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A stock Datsun 1200, in good condition and state of tune, should get around 38 miles/US gallon in highway travel (16 kilometers/liter). Economy will be less in town, stop-and-go traffic. Note that most 1200 Speedometers are off -- almost always reading more miles that you really traveled -- so base your calculations on a corrected speedometer factor.
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Overview
The Datsun 1200 got a fuel efficiency of about 24 city and 38 highway. I used to keep records, and I consistently recorded 32 MPG rural/38 highway (after adjustment for speedometer error, see 'top speed' above).
MPG 37.9 miles/gallon (US gallonsᵂ - 3.79 liters) MPG 31.6 miles/gallon (Imperial gallonsᵂ - 4.55 liters) L/100km 6.20 liters/100 kilometers Km/l 16.1 kilometers/liter
MOTORMAN magazine: Range between 24 and 32 [UK] miles per gallon. Average on test, 28.9mpg.
Consumer Reports 1971 September Road Test: RANGE OF AS MILEAGE TO BE EXPECTED IN NORMAL USE (mpg) ... 23-41 TANK MILEAGE OBSERVED ON 300-MILE TEST TRIP (mpg) ... 35
28 mpg overall: Road Test - Road & Track (November, 1970)
32.5 on the 1973 Datsun 1200: Motor Trend
35.3 mpg:We drove the little Datsun from Daytona to St. Augustine and back -- a total of 106 mi. -- on some second-grade roads. At an average speed of 48-plus mpd, the rig from the Land of the Rising Sun got 35.3 mpg, making the round trip on exactly 3 gallons of gas -- Mechanix Illustrated
B120
B120 Datsun 1200 Truck/ute Sunny Truck had a higher ratio rear differential and so got less fuel economy. The GB120 (long wheelbase) version was also a bit heavier.
NZ Roadstar ute GB120 published figure 17.3 km/l B110 GB120 16.1 17.3 kilometers/liter 37.9 40.7 USA gallons/mile 45.5 48.9 Imperial gallons/mile 6.21 5.78 liters/100 kilometers
Fuel economy was advertised as 17.3 k/liter/49 imperial gallons/mile (41 US gallons/mile), which is very possible with a 5-speed. Or perhaps they measured it at a leisurely 80kph.
Other Sunny Models
B210 and B310 models with FU Engine came with 5-speed and achieved fuel economy that is still unmatched in 2009.
B210
4-speed 41 MPG (US gallons) = 5.74 L/100km = 17.4 k/ℓ 5-speed 48 MPG (US gallons) = 4.90 L/100km = 20.4 k/l 'Plus' 50 MPG (US gallons) = 4.70 L/100km = 21.3 k/l
B210 fuel efficiency improved year on year reaching the peak with the B210 Plus model with its FU Engine and tall 3.7 gearing.
1974 A13-powered B210: 30.4 mpg average (automatic + manual)
1976 B210 with 4-speed: 41 mpg
1977 Introducing the B-210 'Plus'
50 miles per gallon
* 63-series 'dogleg' 5-speed and low-RPM A14 engine
1978 CANADA "Up to 80km/gal ... Transport Canada approved tests"
http://www.fueleconomy.gov/feg/epadata/78guide.txt
CAL Manual: 40/29 2-dr
CAL Automatic: 30/24 4-dr
FED Manual: 40/28 2-dr no catalytic convertor
FED Manual: 48/36 4-dr catalytic convertor
FED Automatic: 28/24 Coupe catalytic convertor
1978 - 48 Highway, 36 City
1978 - 48 highway, 36 city (EPA estimates) B210 GX (5-speed)
Nifty Fifty - 1978 USA B210 'Plus' with 5-speed
* 50 MPG (60 Imperial mpg) 21.3 km/l (4.7 litre/100km)
* A14 with 3.700 diff ratio
B310
1979 B310: Winning Numbers From Datsun
47 MPG
A14 with 3.454 diff ratio
65 HP A14 (instead of regular 80 HP A14)
This little fuel-squeezer recorded a whopping 67.6 mpg in the 35-mpg section of our steady-state fuel-economy testing -- beating the [USA] EPA-champion Volkswagen Rabbit Diesel.
