K6JRF at the mic K6JRF's Page
formerly W6FZC

My Mercedes Benz
S500 Coupe

K6JRF's MB S500 Cpe
(Update: Apr 8, 2008)

Analyze and Troubleshoot "Check Engine" MIL and Electronic Control Units (ECU)!

Acetone in Fuel Increases Mileage

A readily available chemical added to the gas in small proportions improves the fuel's ability to vaporize the fuel completely by reducing the surface tension that inhibits vaporization of some fuel droplets! Doing this has been said to increase your car's gas mileage by 10 to 40%! Sounds too good to be true . . . but it's certainly worth the trouble to do some testing to see for myself!

Acetone in S500 Cpe The impetus for this is simply, today's gas prices. Here in San Diego, gas prices for 'high-test' is $3.21/gal and rising as I write this!  If that isn't enough impetus then I don't know what is!  I've always said that my S500 Cpe is great but its city-driving gas mileage isn't very good, about 15mpg. So if this gives me 20 to 30% improvement, then I'm all for it.

The work was originally reported by Louis LaPointe and has been followed by many. To read the complete article, click on this link: Acetone in Fuel Said to Increase Mileage   Please take the time to read it completely and do some testing for yourself.

I was shown another 'view' of why Acetone works. Here it is FYI:
The vapor/surface tension "thing" just doesn't hold up for about a number of reasons (basic, surfactant chemistry). "They" had the same "discussion" back in the 80/90s when gas was expensive (supposedly) and catalytic converters and oxygen sensors were starting to come in to use.

FYI: The acetone is reacting with the catalyst used in the oxygen sensor making the mixture appear" too rich. As a result - the mixture is leaned out by the computer thus the mileage goes up. The reason it does not work the same on all cars is that there are three different metals used as catalysts in O2 sensors: platinum, palladium and rhodium or in combination. Acetone in combination with NOx (and others) in the exhaust will react differently with each metal to either speed up or slow down the catalytic reaction of the oxygen senor. I am not talking about the catalytic converter.

Question: am I the only one on the planet who remembers this? There seems to be a lot of people skiing behind the "vaporization" boat? The reason I know this is that I used to work for Exxon and fyi, the reason they don't put acetone in gas is that it is hard to get it to stay there and secondly, over time it reacts with different kinds of additives in fuel. This is also a reason why it does not work on some cars - it's the gas not the car.

They have had additives in the past with acetone - old news. It is good that it works though! It simply had gotten more news because of the historic price of gas. Also, this is why ASME standards for elastomers used in cars requires (heavily suggests) that all elastomers be tested with acetone - along with other (i.e . MTBE, M85 ...) Once again, very old (but good) news.

Based on this and the other links contained in the article, I've added some into both my wife's Honda and my Mercedes. Currently testing at 2.2oz/10gals for my Mercedes; 2oz/10gal for the Honda.

As you can see, "less = more". Do not use any more than 3oz/10gals since too much acetone can thin out the mixture. Also in the amounts being used here, the percentage of acetone to gas is close to 0.07%. This is just enough to make the gas vaporize better (allegedly) but not enough to change the octane rating or dilute the gasoline mixture.

It's important to get acetone that is as pure as possible. The recommended sources are beauty supply shops. Looking for sources on the Internet show a number of places that are allegedly 100% pure. Looking further at the MSDS for the products reveal that it's anywhere from 95 - 100% pure.

While in Home Depot, I found a product made by "WM Barr Co" under their "Klean Strip" brand of "Acetone". Checking the MSDS I found it to be between 98 to 100% pure. So to start off, I considered it good enough, so that's what I'm currently using.  Time will tell if it needs to be a better grade.  Price was $5.29 for 32oz (946ml).

A Mercedes owner wrote in with another source for acetone. Walmart has 100% pure acetone sold under the ONYX Professional brand name in a 16 oz. bottle for $1.97 in the cosmetics section.

My wife reports that her Honda is very 'zippy'! Well, funny enough, that's what I feel in the MB. But there's nothing 'scientific' about those statements. Check back here and I will post the mileage for both cars. My emphasis is to improve the city mileage since it's pretty low. If it works for the stop-go driving then it will work wonders on the freeway!

Mercedes Fuel Results
Starting City MPG = 14.6*
 City Avg (mpg)  City (mpg)  Hwg (mpg)  Details (miles/gal)  Cost Savings**  Cumlative Change (%)  Date
 15.6  15.6   - 346.0/22.2  $3.48  6.7  4/30/07
 15.7  16.0   - 339.8/21.3  $3.29  7.9  6/12/07
 15.5  15.1   - 318.6/21.1  $3.36  6.3  7/23/07
 --.-  --.-  19.0 409.4/21.5  $-.--  ---  8/26/07
 15.5  15.3  - 414.8/27.2  $5.65  6.2  11/8/07
 15.5  15.8  - 355.1/22.5  $5.93  6.3  12/28/07
 --.-  --.-  21.6 460.7/21.3  $8.32  13.7  2/16/08
 15.8  17.1  - 385.1/22.5  $7.58  7.5  4/8/08
* The is a composite mileage based on 9+ years of city driving and is the average of all driving
conditions, in summer w/ AC and winter w/o AC.
** The calculation includes cost of gasoline/gal minus the cost of the added Acetone (2oz)

4/10/07:No info yet on the Merecedes since the tank is still over half-full. . . b/c I don't drive that much. Another week or two for the Mercedes results.

