So....reformulated gas(10%ethanol)

[GG-1]

Hello All,
What about Avgas? These are leaded, high octane, and ethanol-free fuels. Owning a 383HP (Commando) 10:1 compression car/Fury, I'm very interested in knowing what experience members here have running with this "aviation fuel" in their own cars. I know it's used more commonly on the dragstrip/racetrack.. and the shop that recently rebuilt my original carburetor(carter afb 4bbl) suggested at each fill-up mixing 5 gallons of the avgas 100LL (blue), with the rest being 91-93 octane ethanol-free unleaded from any auto gas station-- this creating the right levels of lead/octane for my motor to perform as it was originally designed. Other techs concur that my motor will love this.. my carb shop guys also emphasized to never, ever put store bought fuel additive products in my car, ever. It's been 9 months since I've had the carb rebuilt, and I personally replaced the fuel tank, sending unit, fuel line(rubber included), fuel filter, and fuel pump. I have not been able to run her regularly, never mind driving, due to time, distance, and other mystery mechanical issues requiring attention. I have started and ran the engine for 30 minutes at least once a month.. and driven her a total of about 1,000 yards. It kills me to think as she sits that this "jelly" is forming in the carb/fuel system with 10% ethanol pump gas, even if I use premium 93 octane. With 14,410 original miles on my car I have a good opportunity to get this right before it goes wrong.

Avgas 100LL (dyed blue)
Avgas 100 (dyed green)

At smaller local airports here in Westchester County, NY these are currently going for about 7.25 a gallon.. a lot I know but that's the full service price for planes.. with all her charms GG might need to make friends at the pump, yes??

I can't find ethanol-free pump gas anywhere close to me.. if anyone knows of a place in my neck of the woods please do tell! John aka 75LandYaught??

Please tell us what you know fellow C-friends.

Thanks, Alex & GG

ps. My carb rebuilder also insisted on drilling out a certain passage (sorry don't recall which passage) by a few 1/100s which apparently makes it perform better with today's crappy fuels. I'm concerned that this may have messed it up.. but other carb guys I spoke to concurred that this is pretty much mandatory for professional rebuilders nowadays and will not affect performance negatively, regardless of fuel type. Still, was this the right thing to do? I still haven't pinpointed cause(s) of issues with her running badly.. bad coil? I'll be starting new threads for those other things soon.. oh boy.

 

[GG-1]

There may be very useful info here on how to modify our carburetors for use with today's ethanol fuel fuckery syndrome(EFFS)...
THE CARBURETOR SHOP / Use of ethanol in older carbureted vehicles

..goes over things like switching to ethanol resistant accelerator pumps, raising the floats by 1/32", etc..

 

[78Brougham]

I run 100LL in my cars occasionally. At $4.85 a gallon it can get a little pricey, but it's good for a treat. I also put some in at the end of the driving season to negate that crappy "corn squeezins" they call gas these days. They run great. Smell different too. Good old fashioned leaded gas. Not for cat cars though!

 

[GG-1]

I run 100LL in my cars occasionally. At $4.85 a gallon it can get a little pricey, but it's good for a treat. I also put some in at the end of the driving season to negate that crappy "corn squeezins" they call gas these days. They run great. Smell different too. Good old fashioned leaded gas. Not for cat cars though!

Thanks, Good to know! No cats on my 67 Fury to worry about. So tell me, would you run your cars on 100% 100LL all of the time if it weren't so pricey? I've heard that's how it was back when these cars were new.
Also, where do you get your 100LL? That actually seems like a good price for what it is.
That's also a great idea to "winterize" a car after a "corny" summer.

 

[Ripinator]

Outboard 2 stroke oil with tc3 2 oz per 5 gallon of gas. Coats the internal parts with some oil and burns clean through combustion chamber.

Actually, you should use only ONE ounce of marine oil with TC-W3 per five gallons of gas to get the most benefit.

 

[GG-1]

Not true, sitting and evaporating causes the jelly like crap that forms on the floor of the float bowls. Constant driving or at least consistent use would extend the formation time of that crap. IMO

How long does it take for the jelly-like crap to form in the float bowls?

 

[detmatt]

You do have an interesting set of circumstances with that low mileage untouched engine in regards to lead content but I still don't think I would be concerned unless you plan on putting 10K miles a year on it. I'm with Rip on the marine 2 cycle.

