Fuel additives

[Olivier-Rouchard]

I'm looking for the right fuel additive for AVGAS

 

I love mooneyland.com. I'd rather say: I loved mooneyland.com because it was a great source of information... The design was obviously not Zef's priority, but the articles were worth every minute of reading  ...

 

Now the content of the site is GONE... 

 

In one article, Zef was talking about the fuel additives he was using. Can anyone remind me what is was?

 

Thanks, Olivier

[N201MKTurbo]

Avgas is pretty good stuff to start with, what are you trying to improve?

[kmyfm20s]

What are you trying to accomplish with the additive? The only fuel additive I have heard people using is to reduce lead fowling but that can be accomplished by proper leaning technique. I asked the question on this forum about fuel injector cleaner and I could see knuckles coming out of the computer screen between 2 of the members. Oil additive on the other hand has been a hot topic and you can do a search for that. Read all the Savy Aviator and Pelican Perch articles, simple Google search and you will find them.

[pinerunner]

I started out just simply agreeing with the last two replys. Then I noticed you're from France. Could you tell us more about what you have for fuel, regulations, etc. Probably knowledgable europeans would be more help to you but I'm curious.

 

Dave

[aaronk25]

Mogas would be a great additive

[kerry]

Mogas would be a great additive

I agree.  I can't even find mogas in Nevada.  I would love to use it in my experimental.  I wish it was more available here.  Strange on how some parts of the country it's on every street corner.

[Olivier-Rouchard]

The additive I'm looking for is mainly used to increase the engine's life by lubricating the valves, improve the fuel combustion and keep the injectors "spotless". Zef wrote an excellent article about that and he mentioned the product's name.

In France, we have the exact same fuel as in the US and the rules are... The European way :-(

[Marauder]

The additive I'm looking for is mainly used to increase the engine's life by lubricating the valves, improve the fuel combustion and keep the injectors "spotless". Zef wrote an excellent article about that and he mentioned the product's name.

In France, we have the exact same fuel as in the US and the rules are... The European way :-(

 

Are you talking about AvBlend used in the oil? http://www.avblend.com/

 

Or Alcor TCP used in the fuel? http://www.alcorinc.com/index.php/products/tcp-fuel-additive-qt/

[ELT]

Could it be MMO.  Some swear by MMO added to the fuel (Marvel Mystery Oil).  Others swear at it.  Any way MMO is not approved for use in aircraft.

[aaronk25]

Never understood how fuel mixed with snake oil burning at a high temp, could lubricate anything.

[orionflt]

In some of the engines that did not require high octane fuel 100LL would tend to foul the plugs from the higher amount of lead. TCP and MMO (MMO is not approved for use on certified aircraft) scavenges the lead and keeps it from fouling the plugs. The other benefit it produces is the lubricant cleans and lubricates the fuel system...that is until it hits the cylinder and becomes part of the combustion process.

[aaronk25]

What needs to be lubricated in the fuel system and isn't 100ll a heck of a good solvent? I get the whole cam guard stuff, but not sure of the value of fuel additive.

[Rwsavory]

Don't put anything in your avgas.

[WardHolbrook]

Prist makes an fuel anti-icing additive that is commonly used in turbine aircraft that are not equipped with fuel heaters. The additive is available on just about every jet fuel truck for direct injection into the fuel as it is being pumped into the aircraft. Prist is also approved for use in avgas, but it's only needed in extremely cold temperatures. If you check your POH, you'll also may find that you can add up to 1% isopropyl alcohol to your fuel - it also serves as a fuel icing preventitive by removing any free-water in your fuel. Other than than those (and of course TCP) there are no other approved avgas additives that I'm aware of. As for MMO, it has a great placebo effect on some pilots.  

 

Here's a link if you'd like further information: http://www.pristaerospace.com/index.html

[bumper]

Never understood how fuel mixed with snake oil burning at a high temp, could lubricate anything.

 

I don't add snake oil to fuel or oil, but I understand it provides excellent lubrication for snakes . . . otherwise, just wasting money.

 

bumper

[blue eagle]

Now the real story about lubrication of valves:

 

- Old engines (before the 70's) used stellite valve seats, this is a high carbon steel. This steel has a ferritic crystal structure is magnetic and sensitive to decarbonization by high temperatures, this is making this material softer.

- Lead (TEL) does suppress this tendency at higher temperatures, so protecting the valve seats from becoming softer and causing negative valve clearance in engines without hydraulic valve clearance adjusters. This causes burnt valves (remember running an old beetle on unleaded gas will cause burnt valves).

- When unleaded fuel was introduced in the 70's, the problem of the valve seats was solved by using an steel alloy with an austenitic crystal structure. This material is not magnetic and has very good high temperature properties, but it is more expensive. All automotive engines have this valve material as of the end of the 70's and as far is my knowledge is all certified aircraft engines have it even earlier, because it makes the engines much more reliable.

- Valves were already earlier made from better materials because of the high mechanical load at high temperatures, especially the exhaust valves. You don't want a valve to break ever. So before improving the stellite crystal structured steel valve seats the valves were already made from a steel alloy with chromium, vanadium, tungsten to make them strong at high temperatures and resistant to softening by high temperature decarbonization.