4/30/07: This is the results of the first tankful for the Mercedes. Although it much less than I hoped for it's a start! Mileage increase of "1MPG" isn't much but at today's gas prices, it's not as insignificant as it appeared at first glance. Increased the Acetone to 2.5 oz/10gals.

6/12/07: Results for the second tankful for the Mercedes. It's a 'touch' better than last time. Continued the use of 2.5 oz/10gals of Acetone.

7/23/07: Results for the third tankful for the Mercedes. Lost some mileage due to very hot, humid weather and high use of A/C. I guess that's to be expected.

8/26/07: This mileage represents a trip that used 85 - 90% of the gas. The remaining is basically city driving. So strictly speaking this is a hybrid result. Since it's the first highway mileage result, there can be no 'savings'.

11/8/07: This was a 'long' fillup . . car was not driven much in 2 months. This represents all city driving.

11/28/07: Results for this tankful; gain some mileage due to very cool weather. Temps been in the high 30's at night; mid 60's in the day. Not much use of A/C.

2/16/08: 2nd tankful results for "hiway"; quite good and I'm pleased. Speeds were typically 80mph so it could be better. Also no A/C needed since weather has been very cool.

4/8/08: Another 'long' fillup . . b/c I haven't driven it too much; gas prices $3.79/gal is the reason!

Honda Fuel Results
Starting City MPG = 19.4
* Temporarily suspended use of Acetone
 City Avg (mpg)  City (mpg)  Hwg (mpg)  Details (miles/gal)  Cost Savings**  Cumlative Change (%)  Date
 21.5  21.5  -- 216.8/10.1  $6.19   10.7  4/10/07
 21.8  22.1  -- 236.8/10.7  $7.08   12.4  4/21/07
 21.2  20.1  -- 229.0/11.4  $3.63   9.3  5/05/07
 21.4  22.0  -- 242.1/11.0  $4.43   10.3  5/13/07
 21.5  21.9  -- 269.0/12.3  $3.33   10.8  5/27/07
 21.6  22.0  -- 251.4/11.4  $4.25   11.3  6/10/07
 22.0  24.8  -- 297.4/12.0  $4.48   13.8  6/30/07
 22.0  21.9  -- 264.8/12.1  $4.32   13.7  7/12/07
 21.8  20.2  -- 264.5/13.1  $2.94   12.5  8/5/07
 21.7  20.2  -- 222.5/11.0  $2.38   11.7  8/18/07
 21.3*  18.6  -- 225.5/12.1  $2.12   10.2  8/31/07
 21.2  20.3  -- 202.8/10.0  $2.50    9.8  9/8/07
 21.4  22.7  -- 336.2/14.8  $10.26    10.5  11/3/07
 21.5  22.1  -- 285.0/12.9  $9.45    10.8  11/17/07

4/10/07: Here's the first results for the Honda Accord LX (1990) for "city driving" exclusively.

4/21/07: Data is calculated in cumlative manner since roundoff errors affected the calculations.

5/13/07: 4th tankful: a +9% increase. This exactly counters the same "loss" last week. So it seems to be a mystery as to what caused last weeks loss.

6/10/07: 6th tankful: Looks like a plateau has been reached and this is probably the 'best' that this car will do.

6/30/07: 7th tankful: 12.2% gain. The increase in Acetone (2.5oz/10gals) seems to have made this large difference possible. Will continue this usage to see what happens.

7/12/07: 8th tankful: a -11.7% loss. The increase in Acetone did not do what it seemed to do on the last fillup! Will continue this usage to see what happens.

8/5/07: 9th tankful: Lost a bit but weather is hot/sticky, so A/C runs all the time.

8/18/07: 10th tankful: Terrible hot/sticky weather, so A/C runs all the time. Overall gain seems to be suffering!

8/31/07: 11th tankful: Same hot/sticky weather and, to boot, I suspended use of Acetone to see what the would happen. As you see, it mpg dropped to "18.6" for that tankful. Started using Acetone again.

9/8/07: 12th tankful: The weather has cooled abit, so A/C use is intermittant. Also Acetone was used for this tankful and as you can see it jumped from 18.6 to 20.3MPG. So it looks like that's what this car does.

11/3/07: 14th tankful: The weather has cooled. MPG jumped 18.6 to 22.7 MPG!

11/17/07: 15th tankful: Pretty much seems to have stabilized.

I will report the results as more are measured. So far, it's not a miracle but it's a very nice improvement!
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