-go commute driving (no long distance stuff), and my needle is still on F. I even have a fairly good WOT on this tank...did that right after I filled up just to see if it improved things from the last tank and it did.

In anycase, as long as the Acetone keeps 87 octane running as smooth as it does now, I'm happy to stay at 87 and collect that cost saving at the pump each fill-up, even if it is a little hassle dealing with measuring out the oz each time I fill up.

I just thought I'd pass along an interesting discussion that got started over there and has turned into a multiple-vehicle test over there. If you want to read more about how one guy has found a way to go from 23mpg to 30mpg in his V8 by running the engine REALLY lean at cruising loads. Interestingly he's running an Explorer GT40p engine. His E7 Mustang can't do this before it starts acting up, but something about the GT40p heads seem to handle running lean quite nicely at cruising and is giving him some impressive gains in MPG.

To read more about this click here:
MPG Topic... ACETONE increases mileage?,,, about to try it.

The only bad thing for non-Tuners about this thread is there's A LOT of geek-speak specific to tuning that may not make sense to people that don't know a lot about the various scalars/functions/tables in the EEC.