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Fuel Additives

Unit453

Unit453

Cruises comfortably at 140...
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Spin off of Randy's thread as I didnt want to jack his.


I'm curious to know about different fuel additives. There are many out there and we've all seen Spicer's study on which is good and which ones are not.

I've always ran Stanadyne when I was up north. Down here, I switched to two stroke, I never noticed any difference with anything. All our fuel here is 40 cetane, which seems low, considering I've seen up to 55 at some stations up north.

Amsoil has 3 different types of additives that I've researched. I'm curious to know the difference for each one and the benefit for someone like me, who's only running a mild 90 h.p. tune and pretty much granny it around. Do these cetane boost fluids help any? I certainly dont need an anti gel.

I also dont believe that any additive will magically increase your mileage. I think thats all a load of crap. Your engine is either efficient or its not.

I ask this because my mileage has dropped considerably over the last few months. I was getting 22 mpg at 70, straight highway and after this weekend, I couldnt get over 18.5 on a full tank from Suncoast to home. I never once got over 70, no head wind and outside air temps ranged between 45-55.

The additive I've been using is new on the market for road use. They claim that it'll increase mileage up to 3-4 mpg, which I thought to be complete BS the moment I read it. They say you have to run it through at least 5 tanks to see the difference. A couple of you guys know because you've been running it too. Well, I'm at 6 tanks and I lost 4 mpg. Now, either the filter is getting clogged with 5000 miles on it or this additive really sucks and they should stick to the marine industry. I'm curious to know why such a drop has happened. It isnt like I lost 1 mpg, but 4 and I think thats pretty substantial. My S&B was recently cleaned out and I just broke 37k miles.
 
I run power service, both summer (silver) and winter (white) blends. I do not see an improvement in MPG but I have never gelled or had starting issues and thet is why I use it.
 
Thats why I always ran Stanadyne. Up there, you kinda need to use something. I knew too many people who gelled up. Here, I dont have to worry about that. Hell, when it gets to 50, we're freezing our asses off.

I just want something that will help maybe for mileage and power. 40 cetane seems kinda low to me. I suppose that could explain why my mileage dropped but I'm not so sure.
 
I'll address cetane first.

Diesel fuels are classified 1D, 2D, and 4D. Low speed, stationary units use 4D fuels. 4D fuel is not appropriate for most mobile equipment. On-highway and mobile equipment use 1D and 2D fuels. High speed diesel engines use either 1D or 2D fuels. Important characteristics of diesel fuels are its viscosity, pour point, and cetane number. The primary differences between 1D and 2D fuel are the pour point and the viscosity. As you may know, pour point is the lowest temperature at which a liquid will flow, and viscosity is the resistance of a liquid to flow. A 1D fuel is designed for cold weather operation; thus, it is less viscous and has a lower pour point. A 2D fuel is used in warmer weather because it has a higher viscosity and pour point. The higher viscosity provides better lubrication qualities for the moving parts of the fuel injection system. Because 2D fuels contain more Btu's (British thermal units - the amount of heat necessary to raise one (1) pound of water one (1) degree fahrenheit) per gallon, they are able to deliver more power per gallon. This is critical to diesel engine fuel economy. The higher the Btu rating a diesel fuel has, the greater power yield per gallon; thus, higher mpg will result. Cetane rating is the diesel equivalent to gasoline's octane rating. Unlike an octane rating, which rates gasoline's resistance to spontaneous ignition, the cetane rating number (usually 40 to 55 for medium to high speed engines) notes the relative ease with which diesel fuel ignites. The higher the cetane number, the easier the fuel ignites; the higher the octane number, the more resistant the fuel is to ignition. Each manufacturer usually specifies a minimum or maximum cetane rating and the suggested operating temperature for 1D and 2D fuels. A given fuel may meet 1D or 2D specifications, but if the Btu rating is too low, then decreased fuel mpg will result.

Cetane number should not be considered alone when evaluating diesel fuel quality. API gravity, BTU content, distillation range, sulfur content, stability and flash point are all very important. In colder weather, cloud point and low temperature filter plugging point may be critical factors.