EPA rating: 43 highway, 31 city, 29 California city
Observed fuel mileage (steady-state mpg)
35 mph: 67.6
45 mph: 50.8
55 mph: 37.3
Specifications: 1.4 liter engine, 65HP @ 5600 RPM, 75 torque @ 3600 RPM, 5-speed manual, 3.70:1 axle ratio, Tire size 175/70SR13, curb weight 2015 pounds, 0-60 mph: 18.4 seconds
February 1980, page 116
EPA rating: 47 highway, 36 city, 30 California cityObserved fuel mileage (steady-state mpg)
35 mph: 58.0
55 mph: 37.9Specifications: Compression ratio 8.9:1, Tires 155/SR13, Curb weight 1945 pounds, F/R weight distribution 53/47, 0-60 mph 18.0 seconds,
February 1981
1980 - 41mpg (1979 was 47mpg)
Ratings
10-Mode
In Japan, the 10 Mode fuel economy test (10モード燃費ᵂ) was used from 1973-1990. The 10 mode measured the distance traveled per liter of fuel in conditions simulating urban driving. This test is not performed on a real road but on a chassis dynamometer , and the load applied to the drive wheels is classified according to the vehicle weight. Therefore, even for the same vehicle model with the same engine and drive system, slight weight differences can cause the load classification to differ depending on the grade, resulting in differences in fuel efficiency.
For example, 1978 B310 with A12 and 5-speed was rated at 13.0 km/liter or 30.6 MPG (US gallons).
Driving the car slowly, say at 60kph (37mph), resulted in higher fuel economy than the 10-mode test:
- 15.5km/L: 1980 A12 5-speed 10-mode
- 24.0km/L: 1980 A12 5-speed at 60km/h constant speed
Considerations
These factors will greatly decrease your fuel economy:
- Weight: Carrying unnecessary weight in the car, e.g. Tools, spare parts, heavier "upgraded" diffs and transmissions. Also having passengers will lower economy. This applies to acceleration (town traffic) and not at all to flat-road highway driving)
- Dragging brakes. Jack each wheel and ensure they turn freely by hand. It is not uncommon to have stuck brakes, often due to:
- leaking brake fluid
- leaking axle grease
- seized/unlubricated caliper
- incorrectly adjusted drum brakes
- incorrectly adjusted emergency (parking) brake
- Choke not working correctly. With engine fully warm, remove air cleaner and ensure the choke butterfly valve is fully open. Even a little bit off from straight up/down will cause too much fuel to be used
Hyper Economy
blownb310 achieved 74 miles/gallon with an A14 engine during competition
See main forum topic POST A completely different A-series build!
Freeing up disc brakes
Engine Tuning Factors
- Choke freely operating
- Choke pulloff working correctly
- Choke warming up fully
- Distributor Vacuum advance working freely (cars with VA disconnected will use more fuel)
- Distributor centrifigal (mechanical) advance freely working
- Vacuum leaks
- hot Air Cleaner intake correctly functioning (warm air is best for fuel economy)
- Clean oil
- Clean air filter
- Fan belt properly adjusted
- Emission controls connected and operating
- PCV valve not stuck/dirty
Chassis Factors
- Brakes not dragging
- Correct wheel alignment (most especially toe-in)
- Correct tire pressure. Higher pressue is better for fuel economy, up to the limit printed on the tire. However, for proper tire wear, use Datsun's recommendation. Just don't go below it.
Driver Habits
- Do not let car warm up for several minutes before driving -- that is 0 miles/gallon when the car is not moving. Start the engine, and drive off moderately after 30 seconds. If your car won't idle this soon, inspect/repair/re-adjust the choke mechanism.
- Get into your highest gear as soon as possible, but go as slow as reasonable. This means 4th gear @ 35 mph for a stock 1200. Lower gears use more fuel. Higher speeds use more fuel.
- Plan trips. For example, combine two errands into one, instead of making separate trips. Wait for another day to combine errands.
- Avoid short trips on cold days, where the choke-on condition uses twice the fuel
- Avoid jack-rabbit starts
- Avoid last-minute braking
- Anticipate stops, approach gradually
- Let the car coast faster down hills and go slower up hills if speed laws allow. Otherwise maintain a constant speed.
- Install a vacuum gauge in the cockpit and try to keep vacuum as high as possible (by slow, moderate acceleration)
- Do not ride the clutch. Your foot should be off the clutch as soon as the car is moving.
- Do not ride the brake pedal. Your foot should be off unless stopping/slowing the car
- Keep your foot steady on the accelerator pedal
- Use regular-grade (inexpensive) gasoline. Your 1200 is designed to run correctly on today's low-octane fuel.