The Center for Environmental Health (CEH) appears poised to challenge in court the National Air Transport Association’s assertion that General Aviation Modifications Inc.’s G100UL is not commercially available. “G100UL has been approved by FAA and is now in production. There are approximately 1 million gallons available for purchase and distribution into California,” CEH’s lawyer Mark Todzo said in a statement to AVweb. “It is therefore commercially available as that term is defined in CEH’s Consent Judgment.”
That judgment, which settled a lawsuit by CEH against dozens of FBOs and fuel distributors, requires them to sell a fuel with lower lead than 100LL as soon as one becomes commercially available. “The Consent Judgment has an enforcement provision, so if the distributors refuse to distribute G100UL or the FBOs refuse to offer it for sale once it is being distributed into California, the Court will ultimately decide whose interpretation of ‘commercially available’ is correct,” Todzo said. “Nothing has been filed with the Court, yet.” The City of Livermore, near San Francisco, may be the first test case, however.
At the regular meeting of the city council on Monday, (video of meeting here, fuel discussion starts at 25 minutes) a resolution was passed amending the definition of aviation fuel (full text below) and including the provision that “the fuel must have an industry standard detailing specific requirements for the quality and safe use of the fuel (i.e. ASTM) where the fuel is also accompanied by risk mitigation protection with established product liability insurance coverage provided by the manufacturer or distributor.” GAMI has not obtained an ASTM International specification for G100UL but does have an FAA STC that allows its use by virtually every gasoline-powered engine in FAA certified airplanes. Vitol Aviation, the licensed manufacturer of G100UL, says the fuel it has stockpiled is fully insured and is, in fact, for sale.
Aviation fuel consultant Paul Milner told the council that the ASTM specification doesn’t provide indemnification and is not a requirement for fuel to be sold. He said the amendment therefore delays the sale of unleaded fuel at the airport when the intent of the ordinance is to speed it up. He also cast doubt on the objectivity of the ASTM process, noting that oil companies fund participation by their employees on the committees “to protect, defend and establish their rights in the marketplace” and that council should “carefully assess committee participants’ motivations.”
Acting Airport Manager Benny Stuart appeared to contradict the ordinance requirement for an industry standard, saying the STC was enough to allow the sale of G100UL. “GAMI 100 would be allowed under this ordinance,” he said. He also said that while G100UL is a drop-in replacement for 100LL it has not been tested for mixing with Swift 94UL, which is widely available in the Bay Area and might be an issue for visiting aircraft needing fuel.
Pete Sandhu, who runs Five Rivers Aviation, the FBO at Livermore, said customers don’t want G100UL because of the $300-to-$700 cost of the STC, and he predicted that two other 100 octane unleaded fuels in development will force G100UL out of the market in Livermore. VP Aviation is predicting its 100-octane fuel will have FAA fleet authorization by the end of 2025 while Swift Fuels has not set a timeline for STC and ASTM approval of its 100LL replacement.
Sandhu said his customers have made up their minds. “No one will buy [G100UL] and it’s soon to be replaced,” Sandhu said, noting that Swift’s 94UL, which cannot be used by some aircraft, is in use at neighboring airports and is what Livermore customers want. “The market has decided that Swift is the preferred product.”
Too funny… let’s wait until the legal actions start to come through as a result of the engine damage like that experienced by UND in its fleet. I hear Mobil AV1 bells chiming in the distance!!
Oops, sorry. Didn’t intend to report comment. Fat fingers at work. 😉
I just read up on this tree hugging self appointed “save the world” group calling themselves “The Center for Environmental Health (CEH)”. This is a small group of unemployed zealots who decided to save us from ourselves by filing lawsuits and annoying people. It would help if nuisance providers would stay out of the leaded fuel replacement story and let this new product supply sort itself out without idiots asking state bureaucrats to legislate one brand of unleaded fuel over another.
