911 mpg
 

Is it possible for a 1974 911 to get 34 mpg? Just took a trip to New Hampshire, 340 miles round trip. Filled up before we left, gauge reads 1/2 tank upon return. Drove very conservatively around 3200 rpm on the highway and most of the trip was highway miles. I assume the gas gauge may be incorrect Any thoughts?

Thanks

Fill it up at the pump and let us know what your mileage was on this trip. I am curious. My 76 has been getting around 24 on long steady drives.

34 would be pretty impressive. I have seen high 20s when I was stuck driving at 60 to 65 for long trips. On the track I have seen single digit MPG.

34 seems high. I have averaged 25 for a highway trip. but I was doing 70-80.

My 74 2.7 CIS gets about 16.

use a gps to check your real speed and verify it against your speedometer.
Tire size may change your speedo (and odometer) up to 10%.

Rich

A couple weekends back we did a 1800 kms trip on the back highways. A faily spirited drive netted 25.8 mpg for imperial gallons. That works out to 20.6 for US gallon.

I've gotten over 30 mpg driving between 45 and 55 mph through the country on windy roads, cool weather, and the windows down. Mine is a 87 Carrera. Probably couldn't have had better mpg conditions. Otherwise, highway mileage is a pretty steady 25 or 26 at around 70 mph on long trips. Just drove 2500 miles going from NC to NY state to Watkins Glen and back.

I get 20-21 on my 3.2 powered SC...50-50 rural/city...I'm sure I can get 3-4 more on the highway...

Just this weekend I squeezed 25 mpg out of my 3.6 75 targa. Usually I get around 19. I was cruising at about 3000 rpms in 5th the whole trip when I got the 25mpgs

No way - unless you went downhill the whole way...... :-)

Air Filter effects mileage too.

I swapped back to the OEM paper filter and modified the air box cover. I do notice a considerbale drop in mileage per tank.

But cleaner oil is better for her anyways.

34 MPG, Wow that is quite good, almost too good to be true.

+1, Fill then divide mileage, filling will also approximate if the gauge is calibrated/reading properly. But you knew this :D

The best I could ever do in my SC is about 25 mpg.

Most mpg that I ever got in a Porsche was a 68 912, rebuilt motor (1974) on a trip to Florida from DC going around 3400rpm (75-80mph) the whole way, 34 mpg. My 70T averages around 25 around town and the 3.2 is around 23. 34 in a 911 would be most impressive. Steve

I have a '74, I just had the gas gauge on the dash fixed it would read 1/2 tank when it should read "R". Before fixing I always fill up after 300 miles. Combo city / highway the best I get is 19mpg.

Half on the guage is not necessarily half the tank. You have to fill up again, note the number of gallons it took to fill up, then do the math!

Back in the dark days of a the national 55 MPH speed limit I drove my 914 2.0 on a trip. The cops were thick so I drove 55 and got 36 MPG. I don't think my 911 could get 34 even at 55 MPH.

a 36 year old fuel gauge and sender is a poor way to calculate fuel economy.

fill your tank at the pump to determine how much has been consumed on your trip.

If you are after better fuel milage with any car, not just our 911's...then you need to address the whole problem.
Tire pressure...tire size (narrower for better mileage)..brake type (disc pads drag on the rotor)...fuel...weight of foot on throttle (LOL)...and type of terrain (hills bad...flat good).
Carbs or injection can contribute.
Injection system with feedback on both fuel and ignition would be good.
With carbs...the problem is the enrichment system..avery time you wiggle your toes, the gas mileage goes down.
The old SU carbs were good...no accel pumps.
BUT...and this is a big "but"...the car will no longer be a 911..at least not the 911 you want.
For extreme gas mileage...try an old 3 cyl Fiat...they used to get over 80 MPG...but at the price of being a total stone!
Bob

If your referring to me, I'm not kidding. Best I've gotten ever. Filled her up with just shy of 12 gallons at 300 miles. Included driving through grants pass. Was heading north on i5 from medford Oregon. I have 315/35/17's in the rear. I was pretty surprised my self. My 914 got about 37 mpg to portland once but has dropped significantly since going to 205/50/15's