what do you use Seafoam or Lucas ?

[jablair]

I have never been a fan of additives for either diesel or gas engines. I believe almost all are mostly hype and of questionable value.
Now having said that, I do use the Stanadyne Perfomance formula in my Ford 2000 7.3L for three reasons:
1. It was recommended by a long time and experienced diesel mechanic with his own shop. (The only one he would recommend)
2. It is sold by Ford under the Motorcraft name.
3. It does improve mileage anywhere from 1.5 to 2 mile per gallon. So it pays for itself.

[YosemiteBobR]

SeaFoam here, and in my bike as well

[GaryKD]

Hi fxdave,
Stanadyne Performance Formula is for diesel engines.

[Whitofok]

Have 42,000 and never have used a additive in my cummins 400 L series. I do keep it full of diesel when I am going to be parked for any period of time to keep water from accumulating. Been in 4 degree weather and never had any issues with gelling.

Have it serviced once a year and it has never had a issue.

[Mike Canter]

Cummins did some pretty extensive testing with different additives and could find no increase in performance or MPG and they state they don't want additive added in the fuel of the the Cummins diesels. I have been extracting horsepower from 2700-3200 hp supercharged engines for years in drag racing and just changing the fuel by an additive is not going to change MPG or horsepower in a motor. In a gasoline motor that is designed and built to run on regular gasoline will not have a increase in performance because you put premium in it. Now if the increase of octane in the premium gasoline was combined with the ability to advance the ignition timing then you would see an increase in power. You have to do something in the motor. It takes a set amount of horsepower to move a certain weight motor home down the road (thats plain physics) so just adding an additive does not change the horsepower required and to make that horsepower requires a set amount of fuel (Brake Specific Fuel Consumption of BSFC). The problem is on a motorhome trying to measure MPG accurately is so hard to do because wind has such a effect on it as does altitude and temperature. I have tried everything in the world to get repeat readings on MPG on two different MHs but it is impossible to do. There is no way you can get enough repeatability on computing MPG to say anything was done to improve MPG .1 to 1 MPG. Stop and think about this if diesel fuel cost $3 a gallon and you had a 100 gallon tank and you got 9 MPG and the additive cost you $9.00 a can then you would have to have an increase of .27 MPG for it to pay for the can. Major trucking companys would jump on a .27 or greater MPG increase but most national trucking companies ban the use of fuel additives in their trucks. If it worked then they sure would use it. Then people got off onto these Lubricity studies that where really put out by the makers of the additive to worry you to death and make you buy there product. There is nothing wrong with the lubricity of ULSD fuel. It has not shown any validated damage to any diesel motor. You do have those Urban Legends running around that people knew drivers that new other drivers that lost their motors because of problems with the fuel. Stop and think of how few of miles we put on our MH motors compared to a long haul truck. I talked to a truck driver parked next to me at a WalMart and he had right at a million miles on his CAT C-16 and did not do anything but change the oil on a regular basis.

Don't get me wrong here...if you want to spend that extra money and feel better about then good for you. I thought I would just state some facts and opinions. I will not put any in my motor.

[Chuck 1935]

Mike Canter
Well said, you covered all the points perfectly.
My Dad decided to use STP in his car. If a little was good, more would be better. He called me one day to tell me that the car wasn't running very well. It turned out he had bent most of the pushrods. So much for lubrocity as opposed to viscosity.

[DevonJH]

I cant say much toward diesel as I typically run gas everything. But, I use seafoam in my vehicles. Not as a gas additive, but as a cleaner. I suck up about half a can of seafoam in through the vacuum line that goes into the brake booster, let it sit for about 5 minutes, then run the engine till the smoking stops (usually a 15-20 minute drive works). I can't say much about mpg or hp as I've never measure either, but I definitely Feel a difference after the systems been cleaned and the vehicle seems to respond a lot better.

I will also note I tend to run older equipment thats usually carburated, though I've done the same with a fuel injected car and noticed slight improvement. I'll throw it in the tank from time to time but its once every 15-20 tanks or so.

[GaryKD]

Hi Mike Canter,
I guess 28+K miles with no additive and 40+K miles with the additive and the .6 MPG increase over those miles must be a figment of my imagination. Low 7s without the additive and 8.2 with the additive. I know that is not good math. I'm stating a very conservative number to keep the nit picky flames out of this thread.

The mileage increase was immediate and sustained. Both before and after, I've been all over the USA in all kinds of weather. I travel the same speed over Interstate highways. The coach is about 3K lbs. heavier now (mileage with the additive) than it was without the additive.