 

[75LandYacht]

Hello All,
What about Avgas? These are leaded, high octane, and ethanol-free fuels. Owning a 383HP (Commando) 10:1 compression car/Fury, I'm very interested in knowing what experience members here have running with this "aviation fuel" in their own cars. I know it's used more commonly on the dragstrip/racetrack.. and the shop that recently rebuilt my original carburetor(carter afb 4bbl) suggested at each fill-up mixing 5 gallons of the avgas 100LL (blue), with the rest being 91-93 octane ethanol-free unleaded from any auto gas station-- this creating the right levels of lead/octane for my motor to perform as it was originally designed. Other techs concur that my motor will love this.. my carb shop guys also emphasized to never, ever put store bought fuel additive products in my car, ever. It's been 9 months since I've had the carb rebuilt, and replaced the fuel tank, sending unit, fuel line(rubber included), fuel filter, and fuel pump. I have not been able to run her regularly, never mind driving, due to time, distance, and other mystery mechanical issues requiring attention. I have started and ran the engine for 30 minutes at least once a month.. and driven her a total of about 1,000 yards. It kills me to think as she sits that this "jelly" is forming in the carb/fuel system with 10% ethanol pump gas, even if I use premium 93 octane. With 14,410 original miles on my car I have a good opportunity to get this right before it goes wrong.

Avgas 100LL (dyed blue)
Avgas 100 (dyed green)

At smaller local airports here in Westchester County, NY these are currently going for about 7.25 a gallon.. a lot I know but that's the full service price for planes.. with all her charms GG might need to make friends at the pump, yes??

I can't find ethanol-free pump gas anywhere close to me.. if anyone knows of a place in my neck of the woods please do tell! John aka 75LandYaught??

Please tell us what you know fellow C-friends.

Thanks, Alex & GG

ps. My carb rebuilder also insisted on drilling out a certain passage (sorry don't recall which passage) by a few 1/100s which apparently makes it perform better with today's crappy fuels. I'm concerned that this may have messed it up.. but other carb guys I spoke to concurred that this is pretty much mandatory for professional rebuilders nowadays and will not affect performance negatively, regardless of fuel type. Still, was this the right thing to do? I still haven't pinpointed cause(s) of issues with her running badly.. bad coil? I'll be starting new threads for those other things soon.. oh boy.

Sorry Alex, this is all new to me. Interesting topic though. I've run 89 octane in mine and she runs as I think she should, only because I don't know any better I guess. I know fuel isn't what it was when our cars were new. Maybe I should look into runnning some JUICE through her and see what happens.

 

[70bigblockdodge]

How long does it take for the jelly-like crap to form in the float bowls?

I don't know how long it would take. Mine had not been apart in probably 8-10 years. I put 1000-3000 a year depending on weather, free time.

 

[1970cat]

listing of stations with ethanol free gas
Ethanol-free gas stations in the U.S. and Canada

 

[78Brougham]

Thanks, Good to know! No cats on my 67 Fury to worry about. So tell me, would you run your cars on 100% 100LL all of the time if it weren't so pricey? I've heard that's how it was back when these cars were new.
Also, where do you get your 100LL? That actually seems like a low price for what it is.
That's also a great idea to "winterize" a car after a "corny" summer.

I'm sure you can, if you can afford it. It's merely leaded gas at 100 octane. It's required in all piston engined small aircraft no matter what year. I share a '73 Cessna 150 with a friend and that's what's required for it. I get mine at my local General aviation airport. Just pull up to the pump and fill it, or put it in gas cans. Some FBO's may be stickler's about safety and grounding your car or container because it's pretty volatile stuff so be careful. Make sure you get permission and/or instruction on filling. As you mentioned earlier it's blue in color, looks kinda like windshield washer solvent. The green you talked about is MoGas, based along the same lines but less volatile. It's harder to find and not as good imho.

 

[GG-1]

listing of stations with ethanol free gas
Ethanol-free gas stations in the U.S. and Canada

Ah yes thank you. I do know this listing. I check into that for updates, and also always ask around locally too in case something misses that list or springs up.

