Gain 5% mpg...
 

Ok guys, here it is.

I had a previous thread on Diesel Kleen. So that everyone has access to this mpg info, I want to post the reply I got from DK about the extra mpg they claim. It's an "up to 8%", and someone said well, 0% gain is part of "up to". But the bottom line is, sounds like they have a fair claim at about 5% gain by using it. Here's their reply to me.......

Cetane is a very powerful energy compound that helps the fuel to ignite
a split second sooner which helps the fuel burn more completely, reduces
engine knock and helps reduce emissions.

The Department of Energy, Clean Cities Tennessee and Wal Mart
Transportation all conducted their own testing using their own equipment
and test set up and they found that fuel economy did improve, usually
around 5% for mix fleets or vehicles, that emissions went down and the
vehicles had better performance. Clean Cities TN also ran NOx emissions
and found that Diesel Kleen reduce NOx by 9% (running) to 28% (idle).
Total Fina did a study with new injectors and found that when using a
strong detergent and strong Cetane Boost fuel economy increased 2%.

.....Jeff 1991 300d, 111k

Wrong. Cetane is actually short for Cetane Number, the measure given to describe a light oil's ignition delay or, the time period between the start of injection and start of combustion of the fuel in a compression ignition engine. It is not an energy compound.

Tell Diesel Kleen that
 

I don't know. I just live on the planet and buy things. Maybe he skipped a finer point of the description, but that's what they sell, I assume (and hope) that they know what they're talking about.

jeff

http://en.wikipedia.org/wiki/Cetane

It's an energy compound, also called Hexadecane.

Octane is another, and cetane number is related to cetane in the same way that octane number is related to octane.

We don't burn gasoline that is 87% octane. We *certainly* don't buy gasoline that is 110% octane at the track.

I think it's reasonable to assume that clean injectors and increased cetane values can contribute to more complete combustion, which may increase mileage and reduce emissions. Obviously, this will provide more benefit if if your injectors are less than pristine and your compression is on the low side.

I other words, you are not going to improve performance beyond the "like new" condition, but you may help an engine that has degraded performance. You will probably still get more benefit from adjusting your valves and IP timing.

I stand corrected...Cetane Number (CN) is the measure of ignition delay. Cetane is the compound. Cetane has a CN of 100.

hmmm, off the subject, kinda. I wouldnt burn anything OVER 87 octane in a vehicle that didnt call for it, but in my racecar, I wouldnt let pump gas see the inside of my gas can. I would be afraid to see what 110 did to my street car though. (not the benz)

My 99 E300 got 33 mpg cruising at 85mph. Didn't get one thing more with DK. I tried it. Of course, my IP timing was on and the injectors were clean, fluids were good, etc, etc.

There isn't an additive out there where I've noticed a difference in regards to fuel economy. Sometimes there's a bit less smoke, and an interesting odor emanates out the twin-tailpipes. Perhaps a bit more power off the line too, for the first 50 miles. But nothing lasting.

Other than being green there is little financial gain from using these branded products. If the 5% gain in fuel mileage was valid that will give you another 1.25 mpg and that won't cover the bill on a quart of these products with the current fuel prices. If you look at the MSDS's for some of these products that active ingredient is usually methane or alcohol that's is what is pushing the cetane up. It's like selling bottled tap water - it's packaged conveniently for the end user.

the only thing race gas would do to a car with low compression is plug up the catalytic converter.

If it gives you a solid 5% from one engine that uses it vs that same engine when it doesn't use it, you might have something. This is assuming the engine is running in top shape

I have noticed an improvement in mileage when I use power service. It makes the most difference on Diesel No.2 (summer diesel) . This is probably because Diesel No. 1 usually has a higher Cetane rating to aid in starting in the cold.

I played a bit with adding a double dose of Power Service my last road trip and I got even better mileage. It did seem to drop some of the power though. Just topping off the tank remedied that.

IMHO Power Service definitely more than pays for itself when used with Diesel No. 2. In the winter its probably a wash.

Have to use it from time to time
 

I think you have to use DK from time to time to clean the injectors. My car runs quieter when I run it through, and you can't just use 4 oz. in a tank one time and say it didn't do anything. You have to run it through a few tankfuls to see a real difference, and it should quiet your engine down if it clacks. Mine clacks louder at startup of course, but then after that it quiets down.

