Fuel Consumption

[Spinning]

Hey every one, Ive got a R32 Rb20det Gtst thats only getting around 250kms per tank with BP98 driving sensibly. It has a 3" straight through exhaust, a big front mount and a RB25 turbo.

I cant find a reason why im getting such low K's!

Could it be it just needs a tune with those mods?

Could any one suggest any thing to check please.

[StevenCJR31]

check your oxygen sensor is functioning

[L33SH]

but be careful replacing it, Ive replaced mine twice now and its even worse on fuel...

[StevenCJR31]

but be careful replacing it, Ive replaced mine twice now and its even worse on fuel...

then your engine must have other issues

[niZmO_Man]

What ECU are you running? What turbo pressure? What else has been done to the engine? Most importantly, how are you driving it?

[mad082]

How much fuel are you putting in? without that this thread is useless

[Chris32]

I'd look at the timing first, then the 02 sensor. A mates car had similar issues

[Spinning]

I'm running 10 psi through a rb25 turbo. It's a stock computer. I get 250ks with a full tank of Bp98. Sorry guys!

[mad082]

how many litres are you calling a "full tank"? the tank is 65L. are you running it until the car simply runs out of fuel? are you running it until the fuel light comes on, cause there is roughly a 10L difference in amount of fuel used there. and if the light isn't coming on before you get fuel then there could be anywhere up to about 20L of difference in fuel used.

so how about you start calculating your actual fuel economy in litres per 100kms driven, and then we can give you an indication of whether you are just getting the typically poor fuel economy that turbo skylines get, or whether you have something actually wrong.

[Spinning]

Thanks man, I didn't really relise that. When I fill up I put around 40l in.

[mad082]

Ok so that's roughly 16l/100kms. Depending on how you drive then that's only slightly poor economy. If you like to give it a squirt and do a fair bit of driving in stop/start traffic then it isn't too bad. If you do plenty of highway driving then it is a bit crappy

[Spinning]

Okay so the fuel light came on today and ive only driven 229KM... Thats driving pretty normal!

[Kinks]

As above the fuel light is ridiculously conservative. Your R32 may be different but on my R33 I have seen the fuel light come on at 1/4 tank before!! I wait until my needle first drops BELOW the empty mark and then I know I have about 10 litres left in the tank and a range of around 50km before I really should fill up. I can consistently put in between 55L and 58L so you are filling up way too soon.

km per tank is meaningless, unless you are really pushing it close to empty it's not "a tank" anyway. The ONLY way to tell people your consumption is in litres per 100km.

My r33 gets around 12.5L/100km in typical, gentle driving to and from work. Bear in mind I have minimal start-stop traffic it's usually cruising at a steady 60-80km/h depending on the speed zone. If you are in start stop traffic your consumption goes to poo. If you put the boot into it your consumption goes to poo. If your O2 sensor is stuffed or you got a cheap tune your consumption goes to poo. I did a tank recently after flogging my car more than usual and it was above 14L/100km, it surprised me. But that's a car that I know is in perfect nick because I always get great economy on it. A dud O2 sensor will easily cost you more in fuel.

[mad082]

As above, there are so many variables in fuel economy. If you let the car suit and idle for a while before driving then you will get worse economy (and it's not needed). While low revs help economy, low amounts of throttle help more. If you floor it but only rev to 3500rpm you will use more fuel than someone who revs to 4500rpm but uses light throttle. Also driving short trips will result in poor economy.

There are mechanical issues that can cause poor fuel economy though. O2 sensor as already mention, dodgy thermostat (if the car doesn't come up to temp within about 5 mins if driving then get a new thermostat), dirty air flow meter, sticky brakes.