 

[GG-1]

I'm sure you can, if you can afford it. It's merely leaded gas at 100 octane. It's required in all piston engined small aircraft no matter what year. I share a '73 Cessna 150 with a friend and that's what's required for it. I get mine at my local General aviation airport. Just pull up to the pump and fill it, or put it in gas cans. Some FBO's may be stickler's about safety and grounding your car or container because it's pretty volatile stuff so be careful. Make sure you get permission and/or instruction on filling. As you mentioned earlier it's blue in color, looks kinda like windshield washer solvent. The green you talked about is MoGas, based along the same lines but less volatile. It's harder to find and not as good imho.

You fly.. very nice. Thanks for the info. I'll have to figure out my local airport policies.. and I may have an in through a friend if necessary.
I've been researching 100LL a little on some other forums and most who use it claim it's great with no down side. Maybe just keeping the valves and cylinders clean with the right detergents in the fuel periodically will be in order.
Though, this is the first I've heard regarding high volatility. I wonder if it's ok/compatible to blend this with a lower octane unleaded at the name brand pumps.

 

[GG-1]

I hear reformulated gas is murder on carbs. Anything I can do to offset the damaging effects of RFG? The nearest station with real gas is 40 miles away

This isn't a plug, and I don't know these guys from Adam, although this seems to be the ultimate solution to the ethanol problem. This particular fuel delivery service out in PA delivers one kind of gasoline straight to your home or garage, and it's ethanol-free. They actually stopped supplying ethanol gas because of the constant damage they experienced with their own equipment. Seems all you would need is a bulk tank on your property for them to deliver. These guys have a minimum per delivery of 150 gallons. Just looking around the interwebs quick I'm seeing new 500 gallon bulk tanks w/pump for as low as $600. I don't know what rates are per gallon but buying bulk has gotta be cheaper than what's at the name brand pumps.
Home heating oil companies who also supply gasoline may be the way to go. I'm definitely looking into it.

Elite Fuel Service | Unleaded Gasoline

 

[CBODY67]

ONE important point about "octane" numbers . . . until the earlier 1970s, if you saw an octane number mentioned, it was always "Research" Octane. After about 1972, "Pump octane" is the average of the two anti-knock rating numbers. In those transition times, 100 Research octane Premium fuel usually had a Pump octane posted as "95". even up to 95.5 in one case I know of. "Regular" gas was 95 Research Octane and "Sub-Regular" was 91 Research octane. These were for normal leaded fuels, which had something like 4gm/gal of tetraethyl lead. When the engines were running well, the interior of the exhaust pipes were a light gray color.

When "low-lead" fuel came around, the octane numbers didn't change that much as other items (including a little bit of the octane enhancer "alcohol-based" additive could be added into the blend. When lead was finally removed, more items were added to help keep octane levels were they'd been. End result is that to go from Pump Octane to Research Octane, take PO and add about "4" to get to an approximate RO number.

When the first RB/B engines appeared in 1957, the SAE paper I found mentioned they were spec'd for 97 Research Octane with their 10.0 compression ratio. Octane levels tended to peak and plateau about 1962. The later-increased Research octane levels would allow for more "better" camshaft timing events and better-optimized ignition timing advance curves.

Avgas might seem like a good alternative, but we had those discussions 40 years ago and it came out as "not too good", although the numbers looked good. Avgas is optimized to work at the higher altitudes, just as normal motor fuel is optimized for use at "ground level". The two fuels don't work in each other's place, as one person noted as he was glad to get back to ground level after his friend filled his airplane's tank with normal unleaded "car" gas.

The other issue is "road tax", which Avgas sellers don't collect. This can vary with state, possibly.

Storing "amounts" of fuel on private property might also come under the jurisdiction of the local fire marshall and require inspections and permits.

If you want "race gas", that's a better deal. Some speed shops sell it and it usually can be purchased from a vendor at many weekend drag strip events.

RFG is NOT what we now have, RFG was only about 5% ethanol and came before E10. I used it in a 1970 model at with no longevity or performance issues. Other than a 3% loss of fuel economy. RFG was also supposed to have its main oxygenate as MTBE, which has since been outlawed as it was found in the water supplies of many large cities (in minute traces). When that happened, the "10% oxygenate" slack was taken up by ethanol (which was the other oxygenate component of RFG).

