Other: Fuel Mileage

[mjeansonne]

I drove the 62 Hawk on a trip yesterday and found that at 70 mph, I got 13 miles per gallon and at 65 mph, I got 14 miles per gallon. Relatively flat Interstate Highway here in Louisiana. Neither mileages are very good and since I want to drive the car to Colorado Spring for the meet, I'm going to have to bring a lot of extra money for gasoline and be looking for a gas station every 200 miles.

Trying to determine what to do to get better mileage, if possible. I rebuilt the engine last year, new pistons, main and rod bearings, rebuilt heads, waterpump, Dave Thibault Distributor, Edelbrock Carb (4 barrel), new fuel tank, fuel pump, master cylinder, brake cylinders, brake shoes. I have even upgraded the A/C system to include a Sanden Compressor and even a cruise control!!

Is this the best I can expect or am I missing something? Driving from Louisiana to Colorado Springs may cost as much as a roundtrip air ticket!!

HELP!!!

[JimC]

Maybe try drafting semi trucks on the way there?

I use this great program on my phone called acar to track gas and other expenses. I'm getting a very similar mileage to you (about 13mpg), and I have a sloppy, never rebuilt engine with 104,000 miles on it, a three speed automatic transmission without overdrive coupled with a noisy 3.73 rear diff, a 2bbl carb that keeps giving me a mixture that's way too rich no matter how I tweak it, and I don't even have cruise control. Given all of that, packaged in my boxy Lark, I'd think in your Hawk you should be blowing me away in fuel economy.

Do you have overdrive? I seriously doubt that unless you have the parts all lying around today that you would have the time to swap over to an overdrive setup before the trip, but that would probably really help on the long hauls. Beyond that, you have a really decent setup.

[mjeansonne]

Sorry, forgot to mention that I have a Flight O Matic transmission. I think I should be getting better mileage too. Just don't know what the problem could be... even made sure the tires were aired up properly!!!

[Chucks Stude]

What rear end are you running? I am getting better than that, with a 3.08 rear end and 4 speed with air. I try not to run it much over 70. Hit 19 on I-45 once, but must have had a tail wind. It is kind of a dog off the line, but in Texas it is more important to be a highway cruiser.

[GThawkwind]

I'm alll about stude powered studes, but when it somes to trannies I'm not a purist. Maybe you should look into converting to a later GM tranny maybe a 700R4 setup. It will be expensive but will improve overall driveability, the money saved might cover half the cost of the swap. Something to think about at least.

[Bud]

There is something wrong, I've seen 22 mpg out of my 62 Hawk with a 4 speed and a 3.31 diff. I had another 62 Hawk with a 3 speed and overdrive that would give me a consistant 23 or 24 mpg on the interstate. The 4 speed Hawk has a later Carter 500 cfm AFB and the 62 with overdrive had a Stromberg 2 bbl on it. If your engine is tuned properly, the internal engine parts are in good condition and the tires inflated correctly, the mileage should be closer to 20 even with an auto trans. Bud

[JoeHall]

If you go to the link below, it will tell you how I tweaked my GT to get 25-35 percent better than you have logged so far. Overall average was a little better than 16.5 MPG, with a range of 15.5 to 18. First & foremost I'd go with a 3.07 rear end, then economiser carb, clutch fan, and thin head gaskets, in that order.

http://forum.studebakerdriversclub.com/showthread.php?71470-Overall-Average-MPG-In-A-Stude-Take-II

[Dan Timberlake]

Is the vacuum advance hooked up?

Any work done mapping the actual mechanical and vac advance curves?

[mjeansonne]

As best I can tell, I have a 3.31 rear end. And yes, the vacuum advance is hooked up.

[Tom Bredehoft]

For comparison only. I have a '55 Land Cruiser (yeah, I know its a President State Sedan) with a '63 289, original Carter 4 bbl carb, single exhaust and original Detroit Gear 250M transmission, and 3.31 rear axle. on one trip of 212 miles, averaging 62.8 mph, I got 17.3 mpg on 89 octaine gas. Speed, distance from GPS, mileage actual, fuel burned. This was mostly on Interstate 70. Average about town mileage is 15.91

[PackardV8]

It will be expensive but will improve overall driveability, the money saved might cover half the cost of the swap. Something to think about at least.

How many miles does one drive a collector Stude these days? A typical 700R4 conversion costs $3000, equal to 750 gallons of gas. (Yes, some have done it the CASO way, but they're the exception) In my experience, the overdrive will improve 3-4 MPG on straight highway cruise, or 20% farther on the same fuel. By a rough calculation, the half-payback would be 30,000 miles.

In my experience, a good standard 289" with automatic and a 3.31 is a 16-17 MPG car. Your results may vary.

jack vines

[Studebakercenteroforegon]

Since you have an Edelbrock carb. it is quite easy to experiment with the metering rods. The Edelbrock literature tells you what rods and primary jets are "standard" for each carb. model - determine that and go leaner from there. Next I would play with the distributor static advance - set it 8 degrees or so and see what that does.

[63 R2 Hawk]

Do you know if your speedometer/odometer is correct? Check it against a GPS to be sure. Larger diameter tires will give you a slight numerically lower final drive ratio. As Studebaker center... says, check the metering parts of your carb. One clue is, if the exhaust pipes are sooty after a long high speed trip,you might be able to reduce jet size, likewise, try reading the spark plugs (google for more info).

[GThawkwind]

How many miles does one drive a collector Stude these days? A typical 700R4 conversion costs $3000, equal to 750 gallons of gas. (Yes, some have done it the CASO way, but they're the exception) In my experience, the overdrive will improve 3-4 MPG on straight highway cruise, or 20% farther on the same fuel. By a rough calculation, the half-payback would be 30,000 miles.

In my experience, a good standard 289" with automatic and a 3.31 is a 16-17 MPG car. Your results may vary.

jack vines

I was figuring used tranny with an adapter, still probably not worth it.

[wittsend]

For some reason certain cars are just bad for mileage. I have a '73 Valiant, 318 Auto with 2.76 rear gears. The speedometer has been checked multiple ways and is dead on. The brakes aren't dragging and the wheel bearings are not (too) tight. The engine has good compression. People tell me this should be a 16-18 MPG car and maybe even 20 MPG.

I have driven this car a fair distance at only 55 MPH, with a very light foot, and the best I can get is 14.7 MPG. The average is closer to 12.5-13 MPG. I went to the late model Mopar swirl port heads (better combustion and slight compression increase), a Performer intake, cam and carb. I added a clutch fan and installed a Transgo shift kit. I increased the exhaust size and went to a Flowmaster muffler. All this added up absolutely ZERO increase (or decrease) in mileage. I've moved the timing up and down, I've tried three different carburetors - the stock 2 bbl., a Holley 450 and the Edelbrock. NOTHING made a difference. It is like the car is stuck in a 13 MPG vortex it can't get out of.

So, I hate to be the voice of discouragement but after numerous postings on the Allpar site I was basically told some cars (for reasons unknown) just get bad mileage and others great mileage. Now, that said, I often wonder how accurate people really are when they check. If they just fill the tank until the pump shuts off they can be WAY off. My daily driver is a Mazda with a 12.5 gallon tank. It wants to shut off at about 10-11 gallons. Yet I can cram in 14 gallons if I fill it until it flows out. Those discrepancies can make HUGE differences in mileage calculations. Anyway, you have my sympathies. It is rather painful when a 25 mile round trip to the store cost nearly $10 in gas!
Tom