Anyone got tips for better fuel economy?

[MG's VH Wag]

Hi all, I have a few days off work cause i just had an operation and i'm gettin bored at home. My VT uses a fair bit of fuel as do many VT's lol. I was wondering if there are any things that can be replaced or any tips i can do to my VT to make it a bit better on fuel. It has done 260,000 km's and was serviced last week. I use cruise control on the highway and drive sensibly around town, when im on the highway and have half a tank left the trip computer says 400km till empty so i assume i'd get 800km on a full tank of fuel doing highway driving. If you have any tips let me know!

Thanks

[danja]

Keep car in good mechanical condition, and drive sensibly.

I used to have a VT V6, would consistently get 12-13L/100 and that was with two Sydney peak hour runs per day, city/suburban driving only.

Best gains I got were from new O2 sensors. Do those if you haven't done them before, they'll set you back about $120 for a pair and half an hour under the car with a spanner. I went from 15-17L/100 to always under 14L

Other than that regular oil changes/air filter/fuel filter/clean the MAF, keep the tyres at the right PSI, don't carry lots of crap in the car you don't need, keep the transmission and diff serviced and you should be doing pretty well.

[nicko]

40psi in the tyres and take it easy

[Salmon]

new exhaust and extractors

[danja]

new exhaust and extractors

Yeah, because you'll recoup that $1500+ of exhaust in fuel savings in no time right?

[dynoryder]

some injector cleaner wouldent go astray

[dynoryder]

and one of those fan things that dont move to swirl the air or a elec supercharger $300 no power gain but will help in keeping the air moveing for fule atomizeation

well that is my theroy

[Salmon]

Yeah, because you'll recoup that $1500+ of exhaust in fuel savings in no time right?

with todays fuel cost yer probs haha

[danja]

with todays fuel cost yer probs haha

Touché

and one of those fan things that dont move to swirl the air or a elec supercharger $300 no power gain but will help in keeping the air moveing for fule atomizeation

well that is my theroy

You must be kidding right?..

[savage1987]

cheapest second hand exhaust and extractors you can find

^fixed

basics. Intake, exhaust, tune, don't drive like a retard, convert to manual, get a L3 cluster so you can keep tabs on everything in real time.

sam

[D-Man]

lol best way is to have the car serviced regularly (as already stated) and make sure you keep that right foot in check all the time... acceleration is the biggest killer of your fuel.... come to think of it it's just about the only one.. anyway - dont accelerate hard is what im trying to say haha

[kane88]

Either take it on the chin or buy a bloody pushbike...
There's only so much you can realistically expect from a car that was designed to lug families around for extended periods of time.

[DavidPartay]

I've converted mine to a manual and have just started running Caltex 95 octane.

I'm hoping to see a drop from 12 - 13.5L/100 down to 10-11L/100

[jakstas]

My vt2 ss gets 8.5L/100 highway, manual, 3.9 gear set, free flowing exhaust, and a 2hM intake. Mind you, I can give it a hiding and use 20L in an hour if I want. Just go easy on the throttle, and try to keep the engine in it's optimum rev range. Labouring your engine will use unnessecary fuel also.

[MG's VH Wag]

Ok thanks guys. I can't do any modifications to the exhaust or intake etc because i'm on red p's. I'll change the oxygen sensors and run some injector cleaner through it. Also i'll give the transmission a service.

Either take it on the chin or buy a bloody pushbike...
There's only so much you can realistically expect from a car that was designed to lug families around for extended periods of time.

Yeah mate i know that, i wasn't complaining i was just asking if anyone had some tips. I'm only comparing it to my VR in fuel consumption and yes i know there different weight etc but they are both as you say designed to lug families around for extended periods of time.

[kane88]

Don't take it to heart mate, but seriously if you were mad keen on fuel savings you wouldn't have bought a commodore. Going easy on the juice isn't exactly their forte... (sp?)

[lout]

fit a vacume gauge and keep an eye on your right foot is the biggest improvement you will see.
if you already drive sensibly ie not like the majority of red P platers and your car is well serviced then correct tyre pressure and correct grade of oil and good quality fuel not your local independant or ethanol may show some improvement

[Cheap6]

There is heaps of info. around on how to minimise fuel consumption through people identifying themselves as "hypermilers", so that will be worth a search.

There will be small gains in lots of little things that add up to a lot when done together.

Some randoms/stream of consciousness:

A/C use is worth about 0.3l/hour when on. The cooling fan alone - on with A/C at low road speed - is about 150W in VN-VR, 80W, low, + 120W, high, in VT-VX. That power has to come from fuel -> engine power -> alternator, with losses in each energy conversion => downstream energy savings (i.e. accessories) are worth more than those upstream (i.e. the engine).