- Aviation engines don't need TEL for valve lubrication or valve seat scavenging. The only reason for TEL is Motor Octane Number (MON) period. So if there is a fuel with  a sufficient MON leaded or unleaded it is suited for aircraft engines. Unfortunately at this moment TEL is the one of the most effective octane boosters. Otherwise we would have had already an alternative for the Leaded 100LL.  I tried to run my turbo normalized IO360 engine on premium unleaded but saw after only a minute with a leaned engine that nr 2 CHT went up dramatically. Switching to the other tank with 100LL solved the nr 2 high CHT immediately. This process could be repeated by switching from one tank to the other. I did not test blends because this is for my a risk of not getting the ratio when filling the tanks. So I decided to stick to 100LL , proving that Lycoming is right about the statement that the angled valve head engines like the 200 HP IO360 are not suitable for unleaded Mogas.

 

 

regards,

Blue Eagle

[jetdriven]

Excellent write up, Blue.

[Olivier-Rouchard]

That's it; it is the Marvel Mystery Oil I was looking for... Thank you all

 

Regards, Olivier

[carusoam]

So, you put automotive fuel in your plane and it didn't work the way you expected...

On the other thread, you were pro-alcohol...

Where are you going Blue?

Are you in the business of fuel testing?

-a-

[Olivier-Rouchard]

No, not at all. 

[Rich]

Not that I've ever done it, but wouldn't MMO be good when running LOP since the naysayers state that it's the lack of Pb when running lean that provides inadequate lube to valves?

[Mooneymite]

I add 95% water to my avgas.  The fuel economy is incredible.  I'm on the same tank of gas for the last 13 years.....since the airplane won't start!  

[David Brown]

I love these threads, it stresses me no end the amount of OWT's that still exist.

 

As posted earlier, TEL is used as a very potent octane booster, and nothing beats it. Nothing. It does not lubricate valves or valve guides, and think about where it goes and how it gets there. It does not get into the valve guides and the avgas that carries it is a great solvent, often up to 20% toluene and that is a brilliant solvent. So no help to the inlet valve is there? Next the Exhaust guides…..nope its now a salt and very abrasive. Last I checked abrasives made poor lubricants.

 

Next point about MOGAS, the Reid vapour Pressure is a problem, contamination is a problem, and lower octane is a problem for many engines, and just because you stick it in your experimental none of these issues change.

 

The biggest concern is gum content and carb engines. AVGAS has very strict limits on gum formation.

 

By this time next year I would hope to see G100UL becoming available, that will then be a big bonus to engine health.

 

But adding anything to avgas will only lower the octane. Just do not do it. Especially MMO, that is best for freeing up seized bolts on your boat trailer or something. Keep it away from your oil and fuel.

[aaronk25]

I love these threads, it stresses me no end the amount of OWT's that still exist.

As posted earlier, TEL is used as a very potent octane booster, and nothing beats it. Nothing. It does not lubricate valves or valve guides, and think about where it goes and how it gets there. It does not get into the valve guides and the avgas that carries it is a great solvent, often up to 20% toluene and that is a brilliant solvent. So no help to the inlet valve is there? Next the Exhaust guides…..nope its now a salt and very abrasive. Last I checked abrasives made poor lubricants.

Next point about MOGAS, the Reid vapour Pressure is a problem, contamination is a problem, and lower octane is a problem for many engines, and just because you stick it in your experimental none of these issues change.

The biggest concern is gum content and carb engines. AVGAS has very strict limits on gum formation.

By this time next year I would hope to see G100UL becoming available, that will then be a big bonus to engine health.

But adding anything to avgas will only lower the octane. Just do not do it. Especially MMO, that is best for freeing up seized bolts on your boat trailer or something. Keep it away from your oil and fuel.

Except that Reid vapor pressure has come down a lot and mogas is closer to avgas that it was 15 years ago. Agreed there are some concerns but if we put fuel pumps in the tanks and pressurized the fuel like autos do vapor lock would be thing of the past. As far as detonation if a engine monitor was installed that becomes a mute point too. Look at what rotax has done by just putting liquid cool heads on the engine they mitigated detonation.

Maybe after the non-commercial standard is passed someone will make a option for liquid cooled heads and then we can get knock sensors and be home free.

With liquid cools heads no aircraft engine would need more than. 91 octane!

[mike_elliott]

Except that Reid vapor pressure has come down a lot and mogas is closer to avgas that it was 15 years ago. Agreed there are some concerns but if we put fuel pumps in the tanks and pressurized the fuel like autos do vapor lock would be thing of the past. As far as detonation if a engine monitor was installed that becomes a mute point too. Look at what rotax has done by just putting liquid cool heads on the engine they mitigated detonation.

Maybe after the non-commercial standard is passed someone will make a option for liquid cooled heads and then we can get knock sensors and be home free.

With liquid cools heads no aircraft engine would need more than. 91 octane!

 

 

Probably more than what you wanted to know about fuel, but really explains where we are and where we are going. Pg. 3

http://www.iac38.org/newsletter/Jul2011NLhigh.pdf