Highway Mileage

[jhorton3]

For those of you with 1275 motors, twin SU carburetors and the original 4-speed transmission, what highway mileage are you getting at speeds between 55-65 mph?

 

[pakiwi]

I am guessing you either meen fuel consumption or RPM. Yesterday I was out on the Highway and speed was between 55 - 75 for two hours. I averaged 26 mpg. Car is stock 4 speed, twin sun with 20,000 miles on the engine. In 80 degrees car ran at right on N all day.
Allan

 

[bugimike]

Mine has been on blocks for a little while now,but before I put it up, I was getting pretty consistent 24/26 mpg on daily commutes on I95 at speeds between 55 and 65! The best I ever got was 30 mpg!

 

[jlaird]

948 etc, etc, all orginal. Best ever, almost 1500 miles cross country on interstate 49 MPG

Miss Agatha gets just at 31 and very rairly goes more than 10 miles at a time. Local area only, maybe mostly 35 mph.

 

[jhorton3]

Alan-Yes, I meant fuel consumption. Thanks everyone for your information. Two more questions. What kind of terrain were you driving in to get that kind of mileage, and are you running with a stock fuel tank(which I assume is about 6.5 gallon capacity)?

 

[pakiwi]

Realatively flat with rolling hills. If you are familiar with area it is 78 between Harrisburg and Allentown. Tank is standard.

 

[leecreek]

1275 dual SU's. 36 MPG average on the trip to LOTO last year. Blue highways with a 3.73 rear gear. Regular tank and stopped every 2 hrs for fuel and to get the kinks out.

 

[Woblynne]

Hi, not sure of the equation but I get approx 40-42mpg (UK Gallons though) on a good flat motorway run at 55-60 mph.
MG Metro head (cooper S sized valves), LCB header/sports exhaust/K&N filter/twin 1.25" SU's.

Thanks
Mark

 

[regularman]

I never had SUs on mine but with the weber and 3.90 gear and 4 speed I got 36-38 mpg. With my 3.55 and 5 speed and 175/70/13 tires,I get in the low 40s but then 70 is only about 3100 rpms now in 5th. I set this car up for long trips and just cruising but the disappearing water problem is still holding me back on that.