Just thought you all may like a brief history of the Holden Commodore which is not on the Opel Omega/Cadillac Catera, even though many of you have been told that the GTO is based on an Opel Omega chassis. I live in Australia and I know the full history of the adaptation of the Opel Senator into the Holden Commodore.
Here’s the true story. Opel had a model called ‘Senator’ which Holden decided to base their new car on in the late 70’s to replace their ‘Kingswood’ (and eventually it’s LWB ‘Statesman’) large car range in response to the oil crisis. It also had to replace the smaller Holden Torana. But they had to use Holden’s own designed old cast iron pushrod V8’s and sixes in the new car. But Opel’s Senator was too expensive with independent rear suspension. However Opel had a shorter lighter model called the ‘Record’ which shared most of the passenger cell with the Senator. So Opel and Holden decided to resurrect an old Opel name and created the 1978 'Commodore’ VB model by using the longer front from the Senator (which could take Holden’s 6-cylinder engine) and the rear doors, quarter panels and suspension of the Record which used a cheap live rear axle. And so the first large Holden to be based on an Opel used the Senator’s frame. You can see how the Holden Commodore (below top) uses the front of the Senator (below middle) and the rear of the Record (below bottom).
However, Holden did a lot of engineering changes for Australia’s harsh conditions but mainly to use as many parts from the old Kingswood to keeps costs down and limit reengineering for it’s local car parts suppliers here in OZ. Australia is a small market and low costs are critical. And this single fact dictates the entire rest of this story, because Holden and especially it’s suppliers could never afford to use a whole Opel design. They took the basic new Opel design and crammed it as full of carryover tough, rugged and proven components from previous Holden models. And they still do. Holden eventually upgraded it’s first Commodore by adding the rear doors, third rear window and rear quarters from the Senator making the 1984 Holden Commodore VK (below) virtually an Opel Senator body fitted over a modified Holden Kingswood components and drivetrain.
Then in 1987 Opel brought out the new Senator B (below top) and Holden followed with the 1988 Commodore VN (below middle) except that while it looks like the Opel Senator B with different grill and rear lights - only the doors are shared with the Opel’s body. Because Holden couldn’t afford to wind tunnel test and develop a new body on it’s own, it used just the shape of the new Opel. But because it had lost sales to Ford’s much larger ‘Falcon’ for ten years it knew it couldn’t use a shape as narrow as the Opel body. Holden also couldn’t afford to use new Opel frame and suspension, which it would have to reengineer to tougher standards and to suit local parts suppliers anyway. Therefore Holden simply welded sill extensions to it’s previous ten year old Commodore’s floorpan/frame and mounted over that a copy of the new Opel’s body, which had been widened by a few inches. Only the door skins were shared. Unfortunately people complained that the old track width of the wheels looked too skinny under the new wider body and so eventually Holden developed a new Holden designed wider tracked suspension which was fitted to later models of that body style. In 1990 Holden also reintroduced the Statesman model name with a stretched LWB version of the VN Commodore. And this LWB VQ and then VR Statesman (below bottom) was fitted with a wider and tougher version of Opel’s independent rear suspension, which Holden had developed. This IRS was later offered as an option on some Commodore models in this body style series from 1991 onwards.
Then in 1994 Opel brought out the brand new Omega B (below top) that replaced both the Record and Senator models and ended the inline 6 engines for Opel, using a new V6 and I4 engines (It was also sold in the US as the Cadillac Catera). Again Holden decided to save money by using the wind tunnel tested and developed ‘shape’ of the new Opel. But it again had to widen it. This resulted in the new 1997 VT Commodore using a stylized copy of the now 3 year old Opel Omega. But again locally designed suspension and other locally sourced parts had to carry over into the new design. Again, only the doors were to be shared with the Opel, as well as a strengthened and modified copy of it’s independent rear suspension (which had been reengineered into a unique Holden version during the previous body) was used. However, as the body team worked on the style of the new VT Commodore (from which the Monaro/GTO was later engineered), even the rear door skins and glass were reshaped and so only the front doors were common with the Opel Omega B/Cadillac Catera. And of course the Holden Commodore now used the Buick 3.8 pushrod motor (with and without supercharger) and the Chevy Corvette LS1 engines matched to locally designed and sourced drivetrains and brakes etc. This also required a totally unique floorpan and framework than the narrower and lighter Opel/Catera.
To reaffirm that the Commodore and Omega are two different engineering products you can visually see that the Commodore is a much wider and bigger vehicle than the Omega. And look at things like the roof of each below. Note that the Omega’s roof is a single pressing while the Commodore has a three-piece pressing. Given that the passenger cell is a major frame component in a monocoque design - this is a significant difference on it’s own. But also follow the carriage line under the side windows forward to where they intersect the front. Note how this virtually straight line sweeps over the top of the Omega headlights yet intersects the side blinkers on the Commodore. And the bonnet shut lines on the Commodore are more inboard than the Omega’s. This is because the entire shape of the front and even the substructure in the Commodore are different And underneath is even more different. A car needing to carry a heavy 5.7 LS1 has to have a different frame from a vehicle that’s heaviest engine is a 3.0 V6.
