The introduction of the LS1 5.7-litre V8 has given the local Holden VT-onwards Commodores an abundance of power and torque. The entry-level LS1 Exec/SS now pushes out 225kW/460Nm, the Clubsport R8 ups the ante to 255kW/475Nm and the near-$100,000 HSV GTS cranks a full 300kW/510Nm. Impressive numbers for a car that's based on a family sedan.
But what if you want significantly more?
Paul Sharp is the owner of an automatic Clubsport R8 and - living in Australia's speed limit-free Northern Territory - he can regularly give it extended periods of WOT.
Half his luck!
When Paul wanted more power, he knew that he needed more than just a few small bolt-ons - he wanted to create a highway hell raiser. Supercharging was his preferred path to power, and it was CAPA (Centrifugal Air Pumps Australia) that won the contest with their Vortech kit. The installation of the supercharger kit - plus the optional intercooler and a replacement rear muffler - was handed to Adelaide's Awesome Automotive.
Note that the same CAPA kit can be used on all 1999-onward Commodore LS1s and it comes complete with absolutely all necessary parts - no matter how seemingly insignificant.
Commencing Installation
The first requirement in performing the CAPA Vortech blower conversion is to strip the front of the vehicle. Among the items to be removed is the battery, airbox, radiator reservoir, cooling fan assembly, front bumper, left headlight, engine belt and tensioner, computer module and the power steering pulley. The engine oil should also be drained and refilled with a 5W-40 synthetic grade (along with the fitting of a new oil filter, of course).
Mod One is to relocate the factory engine management computer closer to the firewall (making room to fit the blower). This involves slightly bending and then insulating the air conditioning tube, trimming the ECU heat shield and re-fitting the computer. Note that CAPA must have first received the factory computer in order to reprogram it; new maps are essential.
Mounting Hardware and Pullies
Next, the top alternator mounting bolt must be removed and a small idler pulley installed in its place (shimmed as required). Following this, a steel spacer is used to fit a heavy-duty supercharger bracket to the left cylinder head and the power steering pump. A CAPA power steering pulley can then be installed in place of the original - this large diameter toothed pulley provides drive for the supercharger.
With the supercharger mounting bracket and drive pulley set up, a CAPA engine belt tensioner is fitted, along with a replacement engine belt. The kit sees the replacement engine belt connect the new idler pulley, alternator and power steering. With these in place, the cooling fan assembly can be re-fitted to the vehicle.
Blower Lubrication System
The supercharger uses its own pumped, self-contained oiling system - which even includes an oil cooler! With the bumper bar still removed, the oil reservoir is bolted to the front body panel. A hole is drilled through the inner guard so that the reservoir's filler neck can be easily accessed. The horn must also be relocated.
The oil cooler for the supercharger is then mounted in front of the air conditioning condenser. The blower is positioned (but not yet fixed) inside its mounting bracket and the supercharger oil hoses are attached to the fittings on the newly installed oil reservoir. Oil passes into the supercharger after flowing through the oil cooler, with the system pressurised by an electric pump located at the bottom of the oil reservoir. The pump runs whenever the standard fuel pump is operating. An oil pressure warning buzzer is included in the kit, taking its feed from a switch on the CAPA supercharger oil cooler. Lastly, the reservoir is filled with 1.95 litres of the supplied 5W30 oil; only 1.75 litres is required for each supercharger oil change thereafter.
More Hardware and Pullies
Now comes the fun fit - bolting in the big Vortech V-1 centrifugal supercharger. The blower unit itself is made in the US and uses top quality materials (such as 356 aircraft spec aluminium alloy, treated to T-6 hardness) and specially made bearings. As such, the Vortech centrifugal blower is regarded as one of the best on the market.
A CAPA belt tensioner assembly is introduced between the blower and the toothed power steering pulley. This tensioner is again shimmed as required, and the 30mm toothed drive belt is installed. CAPA recommends that the blower belt has 25mm of vertical slack when it's cold - it's suggested that the supercharger and its mounting bracket will expand with heat and cause the belt to tighten.
Cooling the Charge
Given Paul's application (fast highway travel under sustained boost) he wisely decided to go for CAPA's optional intercooler kit. This is fitted in addition to the water injection system that is included as part of the Vortech blower kit. The first step involved in the intercooling department is to fit the ducting that directs charge air toward the front of the vehicle.
Now comes the really tricky bit.
Because there's limited space in the VT's nose, the CAPA intercooler kit passes compressed air through a replacement bumper bar skeleton. This structural component doubles to form the passage that takes air from the blower to the intercooler. Neat, eh? The front-mount intercooler itself is quite large and uses a tube-and-fin core design. Once the charge air temperature has been cooled, it then flows into a mandrel bent pipe that neatly snakes into the factory throttle body.
A Bosch blow-off valve is inserted into the hole in the intercooler-to-throttle pipe and a 25mm hose directs vented charge-air back to the inlet of the supercharger.
