The myth of the 100 mpg carb


Just keep it clean please....

Golden Jubilee
Golden Jubilee

Posts: 4068

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Nov 24, 2019 3:22 pm

The myth of the 100 mpg carb

The Myth of the 100 MPG Carburetor!


Growing up in the 60’s there was always a story making the rounds about a guy who invented a carburetor that if used on a big V-8 would get 100 mpg! Another variant was from an add in the back of Popular Science about a guy who made a “discovery” while mowing his lawn, a stone got kicked up and put a hole in the fuel tank of the mower, wanting to finish he stuffed a vacuum line in the hole and connected to the engine, and with almost no fuel managed to finish the lawn that would have normally taken several tanks of fuel. Send him X amount and he’ll send you the plans.
Both of these stories seamed to die out with the onset of electronic fuel injection. I was very surprised to read about it on a forum recently post by someone who believed it to be true.
The story always starts like this: an older mechanic was working late at night when an old man comes in needing a special spring for the carb on his car. He explains that is a hush-hush special carb that he designed that gets 100 mpg but he can’t talk about it because he sold the rights to (insert the name of an oil company here), who bought it and was suppressing it so they could make all kinds of money selling gas.
In exploding these mythical inventions I will take two paths. 1st is the sold and suppressed path, second is the fact that it can’t be true.

Part one: Sold and suppressed.
For this to be true, you have to accept the laughable notion that an oil company would rather speculate on drilling and processing oil than sit back and collect royalties, with no work, on the invention they supposedly bought! Add to that fact, for them to buy the “rights” it has to be patented, without a patent, there is no legally enforceable right to the design. Without the patent, the inventor could go on building and “selling” his design as much as he wants. With a patent, the design and description would registered at the patent office in Washington. No patent number or even inventor name is ever given, but with most if not all patents available on line a patent search should disclose such a device if it existed.

Part 2 why it can not be:
Any fuel has to be in the presents of oxygen to burn. There has to be enough oxygen or combustion will not happen. Too much (lean condition) or too little (rich condition) and combustion will not happen. More over liquid gasoline can not mix with oxygen, it needs to be in vapor form. Sure you can dump gas on the ground and throw a match to it, but it is vapor rising off the liquid that mixes with air and burns, the heat given off turns more of the liquid to vapor and the burning continues. Out in the open, the vapor will mix until in the combustible range, and if there is an ignition source (spark or flame) will burn, until the mixture is too lean or rich to continue.
In a spark ignited engine the fuel and air is mixed prior to igniting, so the mixture has to be in a vary narrow band or simple put it will not burn.
With today’s electronics it is possible to monitor in real time the mixture and burning of the fuel as well as detonation before it even happens thru the spark voltage. In short if it were possible for a large V-8 to get 100 mpg, electronics should have achieved that. With the electronic controls available we can set the mixture to whatever you like and hold it there regardless of throttle or atmospheric conditions. Much more control that carbs ever had.
While have seen great strides in engine longevity, we haven’t seen mileage improve by the factor of 4 or 5 that this carburetor claims.
The reason is simple. A spark ignition piston engine burns fuel to create heat. But it isn’t the burning of the fuel that makes the power. In fact if you mixed gasoline and pure oxygen in chemically perfect ratio the engine wouldn’t even run. It is the heat acting on the other elements in air, primarily nitrogen, that causes them to expand and make the pressure in the cylinder that makes the power.
This 100 mpg carburetor claims to make the same power on ¼ to 1/5th the fuel, but because the fuel has to be mixed in the correct ratio with air, it also claims to make the same power on ¼ to 1/5th the amount of air!
In short, there is just not enough of gains possible for fuel mixing or ratio to achieve the gains claimed. There just isn’t enough gasses present to make the power needed to move the big car down the road.
But what about diesels? Compression ignition engines? They run with an excess of air below full power. Yes, but they work like the above description of dumping gasoline on the ground, diesel is injected into a chamber hot enough to ignite the fuel. So as soon as the fuel vaporizes and mixes to the point of supporting combustion it burns, it short it still has to be in the combustible range before it will burn, the fact that there is more air than needed just mean there is more gas for the heat to act on, which is why diesels get good part load fuel economy.
The holy grail of gasoline would be to find a way to inject at temps and pressures of other compression ignition engines. If you can have compression ignition gasoline, diesels will loose a lot of their “advantages”. The thing keeping that from happening is gasoline is a solvent and diesel is a lubricant. You can run gasoline in a diesel today, but the fuel injection system will last a matter of minutes before it seizes. The closest thing we have is military multi-fuel engines, but they require oil to be added and gasoline is only to be used in an emergency for short time frames.
User avatar

Rusty Driver
Rusty Driver

Posts: 107

Joined: Mon Feb 09, 2015 7:10 pm

Location: Eldon, Missouri USA

Post Sun Nov 24, 2019 5:01 pm

Re: The myth of the 100 mpg carb

CB - thanks for the thread.

A quote attributed to P. T. Barnum says it best "There's a sucker born every minute".

But often, if one digs sufficiently deep; or more accurately, finds a bit of interesting material when searching for something else.......................