It is time to put 100LL in the rear view mirror. If the problem with getting 100UL out of the chocks is the required $700 STC, perhaps the solution is for the FAA to add GAMI 100UL to all appropriate TC’s…..tomorrow!
The clean burning 100UL in the AOPA Baron is enough to convince me that GAMI has broken the code on aviation fuel. If the roles were reversed whereby Exxon/Mobil was trying introduce 100LL, to replace 100UL, you would NEVER buy into it after one look at the comparative cylinders. Who would ever want the lead and carbon deposits (in cylinders) created by 100LL? Not I.
I am not sure that ASTM even existed when 100LL was introduced as the new standard to replace leaded 100 OCT. How did we ever live without ASTM?
As humans we have a hard time with any change. Opposition to any change is in our genes. I remember when the law changed to require aircraft flying within 30 miles of a TCA (Class B today) to be transponder equipped. OMG one would have thought the world was coming to an end. Flying magazine published my comments. “It takes two to have a mid-air collision, the one with a transponder and one without”. You should have seen the hate mail. To all of you who were saved by your transponder….you are welcome!
Well put, Jeff. I agree completely, and recall similar reactions with the ADSB mandate which allowed a dear friend to turn a potential mid-air into a near miss while flying below a segment of the St. Louis Class B near Spirit.
“It takes two to have a mid-air collision, the one with a transponder and one without”.
If that is the case, then eliminating transponders would eliminate collisions.
ASTM has been around for 125 years. How long has Jeff Welch been around?
P.S. you can always find an activist mother who lost a child to something. That doesn’t make it a causal relationship (except drunk driving). How is it that for a half-century nearly all airlines, nearly all general aviation, all military flying and all automobiles used leaded gasoline and no mad mothers complained about lead in the soil – why is it that my generation (b. 1945) is not comprised of a bunch of lead-infested stupid boobs with no intelligence?
I don’t advocate lead in the environment, but I do advocate truth in environmentalism and there is precious little of that. Show that the environmental lead found hither and yon is due solely or predominately to the small amount of lead in avgas and nothing else, such as formerly leaded mogas and paint, or even natural lead in the soil.
I am a customer of Five Rivers, I know Mr. Sandhu and have confidence in his evaluation of the fuel supply and market. My O-540 was designed for 91/96 octane avgas and I would use it if it were available.
Firstly the Mayor and Council here by creating with the City Counsel, a new ammendment for a revised definition of ” commercially available ” actually shot themselves in the foot if their intentions were to move the Braly brew G100UL in a faster time frame to the pump to the tank.
They just redefined ” commercially available ” as one having ” ASTM ” approval, which of course , Braly G100UL fuel does not have and never will have.
“The Council amended the definition of aviation fuel (full text below) and including the provision that “the fuel must have an industry standard detailing specific requirements for the quality and safe use of the fuel (i.e. ASTM) where the fuel is also accompanied by risk mitigation protection with established product liability insurance coverage provided by the manufacturer or distributor.”
Secondly, the Mayor and the Council here in this meeting whereby they redefined in ordinance, the definition of commercially available fuel as one with an ASTM blessing, also took recorded statements from both a fuel ” consultant ” and a local area FBO owner / operator that Braly G100UL may or may not mix well with widely available to that regions – Swift 94UL – and that aircraft owners and pilots do not want Braly G100UL with its attached $300 to $ 700 STC for each engine field with Braly G100UL and are waiting for the 2025 to 2030 ? two other unleaded fuels currently under going development.
I know that several FBO’s in my area have no intention of stocking ,supplying or retailing G100UL or any unleaded av fuel without an ASTM endorsement.
Seems like a PMA approval for a hardened replacement valve seat around the same time as cars switched to unleaded would’ve made this a non-issue in 2024 and we could be running straight unleaded without any additives. Why is the focus on a patented (revenue generating) solution and not on the same solution that worked in the automotive industry? Obviously this is addressing the seat recession issues.
