430kw of supercharged V8 power in a Colorado ute – yes, it’s nuts!
PROD THE THROTTLE. GO ON, YOU WANT
to. The red devil on the right shoulder is whispering evil instructions into your right ear. A few quick blips and the thunderous br-r-r-r-u-mmm of a big capacity V8 cracks off nearby concrete walls, inducing a sly, evil smile.like visiting New York-new York Hotel Casino in Las Vegas, the sights and sounds are all deeply familiar, but the location is totally foreign. This is a dirty big V8; in a Holden Colorado; and it’s supercharged! But unlike the Vegas hotel, what’s different about this beast is that it totally looks and feels like it belongs there in every way. It’s an unholy union with a heavenly result, that turns a solid, popular and quick Holden Colorado into something that is embarrassingly supercar quick, laughably easy to drive, and as reliable as a standard version, because - to quote Ben Kenobi - it is… ‘from a certain point of view’. We discovered two issues ago that the Colorado Z71 is the quickest of the fourcylinder ute group, when it dominated the drag racing component of our Ute-lympics test, being substantially faster than both Ranger and Hilux. But the Colorado ‘GTS’ takes it up not just a step, but the whole ladder: it’s insanely fast with supercar sounds and the comfort of a high-riding double cab ute. This awesome creation is the work of Silverdale-based Extreme Conversions (EC), an hour north of Auckland, by business partners and mates Director Heath Moy and Sales & Marketing Manager Rick Grant.
With a family tradition of Holdens and Commodores, this was a natural fit for Heath, and with Rick’s Chevy passion, and a shared love of LS engines and speed, the guys have spent recent times putting together this, the Extreme Conversions Colorado GTS #01. It’s the first of its type in NZ, with a handful of similar conversions proven and successful in Australia. This is no backyard build – run from their Silverdale mechanical workshop, the EC Colorado is basically a replication of what HSV would do to a Colorado if it could. Cost and production numbers probably don’t bode well for a manufacturer to change engines for a sports model, but for smaller companies like EC, it’s the ideal chance to showcase the ultimate 2018 ute. At a time when the HSV’S Maloo has taken its last breath, this Colorado ‘GTS’ has timed its run perfectly, ready and able to take over the mantle as the General’s fastest ute.
The build starts with a ‘donor’ Colorado ute. “It doesn’t have to be the Z71,” explains Heath. “A customer can choose any spec level he wants, any 4WD Colorado from 2012 on, though a 2WD conversion is in the works. “We can build a total sleeper, or something bold and brash – even V8 an HSV Sportscat! “We used the Z71 for our car to showcase it,” added Rick. The EC Colorado GTS is basically built to ‘factory’ specs. The 2.8-litre turbo diesel four-cylinder is removed, which the customer can sell or use for spares. Impressively, there isn’t a huge weight difference between the heavy cast iron block turbocharged diesel engine, and the alloy block V8, resulting in minimal affect to overall weight, handling or balance. To compensate,
Wanting a thrill-ride for the entire family? The LSA supercharged V8 conversion also fits the seven-seat Trailblazer SUV!
and reduce front roll, Extreme fits heavier Dobi Sport front springs, which raise the front end 75mm, level out the rake, and minimise the effect of any added weight to the front end. In its place is a brand new GM ‘crate motor’ LSA supercharged V8, and matching six-speed auto via a custom transfer case, basically replicating the drivetrain as seen in the HSV GTS. On custom engine and gearbox mounts, the V8 lowers into the large engine bay like it was made for it, thanks partly to a GM lowengine sump. There’s a factory wiring loom, customised to suit, two-piece heavy duty driveshaft and fully engineered and complied safety loop. The base exhaust is a two-into-one threeinch system, using LSA catalytic convertors and the same four oxygen sensors, and emits a meaty rumble; though the guys are also working on an optional bi-modal system, similar to the HSV system, that quietens it at the touch of a button. There’s no doubt it’s a V8 at idle, a rumble whose pitch is flattened a little by the supercharger. Ancillaries are where just as much work is, but vitally, it’s kept as ‘GM’ as possible. The ECU was moved from the right to the left side of the bay; there’s a factory airbox with an upgraded lid, Bosch air-flow meter, and a four-inch feed pipe; though Heath, ever the perfectionist, is aiming to produce a moulded pipe to complete the factory look. Custom upper radiator hoses, GM filters, GM clamps, hoses and fittings and even oils continue the factory theme, with a revised fuelling system required for the change from diesel to premium unleaded, including all the emissions equipment, and a neat little reminder sticker in the fuel flap that PULP is the juice.
