How do I increase fuel economy in stock VS-II
Hey fellas,
I'm trying to figure if I can increase my fuel economy in my VS-II. It's totally stock and now has near 240,000K's on the clock. I've had it since new, but over the last few years i've been unable to spend the big bucks on it to keep up the maintenence as well as I should "due to major health problems and 2 totalled knees!". On average she clocks around 550K's per tank but as we're using it a lot more now because we're trying to cut down the usage on the poor old honda i'm finding the fuel bill is around 30% more on the commodore that what it is in the honda. 550K's per tank on a massively undersericed motor is probably pretty good, but I generally drive it like an old person unless iv'e gotta overtake someone that's going slower than me along the highways which happens on most days. Although the honda is an 05' model, we've clocked near 160,000K's on it already and it's already starting to fall apart not to mention the roads here are quite bad, narrow and full of pott-holes. I've just done my first major upgrade to the car by doing the VT big brake upgrade on the front and that has worked out nicely.
I know she's due for a major service so I might start there. I have just installed one of those supercharged-type GM intake systems with a hi-flow pannel filter and have cleaned out the entire throttle body and intake system with throttle body cleaner. I have also just brought a new memcal with the 10 GM updates. Apparently this will cause my car to run more responsive, smoother and should increase the fuel mileage by around 50K's per tank. I haven't noticed any major economy difference from running straight unleaded compared to premium but it does seem better on premium.
I haven't been able to do any real servicing on the motor except for the engine oil and oil filter change which I had done around 3,000Ks ago. The plug leads are original since new, the battery's got a dead cell and if left for 5-7 days the car won't start. I haven't had a chance to change the plugs and trans fluid for around 70,000km's and have never had the injectors cleaned since the last major service my holden in around 2002 at 90,000Km's. Car has been hard to start the last 40,000k's but i'm certain that's due to the old bad spark plugs. Also noticed that one of my plug leads has touched the exhaust manifold and that may be causing her to run slightly rough.
I'm hoping to get the old girl back to where she was originally where I was able to clock 700-800K's on the one tank of juice.
Hopefully replacing what i've mentioned will make a difference. If you've got any other tips to help the efficiency of my engine i'd be happy to know!
Cheers Fellas!
550 kays to a tank? Jeez your going well! What is that highway driving? City driving will only see around 380 kays to a tank. 65L that is.
Yeah, I guess 550 isn't too bad but no-where near what she was when she was new. Most of my mileage is sort of country highways, although the roads are quite terrible and there are some very slight inclines. My driving conditions are a little mixed as the forst 30K's are windy narrow dodgey roads followed by about 40 k's of highways with some slight bends, another 10K's of windy roads followed by a clean run of about 70K's of reasonably good highway. Our roads here in Tas are really shocking in some places and recently some world class engineers came to rate tassie on its infrastructire. Our roads got an 'F' rating. Guessing the F means F*&^ed! lol. Where I live i've got probably the worst roads in the entire state from what i've seen.
Wonder how she'll react on fuel economy now, now that it has the GM CAI, Hi-flow pannel filter and new updated memcal. Doesn't seem to run excessively rich on cold starts now and has lost that fuel smell. Driving it around it seems to run better and more refined. Idling has improved a lot also.
change all fluids.
coolant engine oil trans oil.
change spark pulgs spark leads
with premium there isnt any point running your car on it as your car is tuned from factory so the only bennefit of using premium is to the oil companys.
make sure your battery levels are up aswell. if it has a dead cell might not hurt to get a new one.
check wheel bearings if they are causeing rolling resistance that will add to the fuel consumpion as well (not heaps but every little bit counts)
clean the maf out aswell
and also would hurt to replace the oxy sensors as i guess they are still the originals to..
i have no trouble getting 7-750 out of a tank of fuel highway driving in my vs.
Originally Posted by TrikkBen
as for using premium fuels, The computer will adjust the spark to get the best out of the fuel your using.
The only thing is it takes 2-3 tanks of fuel for the computer to realise it has better fuel & over the 2-3 tanks if you keep using it your milage will improve.
i have actually proven this for myself on a 100km road trip when I was commuting to and from my work in the city.
I used the trip computer on my wifes VR 5.0lt Calais.
I would put 3 tanks of Fuel through the car then the test tank.
with 91ron (regular unleaded) i used 15L/100km
with 95ron (Premium Unleaded) i used 13.8L/100km
with 98ron (BP Ultimate Unleaded) i used 12.2L/100km
The only only fuel I use now days especially when I'm chasing economy is 98ron.
as I said, I done those tests for my self & thats how my mind was made up.
I hope that helps in some way.
I get heaps better economy when using 98 octane fuel.My VSV6 runs like crap on 91 octane fuel and it uses a lot more of it too,which in the long run ends up costing me more than when I use the 98 stuff.
if your car is tuned to run 98 ron then of corse it will run better on it.
stock VS from factory is designed for 91ron.
this has been argued 1000s of times.