The "jelly" you're seeing is probably phase separation from the absorption of atmospheric humid air. There's a YouTube video on that happening with an open glass cup of gasoline and a fan blowing air across it in FL. There's also a YouTube video of how ethanol degrades rubber hoses, too!

Some people make their own de-ethanoled fuel by adding water, letting the water be absorbed by the ethanol, the "gunk" settles to the bottom of the container, then what's on top is used as normal gasoline, but with a slightly decreased octane level. But this takes time and effort to do.

Remember, too, that drilling out any calibration "holes" in a carburetor part that is not replaceable might not be the best idea. Adding a little larger main jet would be easier to do, but there are a humongous number of unmodified cars running around and using E10 with no issues, other than a noted 6% fuel economy loss. As with other hot rod mods of old, there are several different approaches to the same problem. Usually, for what it takes to do them competently (in time and money) will not be recovered in better performance, by observation.

If you feel you need to chase non-ethanol fuel, that's fine. Just compare the higher cost to how far you have to go to get it against using a fuel additive as Lucas "green stuff" ethanol fuel additive.

Ethanol can do a lot of bad things, but the damage tends to be proportionate to the consistent local humidity levels, IF any real damage results. The other thing is to not let ethanol "sit", keep the cars being driven rather than sitting around. When the fuel pump diaphragm, even with "ethanol resistant neoprene" diaphrams, are allowed to dry out, they allegedly become brittle and subsequently leak/fail. Once the degradation of ethanol has been done, no way to compensate for it with later ethanol-free fuels.

Things are not always as bad as they might be made out to be.

CBODY67

 

[78Brougham]

Avgas is optimized to work at the higher altitudes, just as normal motor fuel is optimized for use at "ground level". The two fuels don't work in each other's place, as one person noted as he was glad to get back to ground level after his friend filled his airplane's tank with normal unleaded "car" gas.

I'm afraid I have to disagree. 100 octane is 100 octane there is no difference whether your at sea level or at 8,000 feet. Mostly the reason for the high octane in airplane fuel is because at that level of octane the fuel has a more consistent burn. The last thing you want in an airplane engine is pre-ignition and/or detonation. The lead is in it for the obvious health benefits to the valves etc.
As far as road taxes, there is no road tax on avgas, however there is a huge tax on it that the faa collects and disperses to the airports for improvements, maintenance etc.

I'm not so sure I would put too much credence into the story of the guy running regular unleaded gas in that plane. I'm gonna have to raise the bullshit flag on that. How did he get the gas. They only sell avgas at airports, unless that pilot is a complete numbskull and jerry jugged it there. Besides no pilot with even half a brain would take that chance when your life is at stake.

 

[GG-1]

Some more info on AVGAS 100 use in passenger vehicles:

AVGAS 100LL was formulated some 25 years ago in order to replace two grades - AVGAS 80/87 and AVGAS 100/130 - by one single grade.

80/87 contained very little lead or was unleaded. 100LL contains so little lead that it could be accepted by manufacturers of 80/87-optimized engines without excessive fouling of the spark plugs, while maintaining the knock resistance of 100/130.

The "LL" suffix of 100LL actually means "low lead".

One important property of AVGAS (vs. MOGAS - ordinary gas for cars) is that it totally lacks components with very low boiling temperature. Boiling temperature drops with lower ambient pressure, and AVGAS shall not boil in aircraft tanks at high altitude, and especially not in the fuel lines from the tank or in the carburetor or injection system.

Cars on the other hand are mostly operated at ground level. MOGAS is formulated differently according to season of the year. During winter it contains large amounts of hydrocarbon components with low boiling point in order to ease starting at very low temperatures and get a smoother and less polluting ride while warming up.

Summer MOGAS and AVGAS is in this respect not very different. But AVGAS is guaranteed to be totally free of components with low boiling temperature, while you will always get a little winter MOGAS even in summer, since it is blended in the tank at the service station.

If you have an old (pre-1974) carburetor equipped car and run it year around on AVGAS 100LL, then expect a rough star at very low winter temperatures and pull the choke handle somewhat more generously than you would on MOGAS. If you have automatic choke on the carburetor, then expect trouble or at least a rough warm up ride. And in any case you will generate a lot more smoke until the engine is warm.