New GM pulleys, tensioners and three GM belts are used, including the custom brackets needed to relocate the air-conditioning compressor. There’s a larger radiator for improved cooling, with twin electric fans in place of the mechanical fan, a transmission cooler, and a change to the charge cooling, the Colorado now using a more space-efficient water-to-air intercooler in lieu of the factory air-to-air intercooler. All this cooling has clearly paid off: “Even stuck in traffic,” recalls Heath, “the gauge sits just above half, before the fan kicks in. In the diesel, it sat just under a quarter... so it’s just where it sits with the V8.” The best part is that everything works. It sounds obvious and easy, but it’s far from it, with the Colorado GTS starting, running and performing exactly like a ‘standard’ car: no check engine lights, the hill descent control works perfectly, as does the tiptronic sequential gear shifter. There is one caveat, however, as the diesel-scaled tachometer only spans to 5000rpm, but the petrol engine spins to 6600rpm; though it’s an auto, and retains the rev limiter, so that isn’t an issue. Stopping power is improved a little with Bendix brake pads, though a Harrop conversion is available, and was fitted just after the photos. The LSA conversion kit is actually four pages long, and includes things like a new starter motor and alternator, listing every component from GM bolts to the LSA badges. There’s even a full 10,000km, six-month warranty, 40-litres of premium fuel and a full wash, vacuum and detail. It’s almost like buying a new car again. A true drive-away package, this is the ultimate performance dual-cab ute, and one that is fully configurable and customisable. The show car, for example, uses Holden flares for a fatter but factory look, but there’s a range of options from shocks, springs, interior upgrades, brakes, wheels and tyres, such as the 20-inch BG Wheels and Cooper tyre package fitted to this car. Supercharger pulley changes can even reap more power, if 430kw just isn’t enough! The conversion can be done to new or used Colorados, and Extreme Conversions does everything properly, using either factory or top quality components, from the GM engine, down to Wurth washers and bolts.
But one of the biggest achievements for the company is the compliance plate affixed to the engine bay, one of the hardest parts of the build according to Heath and Rick. The full basic conversion takes around 4-6 weeks and the fit, finish and end result is typical of any showroom model. The Colorado GTS is designed to appeal to the premium ute buyer, one who doesn’t flinch at $100,000 for an optioned up V6 Amarok, an accessorised Ranger Wildtrak, or even the HSV Sportscat ‘+’ buyer who wants the performance befitting of the traditional HSV brand. From $45,000+GST for the drive-in/driveout kit, on a manual LTZ (the cheapest dualcab), that equates to around $108,000 for a ‘brand new’ V8 Colorado Lsa-powered ute. And that is a mighty vehicle. Even looking used, take a three-year old Colorado which are on Trademe for around $30-$40k, and the result is a 2015 Colorado worth around $75-$85k. Want a thrill-ride for the entire family? The conversion isn’t just for Colorado, either EC is also able to convert the seven-seat SUV Trailblazer sibling. Kids playing up? Nail the throttle and they’ll quickly snap into line!
