Take one standard SS Commodore. Add a dose of Harrop…

It’s 1am in the morning and it’s been a fruitful night fishing. Having distributed the haul I now have to drop off a couple of fishing buddies back home. As we are travelling down the motorway we notice that the west-bound lanes have been totally blocked off for, you guessed it, ‘road works’. Now this would normally send me into a tail spin, as I am not the most patient of people at the best of times, particularly when all I want to do is get some shut-eye. However in this case I was remarkably calm, and it may have had something to do with the fact that I had just taken delivery of a Holden Commodore SS – and not any old SS but a Harrop Enhanced SS, complete with a supercharger, upgraded brake package and an upgraded differential. Having to take the alternative (longer) route home suddenly wasn’t such a chore, and a 10-minute journey down the road turned into a 30-minute trip back, but hey, who’s counting.

Having been for a ride in Harrop Industries general manager Ken Nunn’s car in Melbourne, I had an appreciation of what it would be like driving a Harrop supercharged V8, but you wonder what it would be like owning one. Or in this case living with one for a couple of weeks. The short answer is, it’s a lot of fun. This car is just like any other SS on the road, and other than a discreet Harrop badge on the rear and red Harrop callipers tucked behind the alloys, you would not pick it from the crowd. In fact it doesn’t even have a big-bore exhaust. This is the type of performance car that can quite happily trundle down to the supermarket and can be used as a daily runner around town.

S is for Supercharger

The only time there is a hint of what lies beneath is when you depress the accelerator ever so slightly, and you notice that you are accelerating slightly faster than you thought you would, as the supercharger is quietly doing its job from the word go. Push the throttle a bit further and you start to hear the whine of air being forced down the scroll. Floor it and all hell breaks loose as Clark Kent turns into Superman in an instant.

S is for Stunning

The supercharger turns a fast car into an impressively fast car. Whereas the standard 5.7-litre Gen III struggles a bit down low, this car has power constantly on tap. It is quite happy to pull at low revs and so it’s not as critical to be in the right gear. The torque allows you to use sixth gear more comfortably on the open road, even for overtaking. More often than not, with a six-speed LS1 you find yourself having to drop down from sixth to fifth for hills or slower traffic, but not in this car. If you need to overtake quickly it is just fantastic. Chop down to third and floor it, and you feel the instant torque pull you past the obstacle in front and you are back in the safe zone in no time, especially good for avoiding stone chips from fully laden trucks leaving a trail in their path. You do have to be judicious with the accelerator when engaging the clutch as the accelerator is quite sensitive, and to be honest, it did take an hour or so to get used to the electronic throttle/ supercharger combo.

S is for Short Shift

Harrop has also fitted its short shifter upgrade kit, which is designed to reduce the dreaded ‘missed gear’ problems associated with the Tremec T56 Holden six-speeder. The throw for both forward and rear from neutral has been reduced by approximately 30 per cent, making the gear shift feel more positive but without reducing the height of the standard gear lever. Combined with the extra torque, gear changes become effortless and happen more rapidly.

Having spent a week driving around town, the fuel computer was displaying 15.1 litres per 100km which, considering the type of conditions, was a reasonably good figure. You find yourself using the supercharger all the time, whether it’s to merge comfortably with traffic or to get out of a hazardous situation, and it’s nice to know the extra torque is there when you need it. On a day trip out of town this figure dropped to 12.1 litres per 100km and was showing a total distance to fill up of 700km, which is exactly what you would expect from a standard SS.

This article is from NZV8 issue 11. Click here to check it out.

Torque Performance was given the task to install the Harrop additions. The supercharger is the Harrop LS112, which typically provides a boost between six and 9psi. In this case the Torque Performance crew has set the boost at a mellow 7.5psi. In terms of reliability, Harrop state that the life expectancy of the unit will exceed the life of the LS engine, provided the unit is regularly checked as per the servicing requirements. A non intercooled unit weighs 25kg and the intercooled unit is 28kg, fitting neatly under the bonnet with no modifications required. To cope with the increased power a Harrop Enduro diff cover has been fitted. This is a direct bolt-on replacement for the standard rear cover which utilises the standard speed sensors and rear mount, which substantially increases the oil capacity and results in improved cooling and durability.

S is for stopping

If you have the ability to go fast you also need to stop quickly, which is accomplished by the fitting of Harrop performance brakes featuring 343mm-diameter vented single-piece disc rotors front and rear, with eight slots per rotor face for greater braking efficiency. These come with four-piston Harrop callipers and high performance brake pads at each corner. There is no comparison to the standard brakes for an SS Holden, these are true performance brakes which have you sliding out of your seat.

The dyno figures show an impressive 282kW at 6000rpm at the rear wheels and an equally impressive 890Nm of torque at the wheels. The improved torque is noticeable straight away, and by 2000rpm the dyno shows the gap stays steady all the way through to 6000rpm. The reality is that regardless of how much power there is at the top end, the instant power down low does all the talking. You don’t need to be doing break-neck speeds to enjoy and use the available grunt, and whether you’re towing a heavy weight, driving in traffic, avoiding road works or on the open road you will be having fun the whole time.

Apart from the Harrop additions fitted, this SS is standard. We will keep an eye on the progress of any further improvements made in future issues as the team at Harrop throw some more of their product at the SS. Of course we’ll just have to take it off them again to test… What a shame.

2005 Holden Commodore VZ SS – Specifications

Engine: 5665cc Gen III OHV Aluminium alloy block and cylinder heads Electronic Throttle Control
Compression ratio 10.1:1
Transmission: Tremac six-speed manual
Final drive ratio: 3.73:1
Suspension: FE2 sports suspension
Wheels & tyres: 18×8-inch five spoke alloys Potenza RE 040 235/40 ZR18
Harrop Enhancements: Supercharger LS112 Throttle Body 92mm, Intercooler, Harrop Enduro diff cover, Harrop brakes four-piston with performance pads, Short Shifter upgrade kit

Words: Keith Craig Photos: Quinn Hamill

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