Stanadyne Performance Additive does other things in addition to fuel mileage. Count me as one owner and one coach where an additive works for increased MPG.

[Mike Canter]

Gary, I would like to keep this just as a friendly debate or discussion soi don't take me wrong. I am not saying you computed it wrong but with 28K without the additive the diesel was probably just breaking in at the end so I would expect a MPG increase as time went on and .5-.6 mpg would be a good expectation. Also your driving habits might have changed or the tires tread was finally worn down enough to get better MPG or you changed to a different type of tire. I believe Cummins when they did indepth testing on a dyno and on the road and found no difference with or without additives. There are lots of things that cause changes in MPG. The real truth would be to now stop using it and record your MPG.

Just changing your driving speed will change your MPG as we all know. A really good rule of thumb according to CAT is every one MPH will change the MPG by 0.1. So if you got 7.0MPG at 65 and you slowed down to 60 you will see a increase in MPG of 0.5

You don't get the best MPG on a tire until 50% of the tread is worn off.

So how much does it cost to add that Stanadyne additive to 100 gallons of fuel?

[GaryKD]

Hi Mike Canter,
Sorry you took my comments to be less than friendly. I smile when the baseline for a point of view is the manufacturer's testing. Being a retired engineer I am always interested when engineering testing is used to state the basis for an opinion. It is also interesting when a completely different situation (drag racing) is compared to our environment (a diesel engine cruising down the highway) as if the two environments can be compared.

Mike, the bottom line is the change in my MPG was immediate, the very first tank. It has remained consistent ever since. If you read my post, except for the tire wear and the increase in weight, nothing has changed. I did expect you to return the old tale that diesels improve MPG with miles and time. In my case this does not explain the immediate and sustained MPG increase. Instead of continuing the generally known statements, I would be interested in your comments specific to some who has the experience mentioned in my post. When nothing changes and the MPG is immediate and sustained then the preliminary conclusion is there must be some benefit to the additive.

I worked for a manufacturer my entire career. For me, any manufacturer testing is suspect unless I understand the details that went into the testing criteria, objectives, component choices, duration, setup and actual test implementation. Most of the time the details of these items are not available to the general public. Instead, high level information is provided that can be defended in court, but may not provide the general public the ability to determine if the testing applies to their situation.

For me, Stanadyne's reputation among their customers, the company's reputation, history and most important the immediate and sustained improvement in MPG is evidence that Cummins engineering test items mentioned above may need to be investigated a bit more before I would take a position based on the manufacturer's testing. After all they have no joy in saying their engines operate better when using XXX additive.

As to your question on cost. I recently paid $17.40 for 64 ounces of Stanadyne Performance formula. This will treat 250 gallons of diesel fuel.

My post(s) is intended to provide a different view that an additive can produce benefits. Maybe not all additives and maybe not in every situation. However, it would not be correct if a manufacturer's "testing" was the baseline for a member's decision without understanding there are other views and results that, in the real world, have been different than the manufacturer's "testing".

If a member made a decision to try an additive, my recommendation would be to consider the additive for one year of travel or at least 20K miles. One should have MPG data from the same number of miles before adding the additive. Then one can make a decision about the benefits, of the additive, for that particular coach and owner.

[bldrbob]

With 110000 miles I think my motor is broken in. I have been averaging 8.5 mpg since i bought my motorhome with 82000 miles.Going to Ct I decided to try Lucas . My mileage went to 9 mpg since adding the Lucas.I don't think anything else changed.The cost savings breaks even but i think it must be doing some good.

[Mike Canter]

Sorry, I did not take your comments less than friendly. By no means. I was concerned that you might get upset with me continuing the discussion. So we are both alright .

I do find this discussion very interesting because of exactly the same reason of being a retired engineering from the Aerospace Industry. So in keeping our inquisitive minds open lets talk about what would make the MPG increase. Like I said before and everyone can test this and it is basically the same thing. If you have a gasoline car that is designed to run on regular gasoline and you put premium in it the MPG will not change. It will not run faster or better. Now if you take a car that is designed for premium and you put regular in it then the knock sensors in the car will detect valve pinging and it will automatically retard the ignition so it will not detonate and performance will be reduced as well as gas mileage and all that is because the ignition timing was changed. Now when you put the premium into the regular engine if you had in fact advanced the ignition because of the increase in octane allowed it without getting detonation then you would see an increase in performance and gas mileage but only because you changed the ignition timing. So holding those thoughts lets switch over to a diesel engine that is in a MH..........so the only way a diesel engine can make better MPG is to increase the power at the same RPM so you can maintain that same speed going down the road with less throttle so less fuel. How is this going to happen if you don't change anything mechanical or in the ECU and you just add an additive? OK, I can understand an additive cleaning the injectors or "lubricating" the fuel system or "lubricating" the upper cylinders but how is it going to change the MPG at the rate of adding only 0.25 oz per gallon of fuel.