It’s what we all came here for, and the Colorado GTS does not disappoint! Starting the ute is a simple pleasure, the gauges sweeping their factory start-up routine, and the rattle of the Duramax diesel making way for the rumble of the big V8. The exhaust tips are a long way from the driver, but there’s a melodic throb of a V8 that encompasses the cabin, without being intrusive – unless the driver wants it to be. Selecting drive and moving off should come with a slight warning, as the muscle memory of driving a diesel takes a moment to adapt to the eagerness and urgency of a supercharged V8. It isn’t difficult to be smooth at all, but small prods launch the Colorado from standstill with a mountain more speed: yes, the 500Nm @ 2000rpm from the four-cylinder is impressive, but when 740Nm is available, it’s like comparing a cheetah to a Chihuahua. The steering is a touch heavier, maybe five-percent, but it’s forgotten after a few kilometres, and the growl of the V8 is music to the ears as it cruises around town. Floor the throttle, from almost any speed, and the nose lifts and the engine changes from passive and purring to a wild animal, roaring as revs thrash through the range, the six-speed sliding between gears. Interestingly, the V8 is the dominant sound, and like the GTS sedan, there isn’t a howl or whine of a supercharger pumping boost, just a classic, muscle car-like growling bark from a V8 that let’s everyone within 50 metres knows this definitely isn’t the standard 2.8-litre four-cylinder. We power up a hill on 100km/h zoned B-road, and it gets the attention of a farmer or three as the thumping sound hits like a wave. It’s impressive considering that its 430kw is only 10 percent down on a current Australian Supercar racer – and this is a road legal, fully complied double-cab ute with five seats!
Its 0-100km/h time is just 0.8 seconds off the HSV GTS! Did we just test New Zealand’s fastest double-cab ute?!
The simple fact is the Colorado drives like, well, a mix between a Colorado Z71 and an HSV GTS. There’s aren’t any surprises in driveability, it starts with a twist of the key, runs without fault, and sets the standard for what a 2018 ultimate performance ute has become. We’ve saved the best for last: how fast is it? With our VBOX timing gear locked on to satellites, we dialled up the key targets for 0-60km/h, 0-100km/h and the standing quartermile. Having rolled off these numbers with the standard Z71 recently, we had a baseline to work with, plus the ability to compare it to the HSV GTS, which is naturally faster, being a sedan and 300kg (15 percent) lighter. With traction control disabled, 4H mode enabled to minimise any wheelspin, and the throttle loaded to around 2000rpm against the brake, the Colorado GTS unleashes its fury: it lifts the nose, sinks the rear and roars past the limit of the tacho, audibly singing beyond, with a slick shift around… no, wait. We had to check the video, as the GTS just manages to tick over 100km/h in first gear, in just 5.2 seconds! A little shocked at the numbers, we tested it again, with the same 5.2 showing on the display. Not only is that almost HALF the time the standard Z71 takes (10.2 secs), it’s just 0.8 seconds off the HSV GTS! Did we just test New Zealand’s fastest double-cab ute?! Of course the action powers on through second and third gears, with the Colorado piling on the speed, both its size and aerodynamics fighting against the engine, but as it crosses the quarter-mile, the numbers are equally astonishing: 13.6 seconds at 168km/h is a time that HSV would have been happy with for its Clubsport just a decade ago. Of course this kind of performance comes at a price, and with the GTS claiming 15.0l/100km, and the standard Z71 getting around 10l/100km, the heavier Colorado GTS was never claiming to be an economy car, with Heath informing us that around 16-20l/100km is quite normal. But if fuel cost is an issue, you’re probably not the target demographic. If ultimate performance in a double-cab ute ‘is’ your target, then there is nothing like the Extreme Conversions Colorado GTS. It’s high octane V8 juice. Contact: www.ec-nz.co.nz
Factory Holden flares pump up the looks, while keeping it in line with the ‘factory’ appearance.
Ignition on, the gauges run a full diagnostics check before returning to normal, just like the stock set-up, without fault codes or lights.
The rattle of the Duramax diesel four-cylinder makes way for the rumble of a 6.2-litre V8