Eating Crow with a Shovel

[GasSavers_Scott]

Well after my rant about anti-technology, I planned to get an old Volkswagen and reproduce Karcey's 55 mpg VW. It was a great idea, you make plans, then life gets in the way. My other half was supposed to transfer to a cool climate in Northern California. Due to economics, her company decided against expansion. So it looks like we will spend another year here in the sun bleached deserts of Southern Utah. Summer is usually in the 100's, with August averaging 115.

Since the demise of my Focus, I have been driving my fathers SUV, a Jeep Liberty. My fuel expenses have gone from 40 a month to 100. Its a family car and everyone piles in the thing. With the coming of the firey dawn of summer, I need air conditioning.

My time away from technology was used studieing carburetors, ignition curves, aerodynamics, and air-fuel ratios. So I have to get a modern car for the while with air conditioning. Im looking at the Early 90's Honda's, VW's, and the Miata. I want to interface my laptop to the cars computer and start messing around with it. I want to play around with the aerodynamics.

So after turning my back on technology, it has come around and hit me right in the face. Crow is best served with herbs and garlic.

[GasSavers_BEEF]

we all eat crow at some point whether we admit it or not.

I like mine with garlic and basil, and sometimes lemmon pepper.

[Jay2TheRescue]

May I recommend serving it with red skin potatoes roasted in olive oil and sea salt?

[bowtieguy]

early 90s honda? good choice however, mid 90s to 2000 civic was one of the best cars ever made in terms of reliability. easy to work on as well. good luck.

[theholycow]

Hmm...carburetors, ignition curves, aerodynamics, and air-fuel ratios you say? Please come and work on my car.

[GasSavers_Scott]

It seems the carburetor crowd, both Volwkswagen and V8 have gotten into fine tuning emulsion tubes, progression port timing cut offs, venturi, and secondary booster design. Holly, Demon, Edelbrock, EMPI, and Weber, can all be adjusted for 15:1 cruise, and 11:1 at full throttle. They usually calibrate with a Wide Band. The big V8 community sees gas prices going up and their ability to cruise going down. I just read an article with a guy turning 400 horses, on a carbureted daily driver, while still pulling 21 mpg. 10 years ago, he would have gotten 10 or 11 miles to the gallon.

It really inspired me to get into the timing and programming of fuel injection for maximum mpg. I would have gone totally carbureted, but with the air conditioning issue, VW's had an aftermarket kit, that had a complicated dual condenser, and a ton of sensors, that were 40 years old. After 2 months of looking, not one car had an A/C unit. My other choice would have been Nova, Mustang, or Dart. All with 6 cylinders and only hopes for high 20's.

So it will be a year, before I can dive into a classic.

The tricks the carb crowd did was to use a wideband and a vacuum gauge. They found most of the time, the progession circuit overlaps with the mains, creating an overrich condition of 9:1 and cruise around 12:1 for most carbs. They plugged the mains and found where the idle progression circuits lean out. Then took a high vacuum power valve, or custom drill main air vent, to have the main come on right as the idle circuit died out.

Each circuit had to be custom tailored, in the end, they got great gas mileage and great horsepower numbers. But as every engine is different, a carb would have to be set up completely different on each engine. More than just changing jets, the carb would have to be torn down each time. It seemed like a lot of work, but the payoff would be worth the hours of tuning craftsmanship.

[GasSavers_Scott]

Oh yeah, a couple more discoveries. Recurving the distributor, I found most of the old centrifugal advances come in fully at 3800. Most of the mpg modders and hot rodders looking for best efficiency tend to want to get total advance in at 3000. Some even go as low as 2600 for cruise. They set up their distributors to start adding advance 100 rpm off idle. They do this with a bunch of springs, or just stretch them, till they get their target advance.

I expierienced this with my old bug, which I took from 24 to 34 mpg. 7 of those mpg's were by having my advance come in early. I would then hand adjust my initial timing by ping. As soon as it would ping, I would back off 1 degree. The rest of the mpg was via a header and rejet of the carb.

I can just imagine transfering this information to a computer timing map.

Then in the carburetor department, cutting horizontal cuts in the booster venturi, helps release fuel, rather than forming drops.

Then on the mixture area, perfect vaporization, not atomization, would displace too much air. They try for the perfect droplet size, too big doesn't ignite, perfect would enter, break apart and vaporize in the cylinder head. This is why propane should provide 50 mpg, but only equals gasoline, too fine a vapor. This is why Smokey Eunich had to turbocharge his vapor engine, the charge was too hot and expanded.

So it seemed benefitial to go back to the roots of mpg, it gave me a lot of new perspectives and now I want to get into total engine management programming.