[somerandomguy]

Hello,

I have a 1990 corolla diesel TX 1.8 diesel engine.
I am running 175/70/r14 up front
and i have a 165/80/r14 on back left
And a 155/70/r14 on back right.



I am trying to calculate gas mileage with filling up tanks and going on 29 km runs. I can calculate the distance of trip fairly well with odometer and gps apps on phone. GPS app is probably more accurate than odometer.

I dont know if my speedometer is accurate as GPS app speedometer reads 10 km/h lower than the vehicles speedometer.

I think one inconsistency is knowing when tank is full when at gas station. Is it best to let the pump click once and stop filling up? Is it better to keep filling up after pump clicks until fuel is visible in gas tank through the gas tank filler hole?

I have achieved highest fuel economy at 50 km/h =31 mph on a 135 km highway trip at 50 km/h=31mph and when i filled up the tank it received 4.22 litres=1.11 gallons. Thats 135 km/1.11 galon=121 km per gallon=75 mpg.

Dont know how accurate this is because of the possibility of variations such as was the tank really full at one click of fuel pump or was it really full after pumping after the first click of fuel pump.

Interesting that at 60 km/h=37.5 mph on highway fuel consumption goes down to 54 km/g= 34 mpg
Going 50 km/h instead of 60 km/h on highway improves fuel consumption at least two fold



I would like to know more about tire size and its relation to fuel consumption. Is it better for fuel consumption to run 165/80/r14 than 175/70/r14?

I dont have a tachometer installed though i am thinking that one would be a good idea to get better fuel consumpiton?

Thanks and looking forward to being part of the community.