Fuel additives.

[67hat34c]

I have been in a heated debate on another forum regarding additives. Namely Startron which is marketed by Starbrite. They claim their uniqe enzyme formula cleans fuel systems and can improve fuel economy up to 15% claim that the additive allows a more complete fuel burn.

Well I belive almost all additives have the same claim of fuel economy and I cant recall any of them proving it. In my opinion there is no fuel or additive that will improve economy without alterations of the engine.

One person said that by introducing Ethanol which is known to have a lower energy content that gasoline that it causes lower economy, very true. However he says that if you introduce a higher energy source into the gasoline that it should increase fuel economy. I say no unless you are changing compression and fuel air mixture,forced induction etc.

What do you guys think.

 

[MikeP]

You are absolutely correct - just like the folks who think putting premium gas in their car when the engine was not designed to need it will improve power/economy, whatever. The only thing it improves is the gas-refiner's bottom line.

 

[67hat34c]

I wrote to the Petro Chemical Dept at Texas A&M, They responded as follows:



-----Original Message-----
From: Blasingame, Tom [mailto:t-blasingame@pe.tamu.edu]
Sent: Wednesday, July 02, 2008 7:01 PM
To: Hierholzer,Steve
Cc: t-blasingame@tamu.edu
Subject: (Hierholzer)_Need info on gasoline mix and fuel additives

One of our faculty responded to your inquiry as follows:

[... if the additive that he speaks of truly improves the completeness of combustion (what we refer to as "combustion efficiency"), then yes you could potentially improve fuel economy. In other words, more completely burning the fuel introduced to the cylinder will result in more chemical release of energy, which can be converted (partially of course) into more mechanical energy, or work. The same is also true if an additive can somehow "improve" combustion so that it takes place in a shorter period of time within the cycle. In both cases, one is effectively "increasing the area under the P-v curve" and improving the conversion of chemical energy into mechanical energy.

In the case of gasoline / SI engines, combustion efficiencies are around 90 to 95%. But beware of improving that combustion efficiency too much, because the effective operation of the three-way catalyst depends on the presence of unburned fuel (hydrocarbons and CO) to reduce NO. It's conceivable that the oxygen sensor will alter the engine's air-fuel ratio to ensure this "cocktail" feeding the catalyst remains in balance. In other words, the engine controller could simply undo what the additive does (if it works as it says it does).

In the case of diesel / CI engines, combustion efficiencies are around 97-99%. Considering that thermal efficiencies are around 30%, any improvement in combustion efficiency will buy you at most 0.9% improvement in engine efficiency; probably would get lost in the noise.

Probably an equally significant question is, does the additive actually do what is claimed?

...]

 

[Brian Degulis]

Any diesel additive that contains a Cetane booster like Diesel Kleen will lower fuel burn. How much depends on the cetane rating of the fuel your using the lower it is the better the improvment. Then it depends on your engine the more worn the engine the better the improvment. Is it a diffrence you will see probably not and the 15% is just BS. But if you use an additive that makes the engine quieter smoother cleaner and easier to start you are getting some improvement in fuel burn.

Brian

 

[MikeP]

I have never seen any EVIDENCE that fuel additives do anything that they claim as far as improving power. Having someone say "I could tell it revved better," or "I could feel it had more power." is not evidence and it's almost always wrong anyway.

To do a rough evaluation that works quite well, you can do a series of accleration tests - say, 5 runs from say 1000 RPM to WOT, (throttle shoved to the stop like "flooring" it in the car) timing how long it takes to get from 1000 to whatever the WOT RPM is. We don't care about boat speed, just about the acceleration time of the engine itself under load. Then do it again after adding the additive and ensuring it's thoroughly mixed. If there is a decrease in the time needed, THEN I'd call it proof that the additive "added" power. A dyno or 1/4 mile trap speed would be better but I don't see that happening with a Hatteras!

A really classic case of the psychological thing going on is the old case of somebody putting a big 4 barrel carb on a car and FEEELING the "greater" power when those secondaries kicked in. Yep...and when we put the car on the track or the dyno it was SLOWER than it was before because the big secondaries put a big sag in the power curve.

Thats NOT to say that additives can't do other useful things like clean the fuel system but Marvel Mystery Oil will do it better and cheaper - just have plenty of spare filters!

 

[67hat34c]

Mike, those were exactly the same arguements that I used. Even the psychologial effect which is similar to when you get your car freshly detailed inside and out, it will run much better.

One even brough up NO2 which i fired back and said not a fuel or an additive. It does not improve MPG but allows more fuel to burn with the added oxygen that it provides. More Hp with more fuel burn.

Well the other forum is loaded with guys who fall into the "sucker born every day" catigory. Not going to spend any more time with them on that subject.

 

[Boatsb]

The only fuel additive I have seen work is "Liquid Schwartz". Yogurt told me about it but I can't seem to find it in stores around here.

Oh no there Spaceballs, There goes the neighborhood.

 

[Captcoop]

I just did a test with my 45C with QSM 11 engines. I put a cetane boost in both engines and doubled the boost on the starboard side. After 3 hours at cruse speed the starboard side with the double dose burned 2 gal. more fuel. (60gal/58gal). This is according to the computer trip log. I plan to reverse the test when I use the fuel down to about 30%. At this time I'd say the additive was not a good deal.
Good Luck

 

[34Hatt]

Well Steve it is kind of simple that If you Improve fuel quality and get a better burn in some cases it will Improve mileage. All you have to do is prove 15% in one case and that is it. I will say that it does change greatly between different case. I had one guy with a Ford 350 diesel say no change with using AJX. Another one with same exact truck but had a computer with mileage read out said he got about 10% Increase. So is it the truck or did the other one not have good mileage #s. Now for a boat forget about doing #s unless you have a flow scan. One yacht that I was talking with the Captain said he too got a good 10%. My wife's car on the highway goes from 28 mpg to 30 mpg I done this test like 10 times exact same #s. Did the same with my truck saw no change. Wifes car around town no change other people who have tried it said the have seen change around town and highway. Some say no change anywhere. Also Wife's car has 1/3 of my trucks mileage so the older motor verses newer does not apply to that.

 

[Boatsb]

Ethanol is an additive and it definitely affects fuel economy. Just negatively. I had to run round trip to Miami yesterday and used more fuel than expected. I usually get 240 miles for about 12 Gals. yesterday I was at 362 miles and had to grab fuel at the highest prices county in Florida. 14 gallons which means the 20% loss of economy with F-enol.

 

[krush]

He's right on about combustion efficiency and "increasing area under the p-v curve".

The increase in combustion efficiency would almost be neglible. Where one would find more increase is in the THERMAL efficiency of an engine. One simple way to do this: reduce the amount of heat rejected to the head/block/piston and allow it to be used to do more work (aka push the piston down).

Modern engines are pretty damn good at achieving complete combustion.