When you decide to make a haul-arse street car it’s generally the ‘done thing’ to start off with a high-performance platform. But when David Wilzig decided to go all-out on a Holden sedan, he steered clear of SS V8s and HSVs.
His chosen platform is a garden-variety VS V6 Commodore with a live axle. It had to have a live axle...
David has previously owned a HSV Clubsport and hotted-up VP Commodore and knows that the basic Holden live axle lends itself to drag racing better than IRS versions, which tend to tramp and have camber problems. So, you see - there is method to his madness!
And why go for a V6 when you can get the Aussie 5.0 and a heap of aftermarket accessories to suit?
Well, David had previously put his toe in the water by twin-turbocharging his VP V6 Commodore. With a relatively basic set-up (retaining stock engine internals) the VP TT trotted out 280hp (209kW) at the wheels without much sweat. David explains that the later-model VS appealed to him because of its superior cylinder head design and much improved intake manifold, which is nicely suited to a turbo installation.
The VS V6 was always going to be an all-out exercise. David took the car to Vince Rigoli (of V&E Rigoli) and had the 3.8 litre V6 built to handle some serious torque and increased rpm. Scat conrods, forged low-compression Aries pistons and an ARP stud kit give the engine plenty of strength. The crankshaft remains standard, which – due to its heavily offset journals – means the engine shouldn’t be turned at more than about 7000 rpm.
At present, the VS-spec cylinder heads remain standard but a Crow camshaft has been slid in. David says this particular grind is intended as an upgrade for factory supercharged Holden V6s.
On the side of each cylinder head you’ll find a custom exhaust manifold fabricated in ‘steam pipe’ by Vince Rigoli. These mount a pair of Garrett T28 turbos with internal wastegates. A pair of 2 ½ inch dump pipes channel gasses into a single 3 inch pipe with a single straight-through muffler - it’s a combo that’d be w-a-y too loud if there weren’t a pair of turbine wheels chopping up each exhaust pulse. This photo shows the extensive application of heat wrap to the turbine housings and dump pipes – under-bonnet heat management was seen as an important issue for the car.
Induction air begins its journey at a pair of K&N filters (which are fed outside air from Ford XB scoops moulded into the bonnet) and the turbochargers throw it through a custom Mood Motorsport air-to-air intercooler. An atmospheric-venting blow-off valve is fitted on the pipe back to the engine. At the time of photography the car ran a bleed type boost controller but a TurboSmart e-Boost unit is now responsible for maintaining rock-steady boost pressure. A relatively mild 14 psi is the norm.
With 14 psi of boost being stamped into the intake manifold, it’s essential to increase fuel flow. David’s Commodore uses a set of monster 1000cc injectors teamed with a Malpassi pressure regulator, twin Bosch Motorsport pumps and surge tank. The ignition system employs an M&W ignitor and coils.
Controlling the fuel and ignition (and allowing removal of the standard airflow meter) is the latest EMS 8860 programmable management system tuned by Vince.
And just when you think the engine has more than enough done to it David pops the boot... to reveal the nitrous bottle! Yep, that’s right – apparently twin-turbocharging isn’t enough! David says it’s a relatively small (50hp) nitrous shot which is introduced before the throttle. We’re told this is used only for launching.
When we caught up with David and his VS Commodore it was on the rollers of Vince Rigoli’s Dyno Dynamics chassis dyno. On the usual 14 psi boost setting the car cranks out a very respectable 400hp (298kW) at the wheels. With boost bumped up to 18 psi (for tuning purposes) the car responds with 440hp at the tyres. And then Vince hits the nitrous button... On this occasion, power shot to a massive 507hp (378kW) at the wheels - but Vince says he’s sceptical if the actual output is that high. In any case, this configuration saw the engine backfire through the intake manifold and shatter the plenum cover!
Backing the mega-grunt V6 is a fully tricked version of the TH700 4 speed auto trans. A B&W shifter allows easy manual changes while a high rpm stall converter keeps the engine on-song. A B&M oil cooler and a large capacity transmission pan keep the T700 running reliably. The tailshaft is stock and runs to a shorter-than-standard Borg Warner 3.45:1 LSD.
David says the V6 is an inherently torquey engine that, combined with the high-stall auto, means there’s virtually no lag or bottom-end shortcoming. Boost pressure comes on strong at around 2800 rpm and sets you back in the seat. David can launch the car quite cleanly thanks to the faithful ol’ live axle, which is augmented by only Monroe dampers and 50mm lowered King springs. A Whiteline adjustable Panhard rod keeps the axle centred.
For drag racing events, a pair of slick tyres goes under the rear. With its sticky rubber, the car has recently run a time that stunned the Holden LS1 crew – but a string of 10.7 second 127 mph passes is no fluke! David says the car will go significantly faster when he gets a line-locker, modifies the heads and sorts out some small set-up issues. But before he can do that he needs to install a roll cage to meet drag racing guidelines – the car is now running right up there with the best of the best street cars!
David says most people don’t know what to make of the car when it runs a 10 second pass.
“People used to come up and tell me it was quick when I was running mid 11s. Now that it’s in the 10s nobody comes up and says anything – they just look with a confused expression,” he says.
This car gives nothing away through its appearance. The body carries a HSV body kit (minus rear spoiler), aftermarket taillights, headlights and side indicators and those Ford bonnet scoops. Wheels are PCW 18s wearing 235/45 rubbers for street use. It’s a neat package – nothing over the top.
David says there are absolutely no weight-saving measures that contribute to the 10 second performance. The full interior trim remains (with a set of VT HSV seats installed) and you’ll find an add-on tacho, shift light, aftermarket leather wheel, A’PEXi turbo timer, boost gauge and the e-Boost unit. All door trims and the roof lining have avoided the chop.
With more power to come and with no weight reduction, our minds boggle at the thought of how quick this car has the potential to run.
SS V8s and HSVs?
Bah, who needs ‘em!
V&E Rigoli +61 2 9756 3413