Mileage Beta testing

[CZLN6]

Howdy All:

I'd like to propose some in-basket mileage testing. Given the price of gas and reputation of our sixes as gas misers, this might be a good time to make the most of both. This is strictly a self-satisfaction excercise as the only rewards for doing the before and after testing will be spending less for gas and for sharing your successes and debunking myths.

If anyone is interested in participating it would be best if you would agree to some minimum standards.
*Your engine must be in good serviceable tune, have a solid ignition, no leaks, minimize choke function and maximize initial advance, reduced idle speed to minimum, a working odometer or mile measure, consistent weather conditions, and consistent documentation, with refueling at the same pump at the same time of the day and in the same way, driving a repeatable route with not changes in driving habits, making sure to maintain tire psi.

We've already discussed the big gas savers, such as; slowing down, lightening the load, tune up and air up, but these proposals go for the little gains.

Given the above standardazation, I have several questions to pose. The answers could be useful to all. Choose only one test. Move on to another only when you are satisfied that you have completely answered the question.

1st test- If you drive mostly in stop-and-go traffic this test asks that you turn in the low speed air screw from its optimum setting 1/4 to 1/2 turn in, or leaner. This will possibly roughen your idle quality, and only effect gas consumption at idle speeds. Will the gas saving be worth the rough idle? This test is doable on any carb.

2nd test- This test is again for stop-and-go traffic, where on-the-gas, off-the-gas driving is required. On a stock Autolite 1100 the accelerator pump lever has two setting determined by a roll pin. The upper one is marked "LO" and is specified to be used "Above 50 degrees F and/or 5,000 ft elevation". The lower one is marked "HI" and specifies for use "50 degrees F and below".
IF your carb has the fulcrum in the lower "HI" position, which gives a larger, richer pump, establish a before base line and then move the pin to the "LO" or higher hole to lean or lessen the volume of the pump shot.

This test is doable on any carb with a fixed, linkage that is adjustible with hole settings or cams, such as the Holley 2300 or Autolite 2100. It is less repeatable with carbs like the Carter YFs that require a connecting rod to be bent.

I think the only downside to these alterations will be a slight lessening of idle quality and slightly slower acceleration. Gas saving will not be profound, but even at a gallon a month it may be worth it. I know, what I'm proposing is pretty anal and pretty narrow. Hey, if it's not your cup of tea don't sip. I really like documentable results.

If any one has already thought of these and other mileage enhancements please share the results.

keep us posted on your test platform and progress.

Thanks, in advance for sharing.

Adios, David

 

[Stubby]

I might be able to participate.

I need to do a better install on the wideband O2. To be consistent with fueling, I might have to remove the spring in the filler neck.

At 80 to 100 miles a day, I can do a lot of testing.

I am running an Autolite that is different from the 1100. The best I can tell, it came off of a 240.

 

[CZLN6]

Howdy back Stubby:

Is your 240 carb off of a car engine? What year? Most likely a Carter YF.

Is your daily drive highway or city traffic?

Thanks for the response.

Adios, David

 

[jahearne]

I'd be willing to run some tests. Currently driving a '67 Ranchero with C4 & 200 cu in motor. The car is very well maintained and have a lot of documents from previous owner since 1991 and everything works!

The distributor and carb were mismatched SCV and non-SCV. So, I just installed a DUI ignition (pulled off my last Ranchero) and replaced the Carter YF with an Autolite 1100.

My daily commute is about 70 miles round trip from San Francisco to Novato. I got reverse commute against heavy traffic, which is nice but not much stop n go or idling except getting from one side of the city to the other, which is about 4 miles but nearly half the time spent driving.

 

[Stubby]

My carb was a Holley 1940. I say was because while changing the jet, I tore the acc pump cup.

I had to get it drivable, so I installed a Weber 32/36. It had already been dialed in on the Mustang. Then I switched the dizzy over to manifold vac and retarded the timing a little.

I also swapped the 3:20 gears for some 2:83 gears.
Pollished the wheels, then flushed the radiator.

I changed my whole setup. After one roundtrip, it appears that I helped it a lot. I plan to hook up all of the bells and whistles on the LM1 and the AUX box. It will be fun to see what goes on with carb temps and mixtures, with and without the hotwater spacer.

The reason I was playing with the carb was that I lost about 6MPG. After hooking up the O2 sensor I noticed that the AFR in the AM [75 degrees] was 13.5. In the PM [100 degrees] the AFR was 12.0. I don't know what the actual temp is right now. The factory guage reads just under half way AM and about 3/4 PM. It would appear that I was getting average MPG in the AM and terrible MPG in the PM.

I have a big job coming up next week, so I will have to stay with the weber for now. I do plan on reinstalling a one barrel when I get the chance. If you want the Weber info also, I will make it available.

 

[jahearne]

Still trying to set a baseline. Having problems with full power to my DUI dist.

Another issue I can see is getting gas at the same place, same time, same bat channel. So far, I manage to get gas at a Union76 station in the morning, which is good as it's going to get.

So far, I'm averaging 16.5 mpg, the best is 17.2 & the worst is 15 mpg.

 

[Stubby]

I have been averaging 22 to 23 mpg. I haven't gotten a clean run yet. I have been getting heavy rain at least one day a week. When I haven't gotten rain, I have had to make hotshot runs into town.

I have some timing issues that also need to be addressed.

I necently had to replace the back tires. I went larger for rpms and wider for looks. It didn't seem to make a measurable difference, but I have only ran 3/4 of a tank thru it. I had to fill it up in preperation for IKE and then I topped it out again today. It killed my routine.

 

[jahearne]

My odometer got stuck turning over 26000.9 miles, 126,000 miles, so I had to disconnect the speedometer until it's fixed and who knows when that'll happen, so I'm out for now.

Besides, trying to get the automatic choke to work properly for this engine just doesn't quite get it. Either it'll fire right up, but it's too rich or doesn't close all the way and won't start unless I pump it a couple of times. Trial and error, it's kind of in the middle - pump it once, rev it and drive off within 30 seconds otherwise it will load up. I'll keep working on it or maybe go back to a manual choke.

I'll still continue to dial-in this motor and may continue with this test once I get the speedo repaired.

Good luck,