Sadly no where that simple buddy. The problem is far greater than just things to do with valve seats.
Lets not get all ethereal and theoretical.
Unless it’s cheaper and better then it’s not progress.
You cannot justify a product being more expensive and causing some harm. Since you cannot justify it, it has to be forced down onto consumers. This more expensive and worse mandates have even affected the the lowly 5 gallon gas cans.
“Unless it’s cheaper and better then it’s not progress.”
Nonsense. Progress is damn near always accompanied by a higher price tag, at least initially.
Apple is an example. I’m not a fan, never expect to own an iPhone, but they’ve continuously shown expensive progress.
It’s seems real simple. Just go where you can to get the fuel you want and boycott where they don’t sell what you want. Adios. Just say “hell no” to the lunatics in kalifornistan
Really? You think the California mother that Russ Niles wrote about a few days ago is a lunatic? This mother lost a young child to disease. She has found lead in the soil adjacent to a busy training airport and because of this she is somehow a lunatic?
I was born and raised on a joint military civil airport in Michigan (or perhaps Michiganistan in your speak). At this airport we have a serious PFAS problem due to tens of thousands of gallons of fire retardant, laced with forever chemicals, being dumped on the airport grounds over a 60 year period. I lost a kidney to cancer in 1998, I lost my 20 year old daughter to genetic disease in 2010. Do you think I am a lunatic too? Or do you work for Dupont?
I’m assuming you looked into the causes. At the risk of sounding insensitive, were either your cancer and your daughter’s genetic disease, both of which have many causes, linked to the chemicals? This is not a put down but an honest question.
Here in Colorado we have loud opposition over touch-and-go operations at KJBC and part of that was claims of lead from fuel accumulating on window sills and the such. Local towns buried a report that the only noted lead presence was around one house that had documented lead paint problems.
About 40 years ago, there was a lot of noise over building near and on the old Lowry bombing range, and a connection between it and chemicals such as MEK being dumped n the ground while cleaning aircraft and missile parts at Lowry AFB polluting the ground water. Turns out none of this was connected, as the range is several miles from the base, the base flying mission ended in 1964, and the area is on city water, not drawing ground water anywhere. There were no dots to connect, but the effort to get that info out there and disspell the impressions was great.
In CAPITALISM, the mantra for several centuries has been “build a better mousetrap, and the world will beat a path to your door.” Braley succeeded where others have failed.
Then government gets involved–BIG government (the FAA) approved GAMI fuel for almost any piston engine. SMALL GOVERNMENT (California municipalities) thought they ought to have their OWN standards.
Going back to the “better mousetrap”–it appears that THE RATS (California towns) HAVE WON–they have held up the availability for the rest of the country to have access to unleaded fuel, and are bent on eliminating the very person that took the initiative to actually INVENT a fuel that met FAA standards–as shown by the award of the STC.
Why not just quit flying? That’s what the Commiforniaists want anyway! Tax you into oblivion, take away your fuel, close airports! What a country!!! Welcome to the Soviet California!
Hear Hear! Jeff W. The problem is not the STC, as I have a mogas STC since 1993. This STC permits me to buy any brand of mogas as long as it a.) does not have ethanol, b.) meets my octane requirement (80/87), is unleaded or leaded. I have no specific love for ASTM. That standard is written into the STC. The STC states that the above are “per ASTM D439.” That is pretty much all it says. 17 states do not require ASTM D439 or its replacement D4814. G100UL’s STC is different. It permits me to buy that fuel and only that fuel. This means as Jim C says, go where you can get the fuel you want and boycott the others. Except, if G100UL is the only fuel within 200 nm of where you want to be, you are stuck. Monopolists are always in favor of their monopoly, which is exactly the concern of Arthur.