Even with the standard tune theres a heap of difference.If someone runs 98 octane fuel and doesnt notice any difference,then theres probably something elso wrong with the car to start off with.It makes a big difference in mine.I can easily feel the difference in power between the two fuels in my V6,and the economy is way better on 98..As mentioned above,the computer adjusts the ignition timing to suit the fuel.
Well fyi my wifes VR 5.0lt Calais is stock from factory.
The computer does self adjust on its own to a small extent.
"From factory" 98ron was not available until after LRP (lead replacement petrol) was canned in 2000.
so unless my wife went and got an aftermarket tune when I was driving the car constantly & was broke I am wrong.
Read about the tunning of the PCM/ECU & it will tell you that the computer adjusts itself to a small extent when it comes to the spark.
The car used fror the test was & still is 1995 VR Calais 5.0lt 165kw auto (NO Modifications whatso ever!) that was purchased in January 1998.
at the time it had 195,000km on the odometer.
It now has 288,000km on the odometer.
This is just stating the facts.
not meaning to sound grumpy or upset.
I appologise if this has come across as agressive, it is not meant to.
Last edited by BottleFedVS; 21-07-2010 at 04:14 PM. Reason: tired & grumpy old Bstard
550 kms is awsum. i get 450 driving it like a granny in my vs i never saw above 300, think i drove it to hard
The ECU constantly tries to advance the ignition timing until knock or pre detonation (pinging) occurs,which is detected through the knock sensors.Then the ECU will retard the timing until pinging has stopped being detected,then it advances it again and so on.It keeps repeating this over and over.The higher the octane rating of the fuel is,the more advance can be added to the ignition timing before pinging occurs.More ignition advance,(to a point),means better efficiency,a cleaner more complete burning of the fuel /air mixture ,which equals more power and better economy.
Yeah, I noticed that when I done the VT brake upgrade that the bearings didn't sound too good. Wanted to get them done but was straped for cash and couldn't even access them because I needed something like a large allen key to get into the back of them. I have also thought the battery may have an effect as it's just about had it. Still the original ACDelco one. Yeah, I was planning on replacing the oxygen sensors as they are the original ones.
One of my mates has a VS wagon and always brags how he clears 800K's per tank, and he's never that easy on his car.
im never that easy to and i manage to get 700-750 a tank on 91ron with 10L left.
do a major overhaul and you should see a noticable increase!
make a long term investment and convert to gas, my vs calais is on gas, never looked back.
Alot cheaper, runs fine, and has in the end saved me heaps of $$$
Cammed & Eventualy Blown!
dont forget to check ur typre presure too mine was down a fair bit pumped them all up even, getting a fair bit better now never would see above 350kms of town driving, now im at 400 with another knotch til empty
The best economy mod Ive done is fitted a set of tuned length pacemaker extractors and a "sports" exhaust system.I got a good increase in fuel economy, and the engine runs 1 mark cooler on the temp gauge.
Searching for the billion
Start with the battery, plugs and leads and just replace all the consumables as cash allows. Plugs are about $25 a set for those things so bugger all really. A set of top gun or better leads and away you go. IMO don't bother with Oxy sensors until it displays a fault or you have spare cashola.
Yeah, the battery will be the first thing i'll replace. I've got a near new 4x4 yuassa 700cca battery that will fit in there with some minor work, I will install that tomorrow. I'm going to do the plugs and leads next week if the budget will allow it and work it from there. I have a diagnostic connector and efilive4 on my laptop and have checked for error codes a couple of times over the last few months and everything seems fine. Am a little concerned there may be a low voltage in the system due to the battery, but I should have that issue resolved by tomorrow morning.
I've now made a custom metal bracket to fit the yuassa 4x4 battery, and installed it. Also had to move the carbon cannister over to make it fit. The engine cranks over a lot quicker but i've noticed that there's still some hesitation with he motor starting. Since i've done the few basic mods like the updated memcal, the GM CAI and hi-flow filter the terrible fuel smell coming from the exhaust has disappeared. The engine doasn't feel like there's been any real power gains but sounds much smoother. I'm certain that bad plug lead might be an issue as it's dropped of its retainer and has burnt through 1/3rd of the way. I'm going to get a brand new set of irridium plugs and a good set of leads next week so i reckon that'll make her run even smoother.
Cheers for all your help and input fellas! and thanks once again for steering me in the right direction!
I was getting the same (last week 400kms to a tank) I made the following changes............. now looking at around the 700 to 800kms a tank (really very simple changes)
First issue was the thermostat, it had seized. evident by the very low temp on the gauge, now runs just over 1/4.
Second was the earthing issue with the 02 sensors, see here: How To: Fix the VS V6 4 Wire O2 sensor earth problem – Known Holden Problem.
