Fuel Economy

[kessian]

Greetings all,

I did a quick search to find my answers and didn't find anything (or im just really crap at using the search function) so if someone could point me to a thread or answer my question here it would be greatly appreciated.

I have an R34 GTR and its running rich (always leaves a shitload of black crap over the rear bumper). I currently get just under 400kms to a tank (thats with a lot of freeway driving).

Would the following items make a huge difference in fuel economy if i changed them?

New O2 sensor

Hiflow Cat

Power FC and tune

Although this is a how long is a piece of string question, how much roughly have people noticed a change in fuel economy with mods such as these, and what other mods could i do to better the economy.

Thanks muchly,

Matt

[MP_R33]

Thats pretty normal i rekon for an R34 GTR, considering I have a R33 GTST and i can get 600 from alot of freeway driving, if i did a few mods like a front mount and an exhaust i would probably get maybe 500 and urs being a GT-R sounds about right!

I would get a tune done and see how it goes from there.

[jakez88]

i had a r32 gtst with plenty of bolt on mods including a t04e highmount turbo setup. when i first bought the car i tested the fuel economy and got 300kms for a full tank as it was running rich as. checked over the engine to see if i needed to change anything before a good tune and i noticed the oil was black as. changed it over with fresh synthetic and got 50kms extra from that.

so i guess do what you can and its usually the small things that can make a big difference and maybe a good retune will make it perfect.

[GTR-N1]

Already had a HKS F-Con Pro-V instead of a Power FC when I received it. I run just slightly rich & happy to leave it that way.

A 3" Hi Flo Cat didn't make any noticeable difference to my fuel Eco.

So a good tune and attention to the 02 Sensor may improve things for you.

I've always been able to get 460Km out of a tank via a run along the M/H-way and doing a run up and down Mac Pass to home.

...and 430-440/tank in suburban driving (without peak hour traffic) or 500 on a H-way

What injectors are you using?

[kessian]

Basically my mods are standard except for arc airbox and exhaust.

Edited November 4, 2008 by kessian

[some_cs_student]

400 km / tank is ok, a tuned PowerFC will get you more power AND more fuel economy is your tuner is very good and you don't use the accelerator a lot

Normally you do a few mods and get a Power FC and more power, but it's not cheap, and its not going to magically get 600km/tank or something...the best I've ever got was 11l/100km on mostly highway driving in a GTR, with a tuned Power FC.

[Johnny]

Funny this thread pop'd up cos i just did a quick fuel economy test which ended last night at 360km on the trip computer and down just a mm topping the empty line so i would expect 20-30more kays.

My driving was highway at night, very little stop-start and occasional 7000rpm tacho views.

I have most of the bolt-on mods including the power fc.

I also leave plenty of black carbon deposits on my garage floor and pop flames if i change gear on load.

fuel was shell v-power.

[jakez88]

^^^ out of interest use bp ultimate and tell us how you go as i noticed a slight difference changing from v power to ultimate.

[Johnny]

^^^ out of interest use bp ultimate and tell us how you go as i noticed a slight difference changing from v power to ultimate.

I cant resist a test; your on! ill do BP ultimate and check knock + fuel economy as ive used nothing but V-power

[MP_R33]

I cant resist a test; your on! ill do BP ultimate and check knock + fuel economy as ive used nothing but V-power

I would probably try Mobil Synergy too, i find my car likes it better then both ultimate and v-power.

See how you go though

[napower]

lol, everyone should try different fuels and report back to HQ. Ultimate and vortex are my left and right balls

[DLOOOK]

yeah ive been doing some tests with different fuels.

Vortex 98 was the worst ~13.5km/100km mostly suburban driving.

V power was pretty good @ ~12.8km/100km same conditions, even with a lil more spirited driving

now im trying Ultimate.

But the first 2 are more convenient for me to get cos its on my route to work.

[jakez88]

yeh same i've got caltex and shell just outside my house but bp is abit more down the road. but always try and get bp ultimate...for some reason i'm getting about 40kms more on bp ultimate doing the same routes and on and off boosting but it might just be me lolz. otherwise it would be good to see how people go form changing from one fuel to ultimate.

[mad082]

could i just ask, how many litres are you calling a tank? this is something that shits me about most people that ask for advice on fuel economy. they will say a tank and not how many litres they actually used. so if you have a slightly dicky fuel gauge your economy could be 20 or 30% better than you think.

so either state how many litres you are using to go that many kms, or actually work out your economy like DLOOOK did.

[Lippo]

I'm averaging 14L/100km from my R. Thats a 50/50 of h/way and suburban driving daily. And alot of that time, im not going over more than 35% injector duty so im not getting up it too often. Im using BP ultimate only.

[ras1983]

Correct me if I'm wrong but don't R34 GTR's have bigger fuel tanks than R33's?

Anyway, my (stock) R gets an average of 380-400KM from a full tank (~50 litres). And that's mainly city driving. I've noticed that highway economy isn't actually that much better, driving to geelong and back I'll use half a tank and its about a 200Km return trip from my area.

Edited November 11, 2008 by ras1983

[(OO)SKYLINE(OO)]

Run a diagnostics to check both your O2 Sensors, if they are both cycling on the metre then they are fine and no need to change.

High flow cat is alway good as you have a GTR I put one ASAP.

Next time before you fill up, run the fuel tank low to about 1/4 left and put a whole can of injector cleaner in and then fill up with BP Ulitmate (I use IMO)

Next service change your Fuel Filter.

[__PhaseShiftDown]

I reckon you should be able to get a bit more than 400k if you do a lot of freeway runs.

my 32GTR makes about 400km (fuel light comes on) and its pretty much stock, apart from exhaust and ebc. I do about 50/50 highway and suburban driving, occasionally stuck in traffic jam. I also get a a bit of black carbon crap on my rear bumber. Going to replace the cat soon.

But ye, check your O2, clean your AFM, change your plugs, oil, fuel and oil filter, tyre pressure and see how that goes.

[kessian]

Yeah i mainly do freeway driving, and get a lot of black shit over the rear bumper, so it seems to be running extremely rich.

[(OO)SKYLINE(OO)]

Its normal to run alittle rich, but is your rear bar blacked out is it?

Check your ECU...