62 Fulie Expected MPG

[Stephen G.]

I just drive my 62 Fulie to Altoona. I averaged 14 MPG. I have 4:11's and kept the RPM at 3,000 or below, about 55-60 MPH. Would like to know if others have input as to MPG. Don't know if I should play with the fuel unit or leave it alone.

[Bill W.]

Re: 62 Fulie Expected MPG

Mine has 4;11 s I get 7 to 10 around town with a muncie trans.and a little hot rodding.

[Jim L.]

Re: 62 Fulie Expected MPG

Steve,

Taking your last comment first, the best thing you can do to/for your FI unit is to just leave it alone. More good fuelies go bad due to "tinkeritis" than due to any other cause. You know the old saying, "If it ain't broke....."

As to fuel mileage.... Back in the spring of '84 I drove my FI '60 from South Carolina to California (see Spring '85 Restorer for the story). It had 4.11 gears at the time and my mileage was around 13 MPG for the trip. So if you get 14 MPG, you are doing well.

If you want better economy, change the rear gears. That's what I did. I yanked the 4.11s and put in 3.55s prior to a trip to Steamboat Springs CO and it made all the difference in the world. Mileage skyrocketed to nearly 19 MPG. I still run the 3.55s (even with a 2.20 low and an 097 cam) and find them to be very enjoyable.

Jim

[John D.]

Re: 62 Fulie Expected MPG

Stephen, 14 is nothing to brag about on a 62 FI unit. One thing I never figured out about '62 fuel injections is why Rochester Products used three different sized nozzles in them. '62's came with either, Q12's, R13's, or S14's.
Now if your '62 FI has the big S14 nozzles then that could explain the mileage. If you unit is not calibrated correctly or has some issues that could account for the 14 MPH.
As Lockwood said the low gears aren't helping at all. My GMC 6.0 2500 tanker averages a cool 11-12 miles a gallon. Pulling the trailer it gets around 9 MPG.
The 37-1/2 gallon tank and poor mileage puts a dent in the wallet for sure.
My friend Jim said it all though. Don't tinker with the FI like so many do. Typically the tinkering just makes the FI's run worse unless one is trained to work on them.
Ethanol is also the cause of poor mileage. It burns dirty, it reaks and pollutes our atmosphere. About the only thing it's good for it my pal FI Art. JD

[Matt L.]

Re: 62 Fulie Expected MPG

i know we are talking 60 and 62 but my 64 with the 375R gets 17MPG with 4:11s at 3,500-3,700 highway cruising. that is roughly 65-70MPH. i used my GPS as a trip odometer and as a speedometer. i filled up both times to the bottom of the filler neck/top of tank. i told that to another fuel car owner and he didnt believe me but its the truth.

take care,
matt

[Michael H.]

Re: 62 Fulie Expected MPG

Stephen, 14 is nothing to brag about on a 62 FI unit. JD

JD,

Years ago, I drove a FI 63 with a 4.11 rear to Florida from Illinois and got over 20 MPG. (22 MPG average as I remember) This was in the early/mid 70's, just after the new 55 MPH speed limit went into effect so that probably had a lot to do with the high number.

Probably only got 10 MPG on the return trip though.

[Patrick S.]

Re: 62 Fulie Expected MPG

Only getting 10 mpg going home from FL to IL is easy to explain, It is up hill all the way!!!
Pat

[George J.]

Re: 62 Fulie Expected MPG

After changing my rear gears to 3.36 I recorded 21mpg while going down to the Corvette Museum in about '99 with my '65 fi coupe. Interestingly I had one of the other members of the caravan in a '96 LT4 put his car in 4th, which is 1:1, and it also had a 3.36, or 3.31, and look at the instant read on the computer. It said the same 21mpg. This was at about 70mph. I'd be interested to see what a new Corvette would record at the same speed in a direct gear.

George

[Jerry K.]

Re: 62 Fulie Expected MPG

Drove my 1962, 300HP, 4 speed,3:36 gear and got a solid 17mpg on the trip to Altoona,RPM's around 3000.

[George W.]

Re: 62 Fulie Expected MPG

My '61 315 hp fuelie with a 3:55 gets 17 mpg...I wish gas was still a quarter a gallon.

[Duke W.]

Re: 62 Fulie Expected MPG

Lean the economy stop in 1/8 or 1/4 turn increments until you detect some lean surge. Then richen just enough to eliminate the lean surge.

WRITE DOWN where you're at in this process, so you can return the economy stop to the original position if necessary.

I agree that "tinkering" by the amateur can lead to problems. The secret is to just adjust one thing at a time and keep track of where that adjustment is relative to its original position.

My hunch is that the economy stop is set too rich, and adjusting it as lean as possible will yield a measureable improvement in fuel economy.

My 340 HP SWC with 3.08 axle and 6.70-15 Michelin X radials could knock down 22 MPG at 60-70 MPH, but carburetors have to run rich to deal with manifold distribution problems, so the leanest cylinder doesn't missfire. On average they have to run about 14.5:1 at cruise. The FI system should be able to run at 15.5:1, (as long as all eight nozzles are the same code), but the lack of vacuum advance on the '62 will cost fuel. Run the initial at up to 16 if it will tolerate this amount of initial advance without detonation. Also, install lighter springs in the distributor to get all 24 degrees in by about 2500.

Even better would be to install a '64-'65 spec single point FI distributor with vacuum advance.

If your engine was rebuilt with lower compression, torque, power, and fuel economy will be down 5-10 percent even though modern premium gasllines will operate without detonation with the OE compression ratio and spark advance map and will usually tolerate a more aggressive map.

Go to the sticky section and download my San Diego presentation for more info on how to maximize fuel economy.

Duke

[Bill M.]

Re: 62 Fulie Expected MPG

My father bought a new '59 290 FI w. 4.11:1. He kept a log of fuel. From 6036 miles (5/2/60) to 12228 miles (10/3/60) he averaged 14.86 mpg. This would have been mostly suburban commuting at 60 mph.

[John D.]

Re: 62 Fulie Expected MPG

JD,

Years ago, I drove a FI 63 with a 4.11 rear to Florida from Illinois and got over 20 MPG. (22 MPG average as I remember) This was in the early/mid 70's, just after the new 55 MPH speed limit went into effect so that probably had a lot to do with the high number.

Probably only got 10 MPG on the return trip though.

I do believe I heard this info before Mikey.
I do agree that 14 MPG in a 62 FI car no matter what gears is not typical of what one would expect. But remember now
Stephen doesn't have any 260 Sunoco or 100LL. He has wonderful ethanol instead. Therefore very lucky to get even 14 MPG.

Another repeat story. My old GMC 6.0 absolutely screamed when it got a taste of hi-octane non ethanol gas in South Carolina. Don't know about the mileage as too scary to look but the old GMC really flew coming up from the deep south to SW corner of PA. JD

[Jerry G.]

Re: 62 Fulie Expected MPG

Let me think about this. A gallon of "gasoline" averages 116,900 BTU, a gallon of ethanol averages 76,000 BTU. If the blend of ethanol to gasoline is 10% ethanol then that gives us a blended BTU per gallon of 112,081. This is a 3.5% difference. Therefore the milage reduction from 14MPG would be about a 1/2 MPG, or 13.5 MPG. Just saying.

[Stephen G.]

Re: 62 Fulie Expected MPG

John.

This was almost all 100LL. Filled up in Altoona and Carlisle.

Steve