Fuel Consumption On R34

[ShagStR]

Hey guys, I'm new to the R34 world. I drove a GtiR up until i put to much work in her and she become silly for everyday driving. Anyway I've had my 34 for about 6mths now and i only seem to get about 320ks to a tank. Is this standard ? I'll post details below. Anything you think could help my thirsty beast would really help!

Petrol: Shell Optimax or any 98ron

80,000 Service 3mths ago

Mods: 3" exhaust from the turbo back

Apexi twin air filter intake

Boost set to 12

PS: I thought i have been driving her very respectably. I blow her nose every now and then for good health but that's all.

Thanks Guys

[Owens]

Apexi twin air filter intake? Do you own a GTR?

If you're only getting 320km, then I would highly recommend cleaning your Air Flow Meters (AFM's) and replacing the o2 Sensors. I've recently done this and it's made a world of difference to both fuel economy and performance.

See this article about replacing your o2 Sensors: http://wardiz.org/blog/2009/07/30/replacing-an-oxygen-sensor-on-a-r34-gtr/

A couple new sensors will set you back about $176 incl. delivery.

For the AFM's, get some "CRC Air Flow Sensor Cleaner" available at Supercheap or Autobarn: http://www.supercheapauto.com.au/online-store/products/CRC-Mass-Air-Flow-Sensor-Cleaner-300G.aspx?pid=157339#details

The cleaner will set you back about $23 per can. The AFM's need cleaning every now and then because oily residue builds up on the sensor components. This is cause by the "blow by" gas from the cam cover.

[jrm]

I filled up this morning - 315km from 50L - I exclusively use 98RON fuel.

That sort of fuel economy is normal for me - my driving is purely city driving (no more than 10-15minutes, never more than 60kph, lots of stop start, aircon on all the time, and I'm pretty heavy on the accelerator). Last big highway drive I got 500-600km from 50L.

Mods include 3" turbo-back, K&N panel, FMIC & 10psi wastegate actuator - dyno run was 182rwkw (pre-10psi actuator)

I'm currently at 105,000km and I changed my o2 sensor - with a genuine nissan one - at 80,000km (as per 80,000km service guidelines). My fuel economy didn't really change before/after o2 sensor change. As part fo my 100,000km service I fitted new plugs, new coil packs, new timing belt, new thermostat, new water pump, etc. I've also recently serviced (cleaned) my AFM - it's worth noting that none of this seems to have affected my fuel economy.

Purely as a check, find out whether your o2 sensor was changed as part of the 80,000km service (it is one of the bigger items listed, along with your ancillary belts).

All in all, you're getting similar economy to me - so sounds fairly normal.

I'm planning on getting my nistune tuned soon and trying to get some economy back - I know it's running quite rich (which is also fairly normal for a modified car without ECU tuning)

[ShagStR]

Thanks Owens, thats a good idea on the o2 sensors. I really wasn't sure what milage i would get from a GT-T, if that's all your getting JRM maybe with a bit of maintenance i can get her up closer to the 400k mark.

Stupid question; Do intercoolers really improve fuel economy ? I understand the argument that cold air is denser than warm but the space is the same.

[jrm]

I think the main consideration to make is that the standard ECU tuning is - by default - going to richen the mixtures when you modify the car. This is a protection mechanism built in there by the Nissan engineers - richer mixtures are less likely to have detonation, and act to 'cool' the combustion process more - making it much safer for the engine.

I honestly expect my fuel economy to increase fairly dramatically once it's been tuned as they'll make an effort to keep the mixtures more at optimum levels at different load-levels.

[mad082]

how about you take note of how many L's you are putting in instead of just saying "a tank" as that could mean 45L or 65L, or if your fuel gauge is totally fubar'd, 25L. work out your fuel economy into a L/100kms form then you can see exactly how bad your economy is. if you do mostly highway driving and your economy is over 10L/100kms then your o2 sensor needs replacing. if you do mostly city driving and give it the beans a fair bit then you may see anywhere up to 17L/100kms and replacing the o2 sensor won't do a thing since it only used by the ecu on light throttle. if you drive it normally, but do a lot of stop/start driving in traffic then you could see anything from 12L/100kms up to 14L/100kms, it really does depend.

one thing to pay attention to is how long your car takes to come up to temp. if the needle isn't to the centre of the gauge within 5 mins of driving then you need a new thermostat and that should help with economy. also, if you are one of those people who let the car idle until it is up to temp before driving off, then that will be making your economy worse, plus it is a waste of time and fuel and it can actually cause more wear on the engine than driving like a grandma straight away.

[Shazza24]

Seriously just putter around in any turbo like it was a 4cyl n/a and you will get fuel economy even if you have standard ecu with rich mixtures. I had my mother drive my s2 r33 gts-t with light mods and she got better fuel economy than me because it comes down to your right foot.

