You’ve probably heard the superlatives commonly used to describe a car’s performance so there’s no need to bash you over the head with them once again. But think about this.
Colin McGill’s stroked and Whipple supercharged Holden VU ute has so much gut-bustin’ torque that he can launch off the line in third gear (yes, third) and sprint down the quarter mile in low 12s - launching in first or second gear on street tyres achieves nothing but uncontrollable wheelspin. But ease it off the line in first gear with the extra traction of Mickey Thompson slicks and it’ll easy run 11.1 seconds at 129 mph...
Colin’s VU ute is an exercise in extracting maximum horsepower together with monstrous torque all the way through the rev range. It’s a combination that a centrifugal supercharger and a huge cam and heads type engine build can’t hope to match.
The platform for this torque-pumping monster is a stroked version of the original LS1 - an off-the-shelf Eagle stroker kit brings the swept capacity up to 383ci (6.3 litres). CP forged pistons have been included in the engine build and are responsible for delivering a 10.5:1 static compression ratio. This is an incredibly high compression ratio for an engine with forced induction – so why take this approach, you ask? Well, it’s a combination that came about after Colin did ‘the usual’ naturally aspirated stroker engine build and then decided to add the blower. Ideally, he’d prefer to run a lower static compression ratio and add more boost pressure. An ARP heavy-duty stud kit holds the stroked engine together and the block remains standard. Mark from Brisbane's PowerTorque - the company that has worked on the car - says they’ll push it to breaking point and then look at a stronger cast iron block.
The two-valve-per-cylinder cylinder heads are professionally ported and polished and come equipped with bigger valves, upgrade valve springs, retainers and a double-row timing chain. The camshaft selected is PowerTorque’s preferred unit for use in an atmo stroker engine – Mark says he’d prefer a slightly milder cam with wider lobe separation to suit the blower.
In naturally aspirated guise, the 383ci stroker engine pumped out good power and torque but it didn’t give the underpants-soiling acceleration that Colin was chasing. So the next stop was a large displacement Whipple twin-screw supercharger and water-to-air intercooler set-up. This spare-no-expense forced induction arrangement has been installed with a custom 4 inch inlet pipe, conical air filter and a new airbox. A Starr big-bore throttle body is also included.
The exhaust system has the gas flow properties you need when you’re talking 383 cubic inches of Whipple-charged muscle. A pair of 1 7/8 inch Di Filippo heads channel gasses into a Di Filippo twin 3 inch mandrel system with twin cats and mufflers. Colin has also got a pair of side-exit pipes which he installs for car shows and driving events – and the crowd loves it!
Amazingly, the high compression and supercharged engine is happy to run on pump 98 RON fuel. Fuel is delivered from a swirl pot which supplies a Bosch Motorsport pump and Bosch adjustable pressure regulator. The injectors are monster 46lb-ers which are controlled by a remapped version of the standard management system. A 2 Bar MAP load input is employed.
The Whipple twin-screw blower delivers boost from near idle and gives the stroked V8 earth-trembling torque whenever you put your foot down. Sure, the engine is a fairly unconventional set-up but Colin says it works well - the high compression ratio offers awesome low-down grunt and throttle response which is immediately backed by supercharged torque. The powerband is effectively 1000 to 7000 rpm...
In this photo you can see the nozzle for a water injection arrangement but this has recently stepped aside for a high volume methanol injection system. Methanol is now injected into the blower whenever manifold pressure exceeds 4 psi. There’s a pair of 18 litre methanol tanks mounted in the back and, at present, the guys are still sorting the jet size.
At the time of writing there’s no official evidence to show that the methanol injection has increased power but a seat-of-the-pants comparisons leave little doubt. In any case, it was already impossible to achieve an accurate power figure – the team at PowerTorque pulled out all the tricks but, still, they can’t stop this beast from burning its tyres on the chassis dyno rollers. It is predicted that this monster stomps out 700 – 750hp (522 – 560kW) at the wheels.
Of course, channelling this kind of output to the back tyres poses some unique driveline difficulties.
Colin says the car has a total lack of traction through first and second gear when using street tyres. As a result, fast getaways require launching in third gear – and that places loads on the clutch that, well, don’t bear thinking about... Colin has already trashed a couple of clutches but the current ultra heavy-duty twin-plate job is surviving okay. For now. The gearbox is a standard Holden six-speed tied to a modified LSD with heavy duty axles and CVs.
For street duties, Colin runs a custom set of 18 inch rims wearing Bridgestone Potenza 265/30s at the rear. Track outings call for sticky Mickey Thompson 26 x 10 slicks at the rear and a pair of front-runners.
Colin says he’d like to upgrade the brakes but the current arrangement – PBR discs and calipers and the front and performance pads – allow easy fitment of the drag slicks. Bigger brakes would make it difficult to fit the serious wheel/tyre combo required for drag racing. The suspension is enhanced with Koni adjustable dampers and King springs. The car is now on its fifth set of springs – the previous four sets began to collapse and sag after a few hard launches...
The Holden VU body is largely standard but Colin has fitted an aftermarket body kit – one with the largest frontal cooling aperture he could find. Under-bonnet temperature is further reduced thanks to a custom fibreglass bonnet which incorporates a Ford XR8 style ‘power bulge’ with air vents. A pair of Euro-style mirrors (with integrated indicator lights) is also installed.
In its current configuration there is no doubt the car will run a 10 second quarter mile on slicks. But this leaves Colin in an awkward predicament. You see, once the car runs a 10 he’ll need to install a cage – and that almost excludes the car from daily use (Colin currently pedals the ute about 100km a day for work purposes).
So whadaya do when you know you can go faster but you don’t want to spoil the everyday useability?
You keep the car as-is and purchase a dedicated drag weapon. In addition to owning this incredible machine, Colin is now the proud owner of the 1200+hp Holden ute known as CORUPT (see Light Speed LS1).
Life is good when your street car has the potential to run 10s and your ‘real’ race car is in the 8s!
PowerTorque +61 7 3881 2379