Replaced 02 Sensors
Next change is the high flow SS air intake over the radiator..........
possible next is spark plugs and leads ............. still looking into that one. ie what is worth the expense
then tyres.
am chasing the economy as planning to drive the VS from Perth to Sydney at Christmas and back again..........so every bit will count............. fairly unlikely I will go to extractors, just cant see them making the total difference I want for the price. (ie, not chasing power)
I dont think any one thing will make dramatic changes (once the things that need to be right are right) to fuel economy.......... however some sensible small changes will add up...
gases in, gasses out...........improve that, you will improve fuel economy, cold air induction is the way
Mine is dead stock except for a stage 2 shift kit etc in the auto.
Lawrence
Yeah, first thing I done when I replaced the water pump and all 3 idler pulleys and the belt about a month ago. Also flushed out the radiator and added new coolant. Problem is down here in tasmania that at this time of the year the ambient air temperature will range from 8-12 degrees celsius. The car is very slow to warm up. Nowadays instead of just starting the car and taking off I let it idle for 10-15 minutes first. This gives the car it's necessary time to warm up so I can then proceed to drive, and I think that may increase economy as opposed to driving on cold start or choke. I was getting a real bad unburnt fuel smell out of the exhaust, but have since changed the intake to a GM supercharged-type one, added a new hi-flow filter "original filter was extremely blocked", cleaned out the throttle body and updated the PCM memcal which includes apparent 10 GM software updates to make the engine run smoother, idle better with more economy and power. Also replaced near totally dead ACDelco battery with a 710CCA Yuassa 4x4 battery. With what i've done so far i've totally lost that unburnt fuel smell from the exhaust and the car drives like the engine is more refined. The plugs were last done something like 40,000K's ago from memory and are well overdue. Also, my leads are still the original OEM ones so I might replace them next week also. I reckon this will get the slight miss out of the car as i've got one plug lead that's burnt through a bit. And who knows the state or condition of the original spark plugs. They were only standard cheapies, not like the iridium ones of which I heard will last a good 700,000K's before needing replacement.
Regards!
I've got a VY Ecotech with about 140,000km, it is completely stock and has a factory exhaust and intake and there's nothing wrong with the engine at all and it it runs well on all the fuels I have tried, even with E10 I can't notice any drop in power around town.
I'd hazard to guess there may well be slight power improvements to be had using higher octane fuel but the increases would be slight if the motor is stock. I agree the engine management may be able to advance the spark more using a higher octane fuel but for that alone it's probably not going to contribute greatly to power or fuel use. There are 95 octane E10 fuels around as well. The only time I have noticed my car having noticably more power is on a cold winters night when the air is a lot denser and that's on any of the fuels I have tried including E10.
I drove it to Temora on Caltex Vortex 95 and back home on normal 91 and it got better milage on the 91 octane. Economy is not just L/100km it is the cost to travel a certain distance given the price of 95 and more so 98 the improvement in fuel consumption will still result in a higher operating cost hence worse economy.
My car has a 75 litre fuel tank and it will go well over 900km on a tank of 91 octane fuel on the highway. Last trip it averaged around 7.5L/100km which is what it usually gets on the Hume Freeway.
My local garage has just stopped selling 91 Unleaded so there is just E10 or the premium fuels. Given the extra cost of the premium fuels and increased fuel consumption using E10 at the price difference my first guess is it would still be more economical to use the E10 especially for day to day running around.
Before using any E10 my trip computer was reading about 9.91 L/100km around town and after adding E10 95 Octane 3 or 4 times (mostly aboue 1/2 a tank) it is now at 10.41 L/100km I have not had a chance to compare it's highway economy with E10 yet.
Last edited by wortus; 23-07-2010 at 01:22 PM.
It will run just fine on GM plugs and leads which at my local dealership wil cost you about $60 to $65 for the lot. I wouldn't spend the money on the Irridium ones or any other brand of leads. I took my spark plugs out of my VY last service, they were genuine and had been in there about 45,000km and were hardly worn and could have been left in there but I changed them when it recommended. Save your money, same goes with the air cleaner element I get genuine ones for less than $10 and they last 45,000km even at half that distanc eit is cheaper and easier to chuck them away and get a new one than have to worry about cleaning and oiling filters etc.
Premium fuel is actually 3-8% denser than regular fuels + the very slight benefit of higher grade detergents, so you theoretically will get better economy per litre with premium but the cost negates the benefit.
Also a good tip, fill up when its cold (early morning / late night) as petrol pumps measure volume not density, so the cooler the fuel at the pump the more you get in a tank. Realistically you will get 2-4% better fuel economy, well not really you just get more juice
Use a litres/100km's gauge and keep it low, i try to never go above 12l/100k's and cruising at 90 it runs at around 4-5L/100k's
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