Diesel fuels with cetane number lower than minimum engine requirements can cause rough engine operation. They are more difficult to start, expecially in cold weather or at high altitudes, and they accelerate lubricating oil sludge formation. Many low cetane fuels increase engine deposits resulting in more smoke, increased exhaust emissions and greater engine wear.

Increasing the cetane number alone is not a fix for poor quality fuel. Additionally, increasing the cetane number beyond the engine's requirements will not increase performance. However, the cetane number of diesel fuel is not always consistent and you may desire to use a cetane improver to ensure full performance of your engine. If such an additive is to be used, it must not contain alcohol or other water emulsifiers (per GM).

For those of you running aftermarket or custom tunes, it is difficult to say what your minimum cetane requirement is, it may take some trial and error.

More on (Moron:confused:) the other stuff later, I've almost bored myself to tears, I feel bad for you guys reading this.
 
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Nick, one thing that comes to mind is where you went in those 5k miles on that filter. You made a road trip to the Suncoast get-together, right? Did you stop for fuel where you normally do not? If so it is possible it was a bad batch or a fresh batch that had sediment suspended in it from the bottom of their storage tanks.
 
2 thoughts I had:
1) You guys had a batch of pretty cold weather and your distributor could have put some kerosene in a few deliveries to guard against gelling which, as you know from NY will kill your mileage. When we switch over in spring (none too soon I might add!) it takes a few weeks to get back to full #2 performance and clear the tanks of the kero blend.
2) Your new additive may have a solvent effect like soy bio that has partially plugged your 5k fuel filter.

Yes I was a bit bored Wrecker but I might have retained some of that so it was worth it...):h

I'm with Mick though on the PS year round. Mainly because of easy availability.
 
Have you put on new tires recently or new wheels? A suspension lift?

Like others said, probably an additive the distributor is putting in. I use 2 stroke and it works great, and I do notice increased fuel mileage with it even, and my injection pump really needs the lubricant.
 
All good points noted in the above posts. Assuming the only thing different is the fuel additive, try a different additive. Now that you established a good baseline, try some Stanadyne, and see if you notice a difference in mileage and performance. Try 8 oz. of the Performance Formula each tank and see if there is a difference. The silver bottle in the Power Service is very similar to Stanadyne. It is non-scientific, but real world. ;) Keep us posted on the results.
 
Power Service. We add it to every tractor and fuel barrel, and haven't had a tractor or truck gel up in a long time. I also make sure that it gets added at every fill up on the 05.
 
I stick with wal mart 2 stroke; 1/2 oz per gallon and I have an anal routine for adding it to the tank... Buy fuel, 1 gallon goes into a 5 gal can. Go home. Add oil to fuel in can. Shake. Add to truck. Power Service is the only other one I've used and my demented logic tells me that an oil (even dilluted) lubricates the pump better than something that is really solvent-like and thin.
 
Ashton dosent recommend 2 stroke with our modern engines so I wont be using it anymore.

I bought some Amsoil additive from Wrecker so I'm gonna try that out to see if I can get my mileage back.

And to answer all the questions, the only thing that changed was the additive and an S&B intake. No new tires, no lift, nada. Same as it was a year ago, just now with more miles.
 
It seemed like you eluded to a location change too (when you used to be up North), and a possible fuel cetane drop (you saw 55 up North).

Is terrain different, more hills, shorter drives/commutes?
 
This is Florida and its flat. I came from northern NY where its all hills and mountains. But still, this was a flat 400 mile stretch of highway, never exceeding 70. I'm thinking I need to change my filter now.
 
Seems strange, could be something simple, your truck liked that humidity and barometric pressure or what not and decreased fuel output for it, who knows, but probably a fuel source thing. Ive heard of trucks getting better mileage when loaded than empty, doesnt make sense either, except it put the RPM in the right power band and the engine temp and air boost and backpressure better for efficiency.
 
I agree it would be and thats why I'm hesitant. I'm not really sure whats going on.
 
Nick, I didn't catch an answer to the question of whether or not you filled up at a different station while you were out of town for the Suncoast trip? Possible you picked up something foul there.

I've cut open my filters @ 15k and the media is still 1/2 clean, it always shocks me when one bad tank of fuel shuts people down on the road.
 
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