Your suggestion of having the FAA amend the Part 23 TC for all affected aircraft to use G100UL is the ideal solution. As the STC owner has demonstrated, the fuel appears to be acceptable for use in all of these engine/airframe combinations, therefore, it is reasonable. But, based on the FAA’s interpretation of the Owner produced replacement parts in its aging aircraft program, they will try to protect the existing PMA parts unless the cost is extreme. So, I am skeptical that the FAA will even think about this unless the 2030 deadline arrives.
“the fuel appears to be acceptable for use in all of these engine/airframe combinations, therefore, it is reasonable.”
“Appears” to be acceptable is not acceptable.
Thank you, your honor, I just have a few questions for this defendant FBO who pumped fuel into the victim’s airplane.
Q: The fuel you provided to the victim, has it been tested by the government or any 3rd party as safe?
A: No
Q: Has this fuel been tested in many aircraft and at many fuel delivery and distribution facilities and has been shown safe through experience?
A: No
Q: Was it tested to be consistent with industry best practices in terms of safety of fuel mixing, fuel delivery, or storage?
A: No
Q: Is this lack of testing and conformance with industry best practices normal for fuel?
A: No
Q: Is it fair to say that all other fuel available on the market or soon to be available on the market has been tested by the government, 3rd parties, and conforms to industry best practices for production and delivery?
A: Yes
Q: So, why would you ever choose to sell this “fuel” to customers, which has no government or industry testing, no field experience, and no conformance to industry best practice as being safe to use, deliver, or store?
A: Because George Braly told me his secret formula is good and the gummint is out to get him, so you know it’s got to be really good.
Wow, Steve, you make a great plaintiff attorney! Except for one small detail: the correct answer to all your questions should be “yes”, instead of “no”. See as follows:
Q: The fuel you provided to the victim, has it been tested by the government or any 3rd party as safe?
A: Yes. GAMI provided test results to the FAA demonstrating that the fuel did conform to all requirements of the FAA in terms of compatibility with aircraft engine performance under full load conditions that could lead to preignition or detonation. It was also reviewed with respect to compatibility with aircraft fuel tank and fuel line materials so as not to degrade those materials currently in use in legacy airframes. In addition, it was also tested and found to be compatible with materials (storage tanks, fuel lines, fuel trucks, etc.) commonly used by FBOs to store and dispense the fuel. Over an eleven-year period, the FAA conducted ten separate meetings and reviews of the GAMI G100UL formulation regarding these and more issues. Each meeting was attended by a different group of subject matter experts within the FAA who reviewed and subsequently approved the G100UL formulation to be acceptable to the FAA’s fuel standards.
Q: Has this fuel been tested in many aircraft and at many fuel delivery and distribution facilities and has been shown safe through experience?
A: Yes. In addition to the above stated testing, GAMI also conducted real-world flight testing of the fuel at a Florida flight school using their training aircraft fleet. No issues were uncovered using the fuel.
Q: Was it tested to be consistent with industry best practices in terms of safety of fuel mixing, fuel delivery, or storage?
A: Yes. In accordance with FAA requirements, G100UL was tested and proven to be compatible when mixed with 100LL in any variation of concentration. There was no degradation of performance. As for fuel delivery and storage, see above response and also that GAMI provided test data to the FAA that showed the fuel met their standards for aging of the fuel while in storage. As to the question of whether G100UL was tested for compatibility with Swift 94UL, the purpose of G100UL is to be compatible with, and ultimately replace 100LL, not Swift fuels, Mogas or any other type of gasoline compound. Since 100LL is the consensus fuel for all certificated US spark-ignited aircraft engines, that was the standard to which GAMI was tasked by the FAA to accomplish.
Q: Is it fair to say that all other fuel available on the market or soon to be available on the market has been tested by the government, 3rd parties, and conforms to industry best practices for production and delivery?
A: Not really. The question of what “best practices” you reference is irrelevant since the FAA does not require the use of ASTM or any other 3rd party standard for production of aircraft fuels. By issuing the STC for G100UL to be used by all spark-ignited engines in the FAA registry, the Agency has said that the fuel meets its standards, which are all that really matter. Also, G100UL HAS been tested as referenced above to comply with production and delivery best practices.
