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Fly the Coupe

A sexy HSV GTO to eclipse the mighty 300kW GTS...

Words By Michael Knowling, Pix by Julian Edgar

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The HSV GTS Coupe would have to be the most desirable piece of Aussie muscle you could possibly buy. That's a view shared by Simon X of Melbourne, but - like many - he found the $100k-odd asking price a bit steep. Still, after owning a VT Series 2 Clubsport and then a soulless 325Ci BMW, Simon felt the pressing need to jump into some kind of Holden or HSV 2-door. You know how it is - you can't stick with any one car for too long...

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Despite doing the risky thing and taking the ultra seductive GTS Coupe for a test drive, Simon simply couldn't justify rustling up the necessary 100 large. The next best thing, however - the HSV GTO - provided much of the appeal for some 20 grand less. The most noticeable areas where it lacked compared to the GTS were rim size and power - 19-inch versus 18-inch and 300kW versus 255kW. Still, Simon figured some of that 20 grand saving could then be invested bringing the GTO up to - and then beyond - the performance and appeal of that too goddam expensive GTS...

Simon says the stock-standard GTO - bought with the 6-speed manual gearbox - is a pretty good handler with a great driving feel. Still - after having F1 Performance perform some mods on his ol' Clubsport - it wasn't long before he fronted there again with some cash in hand...

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The first round of modifications called for a pair of 4>1 Pacemaker extractors (which are now wrapped in thermal lag), high-flow cat converters and a 2 1/2-inch mandrel twin exhaust with a so-called X-pipe - all of which is designed by F1 Performance. On the intake side of the equation, the HSV cold air induction system was ditched and the airbox was F1 modified for more airflow, plus a drop-in K&N filter was inserted. Things then progressed to include a modified airflow meter (the mesh screens were ripped out), the throttle body was opened out to 78mm and a fat 4-inch pipe replaced the standard induction pipe adjoining the two.

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One of the biggest power limitations of the non-C4B LS1 is the standard camshaft; from all accounts, it really struggles to edge up to the 300kW barrier (not without forced induction anyway!). The F1 Performance team saw to the GTO's gasps for air by fitting a fairly aggressive in-house developed cam (delivering around 570 thou total lift and 224 degrees duration at 50 thou) teamed with Crane 1.8 ratio roller rockers and custom valve springs. The 2-valve-per-cylinder alloy heads were also attacked fairly extensively with the die grinder to ensure the new cam could perform to its fullest potential.

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Rather than having to move to an aftermarket management system, Simon's GTO retains the full logic of the factory ECU and body computer. Anyone that knows this system knows how brilliant it is - GM's countless hours of development aren't something you want to throw away on a whim. Fuelling and ignition timing tweaks using the LS1 Edit program was all that was required to optimise the performance of the new mechanical mods. The end result, Simon says, is so sweet you'd hardly pick it as modified - except for a little attitude from the bumpier camshaft. The trade-off is more than worth it given the 271 Dyno Dynamics certified rear-wheel kilowatts...

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Working our way back, the standard 6-speed 'box was improved with a short shifter and the final drive ratio was shortened to 3.9:1. This really makes the car feel lively in traffic as well as enabling use of the way-tall sixth gear at lower speeds.

Interestingly, F1 Performance has found the standard Holden and HSV power steering cooler is pretty marginal and, therefore, they've replaced the GTO's with a larger aftermarket item. Simon and a few other customers from F1 enjoy nothing more than a friendly racetrack battle from time to time, so there has also been substantial work on the suspension and braking department...

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Simon has made sure his GTO can also be flung through corners with great speed, opting for a full Quadrant/Bilstein suspension upgrade. This included custom valved dampers, lowered uprated springs plus a separate front strut brace. Bridgestone S-03s in a 235/40 18 size do the trick on the street, while semi-race Dunlop D-01Js provide tenacious grip on the circuit.

When the spokes of those sexy GTO 18s stop spinning, you can check out the tough looking Harrop 4-pot front calipers that bite onto 343mm 24-slot discs. Bendix Ultimate pads have been used for street duties and EBC Reds have been the go for track days, but - like another F1 customer - Simon plans to move to Pagids in the future.

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Despite the added weight that a killer sound system brings, Simon couldn't fight the desire to stuff the cabin with an assortment of top-line audio gear. Freeway Car Audio wired in an Eclipse 5-channel amplifier, a pair of 6 ½-inch Focal front splits, two Focal 5 ¼-inch 2-ways in the rear side trims and a pair of Rockford 6 ½-inch woofers in the parcel shelf. Finished off with some sound deadening in the doors, this is not a mega-bass thumper system but this is one of the clearest sounding systems you'll hear.

So what is next for Simon - will he ever get rid of his better-than-GTS Coupe? Well, maybe - one of those about-to-be-released Falcon GTs has some big appeal. U-oh, a vehicle from the dark side...


F1 Performance Equipment
+61 3 9894 4228

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