1998 Holden Commodore Ecomod journey

[bobo333]

Hi guys,

Been a while since ive been active on here, i lost my license for 6 months so ive just been lurking and getting ideas while i waited to be back on the road (my average usage has plummeted dramatically while not driving though haha!)

Well as of 3 days ago im back on the roads so i thought its time i made a thread for my wagon, Its a 1998 Holden VT Commodore Wagon in rare factory manual and with an 'Ecotec' 3.8L V6 (similar to the one in a Firebird/Camaro/Buick/Oldsmobile)

Ive owned it a few years longer than the other 2 cars ive shown you guys (links in my sig) but it has been off the road for the last 2 years getting a full interior transformation to be a demo car for my car audio shop, it also has got full airbag suspension and a ratty zombie hunter themed exterior during its time away from the streets

Well time for pics, Im just gonna start from the last few days since its been back on the road, if i started when i first bought it id have to write a novel lol!







Thanks for looking, Il let that sink in then outline my plans/ideas next post

[bobo333]

Ok so ive kept fuel logs for this car pretty much since i got it 5 years ago, in the time ive been driving it its averaged around 19mpg, with the best tank around 29mpg on a long highway trip interstate and the worst tank probably close to 12mpg towing a car trailer through the city.

Obviously i want to do more tanks closer to the 29mpg and try to beat it if i can

I havnt gone through a full tank since i got it back on the road last friday yet but it needs a good service and most of my driving had been suburban over the last few days so i doubt it will be a good tank, something to start from none the less.

When it did its best tank it didnt have the front bumper it does now or the roof basket, the new front bumper is much lower and more aero looking but with a bigger grill opening, and obviously the roof basket the worst thing i could possibly do lol, it will stay for day to day driving however as i use it all the time due to my boot being full of audio gear

I am thinking about ways to make a hitch mounted spare tire/luggage/tool holder for long highway trips

The tires will be replaced asap as the ones that came with the wheels are too big (both width and height) and are nearly worn out, i probably wont get the most eco tires available though as id rather have decent grip for hills driving

Some of the globes have already been replaced with LEDs and the rest will be when they need replacing, the headlights will also be replaced with a custom combo of HID and LED

Aero mods on the to do list are as much of a flat floor as i can do as well as possibly rear wheel covers, obviously the airbag suspension makes it easy to lower it for minimum drag on the highway, unfortunately the design of the rear suspension means i get lots of toe in and camber when i lower it, which im looking at getting fixed soon too

I think thats all for now, too many things going through my head i dont want to bore you all lol!

[MetroMPG]

That roof basket must go! :O I'd definitely be looking at alternatives for that as your first item.

Nice that it's a manual shift - you should also get fuel economy instrumentation in there, as it will help dramatically with driving style, and the manual gives you a lot more options.

PS: I dig the look of the car. And the airbag system is cool for reducing drag on smooth roads at speed.

[bobo333]

I will definitely look into a hitch mounted carrier for highway trips, the roof rack is far to convenient for day to day use though, on the highway removing it adds around 3mpg, (from 26 to 29) i havnt tested how much difference it makes around town

This is the only car ive owned that a scanguage should actually work in so i am considering getting one, the factory dash has an instant fuel usage readout but its in Litres per hour not per distance so its hard to calculate actual usage while moving at different speeds, A bigger number is obviously worse though so i try to keep it as low as possible

The car also shuts off fuel when decelerating so on hills that are steep enough to not lose too much speed rolling with the engine in gear is more economic than in neutral

an injector kill switch is on the list also as turning the key on/off is too much of a hassle for me to do it often, i just need to find a pin out for the ECU, the other option is cutting the wire directly at the injectors in the engine bay, or will this freak the ECU out?

EDIT: Just googled my engine series to see what cars its used in in the USA, its an L36 similar to the one used in the following vehicles:

1996-2005 Buick Le Sabre
1997-2005 Buick Park Avenue
1996-2004 Buick Regal LS
1995-1997 Buick Riviera
1995 California only, 1996-2002 Chevrolet Camaro
2000-2005 Chevrolet Impala
1997-1999 Chevrolet Lumina LTZ
1998-2005 Chevrolet Monte Carlo (Z34, LT, SS)
Holden Commodore (VS, VT, VX, VY)
Holden Caprice (VS, WH, WK)
Holden Ute (VU, VY)
1995-1999 Oldsmobile Eighty-Eight
1998-1999 Oldsmobile Intrigue
1996-1998 Oldsmobile LSS
1996-1998 Oldsmobile Regency
1995-2005 Pontiac Bonneville
1995 California only, 1996-2002 Pontiac Firebird
1997-2003 Pontiac Grand Prix

Il have to have a look on the forums and see if many people have ecomodded these cars

[320touring]

Ah, a Vauxhall Omega

could get them with a 2.0 4 pot over here, or a BMW 2.5 TD lump, or a 2.5 or 3.0 v6.

lots used as police cars- very capable-just a pity the build quality was guff.

looks good, enjoy and lose the fecking roofbox!

[bobo333]

Ah, a Vauxhall Omega

could get them with a 2.0 4 pot over here, or a BMW 2.5 TD lump, or a 2.5 or 3.0 v6.

lots used as police cars- very capable-just a pity the build quality was guff.

looks good, enjoy and lose the fecking roofbox!

Wow, glad im not over there! they are used as police cars here too but here the smallest engine is the 3.8 V6 that i have, they also come with a 5.0 V8 or the year after mine an LS1, a 2.0 4 pot would be slow as a wet week!

I forgot to mention i also have a WAI on it that i made by accident when i replaced the factory airbox with a pod filter to make room for an extra battery, i was planning to make a new airbox for cold air but never got around to it:

[320touring]

Originally Posted by bobo333

Wow, glad im not over there! they are used as police cars here too but here the smallest engine is the 3.8 V6 that i have, they also come with a 5.0 V8 or the year after mine an LS1, a 2.0 4 pot would be slow as a wet week!

the 2.0/2.2 (facelift) 4 pot was a decent enough lump- circa 130bhp, and 35mpg on a run in manual form.

the v6s liked to eat their headgaskets, but the MV6 is a good lump- 200+bhp, and sounds lovely.


you folks like to seem to be "american" in your approach to displacement

the m51 BMW TD was good for 45mpg on a run

[spacemanspif]

Originally Posted by 320touring

you folks like to seem to be "american" in your approach to displacement

I think the Aussies love their V8s more than us Americans. After all, GM did bring that car to America and called it GTO. First released with the 5.7L LS1 and then getting a bump to the 6.0L LS2. I had no idea they came in station wagons...and I like it!! The last wagon GM made for the American market was the Buick Roadmaster/Caprice Caprice in the Mid 1990s. Australians also love our El Caminos but they call them Utes and didn't stop making them in 1987 like GM did in America...Americans don't need car-trucks they just need big, gas guzzler pickups and SUVs

Those V6s do LOVE to eat head gasket due to those engines being some of the first GM made with iron block and aluminum head...differing expansion rates tore up the gaskets.

Nice car and congrats on getting your license back

[Sporty Modder]

One thing to look out for on that 3.8is the plastic intake. I dont know if gm put them on the aussie cars like they did the american cars. They tend to leak as they get older and injest coolant straight into the cylinders.

[cRiPpLe_rOoStEr]

In Brazil we only had the VT as a sedan, with the same 3.8L engine but only with the automatic transmission, rebadged as Chevrolet Omega, as a replacement to the locally-built version of the early Opel Omega. Regarding engines, a 4-cylinder would actually not be the worst option if you would eventually consider an engine swap. Nowadays even its main opponent is available with a 4-pot...