Walkinshaw WP507 review

It's said that the greatest artists know when to step back from their work and declare it finished. Whether it be music, or painting, or simply renovating the house, the temptation is always there to keep fiddling and refining to the point where you're actually going backwards.

It's a trick that Melbourne-based tuner Walkinshaw Performance, by and large, have down pat. Whereas some aftermarket outfits subscribe to the 'more is more' school of thought, and aren't satisfied until every single part of the vehicle has been tweaked and tuned, Walkinshaw more often than not knows how to build on a car's strength, improve its weaknesses and, crucially, know when it's unlikely to improve something.

It's an attitude that's especially important when the base vehicle in question is HSV's Gen-F GTS. Upon its release in mid-2013, it reset the benchmark in terms of how good an Aussie-built car could be in terms of power and chassis sophistication.

If there was a criticism to be levelled at the GTS, however, it's that it has never quite felt the full 430kW/740Nm; at least in terms of its similarly-powered German opposition, such as the Mercedes-Benz E63 AMG S and BMW M5. With 0-100km/h in the mid-fours and a mid-12 quarter mile, it's certainly no slouch, but it's never felt quite as quick as the Euros.

Walkinshaw has attempted to rectify that with its new WP507 package, yours for $7990 supplied, fitted and tuned. Tweaks are relatively minor, amounting to a revised supercharger pulley to increase boost to 12psi from the stock nine, ceramic-coated headers, a cat-back exhaust and, of course, the obligatory ECU tune to make sure it runs as well as standard. The result is 507kW at 6200rpm and a stonking 850Nm at 4400rpm.

It feels it, too. Whereas the standard GTS is undoubtedly impressive, the WP507 is on another level. On a narrow country road, particularly if there are a few corners in the way, it feels insanely, rabidly fast, to the point that often 75 per cent throttle is more than enough.

At full noise, large numbers appear on the head-up display very quickly indeed. And full noise is an apt description, as the tuned LSX makes a lumpy racket not unlike a hard-tuned old-school small black V8.

At the strip, the WP507 reels off 0-100km/h in 4.38sec and a 12.39sec quarter mile at 189.99km/h. On a stickier surface and a cooler day (temperatures during testing were low-mid 30s) it would easily knock a couple of tenths off both times. That's not to suggest it's a handful, though. Its ability to use the extra power is a large part of why it feels so rapid; very few kilowatts are wasted in wheelspin.

It's testament to the quality of the base package that it can shrug off a 77kW/110Nm increase with no sweat. The huge AP Racing brakes cope with ease and at no point does it feel wild or unruly. What is odd, though, is that Walkinshaw swear it left the suspension alone, yet the WP507 jiggled and fidgeted over small bumps far more readily than the last GTS we drove.

Likewise, the transmission is supposedly untouched, yet no GTS ever shifted this aggressively. However, while this gives it an appealing hot-rod vibe, it would be no lesser a vehicle with the standard transmission mapping.

There's very little not to like about the WP507. The modification cost is relatively minor, it's backed by Walkinshaw's drivetrain warranty for peace of mind, and it gives the HSV GTS the power it's always felt like it's deserved. We reckon it's a fine piece of work.

Four stars

Specs
Engine: 6162cc V8, OHV, 16v, supercharger
Power: 507kW @ 6200rpm
Torque: 850Nm @ 4400rpm
Gearbox: 6-speed manual or automatic
0-100km/h: 4.38sec (tested)
0-400m: 12.39sec @ 189.99km/h (tested)
Price: $103,480 (based on automatic GTS)

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