Commodore Picture Archives

300kW VT GTS

As the world evolves even further, the desire for personal self-improvement seems to escalate higher and higher. The stakes are always on the rise as mankind strives (well, some of us at least) to be better, stronger, faster, leaner and more intelligent. Yesterday's benchmark is today's mediocrity. The same can be said about almost every aspect of life, from sporting achievements to business and commerce. The same evolutionary development theory envelopes cars, the car industry and the performance aftermarket.

Well. Sometimes ...

Most of us are interested in extracting more performance from our Commodores which is, after all, a prime directive of the aftermarket and how it serves its clientele. What changes over time, though, is the expectations put in place by the powers-that-be in terms of the rules which everybody should try to work within. The government, in its infinite wisdom, tighten the rule books in terms of automotive safety and the ways in which motor vehicles react with the environment, constantly moving the legal goalposts closer together for the common good.

This, after all, is a good thing, it forces car manufacturers to produce cleaner and leaner vehicles through tightening safety requirements and emissions regulations whilst still trying to retain and improve a car's character, performance and attributes. They really don't have a choice in the matter and the consumer, at the end of the day, is the winner. Mind you, cars aren't getting any cheaper either,..

The aftermarket, in general, has often been accused of catering to power requirements without so much as an environmental conscience. However, that too is constantly changing as the legal screws continue to tighten on every aspect of the motoring industry, including the aftermarket. Emissions regulation is becoming a big focus for 'big brother' remember, the introduction of compulsory inspection checks just around the corner, This automotive oriented theory of evolution dictates that the performance tuners and aftermarket companies (who are strong enough to approach their craft in a more contemporary fashion) will be the ones who survive whatever tough new 'restrictive' legislation is thrown at them.

It sort of puts a whole new slant on the reference to automotive 'dinosaurs', doesn't it?

One company which is approaching the performance aftermarket with a thoroughly contemporary and evolutionary mindset, is Melbourne's Starr Performance. Company Principal and ex-HRT man, Peter Starr has put his money firmly where his mouth is and built an extraordinarily-modified HSV VT GTS, which showcases his company's very 'millennium friendly' approach to building cars.

These days, of course, aesthetic impact has become paramount and the aforementioned tightening of government policy has meant there is a developing movement within the modified-car scene towards more show and less go. Making Peter Starr's Diablo Red sedan almost a paradox of current trends. From all Appearances it looks like a cool, fat and slammed GTS, albeit a decidedly 'standard' one, If you look under the bonnet, you'd probably have the same reaction, in reality, nothing could be further from the truth.

Hidden beneath the factory-friendly appearance is a hard-tuned performance monster which is just as at home at ten-tenths around Winton or Calder as it is in the hands of your grandmother in a Melbournian torrential downpour, It's a complete and modern performance car which lacks nothing in every department.

The GTS sees double-duty as Peter's personal ride and a demonstration / development vehicle for the way his company approaches Commodore performance tuning. The latter is evident when the owner takes Staff Performance customers for test drives, where all of the touring car experience shines through. This car, just like the motorsport background from whence it came, is all about hard-tuning or, in other words, fine tuning.

Preceding the red beast in the Starr fold was a similarly modified VS Senator which was used in developing the now infamous Starr Performance single throttle-body induction system - the very same one which now graces the newer VT's engine bay. It was a good car, the VS, and a nimble one at that, so jumping into a showroom GTS after developing a tidy and smaller sedan left Peter a little cold. "The standard VT GTS was a big rolly, heavy car," the owner explains, adding, "it didn't point in and was vague in comparison to the (modified) Senator. It looks fantastic but needed to go, stop and corner."

The first 'cab off the rank' was installing one of Start Performance's own aftermarket manifolds to find out what gains the Series I HSV 220i stroker would yield as a baseline. The results were impressive, Using an accurate dyno (the Fitzgerald Racing dyno, which is the registered dynamometer for the Porsche Club Racing series), the bolt-on manifold impressed by increasing the rear-wheel power figure from 156kW to 176kW, showing a substantial torque increase right across the rpm range and a peak gain of 25Nm at 3500rpm. The manifold features a large 90mm throttle body in place of the 65mm factory item, helping the Starr unit flow twice that of the Holden induction, or a whopping 1200cfm. Things were off to a good start.

The suspension, and the Starr package which resulted, was a much more intensive procedure. "We used the same logic as a Supercar team uses," said Peter, regarding the fact a long program of progressive improvements to the chassis wilt suit both the road and circuit work.

Everything throughout the suspension was altered one step at a time (or with one adjustment) in order to determine a positive or detrimental effect. Peter felt that, with the extra weight of the VT he could afford to go with stiffer springs than what HSV specify, whilst still retaining decent ride quality, The front springs are now 22 per cent stiffer, while the rears are bumped-up 33 per cent, all through custom Lovelis coils. The shocks and struts (some purists will cringe at this, I know) were ditched in favor of Koni adjustables. The overall ride height is now 30mm lower than original specs and some selective surgery has been applied to the struts themselves in order to provide an extra 35mm of extra bump travel, effectively giving the GTS an extra 5mm of added suspension travel as the big 18-inch alloys now dip up into the guards, Supercar-style.