Q: So, why would you ever choose to sell this “fuel” to customers, which has no government or industry testing, no field experience, and no conformance to industry best practice as being safe to use, deliver, or store?
A: “Objection your honor. The question is argumentative and makes assumptions already refuted by previous answers to the plaintiff’s questions. The simple fact is that GAMI has had its fuel tested and approved by the FAA, the sole agency responsible for promulgating fuel standards. The FAA has subjected GAMI and its fuel to an exhaustive review for over a decade and, in the end, concluded that the fuel should be considered as an acceptable replacement for the current 100LL.”
We all know that there are likely to be bumps in the road when the fuel is rolled out to the general aviation population. Just ask Swift Fuels (a quality and responsible company) about how that works out. Would it have been better if George Braley had chosen to apply for an ASTM standard for his fuel? Perhaps, but as the article suggests, there are obvious issues as to whether such a standard would ever be issued, owing to the powerful forces dedicated to the status quo. In the end, the only way to finally settle the issue is to roll the fuel out to the public and learn from the results. Personally, I know George well enough to see that he is not a snake oil salesman, and I would be willing to use his fuel in my engine, even if in the short term, it will cost more to do so. I want to see if it will be better that what we now have, and I feel that he and the FAA have done sufficient testing to prove no harm.
Wow! You must be a real lawyer, as only a real lawyer could say so many false things so convincingly. ASTM doesn’t test whether a product is safe for use, or even appropriate for a purpose. Take Swift’s 94UL, for example. It has an ASTM spec, yet was used in UND’s fleet in engines that shouldn’t have been rated for such low octane. They had to stop using it due to detonation-inducted valve seat recession. Where was ASTM on that one? GAMI’s G100UL has been testied more thoroughly than any other STC’d product in the history of the FAA (that’s a fact). You haven’t even bothered to educate yourself on the issues before you started spewing patently false crap. People like you are a big part of the problem.
I have a message for Pete Sandhu: You just keep waiting for the VP Racing Fuel/Lyondell Chemical Teams 100 octane unleaded avgas. They have already issued a written notice to ASTM that their fuel will not work in radial engines. If you think ASTM is a transparent organization, ask them about this.
And, as for Swift…..anybody who claims to know when they will finish their “testing” is probably pulling your leg. Swift Fuels is a good company with a good reputation and their UL94 is a quality product. Those who believe that the UND problem with exhaust valve recession was caused by the fuel are miss-placing the blame on Swift when they should be looking at Lycoming. Time will bear me and Mike Busch out: Lycoming should never have authorized the use of 94 octane fuel (leaded or unleaded) in those engines without mandating a change in magneto timing.
And about the STC: Buying the STC (a one-time purchase) is a form of payment to GAMI for their enormous investment in capital and time to create a clean-burning, drop-in replacement for 100LL that actually can increase our oil change intervals while extending the engine TBO. Perhaps you would prefer to have GAMI take the traditional approach of building royalties into your pump price?
My suggestion to my fellow pilots would be to boycott Five Rivers Aviation with your avgas purchases. Help misguided Pete to see the light.
I have a message for John Caulkins: no such “written notice” was ever issued to ASTM for the simple reason that the fuel has not yet been tested in radials. Three are slated to be tested in the coming months. The three radials require 87 or 90 octane fuel so I am confident the fuel will perform just fine in those engines.
For non-fiction, just go to https://flyeagle.org/resources/
Pete Sanhu flies a Piper Mirage. I wonder if he knows that the other candidate “100 octane” fuels he thinks will be the future won’t work on his plane. They only have a ~85% coverage. The 350 HP Lycomings won’t be covered!