Some people think that a higher octane number means more power. It isn't that simple. There is no more energy in high octane fuel than in low octane fuel. But an engine, which is optimized for high octane fuel, can have a higher efficiency.

Many modern engines have a knock sensor which automatically advances ignition according to fuel octane number. But if such an engine it optimized for, say, 95 octane fuel, then you gain absolutely nothing with 100 octane fuel. Using 95 octane it will advance the ignition to the optimal timing. If it advanced even further, it would drop in power, even if it didn't knock. Only if you use fuel with lower than 95 octane number will it advance less, and drop in power and efficiency.

You will have to modify such an engine with higher compression ratio to get any gain from 100 octane fuel. And then you may still run it on 95 octane and lose that gain again.

But as stated by many contributors before: NEVER EVER use AVGAS on an engine which is equipped with catalytic converter and lambda sensor - cars which are made for unleaded fuel. It destroys both the sensor and the converter.

 

[78Brougham]

Some people think that a higher octane number means more power. It isn't that simple. There is no more energy in high octane fuel than in low octane fuel. But an engine, which is optimized for high octane fuel, can have a higher efficiency.

Agreed, as I stated before the higher the octane, as in 100LL, gives a more consistent or "even" burn in the combustion chamber, I feel that, that more even burn is what actually gives a bit more power because there is more power generated from full even burning than one that's burning all scattered inside the chamber. If your engine is pinging all over the place you're not getting that even burn and losing power. But I may be wrong. I'm no rocket scientist that's for sure! Regardless of who's right or wrong this is a Great conversation!

 

[CBODY67]

I'm afraid I have to disagree. 100 octane is 100 octane there is no difference whether your at sea level or at 8,000 feet. Mostly the reason for the high octane in airplane fuel is because at that level of octane the fuel has a more consistent burn. The last thing you want in an airplane engine is pre-ignition and/or detonation. The lead is in it for the obvious health benefits to the valves etc.
As far as road taxes, there is no road tax on avgas, however there is a huge tax on it that the faa collects and disperses to the airports for improvements, maintenance etc.

I'm not so sure I would put too much credence into the story of the guy running regular unleaded gas in that plane. I'm gonna have to raise the bullshit flag on that. How did he get the gas. They only sell avgas at airports, unless that pilot is a complete numbskull and jerry jugged it there. Besides no pilot with even half a brain would take that chance when your life is at stake.

Agreed, "Octane is octane", whether at 8K feet or sea level. It's how the fuel vaporizes that's important. Correct, there is no "road tax" on Avgas, which is why many airports can get in trouble if the fuel is put in an on-road vehicle of any type. Racing use might be a point of discussion. When compression ratio and octane are synchronized, a smoother burn will result, no matter at which altitude or octane level or compression ratio. There is a reason that "Avgas" is "Avgas", not related to octane or possible lead content, but more to the content of the blended components in the fuel. My friends and associates that tried the Avgas route had better results with normal racing fuel purchased at local drag strip vendors, performance wise.

CBODY67

 

[GG-1]

Agreed, "Octane is octane", whether at 8K feet or sea level. It's how the fuel vaporizes that's important. Correct, there is no "road tax" on Avgas, which is why many airports can get in trouble if the fuel is put in an on-road vehicle of any type. Racing use might be a point of discussion. When compression ratio and octane are synchronized, a smoother burn will result, no matter at which altitude or octane level or compression ratio. There is a reason that "Avgas" is "Avgas", not related to octane or possible lead content, but more to the content of the blended components in the fuel. My friends and associates that tried the Avgas route had better results with normal racing fuel purchased at local drag strip vendors, performance wise.

CBODY67

With seemingly dozens of racing fuels to choose from, I suppose finding/choosing the correct one for the car you drive is the trick. What are you referring to as "normal racing fuel"? And for what car/engine/compression ratio were your friends running? 1960s big-block HP Chryslers? With what results? What were the weak points running the AVGAS?
For example, there is a Sunoco Racing Fuel offered in my area called Optima Sunoco Race Fuels
that seems right for my 383 Commando 10:1...
It's 100 (research octane), so about 96 pump octane,
ethanol-free, but it is unleaded. Claims it will last for years unspoiled in sealed tanks.
The racing fuel menu is a bit daunting to me .. with most being 112 octane and up..
Please enlighten us with some of those numbers if possible. Thanks.