The front end geometry and sway bar settings were just as important. "When you lower a VT, the front roll-centre goes right through the ground," explains Peter, "making the chassis roll onto the front through corners." A unique and very heavy front sway bar design improves things considerably, providing accurate steering response and improving turn-in dramatically, once the front strut angles were reset. Positive castor is now a whopping 9 degrees while negative camber is set at 1 to 11/4 for the road and 3 to 4 for the racetrack. The rear bar is moderately stiffer than factory and integrated to keep the chassis nicely balanced. Rather than using rubber or Nolathane for the sway bars, the custom drop-links which Peter uses (developed and sold through his company) help the bars act immediately, white other rubber suspension bushes have been modified to suit the new setup. After eight months of fine-tuning, the VT now handles like a true thoroughbred while still retaining excellent ride quality.

HSV's massive top-shelf Premium brakes featuring whopping four-piston calipers and 343mm cress-drilled rotors at the pointy end and 315mm units at the rear - remain as the GTS's stopping hardware but have been upgraded further for circuit duties by using Pagid 'blue' race pads, racing brake fluid and flex resistant aircraft quality braided line up front. For more regular street use, the factory HSV pads are still used.

The motor sport approach continued when it came time to modify the 5.7-litre engine, The prodigious power plant makes a maximum power figure on the sunny side of 300kW, but it makes it in an emissions-friendly kind of way, exhibiting a broad and smooth torque curve and excellent tractability. In broad terms, there isn't anything overtly radical about the rebuild and Peter used quite conventional componetry, but such a flexible-yet-powerful unit is born largely from meticulous care and rebuilding to exacting tolerances.

Peter was in for quite a shock when he tore the engine down. It was, after all, drinking an unusually large amount of oil for a brand new motor, but he didn't expect to find that the bores were oval shaped, creating an unprecedented amount of blowby! "After 10,000kms," he says of the premodification period, "it was due for a rebuild!"

The block and heads were acid-dipped and de-burred before the main correction machining was applied. After a tunnel bore, the decks were squared-up and the cylinder bores shaved 30 thou for a more., er., circular result. The Harrop crank and suitable rods were put through some serious racepreparation in order to ensure optimum high-rpm integrity and then connected to ACL high compression pistons loaded with file back moly rings, helping create the higher-than factory 9.46:1 compression ratio, Peter then went to exceptional lengths to ensure that the rotating components connected to the crank were perfectly balanced - including the flywheel/clutch/pressure plate assembly, ancillary engine pulleys and the harmonic balancer - which minimises horsepower-robbing bottom end vibration. Speaking of the flywheel, the modified unit is now 10 pounds lighter than standard after weight was shaved from its outer perimeter, resulting in a more sprightly throttle response without noticeable detriment to the stroker's torque delivery.

At the top end, the head ports were opened up to improve flow as much as possible, as Peter says, "without making big holes", using a broad 2500-6000rpm operational target, About 500hp worth of flow potential resulted in the inlet cavity and about 80 per cent of that in the exhaust port. The standard valves were retained but the remainder of the valvetrain is top-shelf Crane gear, including the custom grind hydraulic roller camshaft. An adjustable Rollmaster dual-row timing chain ties the cam and crank together.

Lubrication, as always, is an important area, but Peter went to town on the GTS system. The high performance sump (Including baffling, windage tray and modified pickup) is a Starr Performance product, as is the custom 'sealed' oil breather system which feeds through the modified rocker covers and into a custom tank on the passenger side strut tower that utilises the factory catch can, Six-and-a-half litres of Mobil 1 is the lifeblood of the engine.

The powerful factory AC Delco computer remains in trusty service and has been carefully reprogrammed by the guys at ChipTorque and the ignition system is standard, Dumping the wasted gas is taken care of through selective, stainless-steel Genie headers (complete with modified collectors) and a dual 2.25-inch stainless-steel Mandrel bent system, using race mufflers and CE cats. Starr Performance have put a lot of time into exhaust development - and it shows. Especially when you consider that a naturally-aspirated 5.7-litre motor can make 300kW and still remain under 90 decibels at full song!

From the bellhousing to the rear wheels, everything is pretty much standard HSV issue with the distinct exception of the clutch, which has been upgraded to a tough Center Force unit. One of the most interesting additions to the GTS, though, is the Race Logic traction control system. (There's that motor racing connection again).

Traction control is a type of modification not commonly integrated into your average modified street car, but the benefits of a system, like the one installed here, are prodigious, By using the factory ABS sensors, each wheel mot[on is monitored 100 times per second and the computer can reduce power through cutting out the fuel injector pulse at random - if a disproportionate amount of wheelspin occurs. The system also has a built-in launch control which can hold the engine at a preset rpm limit until the car is in motion, after which the degree of rear-wheel adhesion is regulated through the traction control itself Very good trick indeed, Peter can also dial in how much traction he wants; from zero wheelspin, for full-wet conditions, up to 20 per cent for hard dry launches, I've embarrassed a few WRX owners ... in the rain," Peter beams with pride.

He has also impressed a couple of Supercar team members, too, with the GTS's prowess alter a quick spin around the block one sunny afternoon. With the traction control switched off, the GTS will light the rear Bridgestones up into third gear.

Such activities, though, are not part of the Diablo Red 4 doors' 'modus operandi'. Peter couldn't care less about quarter mile times, either, es his passion and profession melt together enclosed circuits. In fact, Starr Performance even offer driver training for those customers who have such a package integrated into their own rides, using Winton Raceway to teach owners how to safely harness the full performance potential of their newly Starr tuned vehicles. After all, this is where this type of performance car is really within its element, rather than simply being what Peter refers to as a "Saturday night special".

This attitude is exemplified throughout the rest of the GTS which is, of course, all standard. "HSV build an excellent product", admits the owner, in reference to HSV's styling and interior appointments. "Why mess with it?"

from Street Commodores Nov 1999