And that is the story of how and why the Australian Commodore, from which the Monaro/GTO was derived, may have a similar ‘look’ to Opels, from whom the styling was sourced. However, underneath the skin, which they don’t even share, they are completely different animals.
Up until this point I agree with everything MIGoat has said
Quote:
Originally Posted by MidnightBlueGTO...
I grew up close enough to Detroit that basketball isn't the only winter sport. 12 angry canadians, armed with sticks, skating around on a sheet of ice. What's not to love???
You seem to know your stuff - maybe you could do a quick history on the Holden coupes - Most folks here seem to know about the Monaros, but what about Toranas? Only if you have time...
Yes actually I know quite a lot about all the Holden Coupes. But I don't have the time for the next few days, but on the weekend I'll put together some interesting stuff for you.
Thanks monaro......................great read and great info. Ill spread the word around, alot of people have been misinformed.
You're welcome monaroCountry,
Yes I keep seeing people refer to the Monaro/GTO as a two door Opel Omega and that is just not true. I've found some pictures which I think, if you ignore the thick cladding, show the differences even more so. Compare the pics to the sample Commodore below. What these pics show those who think these two share the same frame is that they don't. Look at the lower panel between the front wheel and the front door on the Opel. This panel on the Opel is clearly thinner than the same panel on the Commodore, even though the Opel's panel would look even thinner if it didn't have the thicker swage-line cladding. What this means is that the front wheel and suspension are closer to the passenger cell. It's simply a smaller car with a different floorpan!!! This is clear if you look at the length between the front doors and the front bumper corners of each, the Commodore is much much longer.
BTW, this pic of the Opel also clearly shows the differences in the rear door. Look at how the rear shut-line rises in a more straight line up from the rear wheel arch (matching the front door shut-line) compared with the more curved shape on the Commodore that doesn't match the front door shut-line. And the rear door glass shut-line on the Commodore curves down and then slightly forward (ala BMW) compared with the Omega's straighter shut-line curve to the rear door glass which doesn't sweep forward at the bottom.
I also believe that while the only shared panel is the front door skin, even the inner front door pressing may not be the same as the Opel, as it had to suit Australian suppliers of electric window-winders etc. It's cheaper to change the die pressing shape, before ordering it made, so as to use a suppliers existing local components, than to have the supplier retool an entire mechanism or electric motor production line.
You seem to know your stuff - maybe you could do a quick history on the Holden coupes - Most folks here seem to know about the Monaros, but what about Toranas? Only if you have time...
Give me the weekend and I should have something for you
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"I still can't spin the wheels all the way down the straight in high gear"
- Mark Donohue (The Unfair Advantage) commenting to the Porsche engineers on the 1100hp 1973 Can-Am Porsche 917-30 when asked whether the car has enough horsepower yet!!
Anybody seen a mag called something like 'Australian Ute ?' There was an article in the March/April edition that said that GM were definitely going to export the ute to the US, and even gave specs (basically a Maloo), but I have not seen anything since.
Good info! I'm curious though. I assume that V6 block you mention is an iron block right?
Seeing as the LS1 is all aluminum, what's the weight difference between these two blocks?
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DYNO: 339rwhp/336rwtq stock (DynoJet) Mods: ¶ JHP Monaro Factory Gauge Pod + 05 Font Upgrade ¶ 2006 Rear Tails ¶ Holden Bluetooth Kit ¶ Tinted Windows ¶ Your car's synchromesh has feelings too!
If you can read this, thank a teacher. If it's English, thank a soldier.
Anybody seen a mag called something like 'Australian Ute ?' There was an article in the March/April edition that said that GM were definitely going to export the ute to the US, and even gave specs (basically a Maloo), but I have not seen anything since.
One of the US Mags had a similar announcement - showed a Maloo - said it would be the new Chevy ElCamino - same name the old chevelle pickup had.
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2004 W40 Pulse Red M6
K&N Panel + HSV MAF Tube + TBBP
GMM Ripshift + CAGS Eliminator
EBC YellowStuff + DBA 4000 discs
Mobil 1 0W-40 + K&N Oil Filter, Optima Redtop
Royal Purple Maxgear 75W-140 + Synchromax
NGK TR55s, Corsa Touring + coated Kooks LTs & Cats.
Bridgestone RE-01R's on stock '17s
Pedders Street-Pack 1
..and the ever important LS1GTO.com stickers!
Next to install: GTP Stage 2 heads+cam+underdrive+tune
Oh, and welcome MonaroSS. There are a few of us Aussies on here trying to keep the yanks informed on everything Australian.
These guys all love our cars (except the odd troll) and suck up every bit of info you can pass on.
Hi isszy, bugeyedbandit and Ford Falcon driver,
I've often visited this site but never really joined in 'till now. Hope to see more of you guys and any other Aussies (or should I say Ossies, given this is an American site. LOL).
2004 GTO Owner
Other Holden/HSV
