S14 mpg? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Kingtal0n · 03-18-2023, 11:09 AM

Factory 240sx should be around 25mpg with automatic
Iirc it could be 28 to 30mpg with 5-speed.

I used to get 33mpg with sr20det 5-speed.

It should not be less than 25mpg no matter what 4 or 6-cylinder at 2800lbs.
Even with a V8 240sx can 30mpg provided proper gear ratio and < 3000lbs.

In terms of tank mileage, its a ~15 gallon tank so at 25mpg (the minimum) it should do 250 miles to 10 gallons of fuel, 2/3 of the tank. I usually fill up with 3 or 4 gallons left so I average 260-280 miles per tank at 25mpg.

To get the mileage there are many factors, here are some
1. friction: tire pressure, alignment, wheel bearings, output, driveshaft and axles bearings/surfaces, no dragging brakes, E_brake isnt stuck on
2. air fuel ratio and cruise timing: 15.0:1 air fuel and proper cruise timing advanced typically 37-43*BTDC
3. healthy engine, good compression, clean fresh lightweight oil, no intake obstructions, no exhaust restrictions (bad cats clogged)
4. Lightweight vehicle (friction component from gravity) do not overload the vehicle with weight
5. Cruise RPM and engine load: Do not cruise outside of ideal engine efficiency range or where high wind resistance is a factor

03-18-2023, 11:09 AM	#10
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 41 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	Factory 240sx should be around 25mpg with automatic Iirc it could be 28 to 30mpg with 5-speed. I used to get 33mpg with sr20det 5-speed. It should not be less than 25mpg no matter what 4 or 6-cylinder at 2800lbs. Even with a V8 240sx can 30mpg provided proper gear ratio and < 3000lbs. In terms of tank mileage, its a ~15 gallon tank so at 25mpg (the minimum) it should do 250 miles to 10 gallons of fuel, 2/3 of the tank. I usually fill up with 3 or 4 gallons left so I average 260-280 miles per tank at 25mpg. To get the mileage there are many factors, here are some 1. friction: tire pressure, alignment, wheel bearings, output, driveshaft and axles bearings/surfaces, no dragging brakes, E_brake isnt stuck on 2. air fuel ratio and cruise timing: 15.0:1 air fuel and proper cruise timing advanced typically 37-43*BTDC 3. healthy engine, good compression, clean fresh lightweight oil, no intake obstructions, no exhaust restrictions (bad cats clogged) 4. Lightweight vehicle (friction component from gravity) do not overload the vehicle with weight 5. Cruise RPM and engine load: Do not cruise outside of ideal engine efficiency range or where high wind resistance is a factor