[choyda]

If thats Afro's old car, doesn't it have a Power FC? Might be worth getting a tune once you've checked the basics.

[nato_wp]

My dead stock (everything) R34 GTT on the dyno at 126,000km had AFR's starting from 11.8 going to 10.2 at the top end (ie, ridiculously rich)

I will eventually be installing a Nistune board and getting it remapped to neaten that fuel map up to be a little more reasonable.

[mad082]

My dead stock (everything) R34 GTT on the dyno at 126,000km had AFR's starting from 11.8 going to 10.2 at the top end (ie, ridiculously rich)

I will eventually be installing a Nistune board and getting it remapped to neaten that fuel map up to be a little more reasonable.

that isn't that bad. mate of mine had a 32 on his dyno that went off the scale (think the lowest the wideband went to was either 9 or 10) and then left a big black wet patch on the wall behind the dyno. it was pretty much pissing out raw fuel, LOL.

also what the car runs are full throttle has little to do with fuel economy when driving sensibly. when you are only using light throttle (accelerating gently or at a steady speed), if your o2 sensor is working properly then your AFR will only be around 14.5:1. this is because the ecu is in closed loop mode and it uses the o2 sensor. if you press the accelerator down more then it may jump out of closed loop mode and it goes back to the ecu mapping (and ignores the o2 sensor) and the AFR's will jump down to around the 11 to 12 range (depending on what rpm you are at).

some people try to get better fuel economy by not reving the car out past a certain rpm range. this helps, but if you use 50 or 60% throttle below that rev range you will still get average fuel economy. you can rev up to 6000rpm with only low throttle (lets say 15%) and get better fuel economy than someone in a higher gear that is using 60% throttle and only reving to 3000rpm. but then at the same time, cruising along at a steady speed it can be better to use a higher gear and a fraction more throttle. i did a test with a consult cable on the missus pulsar. on dead flat ground at 60kmh 5th gear got 10% better economy than 4th, but the moment you got to the slightest incline 4th gear was a fraction better, but they were both better than 3rd gear.

[nato_wp]

that isn't that bad. mate of mine had a 32 on his dyno that went off the scale (think the lowest the wideband went to was either 9 or 10) and then left a big black wet patch on the wall behind the dyno. it was pretty much pissing out raw fuel, LOL.

also what the car runs are full throttle has little to do with fuel economy when driving sensibly. when you are only using light throttle (accelerating gently or at a steady speed), if your o2 sensor is working properly then your AFR will only be around 14.5:1.

Quite valid points, however, I get the feeling that 32 wasn't in completely factory spec (from airbox snorkel through to exhaust tips).

I do intend to check that 0² sensor out, I did specifically ask the guys at the time to check it for me, and they said it was ok, but I never confirmed that myself.

[nismo_d'luxe]

I filled up this morning - 315km from 50L - I exclusively use 98RON fuel.

That sort of fuel economy is normal for me - my driving is purely city driving (no more than 10-15minutes, never more than 60kph, lots of stop start, aircon on all the time, and I'm pretty heavy on the accelerator). Last big highway drive I got 500-600km from 50L.

Mods include 3" turbo-back, K&N panel, FMIC & 10psi wastegate actuator - dyno run was 182rwkw (pre-10psi actuator)

I'm currently at 105,000km and I changed my o2 sensor - with a genuine nissan one - at 80,000km (as per 80,000km service guidelines). My fuel economy didn't really change before/after o2 sensor change. As part fo my 100,000km service I fitted new plugs, new coil packs, new timing belt, new thermostat, new water pump, etc. I've also recently serviced (cleaned) my AFM - it's worth noting that none of this seems to have affected my fuel economy.

Purely as a check, find out whether your o2 sensor was changed as part of the 80,000km service (it is one of the bigger items listed, along with your ancillary belts).

All in all, you're getting similar economy to me - so sounds fairly normal.

I'm planning on getting my nistune tuned soon and trying to get some economy back - I know it's running quite rich (which is also fairly normal for a modified car without ECU tuning)

G'day mate i notice your running a k&n panel filter i run the same filter but only just put it in a few months ago how much attention should i pay to my air flow sensor? (i.e how do you deal with the oil off the panel onto your sensor) i have heard this can be an issue but more often than not its perfectly fine i just dont want to run into any issues further down the track so if you could give us some maintenence advice or a bit of a guide it would be much appreciated thanks mate

[Kinks]

i only seem to get about 320ks to a tank. Is this standard ?

f**k no! It's terrible. unless you are doing major stop-start driving you should be getting between 12 and 12.5L/100km (so 50L will get you 400km). On the open road it should be in the 10's.