I'm sure you'll get better mpg if your injectors are dirty vs if they're now cleaned, but still, my car runs quieter when I put DK in it from time to time.

Jeff 1991 300d, 111k

Cost me $70 to check the injectors and clean the dirty one at 120K. That is after several years. Why bother with that stuff then?

I used 4 oz and went up to 12 oz and didn't see a thing different. Maybe it is quieter but it is already quiet enough that I can't notice the difference. The wife noticed the difference with B20 in the truck. Without DK, the MB runs quiet enough. Even if it was a bit more, would it be worth the effort? IMO, NO.

Actually, a 5% increase in fuel economy will save me almost $0.94 every time I fill the tank.

Calculations based on: 23.5 mpg base milage (average recorded milage over the last 3000 miles)

with a 5% increase = 1.175 mpg (or 24.675 mpg total)

average cost of D2 over the last 3000 miles = $2.91 per gallon

I averaged 332 miles between fill ups (over the last 3000).

When I use DK, I add 12 oz DK at every fill up at a cost of $1.25. (I bought a 96 oz jug of DK at Wal-Mart for 11.96).

So:

A 5% increase in milage saves me 0.673 gallons of D2 at each fill up (13.455 gal vs 14.128 gal), plus adding 12 oz of DK replaces 0.078 gallons of D2. That equals $2.18 worth of D2 saved for every $1.25 worth of DK spent.

Now, lets turn the calculation around. How much of a mpg increase do I need to see before using DK is no more expensive than not using it?

First 12 oz of DK, replaces $0.227 worth of D2.

Therefore, adding 12 oz of DK only increases the cost of a fill up by $1.023.

At 23.5 mpg, I use 14.1276 gallons of fuel at every fill up (332 miles).

To make up the added cost of DK, I need to use 0.3516 gallons less D2 over 332 miles.

This means I need to get 24.1 mpg, or a 2.6% increase in fuel economy.

Provided that the product does no harm, you have very little to lose (or gain) by using it.

If there is little gain, why bother buying something, pouring it out, hoping not to spill the bottle, storage in the vehicle without spilling, etc, etc? For a fleet, maybe it might translate to some savings.

I'm just pointing out that the cost savings (for a w123 300TD) is negligible, if any. But at the same time, expense is negligible. You aren't going to spend much on it, and you definitely aren't going to save much by using it. So, forget the financial cost/benefit argument.

However, if it helps to clean 20+ year old injectors or cylinders over a few tankfuls, or if it helps to increase lubricity, or reduce emissions at all, then its a good thing (and a small price to pay).

If you want better fuel economy, make sure your tire pressures are good and slow down on the highway.

1976 300d 23 ~ 25 Mpg
 

I was hoping other 300D (114/115) owners could chime in on what their 300D MPG figures are.
Same for 123 300Turbo Diesel.
I know these are heavy cars, but if driven conservatively, with gradual accelleration from stand still I was hoping to hit in the high 20's.
thanks,
Rich

Bingo!
 

The little stickers with numbers on the pumps do NOT indicate a percentage. They indicate an anti knock or 'compressability' index. "Better living through chemistry" tells us - here in America - R+M/2 = octane rating.
R = research number IE: content by molecular weights.
M = motor number - fuel is is burned in a test bench engine, if I recall, according to ASTM specs. and the point just below 'knock' is found. Tetra ethyl lead, benzene even kerosene can add octane rating to gasoline without adding octane molecules. In Germany (if not the whole EU) only the research number is used.

I did a paper on 'organics in consumer contexts' in college and if I recall, cetane index is proportional to potential energy content per fuel volume at a specified temperature (I forgot that temp but I'll surf for it.)

ANYWAY having driven a truck, and seeing that 5% gain -vs up to 5%- I thought that would be a MAJOR REVOLUTIONARY breakthrough in transport costs. Think about how much 5% would translate to for ONE coast to coast trip! Some O/O truckers I've met swear by different additives and some don't.

My 240D (W123) has been seeing about 15 mpg (AWFUL!) for some reason, I've been adding half a bottle of DK to each tank I get. I buy the "Treats 100 Gallons for 3 Cetane Numbers", and am treating ~25 gallons with it, and it seems to smoke a bit less and have a bit more power.

Adjusting my valves, and cleaning/replacing injectors might get me up to the high 20s-low 30s, I should hope, but in the mean time...DK it is.

well played. well played.