I have heard the old saw about the great power and/or gas mileage on a new car until the first service, when the dealer removed the carburetor, and the power/mileage hasn't been the same since.

In 1933, Ford Motor Company sent out 1000 V-8s with an experimental (today it might be called a "beta-test") Bracke carburetor, with instructions to the dealers to remove and replace the carburetor at the first service. Bracke was a division of Holley, and it is well known the relationship Ford shared with Holley.

I have a couple of the Bracke carburetors, and can attest they do exist. However, they certainly did not improve power or fuel economy; and other than in the files of a few historians, have ceased to exist. But the modified story certainly does!

Of course, the 1933 Ford was equipped with a single-barrel Detroit Lubricator carburetor. In addition to a couple of these, I also have a three bolt flange two-barrel. I have never found any information about this unit, but it does have Ford linkage. From the same source, I also acquired a Kingston 3 bolt flange two-barrel with Ford linkage. Some will remember that Kingston and Holley were the main suppliers of carburetors for the Ford T.

The experimentals to which you are probably referring are Pogue (a Canadian device), and Fish. John Robert Fish was based in Daytona Beach and sponsered some 1950's NASCAR teams. I have never seen a Pogue carburetor in person, but one was on Ebay several years ago. I would have liked to have had it for my carburetor museum, but the asking price was commensurate with the scarcity; and I didn't want it that badly. I still have a couple of Fish carbs, and have sold several (to restaurants in NASCAR country for decoration - NEVER for performance).

There is also a long story about the cow magnets that I was inadvertently partially responsible for, that anyone interested can probably find with Google, as I have posted the story on at least a couple websites.

Jon.
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri
User avatar

Rusty Driver
Rusty Driver

Posts: 107

Joined: Mon Feb 09, 2015 7:10 pm

Location: Eldon, Missouri USA

Post Sun Nov 24, 2019 5:16 pm

Re: The myth of the 100 mpg carb

Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri

Golden Jubilee
Golden Jubilee

Posts: 4068

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Nov 24, 2019 5:25 pm

Re: The myth of the 100 mpg carb

I worked on a Rochester duo-jet that even a GM dealer couldn't supply gaskets for. It had a carb number, I had it wrote down for a long time incase I ever saw it again, same numbering system that they used on production carbs, but when you tried to look it up you'd only find kits for the number after or before it.
All it had was a modified idle circuit, instead of needle in jet (passage) it had a fixed passage with an "air screw that regulated air to both sides with a single screw.
There are lots of things out there. and I find it neat you have collected many, but the truth is: if there was something much better, we'd all have it by now.
User avatar

Rusty Driver
Rusty Driver

Posts: 107

Joined: Mon Feb 09, 2015 7:10 pm

Location: Eldon, Missouri USA

Post Sun Nov 24, 2019 5:28 pm

Re: The myth of the 100 mpg carb

cornbinder89 wrote: There are lots of things out there. and I find it neat you have collected many, but the truth is: if there was something much better, we'd all have it by now.


Agree completely, but lots of folks still believe in the tooth fairy ;)

Jon
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri

Golden Jubilee
Golden Jubilee

Posts: 4068

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Nov 24, 2019 5:37 pm

Re: The myth of the 100 mpg carb

ever run into an odd-ball duo-jet like I did? IIRC it was on a 231 V-6 but we are talking 35 year ago or more.
User avatar

Rusty Driver
Rusty Driver

Posts: 107

Joined: Mon Feb 09, 2015 7:10 pm

Location: Eldon, Missouri USA

Post Sun Nov 24, 2019 5:55 pm

Re: The myth of the 100 mpg carb

CB - no, my stopping point (with the exception of Carters) is 1974.

Jon.
Good carburetion is fuelish hot air!

If you truly believe one size fits all, try walking a mile in your spouse's shoes!

Owner, The Carburetor Shop in Missouri

Site Admin
Site Admin

Posts: 4826

Joined: Thu Nov 29, 2012 9:10 am

Location: Nampa, Idaho

Post Sun Nov 24, 2019 7:33 pm

Re: The myth of the 100 mpg carb

Just a question, What can you say about the "water injection" system? Had a local guy who swore by it as improving his mileage. Lost track of him once I went into the military back in 1971.

Golden Jubilee
Golden Jubilee

Posts: 4068

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Nov 24, 2019 7:39 pm

Re: The myth of the 100 mpg carb

water injection has some real benefits, mostly in the area of detonation reduction. It can help in fuel economy as enriching the mixture is the other way detonation is quelled. By using water there is no need for excess fuel.
Another advantage is that it can cool the intake air charge, as the water evaporates, it absorbs heat.

Site Admin
Site Admin

Posts: 4826

Joined: Thu Nov 29, 2012 9:10 am

Location: Nampa, Idaho

Post Sun Nov 24, 2019 8:42 pm

Re: The myth of the 100 mpg carb

Thanks, like I said, lost track of him. I got out of " building vehicles" when I left full time service and became a carpenter. Life happens and now I am old and out of shape, and no fixed place to work on anything.
Next

Return to Non-IH discussion

Who is online

Users browsing this forum: No registered users and 2 guests

Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF.