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The ultimate VR/VS fuel usage research page

kopper69

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Hey guys,

Please take a read of what Im about to write because Im sure anyone with a VR/VS commodore will find this very interesting and it will apply to any with a VR/VS commodore (V6 and V8). I also hope to get as many people as possible participating in this “scientific research” we will call it.

What I intend to do is to record my fuel usage based on different things (as we will discuss further on). There have been a number of threads which I will list below which many members have posted in comparing their fuel usage/100kms etc. This is all very interesting except the numbers are not precise and some people may not be very accurate. Which is a shame because with the price of petrol now we are all interested to know if our car is running as efficiently as possible.

Now what I fear is happening is that some people are saying – ok, my trip odometer says 150kms and my fuel gauge says half a tank so I must get 300kms to a tank. This can be inaccurate; I know if I did that in my car it would give me an inaccurate result because my fuel tank jumps around a bit at different points.

I want to keep the results standard so for everyone who intends to participate in this research, they can easily compare their results with the results of others. Therefore, to measure the fuel usage of our cars I want everyone to do the following.

Fill your tank next time your at the fuel pump and reset your trip odometer.
Drive around as you would until you normally fill up again, whether it be half a tank or getting close to empty.
When you go to get fuel again, fill up again, and note the reading on the trip odometer – say 342kms.
Grab your receipt and write on it 342kms, or mark it somewhere anyway
Now note the volume of petrol you have put in your car – say 45.85L

Now these are readings that I got from the car today. You can see that out of 45.85L I have managed to get 342kms. 342kms/45.85L = 7.46km/L

So for every litre I get about 7.46kms. Now the standard fuel tank on my car is 63L. So if I multiply 7.46 by 63L I will get the number of kilometres I should get out of my fuel tank. In this case 470km.

This is a fool proof method of determining the average fuel usage of your car. You put this much fuel in and you will get these many kilometres out.

Now if you can participate please do. For accurate results I want at least four readings, which means the results from stage one wont be complete for four weeks for me – but hey that’s research for you. The more people we get participating the more you will know about your car.

I intend to make readings for four weeks on regular fuel.
After the final week I intend to fill the car with Premium, but I will not take any measurements because I don’t want to mix the regular fuel and premium results.
After that week I will continue to use Premium for four weeks and record the results.
I then want to try other fuel saving ideas that people might have. One thing off ebay is a little magnet box that is supposed to save your fuel by ionizing your fuel. I will run this for four weeks again and record the results.
I will also try things like different additives that claim to clean and increase efficiency and running without air con on. These results are with a CAI so I may take that out and install the stock intake so see what results I come out with.

Now if you do participate please record the following for others to compare:

VR or VS
V6 or V8
Series One or Series Two
Manual or Automatic Transmission
Model (eg executive)
Sedan, Wagon or Ute
Whether you have a CAI (Cold Air Intake)
Whether you have a K&N filter
Whether you have an upgraded exhaust
Whether you know your tyre pressure and if so what is it in PSI
What size rims do you have eg 15” 16” etc
How often you stop and start as an estimated percentage (for traffic/traffic lights etc)
How long your car sits idling (excluding traffic lights) on an average tank of fuel
How much excess luggage do you take in your car (eg 10kgs – spare tyre + tools)
How many people are in your car on average including you
Where was the petrol purchased from (Especially when using premium)
Average speed you think you do on a normal tank
Number of kilometres your car has travelled
How hard do you normally go on a take off (when starting from lights etc)
How big your fuel tank is
(This does differ from 59 to 80. The best way to find out is to go to this site http://www.redbookasiapacific.com/au/vehicle/index.php?make=HOLD Find your car and year of manufacture and then click on specifications. Scroll down this list until you find Fuel Capacity. Unless you have a modified fuel tank this will tell you your fuel tanks capacity)
What percentage of time is the air conditioning on

(If you have anything you want to add to this list PM me)

So to keep everything organised post once and edit your post to update it.

Try and keep everything in the same format to keep it neat and easily read.

Please try and get as many people involved as you can. You don’t have to do the Premium petrol or ebay gadget but even if you just do the regular petrol you will be making a good contribution. If you forget to set the odometer one week don’t stress, just skip a week and catch up next week.

Please give this a go – Reply to this page to get your name on it like I will – copy the list above and start about your car and start doing the test.

Thanks heaps guys

PM me and I will be more than happy to help

Chris – kopper69


This is a list of recent threads about fuel usage incase you're interested:

http://forums.justcommodores.com.au/showthread.php?t=17229

http://forums.justcommodores.com.au/showthread.php?t=7863

http://forums.justcommodores.com.au/showthread.php?t=4164

http://forums.justcommodores.com.au/showthread.php?t=11001

http://forums.justcommodores.com.au/showthread.php?t=21877
 
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kopper69

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Chris – kopper69

VR
V6
Series Two
Automatic Transmission
Acclaim
Sedan
CAI - Yes
K&N filter - No
Upgraded exhaust - Yes
Tyre pressure – Yes, 36 PSI
What size rims - 16”
Stop and start percentage – 20%
How long your car sits idling – 5 mins
Excess luggage – Roughly 10kgs – spare tyre + tools
How many people are in your car on average including you - One
Where was the petrol purchased from (Especially when using premium) - Woolies
Average speed you think you do on a normal tank – 80kms/hour
Number of kilometres your car has travelled – 190,000kms est
How hard do you normally go on a take off (when starting from lights etc) – Don’t race off but faster than most people
Fuel tank – 63L
Air con - 100% of the time

Week one – Regular fuel – 342kms – 45.85L ====== 7.46km/L ====== 470km to a tank ====== 13.4L/100Km (May have had a leak in the tank - fixed during the test)
Week two - Regular fuel - 354.5kms - 42.85L ====== 8.27km/L ====== 521km to a tank ====== 12.09L/100Km
Week three - Regular fuel - 350.5kms - 36.4L ===== 9.63km/L ====== 606km to a tank ====== 10.39L/100Km (Did a highway trip this week as the main run)
Week four - Regular fuel - 386.0kms - 45.06L ===== 8.56km/L ====== 540km to a tank ====== 11.67L/100Km (Air con only on 50% this week).

K&N filter in this week and I reset my cars computer to account for the higher airflow that K&N boast (rolls eyes). But seriously I wonder if it will make a difference.

Week five - Regular fuel - 362.4kms - 44.08L ====== 8.22km/L ====== 518km to a tank ====== 12.16L/100km (K&N filter - no difference)
Week six - Regular fuel - 274.7kms - 30.69L ====== 8.95km/L ====== 564km to a tank ====== 11.17L/100km (Small highway trip this week - fuel was cheap so filled up early)
Week seven - Regular fuel - 327.3kms - 36.71 ===== 8.91km/L ===== 562km to a tank = 11.21L/100km

(Planning on cleaning throttle body this weekend) - Cleaned throttle body after 100kms of driving. No noticable results.
Week eight - Regular fuel - 335.2kms - 41.16L ===== 8.14km/L ===== 513km to a tank ===== 12.28L/100km
Week nine - Regular fuel - 142.8kms - 17.10L ===== 8.35km/L ===== 526km to a tank ====== 11.97L/100km
Week ten - Regular fuel - 384.7kms - 43.12L ====== 8.92km/L ====== 562km to a tank ====== 11.21L/100km

Changed oil and oil filter this week - using 20/50 rather than magnatec

Week eleven - Regular fuel - 356.4kms - 38.61L ====== 9.23km/L ===== 582km to a tank ====== 10.83L/100km
Week twelve - Regular fuel - 344.3kms - 33.94L ====== 10.14km/L ===== 639km to a tank ====== 9.85L/100km (highway trip with 25% slow bumper to bumper)
Week thirteen - Regular fuel - 353.0kms - 35.60L ===== 9.92km/L ===== 625km to a tank ====== 10.08L/100km
Week fourteen - Regular fuel - 391.7kms - 43.45L ===== 9.01km/L ===== 568km to a tank ====== 11.09L/100km
Week fifteen - Regular fuel - 241.1kms - 28.23L ====== 8.54km/L ===== 538km to a tank ====== 11.69L/100km
Week sixteen - Regular fuel - 301.0kms - 34.63L ====== 8.69km/L ===== 548km to a tank ====== 11.50L/100km
( Filled up with premium last week - so 34L of premium and rest is still regular)
Week seventeen - Premium - 290.6kms - 31.95L ===== 9.10km/L ===== 573km to a tank ====== 10.99L/100km

Week eighteen - Premium - 454.1kms - 50.83L ====== 8.93km/L ====== 563km to a tank ====== 11.19L/100km
Going to put in some injector cleaner in this week - see if it makes any diff - thats why i ran the fuel down - Results as follows
Week nineteen - Premium (with injector cleaner) - 388.7kms - 43.57L ====== 8.92km/L ====== 562km to a tank ======= 11.21L/100km

Well as the results show, premium doesnt make any huge difference. Does get an extra 20-30km from a tank, but the cost means that Im not getting any better economy. The 20-30km works out to be how much I would save if I got the cheaper regular fuel. Didnt notice car running any smoother or any extra horsies from the premium or injector cleaner.

Switched back to regular unleaded today - See what the results do over the next few weeks.

Week twenty - Regular - 272.7kms - 31.70L ====== 8.60km/L ====== 542km to a tank ===== 11.62L/100km (Towed a boat for about 30kms this week)
Week twenty-one - Regular - 319.8kms - 39.34L ===== 8.13km/L ===== 512 km to a tank ===== 12.3L/100km (Towed a boat about 150kms - yeah i just got a boat)
Week twenty-two - Regular - 241.0kms - 29.94L ===== 8.04km/L ===== 507 km to a tank ===== 12.42L/100km (Towed the boat another 150ish kms)
Week twenty-three - Regular - 233.1kms - 26.42L ===== 8.82km/L ===== 556 km to a tank ===== 11.33L/100km
Week twenty-four - Regular - 163.9kms - 21.48L ===== 7.63km/L ===== 481km to a tank ===== 13.11L/100km (Towed the boat 50kms - Wow this is my worst week ever)

Installed a new ebay memcal this week after 90kms

Week twenty-five - Regular - 386.1kms - 46.74L ====== 8.26km/L ===== 520km to a tank ===== 12.1L/100km (Any improvement? Dont think so)
Week twenty-six - Regular - 213.8kms - 25.93L ====== 8.24km/L ===== 519km to a tank ===== 12.13L/100km
Week twenty-seven - Regular - 311.3kms - 38.49L ===== 8.09km/L ===== 510km to a tank ====== 12.36L/100km
Week twenty-eight - Regular - 302.3kms - 30.14L ===== 10.02km/L ===== 632km to a tank ====== 9.97L/100km (Don't think the fuel tank filled all the way up this week - kept clicking off. See if next week is really crap economy or maybe my car is just running better - *hopes like hell*)
Week twenty-nine - Regular - 151.2kms - 22.5L ===== 6.72km/L ====== 423.36km to a tank ====== 14.88L/100km (Must have been a screw up last week - Changed oil and did a big service though, so hoping things will look great in the next few weeks, or i will return that ebay chip!)

Week thirty - Regular - 274.6kms - 31.94L ===== 8.60km/L ===== 542km to a tank ====== 11.63L/100km
Week thirty-one - Regular - 406.2kms - 46.64L ===== 8.71km/L ===== 549 km to a tank ===== 11.48L/100km
Week thirty-two - Regular - 307.0kms - 35.96L ===== 8.54km/L ===== 538 km to a tank ===== 11.71L/100km (Changed fuel filter this week after 200 or so kms, so leaked a little bit of petrol)
Week thirty-three - Regular - 257.5kms - 31.16L ===== 8.26km/L ===== 521km to a tank ===== 12.10L/100km (New spark plugs)
Week thirty-four - Regular - 429.9 kms - 41.17L ===== 10.44km/L ===== 658km to a tank ===== 9.58L/100km (Highway trip)
Week thirty-five - Regular - 219.0kms - 26.75L ===== 8.19km/L ====== 516km to a tank ====== 12.21L/100km
Week thirty-six - Regular - 330.6kms - 39.49L ===== 8.37km/L ====== 527km to a tank ===== 11.94L/100km
Week thirty-seven - Regular - 290.3kms - 32.42L ===== 8.95km/L ===== 564km to a tank ====== 11.17L/100km (Small highway trip)
Week thirty-eight - Premium - 305.1kms - 36.15L ===== 8.44km/L ===== 532km to a tank ====== 11.85L/100km
Week thirty-nine - Premium - 433.8kms - 45.10L ===== 9.62km/L ===== 606km to a tank ====== 10.40L/100km (100kms of that was a highway trip)
Week forty - Premium - 335.6kms - 40.22L ===== 8.34km/L ===== 526km to a tank ====== 11.98L/100km (had car running a bit without driving while i worked on it this week, which would account for bad fuel reading. Installed original ecu after 100kms)
Week forty-one - Premium - 260.6kms - 29.15L ====== 8.94km/L ===== 563 km to a tank ====== 11.19L/100km
Week forty-two - Premium - 264.8kms - 30.88L ====== 8.58km/L ===== 540 km to a tank ====== 11.66L/100km
Week forty-three - Regular - 161.7kms - 19.55L ====== 8.27km/L ===== 521 km to a tank ====== 12.09L/100km
Week forty-four - Regular - 244.1kms - 27.61L ====== 8.84km/L ===== 557 km to a tank ====== 11.31L/100km
Week forty-five - Regular - 235.6kms - 26.79L ====== 8.79km/L ===== 554 km to a tank ====== 11.37L/100km
Week forty-six - Regular - 324.8kms - 34.59L ====== 9.39km/L ===== 592km to a tank ====== 10.65L/100km (200km highway trip)
Week forty-seven - Regular - 246.8kms - 28.58L ===== 8.64km/L ===== 544km to a tank ===== 11.58L/100km
Week forty-eight - Regular - 208.4kms - 25.32L ===== 8.23km/L ===== 519km to a tank ===== 12.15L/100km
Week forty-nine - Regular - 176.7kms - 20.49L ===== 8.62km/L ===== 543km to a tank ===== 11.60L/100km
Week fifty - Regular - 275.8kms - 34.20L ====== 8.06km/L ===== 508.5km to a tank ====== 12.40L/100km (2x city trips + 50 towing boat)
Week fifty-one - Regular - 239.6kms - 26.81L ====== 8.94km/L ===== 563km to a tank ====== 11.19L/100km
Week fifty-two - Regular - 202.2kms - 23.83L ====== 8.49km/L ===== 534km to a tank ====== 11.79L/100km
Week fifty-three - Regular - 350.3kms - 39.91L====== 8.78km/L ====== 553km to a tank ====== 11.39L/100km (Pumped tyres up, installed ebay memcal after 130kms)
Week fifty-four - Regular - 401.7kms - 45.16L ===== 8.90km/L ====== 560km to a tank ====== 11.24L/100km (Added a bottle of injector cleaner this week)
Week fifty-five - Regular - 273.0kms - 32.74L ===== 8.34km/L ====== 525km to a tank ====== 11.99L/100km (Towed the boat 80kms)
 
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filtnineee

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why would u bbother working it out like that?
in your case 45.85 * 100 divide 342 which equals 13.4 liters per 100 kay.
now you can do that with how ever how much liters or kays u have done.
just keep it simple. new cars dont give u the kays per liter vaule do they, its the liters per 100 kay
 

nomad

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Is this suppose to be an ongoing weekly posting? If so, I'll just tell you my average fuel consumption now, and be done with it, as it hardly changes from one fill up to the next.

Since I've had the car, '94 VR Berlina auto wagon, the trip comp shows around 9.2 to 9.4 L/100kms. I've checked the calcs manually to compare & the TC is just about spot on.
 

hako

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I think its a great idea Kopper69....either as a regular weekly thing or a single post which has everything about consumption in the one place. Great stuff.
 

sixshooter

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kopper69 said:
Now these are readings that I got from the car today. You can see that out of 45.85L I have managed to get 342kms. 342kms/45.85L = 7.46km/L

So for every litre I get about 7.46kms. Now the standard fuel tank on my car is 63L. So if I multiply 7.46 by 63L I will get the number of kilometres I should get out of my fuel tank. In this case 470km

I think you are forgetting that as the car uses fuel the car becomes lighter so the fuel effieciency will become better as you dont need to use the accelerator as much as the tank emptys... therefore your figures will be somewhat inaccurate leaning towards a thirstier fuel efficiency...
 

hako

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sixshooter - you are correct.....however I think Kopper69 has applied the KISS principle otherwise there would be questions like 'what mood was I in' or 'is it the weekend'. Actually I think the mood you are in definitely affects your driving!!!!
 

sixshooter

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hako said:
sixshooter - you are correct.....however I think Kopper69 has applied the KISS principle otherwise there would be questions like 'what mood was I in' or 'is it the weekend'. Actually I think the mood you are in definitely affects your driving!!!!

Awe come on we should have some calculus calculations just for fun...LOL
 

kopper69

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I understand that as the car gets lighter it will use less fuel. But in the interest of people looking after their cars and not running them dry and causing problems like sucking crap into the filter.

The small difference is negligible, because people do not run their car dry normally and so you would be creating inaccurate results. By filling up when you normally would you are preserving only accurate results for calculation. I will be posting every week for anyone whos interested, this is an on-going thing for me.

As people like nomad have failed to read I will be comparing these results for different things, like premium fuel/fuel saving devices. I may also try things like air con off etc to see differences of fuel consumption.
 

MattK

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Okay

95 VS BT1 197,000Ks V6
See sig for mods : Ooops - Fuel = Reg Unleaded ...

Drove to Brisbane and back last year :
Speed 110 to 130 HWY + slowing for towns etc
I averaged 8 to 8.3 Ltrs per 100 for the entire trip
I drove 753 km on a tank of fuel , fueled up in Queensland , and drove to the otherside of Sydney where the Hume HWY starts , there is a Truck stop there , just a few hundred meters from the start of the Hume ...

So from the start of the hume / where Syd ends , I could have driven all the way to melb , where the North Subs Start [ Maybe ] Didnt want to try but I think I could have done Syd to Melb on a Full Tank ... [ 110KMH + ]

Esp if I had kept to say 100kmh all the way , hmmmm , guess thats not too bad ...

How I checked fuel used :

I filled my tank , set trip to 0 , and everytime I stopped for fuel , I would see how much it took to fill the tank , and then checked km driven ...
+ In Queensland they have markers to check your trip meter , mine was really close , about 99% accurate

Matt
 
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