A spare tyre is worth about 20kg, the jack and wheel brace are superfluous if that is removed = another 3-4kg. One of the tyre gel canisters is <1kg. I'd only do that in urban/suburban driving where worst case you can scrounge a rescue from a mate/family or a taxi ride to get the spare.

15" wheels and tyres will be much easier to accelerate than will larger sizes. Alloys will be better than steel.

Floor mats, street directories, anti-theft locks, coins, CD's can add up to a few kg.

Gut the (rear) doors? No one needs to open the (rear) windows anyway .

Driving style matters a lot. It's best to keep the rpm between ~2000 and 3500 with a lot of accelerator pedal (but not so much as to go into open loop fuel control/enrichment). The idea is to maximise inlet manifold pressure for a given engine power requirement while keeping rpm low without getting into labouring (which is virtually impossible to do in an auto. anyway).

A scan tool helps a lot to observe what is going on but even a couple of voltmeters (~$30?)attached to the TPS signal voltage and one rigged up to an added MAP sensor (~$10?)would do. Being able to see the absolute values in % throttle open and manifold pressure in kPa isn't necessary if you know what TPS voltage corresponds to open loop - just maximise the MAP voltage up to that point.

Pick a route and travel times to minimise consumption. The best fuel consumption figure I have got is over a stretch of road that has a series of hills just the right height to give high engine load up and a nice coast down the other side. In a four cylinder petrol, that normally gets a consistent 6.5l/100km, I got down to an average of 3.6l/100km, over 30-40km (on a scan gauge which I know is accurate to +/- ~5%).

Coasting off the throttle means a total fuel cut, at least under certain conditions. It can be seen really easily with a scan tool but also on the cheap LED O2 sensor gauges - ~$15.

Correct wheel alignment will help some. And save on tyre wear $$$.

You might pick up a little with a lower viscosity engine oil (within the range of those recommended by GMH).

Running engine oil on the low end of the range indicated on the dipstick is supposed to be worth a % or two.

[danja]

Another tip is to put the trip computer into "special mode" (hold "mode" + "set" as you start the car) and switch it to the screen which shows real time fuel consumption. It's in L/hour so you need to do the maths in your head to work it out in L/100 if you think that way, but even then it's a good relative measure. You'd be surprised how much difference a couple of millimeters of throttle make.

I used to try and keep it under 10L/100 using that screen, so if you're doing 60km/h try keep the screen under 6L/hr, if you're doing 80km/h keep it under 8L/hr. Not always possible, but a realistic goal to aim for I found. You can do it without being a complete granny driver.

[MG's VH Wag]

Thanks for all your help guys there are a few handy tips there. Hopefully i'll be able to put some of them to the test.

I drive pretty sensibly i like to just cruise around lol and i only get my car over 3500rpm when i have to overtake or something like that.

[pablo]

You could have the engine control computer re calibrated for economy!

[savage1987]

I've converted mine to a manual and have just started running Caltex 95 octane.

I hope you had a tune written for that fuel otherwise you are wasting your money and getting your hopes up for nothing. If you can't already get under 13L/100km you are failing hard.

Ok thanks guys. I can't do any modifications to the exhaust or intake etc because i'm on red p's.

It escapes me why you possibly asked this question in the first place when you HAD to know everyone would suggest bolt on modifications. Also, next time you have a question that seems like it might have been covered a thousand times before, DO A SEARCH!!

fit a vacume gauge and keep an eye on your right foot is the biggest improvement you will see.

How is a v-a-c-U-U-M gauge going to possibly help your fuel economy any more than an L3 cluster with a fuel readout?

Sam

[White Tiger]

gas conversion my fuel gauge needle dosent move for 400 k's

[MG's VH Wag]

It escapes me why you possibly asked this question in the first place when you HAD to know everyone would suggest bolt on modifications. Also, next time you have a question that seems like it might have been covered a thousand times before, DO A SEARCH!!

Sam

Mate, I was asking for tips, little things that i can do at home that don't take alot of time. I wanted tips for better economy but not to the extent of modifications. And yes i did a search because i thought it would of been covered but all i got back was threads about how many km's do you get to a tank of fuel etc!

[DavidPartay]

Savage - It's an experiment. I got improved fuel economy in my '89 VN Commodore V6 using premium fuel, so I'm waiting to see if it makes a difference in my VX for myself.

Besides, the higher octane fuel keeps the engine cleaner AND there is a noticeable boost in power, so it's all good.

And I never said we weren't getting below 13L, I don't know where you got that idea from. I know that the manual gets better economy and I'm certain that I'll be able to do much better economy in it. The biggest problem is that my wife has a lead foot and she does most of the driving in that car .