Struggling To Reach 400Km A Tank On My R33 Gts25 Auto

[R33mkd]

ive had this car for about 5 months now, the car is stock (r33 gts25 auto) as can be. i have only managed to clock over 400km twice and hit 450km once.

Driving during peak our traffic the car seems to struggle on efficiency and only got about 45km out of the last 1/4 on the tank.

i am running it on premium but was told that i should try 98 as it is better for the engine.

can anyone help me, thanks

[iseekool]

Check the following.

- Air filter

- Spark plugs

- Tire pressure

- 02 sensor

- AFM

- Vacum leaks

[mad082]

first thing to do is to not start looking at how far you are getting "on a tank" and start looking at what your actual economy is. put it into litre per 100kms because that will give you a better idea of how poor your economy it is and whether your fuel gauge is just a bit dodgy. things to test with the car will be the O2 sensor (can be done with a multimeter or a consult cable) and take note of how long the car takes to warm up when driving. the car should come up to temp (middle of the temp gauge) within about 5 mins of driving. if it takes longer than that, or doesn't come up to the middle of the gauge, then the thermostat may be dodgy and this will cause excess fuel usage.

and peak hour traffic is going to kill your economy. driving style will have the biggest effect on economy. light on the throttle. coast as much as possible. if there are a few lights in a row and the next one is red, don't floor it to the speed limit and then get hard on the brakes. just cruise along at 30 or 40kmh, then just lift off and cruise to a stop.

having said all that, i'm guessing (without knowing how much fuel you are actually putting in) that your economy is probably only around 13L/100kms to 14L/100kms, which for an auto skyline in peak hour traffic isn't too bad. it will never have the same economy as something like a 4 cylinder hatch, as they are a smaller, detuned engine in a lighter car.

[R33mkd]

thanks, ill go check everything out, what do you think would be the best tyre pressure. im getting about roughly about 15-17L/100km. thats of about 55 Litres.

[mad082]

what size tyres? for stockies then mid 30's. bit higher for lower profile tyres.

[mad082]

a simple way to rule out any mechanical issues is to fill up with fuel (somewhere close to where the motorway starts so you can do a pure highway driving test), go for a cruise up the highway for 50 or 60kms, turn around and come home and fill up again. see what economy you got on the trip and if it's down around 10L/100kms then there is nothing wrong with the car and it's purely the traffic conditions and possibly your driving style that is causing the poor economy. when cruising on the highway the ecu uses the o2 sensor for fuel economy, so if it isn't working you will use more fuel. the ecu ignores it when accelerating above a certain load point (uses it for light acceleration, but not for heavy)

[R33mkd]

thanks again.

ill go try that out some day when im not to busy.