Mpg?

Pilotdave

Pilotdave

Well-known member
I'm curious about gasoline consumption. As a newbie Model A (1930 Tudor) driver I'm hoping that the experts can shed some light on what I should expect for mpg.

First, I have to confess that I haven't been keeping careful records, partly because our odometer was not functioning until repaired over the winter. And I did not note how full the tank was before starting to drive the car this spring. I'm guessing it was between 1/2 and 3/4 full when we put it away for the winter. Yesterday the gauge said we had 1/4 tank - took 7.26 gals to fill it. Distance traveled per odometer is about 40 miles. If we started with 1/2 a tank and ran it down to 1/4, then we're getting 16 mpg. On the other hand, if we started with 3/4 tank the mpg is about 8!

Some other data: no observable gas leaks or gas odors when sitting in the garage; spark plug centers are light tan with no carbon buildup anywhere; tail pipe is a light gray color. So gas isn't being lost to leaks and the air/fuel mixture must be about right.

Is there some other way to lose gas in a Model A? I'm wondering about evaporation loss in a car that has sat for several months.

Needless to say, I'll be watching this carefully as we drive the car this spring. We plan to use our gps to monitor the odometer once we get going. In the meantime, I'll appreciate any advice!
 
if your getting 16 mph , you doin ok . highway should be a little better . i would drive it & have fun . it sounds like its doin good . my car never sets , so i can not help on evap ! ................... steve
 
To determine your mileage. First fill your tank up to a few inches from the top (look inside the fill hole or measure the depth down with a wooden ruler). Then drive your car and record the mileage driven at your next fill up. Record the mileage at the fill up and the amount of gallons to bring the tank up to the exact same level as before. Divide your miles driven by your gallons to refill for "miles per gallon". Be consistant on your fill points (ie how high to the top you fill your tank). do not use the gas guage to determine anything. that is why your numbers are off.
 
About 16 mpg from a sedan is pretty respectable. Remember these cars are as aerodynamic as a house, so going from 40-55 puts a huge wind drag on the car and consumption will skyrocket. Also, make sure you set your fuel mixture properly via the GAV, gas air valve? Running rich will also eat up fuel. Is your timing set properly and are you setting your spark advance enough? A retarded spark will also wast fuel.
 
28 Phaeton around town with several stop's 16 MPG is doing fine. On my trip to S.D. driving country roads with little traffic and travelling 42 to 45 MPH I got 22 MPG. I have a stock engine with 50 lbs. compression and 3.70 rear end.

I'd like to try a high compression head and overdrive to see what I could get.
 
Thanks for the replies. Our plan is to record miles with the gps (and check the odometer and speedometer at the same time) and do the "miles divided by gallons" calculation. My immediate need was to get an idea of what we should expect for mpg. Driving around here might be tough on mileage as we have a lot of hills and stop signs!
 
Tom Wesenberg said:
28 Phaeton around town with several stop's 16 MPG is doing fine. On my trip to S.D. driving country roads with little traffic and travelling 42 to 45 MPH I got 22 MPG. I have a stock engine with 50 lbs. compression and 3.70 rear end.

I'd like to try a high compression head and overdrive to see what I could get.
Click to expand...

You would love your overdrive and high comp head so much you wouldnt care how much more mpg you would be getting. But with my overdrive and 2 barrel carb i get about 25 mpg at 55 mph.
 
The survey data is helpful. Thanks.

Some additional data. I turned the gas off when I shut the car off yesterday afternoon. Decided today to check further for possible leaks. Found the bottom of the carburetor was wet with gas. Removed carb and found the bowl had about 1 tsp of gas in the bottom. I expected to find the bowl filled to the float line. Sounds like the carb is leaking somewhere. Haven't spotted any obvious leaks yet. Any suggestions from those experienced with the Zenith 1 carburetor? Thanks again.
 
Hi Logan, I'm curious about your 2 barrel carb set up. I have a nice tight 1000 mile or so old rebuild with Bill Stipe Cam & 5.9 HC head & just finished the install of F-150 RTS ****** & it runs great but I always question the carbuation part of the set up. I have both a B carb & a new Zenith as well as an old stand by Tilly but i can't seem to get more than 14 to 15 MPG with any of them. What are you using?
 
JTJ: With your set-up I'd use a Weber down draft. I have one on my rig with a 5.5 head and love it. F150 overdrive ****** going in next.
 
What was the source of your intake manifold? & what model weber are you using? any pictures? The F-150 is by far the most enjoyable upgrade to my tudor I have ever done. It was a long haul about 2 years of gathering parts & getting machine work done but well worth all the effort. Al from Newburgh, NY's install was what I based my set up on & I did save some $ doing it the peicemill way ( I figure I have about 1500 to 1600 in it) but if I had it to do over again I think I would just buy one fo the kits for around 3000. A lot of little issues to work out, if your not a welder & machinist, but it was rewarding to overcome all the little issues & it is sooo much smoother & quieter that I have to keep an eye on the tach or I find it winding up to 2500rpm w/o even realizing it compared to the stock set up that was so loud & full of vibrations that 2200 to 2300 felt like 5000 rpm. You will really love it, so much more fun to drive!!!!
 
I can get in the low 20s --even when I drive 55-60, i do run the mixture somewhat lean, stock head, B cam, stock rear, thermostat(160), full advance most times.
I have had it on the emission dyne, can get the HC, and CO low enough that it could pass emissions for a late 80s car, the plugs will burn white at 1% CO, and hydrocarbons under 100 ppm, --this is with all old plugs, points, and jets, under 1% is not driveable, at 2-3% it drives fine ---my car needs 3/4 turn of GAV at 55, 1/4 at 40 to run at 3%, this gives a light brown to the plugs, and fuel mileage around 20.

Just adding a thermostat was good for 2 mpg.
 
JtownJoe said:
Hi Logan, I'm curious about your 2 barrel carb set up. I have a nice tight 1000 mile or so old rebuild with Bill Stipe Cam & 5.9 HC head & just finished the install of F-150 RTS ****** & it runs great but I always question the carbuation part of the set up. I have both a B carb & a new Zenith as well as an old stand by Tilly but i can't seem to get more than 14 to 15 MPG with any of them. What are you using?
Click to expand...

I am using the weber progressive 2 barrel. Its the same one sold from all the big vendors. I too have the 4 speed, but a stock motor otherwise. Another thing to remember is I have a coupe (alot less weight than your sedan) with a 25k mile engine rebuild. The weber gets more mpg in my opinion, and its self adjusting. You dont have to mess wih a gav setting while driving. Imo its a far better set up than a stock carb, and its better than the modern zenith (the forklift carb). But i do however have a high comp head and forklift carb on a sedan and it gets right at 16-18 mpg.
 
31 tudor 7-1 head ,counter weighted crank, balanced assembly, strongberg 84 , single down draft carb, tube header and 354 gears give me 23-25 mpg. More efficient running less fuel out the tail pipe.
 
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