There are good reasons for caution re. G1000UL. First, the issue with removing the lead is that unfortunately, lead is an excellent octane booster, and therefore hard to replace. G1000UL is (reportedly) 100 octane – but don’t you dare test it. And, lest you are a “don’t worry, be happy” type, consider that almost all of our engines were certified on 100LL – which typically runs at 102-103 octane. So, has it been tested to work in YOUR engine, at ALL power, temperature, and mixture settings? Wanna bet your engine?
And then there’s the matter on the Rest of your fuel system. What’s your tank made out of? Was G1000UL tested with that material? Or your fuel lines, fuel selector valve, fuel pump, etc.???
There are good reasons for caution here. Look, I salute GAMI and hope that George becomes a multi-zillionare. I really don’t care. But I DO care, GREATLY, about MY engine and MY fuel system.
And, lastly, of course, there’s the issue of mixing G1000UL with 100LL, or Swift, or … Has any of that been tested and proven safe???
Be aware…
AF, your caution is wise, but a number of your statements (assumptions) are not correct. GAMI has exhaustively tested the fuel under the conditions you mention in both normally aspirated and turbocharged engines and proven to the FAA that it performs as well or better than the “standard” 100LL commercially available. It has also been tested for compatibility with legacy fuel systems and has satisfied the FAA that it will cause no more harm than 100LL may do. As for testing against other fuels, it has been demonstrated to work with 100LL in any concentration from 1% to 99%. As for testing against Swift, its purpose is to work with and eventually replace 100LL, not Swift, Mogas or whatever else a pilot may choose to use. It is unfortunate that FBOs are unwilling or unable to offer more than one fuel grade, so you can have a choice between G100UL or Swift, but the economics of that simply are not there. Next time I see George Braley, I will ask him whether he has tested for compatibility with Swift 94, but since the FAA has not required that testing of his, or any other competing fuel blend currently under development, I suspect he has not. If you choose to avoid G100UL if it gets rolled out, you are free to do so. However, you seem to feel that Swift 94 is okay, and it has had no more testing than G100UL has undergone, so Caveat Emptor. YMMV
“tested for compatibility with Swift 94 …”
Swift has stated that they will replace their Swift 94 octane product with their 100 octane fuel when (and if) it becomes available, so it’s hard to see much value in testing blending results against an explicitly temporary product. Those current operators who are satisfied with Swift 94 will hardly be eager to change to G100UL as long as Swift 94 is available; the operators of planes that need 100 octane fuel wouldn’t legally be able to mix-and-match a lower-octane blend. There’s no sensible reason to do serious testing of a 94/100 fuel blend with a likely market of exactly zero.
This FBO owner is quite adamant and speaking nonsense. I can only assume he has several fleet users who want the Swift 94, and those are actually the only customers he cares about. Certainly, he doesn’t care about owners who cannot use 94 because he acts like they do not exist.
His own aircraft (Piper Mirage) can’t use 94UL, and likely won’t be able to use the upcoming Swift 100R.
I had half a tank of 100LL and topped off with 94UL at KRHV. It was 90F outside. the airplane didnt run smooth during taxi. never had an issue with straight 100LL.
Now I read above that the timing should be changed for 94UL?
Please bring on 100UL. i want to try that. I dont like 94UL.
I read that the G100UL is actually based on a fuel post-WW2 designed for the big radial bombers that were soon replaced with jets and that it might be close to 130 octane. If true, bring it on!
For JohnS and others:
G100UL Avgas is not 100 / 130 (ASTM D2700 “MON” / ASTM D909 “RICH”)
G100UL Avgas is 100 / >150 (ASTM D2700 “MON” / ASTM D909 “RICH” )
On December 16th, 2020, about 2:30pm, with the senior FAA propulsion engineer sitting next to me in the GAMI CGME test cell, we completed the entire two day detonation test runs (about 37 line items with a matrix of about 16 different fuels and mongrel fuel combinations.
The FAA engineer (Kevin Marks) said,
“George are we done, based on the raw data, G100UL passes all of the detonation requirements.”
GWB: “But Kevin, there was one “optional” line item.
