N/a Fuel Economy Thread

[ShyBoi]

I can get 470k's city use before light comes on or 600 for highway kms

All I've gots a 3" Varex Exhaust, as stated by others with my exhaust closed it does starting drinkin petrol

I've got a 95 R33 GTS-4 regularly serviced every 10,000kms

[84LLR]

What would you guys say are the best mods ti improve fuel economy other than full service. My skyline hasnt been serviced since i bought it and I have put almost 20,000k's on it! It is now over 180,000k's and I get between 400-500k's per tank on bp ultimate.

[AYW550]

What would you guys say are the best mods ti improve fuel economy other than full service. My skyline hasnt been serviced since i bought it and I have put almost 20,000k's on it! It is now over 180,000k's and I get between 400-500k's per tank on bp ultimate.

high flow filter and high flow exhaust, after that something like a Power FC

Edited January 15, 2010 by AYW550

[mad082]

not really mods, but check tyre pressure and wear. low tyre pressures and incorrect alignment create extra resistance. and depending on driving style, sometimes the stock exhaust can be better for fuel economy than an aftermarket one as a lot of the time the stock exhausts perform better down low and if you only use low revs and don't rev it's ring off then the stock exhaust will be better for you. but a ecu upgrade of some sort will help as it will allow you to tune it to make sure it isn't running too rich.

that said, you are getting pretty good economy as it is, depending on your driving and how much fuel you are classing as a tank (how many litres not where the needle on the gauge is, cause that doesn't mean squat).

and why did you leave it so long between services? you are about 10,000kms or more overdue for an oil change. not the best thing to do to en engine.

[AYW550]

not really mods, but check tyre pressure and wear. low tyre pressures and incorrect alignment create extra resistance. and depending on driving style, sometimes the stock exhaust can be better for fuel economy than an aftermarket one as a lot of the time the stock exhausts perform better down low and if you only use low revs and don't rev it's ring off then the stock exhaust will be better for you. but a ecu upgrade of some sort will help as it will allow you to tune it to make sure it isn't running too rich.

that said, you are getting pretty good economy as it is, depending on your driving and how much fuel you are classing as a tank (how many litres not where the needle on the gauge is, cause that doesn't mean squat).

and why did you leave it so long between services? you are about 10,000kms or more overdue for an oil change. not the best thing to do to en engine.

yup, sorry, thats what i was thinking when i suggested exhaust...the aftermarket being better on fuel for open highway cruising and not hooning your way about town

and im really hoping he meant 20000km since a "full service"!!

[mad082]

yup, sorry, thats what i was thinking when i suggested exhaust...the aftermarket being better on fuel for open highway cruising and not hooning your way about town

and im really hoping he meant 20000km since a "full service"!!

i was actually meaning the opposite. a stock exhaust will give better economy on the highway and puttering around town because sports exhausts often result in a slight loss of low end torque in exchange for better top end. on bigger engines with lower rev ranges this isn't so noticable, but for smaller cars with higher rev limits i have found this to be more noticable. this is more to do with the headers than the actual exhaust though.

[Tony de Wonderful]

i was actually meaning the opposite. a stock exhaust will give better economy on the highway and puttering around town because sports exhausts often result in a slight loss of low end torque in exchange for better top end. on bigger engines with lower rev ranges this isn't so noticable, but for smaller cars with higher rev limits i have found this to be more noticable. this is more to do with the headers than the actual exhaust though.

I thought this 'need for back pressure' thing was a myth. You don't see racecars running restrictive exhausts to 'get more torque'. An engine runs most effectively with no restriction of air coming in and going out when set up ideally.

OTOH I have heard about the 'Kadenacy effect' where pressure waves (the low pressure part of the wave) of the air exiting the the exhaust system help to either clear the cylinder of waste or suck in a new charge? But I think this is a phenomenon not directly related to back pressure buy coincident to it...it's to do with the shape and profile of the exhaust system and how it relates to the dynamics of pressure waves in air. Anyway I think that an engine can benefit from this must mean something else is inadaquete with the engine, like the tune, header, or cams?

[AYW550]

i was actually meaning the opposite. a stock exhaust will give better economy on the highway and puttering around town because sports exhausts often result in a slight loss of low end torque in exchange for better top end. on bigger engines with lower rev ranges this isn't so noticable, but for smaller cars with higher rev limits i have found this to be more noticable. this is more to do with the headers than the actual exhaust though.

hmm, well ive replaced my entire exhaust, including extractors and im sure im now getting better fuel economy and im sure my driving styles before and after have been similar

.... and i thought that the bigger diamter pipes and straighter lines allowed exhaust gas to excape faster and the engine would be able to push the exhuast out easier and not have to work as hard??

i could be all wrong too tho, lol

[r32na]

my old n/a 32 (rb25) was so poor on fuel... got like 350 outa a tank... i know own a gtst and i get alot more out of it, but then again if you just cruise and not hit boost the turbo just pulls you along... when i rape it .. then you can see it sucking the fuel up

[mad082]

the reason why smaller piping can give better results at low revs has nothing to do with back pressure, but a scavenging effect. this is the same reason why on a NA car if you go too big of an exhaust you can lose power. i have seen info on back to back tests on a v6 magna where they went from a 2.5" system to a 3" system, dynoing both and gained nothing up top but lost a bit of bottom end. it isn't back pressure that you need so much as a slight bit of turbulence (not exactly the best work to describe it but all i can think of) to keep things moving.

it is a little bit like how if you fill a bottle of water up then turn it upside and tip it out, the way to get the water out the fastest (without squeezing it) is to make the water spin first.

