Starr Charger - Part Two

In Part One of this two-part series we looked at the components in Starr Performance’s supercharger kit for LS1s. Using a highly efficient Whipple supercharger, water-to-air intercooling, water injection and a modified factory management system, this is one of the most sophisticated supercharger kits available. There’s no question about it.

Now it’s time to see how the kit performs on the road.

The Starr Performance Demo Vehicle

Peter Starr owns this 2004 Holden Adventra LX8, which serves as a demo vehicle as well as a long-term test mule. Why pick an Adventra, you ask? Peter has a two-part answer to that question. First, he wanted to identify any weaknesses in Holden’s AWD system, which is soon to be released across the range. Second, there’s simply no better way to get the huge amount of supercharged grunt to the bitumen. Two-wheel-drive has its limitations.

Peter says the Whipple kit has been fitted on the Adventra for four months and has covered about 6000 kilometres. We’re told there haven’t been any mechanical problems. The car is completely standard apart from the supercharger kit - the only exception is a modified valve body for the automatic transmission.

Now let’s give you the run-down.

With the key slipped into the ignition, the Whipple-charged LS1 fires into life just like a stocker. Peter says this is one of the biggest advantages of retaining the factory management system – the ECU is already programmed to cope with every conceivable starting condition.

Driven sedately, the Starr Adventra is very nearly as quiet as the stock vehicle. There’s no noticeable blower noise from inside the cabin, but there is induction noise from the custom airbox and pod filter arrangement. This noise is most noticeable on throttle application.

With gentle throttle movements, the Whipple-charged Adventra is responsive and has ample useable torque. We did not hear detonation at any time during our test. Peter says the supercharged engine should always be run on 98 RON fuel but it can cope with normal unleaded – in this case, the recalibrated ECU will revert to its conservative ignition timing table.

Now it’s time to up the pace.

Push the accelerator pedal to the floor and the supercharged Adventra torques over on its suspension and points its nose heavenward. There’s no question that this is a very fast vehicle.

How fast?

Well, with three blokes on-board we hand timed it to 100 km/h in just 5.6 seconds. This Adventra is supercar fast – and keep in mind it weighs 1983kg from factory and comes with a standard automatic transmission. Off-the-line performance is nothing short of awesome – note, however, you can’t stall it up much because the standard brakes can’t hold the grunt.

We must point out that Starr Performance’s demo Adventra is obviously stifled by its standard exhaust system. The loud rush of gas heard from the tailpipes points to a considerable amount of exhaust restriction. Peter hasn’t yet measured exhaust backpressure but agrees it is, well, on the high side... A high-flow exhaust will certainly shave a noticeable amount of time from its 0 – 100 km/h time and give a fantastic top-end improvement.

And there’s one other criticism – one that can’t be as easily addressed.

The Whipple supercharger is very noisy when it’s pumping in boost. It lets out a kind of whirring scream. We imagine some people will like the performance connotations of supercharger noise but it would certainly become tiring. Note that the noise of the supercharger is most noticeable when the standard exhaust system is retained – it’s not as loud over the bark of an aftermarket system.

At the time of our test, Starr Performance was still fine-tuning the behaviour of the Adventra’s automatic transmission. The ECU had been programmed to make up-shifts just before the rev limiter, but on a couple of occasions we saw the engine bounce off the limiter before the next gear was engaged. Part-throttle down-change characteristics also needed some revision. The trans was too eager to kick-down when it could have easily held a high gear and utilised all that supercharged torque. As we said, Starr Performance is still fine-tuning this area.

We were unable to run any fuel consumption checks on the supercharged Adventra but Peter claims the vehicle now consumes 16.9 litres per 100km in city conditions. In standard form we’re told it struggled to better 17.5 litres per 100km. This improved fuel efficiency is apparently due to the optimised ECU tune and the breathing efficiency of the supercharger.

Cost, Warranty and All That

The Starr Whipple kit is not cheap – retail price is AUD$17,800 fitted and tuned (including GST). In comparison, a centrifugal blower kit producing similar power costs approximately AUD$11,000 plus fitting.

But let’s not make comparisons purely on the basis of top-end power – a twin-screw supercharger drives completely differently to a centrifugal supercharger. It’s not an apples and apples comparison.

Peter says the kit is aimed predominantly at new car buyers. Starr offers the option of purchasing a brand-new vehicle already fitted with the supercharger kit – you pay your money and you take delivery of your new supercharged vehicle at Starr Performance’s workshop. One customer has already taken this route with a new Adventra. We’re told Starr Performance is offering a warranty on the supercharger kit but this has not yet been concreted. Don’t expect Holden to provide warranty coverage on anything to do with the driveline.

With a conservatively advertised 400kW at the flywheel, rapid boost response and a strong spread of torque, the Starr Whipple kit is the thing traditional-style V8 fans have been waiting for.

If you have enough cash and don’t mind supercharger noise this is a top-level upgrade for your LS1.

Contact: Starr Performance +61 3 9894 8860 www.starrperformance.com.au