Kevin: “George, you are NOT required to conduct that test. Are you sure ? ”
George: “Kevin: The engine is conformed. The fuel is conformed. The instrumentation is conformed. The software is conformed. The FAA is here to observe. In person. Will there ever be a better time to run that test ?”
[Note: The test was to serially re-run the full power – hot day – hot CHT detonation lean down test on the 8.9:1 CR IO-550N – – with software controlled waste gates – – at progressively higher and higher manifold pressures – – until we destroyed the engine.]
George: “Lets start with 35″ MAP (rather than normal redline of 30, for that 310 BHp engine.)”
Kevin: “That worked. What next ? ”
George: (to my computer operator) “Lorilei, give me 38″ MAP.”
Kevin: “That worked, too. Do you want to stop ?”
George: “Lorilei, give me 42″ MAP.”
Two minutes later.
George: “Lorilei, I want 42″, not 41 or 41.5″ MAP.”
Lorilei: Taps one of the seven computer monitors, pointing at the waste gate position indicator. It is sitting on 100% closed.
George: “Alright, we have about 410 to 420 corrected Brake Horsepower (rather than rated 310), lets start the detonation lean down test.”
(Leaning from full rich down by 10%, without detonation, = ‘pass’ for the 14 CFR 33.47 detonation test.)
Kevin: “George, your are at 20% below full power. There is no detonation. Please stop!”
Note: At 41.5″ MAP x 2700 and 20% lean of full rich.
That 20% “lean of full rich” demonstrated a detonation margin, at ~ 130% of max rated BHp of more than twice that required for certification.
Thanks very much.
I don’t know what the guy at Livermore is hearing from his customers, but I’ve told the airport management and the fuel supplier at San Carlos in no uncertain terms that I’ve already paid for the G100UL STC and I want to be able to buy it ASAP.
Hi George B. I see you are reading these comments. A couple of questions for you:
1. What testing did you perform on G100UL with relation to valve seat recession (VSR)? How do you know that we will not have that issue with G100UL?
2. What happened at UND with 94UL?
3. Why is Swift adding an anti-VSR additive to their fuel? Does G100UL have such an additive?
4. Will using G100UL require a change in leaning procedures to avoid VSR?
Let me respond, in line.
Q1. What testing did you perform on G100UL with relation to valve seat recession (VSR)? How do you know that we will not have that issue with G100UL?
A1a VSR has nothing to do with lead or the absence of lead. The FAA WJH Tech Center ran some definitive tests in 1988 – 1992 time frame. Those are public test reports. No detectable difference in VSR between unleaded fuels and 100LL.
A1b ERAU ran an engine for the FAA G100UL avgas durability testing. ERAU mechanics did the engine tear down with the FAA on site observing. No detectable VSR.
A1c We have a TN IO-550 on our test stand. The same engine used for the detonation testing. I bore-scoped one of the cylinders, yesterday. After several hundred hours of rather extreme fuel testing abuse – – the intake and exhaust valves are pristine and look very much like the valves in the LH engine (G100UL avgas side) in the AOPA Baron at 150 hours.
Q2. What happened at UND with 94UL?
A2. Let me answer your question with a question:
Other than the “lead protects valve seats” hypothesis – – what would be another competent cause for excessive valve wear in an 8.6:1 CR engine operated on 94 MON unleaded gasoline ?
Q3. Why is Swift adding an anti-VSR additive to their fuel? Does G100UL have such an additive?
A3. That remains a mystery! Seriously, we have, over time, tested a variety of fuel chemistries similar to or the same as those ETBE based fuel chemistries identified by Swift Fuels in its publicly available information. Those fuels may cause VSR – – but not as a result of a lack of lead.
Q4. Will using G100UL require a change in leaning procedures to avoid VSR?
A4. Since use of G100UL Avgas does not cause VSR – – then no changes in any operating practice is required for any reason – – “VSR” or otherwise.