PCV Re-Route
To prevent boosted induction air wreaking havoc with the emission system, the PCV breather hose inlet fitting is removed from the throttle body and the fitting is plugged. The remaining hose end is then re-routed from the valve cover into the supercharger inlet. CAPA stresses that whenever oil is being poured into the engine, the PCV hose should be always disconnected at the valve cover. Engine damage may otherwise occur.
Pre-Supercharger Air Intake
With the left headlight still absent, a 4-inch flexible convoluted tube can be fed into the inlet at the back of the supercharger. The opposite end of the tube is equipped with the original airflow meter body. Note that the airflow meter is not completely standard, however; CAPA modify it at the same time that they reprogram the engine management computer. The atmospheric side of the airflow meter is then equipped with a K&N pod air filter.
The next step is to lengthen the inlet air temp sensor wires and insert the probe into a hole in the convoluted intake tube. In addition, the wires for the airflow meter also need to be extended to meet its new location. Completing the intake, the aforementioned blow-off valve and PCV hoses are inserted into the side of the convoluted duct.
Water Injection
CAPA's water injection system involves removing the factory washer bottle and drilling a 10mm hole into it; this is the source for the water injection. A "No Soap" sticker is put on top of the bottle to prevent people adding detergent which will then enter the supercharger compressor. Water is drawn from the factory bottle and is pumped to the injection nozzle by a small 12-volt pump. The "nozzle" actually comprises a small hose with eight pinholes in the end - it's not what we'd call a proper water injection nozzle. A 5mm hole is then melted into the convoluted intake duct and the nozzle is sealed in.
A manifold pressure switch triggers at 1.5 psi boost, activating a relay that puts 12-volts to the water injection pump. A fusible link is inserted into the power supply wire for maximum circuit protection.
CAPA points out that a considerable amount of water will be consumed if there are extended periods of boost pressures over 1.5 psi. Accordingly, a low water level switch is fitted inside the factory water bottle. When a low level is detected, the handbrake warning light is illuminates. In addition to this, a red light inside the cabin shows when the water injection pump is operating.
After the water injection system is installed, the front bar and wheel arch cover are re-installed.
Fuel System Upgrade
CAPA supplies a T/Rex fuel pump to deliver more fuel to the standard injectors whenever the standard fuel pump reaches its limits. Depending on the vehicle, this occurs at around 3-4 psi boost. Switching the T/Rex on is another manifold boost pressure sensor that's mounted on the existing fuel rail bracket.
The T/Rex pump is mounted under the body using the supplied brackets. It is plumbed in series with the standard pump, and in parallel with a one-way check valve. The check valve allows the standard pump to flow fuel which bypasses the new pump when the engine is off-boost, while allowing the new pump to come on stream as required without fuel back-flowing. The fuel that passes through the one-way check valve and the T/Rex pump merge into a shared line.
The Clubsport R8 - like various other LS1 HSVs - requires the use of CAPA's "fuel pump soft start" system; automatic and manual transmission vehicles require different approaches. This system comprises a heat sink'd heavy-duty resistor to drop pump voltage. The pump is initially activated at the lower voltage by the water injection pressure switch (~1.5 psi) then switched to full power by the fuel pump pressure switch (3-4 psi).
Note that CAPA also offers an optional larger set of injectors.
Before Going Ballistic...
Once the entire kit has been fitted, CAPA recommends some degree of "breaking in". This involves idling the engine for 5-10 minutes and then switching the engine off for 10 minutes to allow the blower to cool. Following this, the car should be driven without boost and at less than 3,000 rpm for around 10 minutes and then switched off. The final phase is to drive the car for 100km using no boost and keeping to a maximum of 3500 rpm.
The entire system should then be thoroughly checked - paying specific attention to belt tension and clearances.
Going Ballistic
Awesome Automotive took around 3 days to install the CAPA Vortech kit and - once broken in - they were impressed by the ease in which the blower improved power. Running PULP and boosting up to 7 psi (as the kit is geared to do), the R8's baseline power figure of 193kW (258hp) was king-hit by a new output of 273kW (365hp). That's a 41 percent power gain! (All figures at the wheels on a Dyno Dynamics dyno.)
Out on those long, un-speed-limited NT roads, Paul is very happy with the extra urge that the blower delivers. And in urban conditions the big LS1 always feels ready to react to driver inputs. It's got mega-torque at all revs, yet it's quite progressive and controllable. That's not to say that a killer burnout is difficult though...
So how much did Paul pay for his R8's 41 percent additional power?
Well, his final bill can be broken down like this: $9150 for the Vortech kit, $2200 for the intercooler kit and $400 for the HSV rear muffler replacement. Add to this Awesome Automotive's $2400 labour charge; that gives a total of $14,150.
Still - other than the water injection "nozzle" - the CAPA Vortech kit looks very well engineered and comes backed by a 12-month (unlimited kilometre) parts warranty.
No matter how you look at it, boosting the output of the LS1 by 41 percent will give you a tremendous amount of driving enjoyment!
Contacts:
Awesome Automotive
+61 8 8277 3927
CAPA (Centrifugal Air Pumps Australia)
+61 8 85 823 499
www.capa.com.au
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