One of the biggest problems I have found is the inability to compute accurate MPG in a MH. I can read out instaneous mileage on the computer but that really doesn't help because you need a long time average to be worth anything. Wind has such an effect on the MPG and that is always changing, then there is temperature versus air density which makes it harder to push a square box through the air the cooler the temperature is and this changes MPG. Then there are types of road surfaces that change the rolling resistance of tires and change MPG. Running a diesel generator or a Aqua Hot changes the amount of fuel taken out of the tank so that changes MPG computed at the fillup. Then there is the route driven and if there is traffic or there are small hills or big hills or all slightly downhill and all that changes the MPG. Then there is actually density altitude (or corrected altitude) and that is what the engine sees and that is computed from raw barometric pressure, humidity and temperature and that is constantly changing and changes the amount of power the motor puts out. Just because you are at 100 ft above sea level on your GPS does mean that your motor is not really seeing the 3000 ft actual or 5000ft. Just to demonstrate we change the amount of fuel into our race car engines by almost a gallon per minute flow for every 1000ft of density altitude change plus on top of that our power output decreases still the higher the density altitude. Another factor that really screws up the computation is putting the fuel into our tanks. The tank is so large in surface area lets say 7ft long by 2ft wide that a 1/8 inch or 1/2 inch difference in the height of the fuel when we shutoff the nozzle makes a tremendous difference in the amount of gallons pumped in. Was the pad you were sitting on level when you fueled to compute the MPG. The only way you can do it accuretly is to first level your MH then fill to a set mark in the fill neck and I mean to be right on everytime with no foam or anything. So far with two motor homes the variables are too great to compute accurate MPG. My old MH was easier because I could just fill the fuel until it backup the real small filler neck but no way on one with a big tank and a big short filler neck. I know we have all played with trying to get as much fuel into the tank as possible. You can fill it up to a mark and turn around then look back and the level changed. Some pumps let you do it and some pumps just don't. Never figured out the difference.

Don't get me wrong here....if you want to continue to use an additive then that is your own business. I for one will not waste my time or money on something that I don't thinks makes a difference and is just marketed to make somebody rich. I have said this before if major trucking companies saw something that would increase MPG on their long haul trucks then they would all be using it. Every long haul trucking outfit that I know of that the fuel and tractor is paid by the company does not allow fuel additives to be added. Just think of the miles they drive and all their trucks a change of .5 MPG would be a gigantic saving. Look at the ad for UPS saving a little fuel by always making right turns multiplied over their entire fleet of trucks. So why wouldn't it be better to put an additive in those trucks that gave them a .5 mpg increase. Stop and think about it.

[GaryKD]

Hi Mike,
There are few people that have well thought out posts. You are one of them. What got me to respond to your post was:

1. statements of facts that may be unrelated to a coach owners environment.

2. part of the last sentence that says "if you want to spend that extra money and feel better about then good for you." That statement seemed quite pompous. It did not reflect the knowledge mentioned earlier in the post. For me it insinuated those of us who use additives are somehow wasting our money or not very smart because we use an additive.

Almost of the posts that have these insinuations I do not respond to because that particular member's posts follow a trend of lacking training, knowledge and/or skill. It is easy for readers to determine what to do with the information. So, I guess you can feel complimented (in a weird sort of way) that we had this exchange.

I was a consultant to the OTR trucking industry for a few years (new I/T technologies). Why they do not use fuel additives I am not able to post. I already made one statement of fact about OTR drivers and got more flames in a few days than I have in all the years on iRV2. Even in our modern times sometimes the messenger gets killed.

As we continue to have our views of additives we will each be pleased with our individual positions. No harm done.

[Mike Canter]

[QUOTE=GaryKD;794409]

2. part of the last sentence that says "if you want to spend that extra money and feel better about then good for you." That statement seemed quite pompous. It did not reflect the knowledge mentioned earlier in the post. For me it insinuated those of us who use additives are somehow wasting our money or not very smart because we use an additive.
[UQUOTE]

That is not how how intended that statement to come across. It was not meant to be pompous or insinuate anything other than ...Its your money and your MH and its your decision.