[hr32gts]

Here is my stats ...

1992 Nissan Skyline R32 GTS

250,000km on the odometer

RB20DE

Auto 4 spd (R33 GTS-t box)

Pod filter with adapter on stock AFM

Coby Extractors with 2.5" outlet

Catco 3" Hiflow cat converter

(restricted 2.25" exhaust with big twin mufflers for rego) normally runs a nice straight through 2.5" system with single muffler and Cannon @ rear

Around town on 98 octane Currently I get around 430-450km from a tank

(I think I got slightly better economy with the straight through exhaust on it around 450-470km but rego dont like it rather loud although last time it was tested the car had no catalytic converter installed)

I am also not 100% sure on my ignition timing as it feels fairly retarded @ the moment but will have to check that out with a better timing light

[brmusty]

I have a series 2 r33 gts manual and the most i've got on a full tank is 450kms, and you were all mentioning a light coming on when your low... i think my light is busted cause i've never seen a light come on before lol.

[mad082]

how many litres are you classing as a full tank as "a full tank" isn't a unit of measure and may also be the reason why you haven't see the light yet as you may still have a few litres to go before it comes on. gemerally it comes on with about 8-10L left in the tank, so that would mean about 55 to 60L used (depending on how much you fill up after the first click)

[Reggi34dr]

i'll have to put up my figures for my drive up to townsville then cairns from bris before x-mas

[Socrates]

1978 C210 Skyline

lucky to get 400km to a 60L tank.

With both spirited & conservative driving.

I drove it till the needle was past empty and i only just broke 400km.

No fuel light coming on though.

Engine. 2.4L Straight 6 OHC L24

[Reggi34dr]

my move north started with a full tank of Ultimate at eight mile plains BP. should also note that the car was 90% loaded up with clothes/suitcases, computers and boxes with misc. household/work stuff. the rear Teins were raised a little to accommodate the load.

so my fill-ups

eight mile plains bp to rockhampton mobil (if i had drove a lil further up the road i would've found the bp, doh!)

travelled - 664.6 K's

low fuel light K's = 68.3 K's after the light came on at 596 K's

i then refuelled with mobil premium ULP with 58.6L

I have no doubt I would've made 700 K's from this tank but unfortunately the 700 Km mark would've left me stranded between towns. I normally push 100 Km's with the fuel light on.

Rocky Mobil to Ayr BP

travelled 649.2 K's

low fuel light K's = 106.7 K's

refilled with 61L of Ultimate.

From Ayr, I got to Townsville dumped all the stuff i didn't need then headed on to Cairns for x-mas and new years.

So....

Ayr BP -> Townsville -> Cairns -> refilled at Tully Shell with V-Power on return journey to Townsville. Tully BP had run out of Ultimate.

travelled - 627.4 K's

low fuel light K's - 59.1 K's

low fuel light came on at 568 K's

refilled with 58L

I'm happy with these numbers.

[iseekool]

Hi Fellas,

I'm going slightly off topic. But the car is still an N/A and a Nissan

Mrs. and I recently bought an N15 Pulsar 1.6L Auto sedan (granny spec??) as a our runabout/train station/shopping center/park anywhere kind of car. Car is 100% stock and has 170,000km on the clock.

I've been driving it lots lately (to work and back ~100km round trip) to get a proper grasp of the fuel economy as I've suspected the car is guzzling fuel, as we all know short trips are a bad gauge of measuring fuel economy - mainly used to go to the local train station/shops.

My route is mixed urban and freeway driving. I'm not too happy with the fuel consumption. I'm getting around 9L/100km when intentionally babying it and 10L/100km when driving "normal" (not thrashing it).

I thought this kind of car should be using around 7 to 8L/100km - being realistic, I don't believe the figures posted by Redbook (quoted combined 6.2L/100).

I've made sure tires are inflated to the correct pressure and did a an oil (Nulon Semi-Syn 10w40) and filter change. I'm currently running the car on Shell V Power every fill in the hope it will clean the engine.

Just wondering is anybody out there is having the same consumption with the same car or a car with a similar sized engine, 1.6L Auto.

For comparison purposes my Lexus IS 2.0L 6 speed manual gets 9L/100 and my R34 2.5L auto gets 11L/100, for the same route....

[Ben C34]

Grab a new o2 sensor.

[niZmO_Man]

New O2 sensor, replace fuel filter, probably get the injectors cleaned as well. Did you replace the panel filter?

Does the auto operate well?

My N16 temporary runaround (manual 1.8L) does 8L/100km cold start station and back (~6km round trip) plus shopping runs.

On the motorways it does 6L/100km.

[iseekool]

New O2 sensor, replace fuel filter, probably get the injectors cleaned as well. Did you replace the panel filter?

Does the auto operate well?

My N16 temporary runaround (manual 1.8L) does 8L/100km cold start station and back (~6km round trip) plus shopping runs.

On the motorways it does 6L/100km.

I forgot to mention - I did change the panel (air) filter.

Also changed the coolant too, recommended 33% mixture - don't think that makes a difference in fuel economy though.

The auto seems to shift and operate consistently - the trans fluid level seems correct (I haven't changed the fluid in it yet though). Regular acceleration it seems to shift up at around 2500rpm to 3000rpm. Light acceleration it upshift more or less at 2000rpm. At 60km/h it revving at 1500rpm and at 100km/h revving at 2500rpm.

New 02 sensor it is...

I'll tell you guys how it all goes afterward.