GMC Syclone vs Typhoon: cooking up a storm

Mesmerising though these figures were, on the face of it there was no sound reason to produce what was then termed ‘the world’s fastest truck’, along with its later SUV-bodied sibling, the Typhoon.

But in the late 1980s, General Motors’ GMC (General Motors Company) brand was at the premium end of America’s truck market, at a time when the sector had just started to transition towards more leisure-orientated vehicles.

The Syclone’s supercar-slaying acceleration made it a genuine pioneer, not only pre-dating other performance flatbeds, such as Ford’s F-150 Lightning and Dodge’s mighty Ram SRT-10, but also, arguably, the wider performance SUV market as we know it today.

The GMC Syclone’s usefulness as a load-carrier is limited by its mere 500lb payload

Yet it was Buick, not GMC, that first inspired the Syclone.

After retiring its Grand National performance model in 1987, the brand dropped one of its outgoing turbocharged 3.8-litre V6s into a Chevrolet S-10 pick-up.

Hunkered down on lowered suspension and wearing wide, very un-truck-like alloys, it was touted to GM management and to Chevrolet as a range-topping ‘halo’ truck.

Fabric-trimmed bucket seats give the Syclone’s interior a purposeful look

The concept was initially rejected, but when GMC got wind of the project it immediately saw the potential, although not with the Grand National engine.

Instead, GMC chose to retain the existing 4.3-litre Vortec V6 in its S-15 – the marque’s S-10 sibling – and uprate the unit to liberate even more giant-killing performance.

All the same, when GM first presented the Syclone (Mercury owned the ‘Cyclone’ name, hence the spelling), along with a four-door GMC Jimmy-based vehicle called the Kalahari, under the ‘concept trucks’ banner at 1989’s Detroit show, the company had ‘no firm production plans’ for either, according to Autoweek.

The Syclone’s Mitsubishi-sourced turbocharger delivers up to 14psi of boost

At the time, the Syclone still used Buick’s blown 3.8 lump, whereas the Kalahari – later to become the Typhoon – had GM’s 4.3 V6.

But by the time the pair reappeared at the New York International Automobile Show seven months later, the company line had changed to ‘not scheduled for production yet’ (Design News), hinting that both would become a reality.

And that was reinforced when GMC took a modified S-15 to Bonneville and broke the Category E production speed record, with a 194.77mph flying mile.

Suddenly, GMC had Ferrari and Porsche in its sights.

Sitting low on a set of 16in alloy rims, the Syclone certainly looks the part

You couldn’t fault its commitment to the performance cause.

The problem was that developing such a niche offering in-house would have cost GM dear: $200million was mooted, along with a seven-year gestation before the Syclone reached showrooms.

Fortunately, GMC product marketing man Kim Nielsen, who had driven the project from the start, had a trick up his sleeve.

By outsourcing the engineering and manufacturing of everything that transformed a cooking S-15 into a Syclone, costs were brought down massively and the programme became viable.

‘The Syclone’s soundtrack is loud and proud’

Two companies – ASC McLaren and Production Automotive Services (PAS) – pitched for the work, but while ASC retained the stock S-15’s rear-drive transmission, PAS integrated the Chevrolet Astro Van’s four-wheel-drive system, complete with viscous centre differential.

Given that both companies were proposing 280bhp and 350lb ft outputs, and the Syclone’s rear axle was carrying a mere 37% of the overall weight, rear-drive would only have achieved the biggest smokescreen ever.

PAS won the contract, and at a sniff over $14million.

The original Vortec unit’s outputs were increased by 115bhp and 115lb ft for the Syclone

The firm, based in nearby Troy, Michigan, and collaborating with Nielsen, worked flat-out for the next 18 months to make sure the Syclone fulfilled the concept’s remit.

To increase the Vortec engine’s outputs by 115bhp and 115lb ft, PAS added a Mitsubishi TD06-17C turbocharger running up to 14psi of boost, allied to a Garrett water-to-air intercooler.

Lower-compression pistons were fitted, along with bespoke intake and exhaust manifolds.

Larger throttle bodies were sourced from the Corvette parts bin, and a multi-point fuel-injection system was installed.

Both models share the 280bhp V6 powertrain and feature all-wheel drive

The Astro Van’s Borg-Warner transfer case delivered 65% of drive to the LSD-equipped rear axle and 35% to the front, so the potent turbocharged V6 could deploy all of its grunt without smoking most of it away.

Underneath, the Syclone’s body-on-frame chassis was still suspended in traditional pick-up fashion: an independent front end with torsion bars, and a live rear axle with semi-elliptic leaf springs, but sitting lower than the standard S-15.

Anti-lock braking (the Syclone was the first of its kind to carry the technology) was the only nod to chassis sophistication.

But who cared about that on the drag strip?

The GMC Typhoon arrived in 1992

What buyers did care about was appearance.

While to these eyes the Syclone remains conservatively embellished for an American performance truck, the end result still smacks of muted aggression.

The Syclone sits low on its six-spoke, 16in alloy rims shod with 245/50 Firestone Firehawks, with unique, PAS-designed body cladding that blended with a front spoiler inset with foglights and a black grille with ‘GMC’ picked out in red, matching the red ‘Syclone’ graphics on each door and the tailgate.

The badging is more understated on the Typhoon

Inside, the gauge pack was plucked from Pontiac’s Sunbird Turbo, with its integrated turbo-boost dial, and new fabric-trimmed bucket seats were fitted.

PAS even sneaked in a Corvette gearshifter.

Marcus Hawker has owned the smart black Syclone you see here (all were originally painted black) for 12 years.

Now showing just over 40,000 miles, the ex-Florida vehicle is thought to be one of only 10 in the UK.

‘Coming on and off the throttle, the diesel-like torque is addictive, along with the “che-chow” from the turbo’s wastegate’

Apart from a few upgrades, including a larger turbo and injectors, methanol injection and uprated suspension with polyurethane bushes, Marcus’ Syclone is very much as it left the factory.

It’s remarkably compact, even by European SUV standards, and whether or not you’re a pick-up fan, the proportions are undeniably well balanced.

Inside, you’re perched quite high before a large, leather-rimmed two-spoke wheel on an adjustable column.

A boxy instrument binnacle faces you, displaying dials for fuel, oil and water, plus a 120mph speedo (despite its 124mph top speed) and tachometer with a yellow/redline starting at 4800rpm – although the ignition cuts at 4700rpm.

The Typhoon gets plush leather seats

Fire up, and the Syclone’s soundtrack is loud and proud, with a more crisp tone than that of a V8.

Select Drive in the four-speed auto, mash the long-travel throttle and what you’re expecting – even childishly aiming for – is good ol’ wheelspin tamed by a dab of oppo’, just like in the movies.

But that doesn’t happen.

The Syclone’s rear end dips, but not one pound-foot of torque is wasted in slip; it just grips and you’re jettisoned up the road, accompanied by the V6’s strident bark, mixed with an even louder turbo whistle as you keep the throttle nailed.

There’s comfortable seating for two in the Typhoon’s rear

It’s laughably quick to around 60 or 70mph, and slightly unhinged – more like the creation of a competent aftermarket tuner rather than a vehicle from a global automotive powerhouse.

Coming on and off the throttle, the Syclone’s diesel-like torque is addictive, along with the corresponding ‘che-chow’ from the turbo’s wastegate.

But it’s no sports car. Even on quite smooth surfaces, every camber change is registered through the steering, which itself is quite low-geared, vague off-centre and devoid of much feel.

This is not helped by the typically detached body control inherent with most separate-chassis vehicles.

Heater controls sit behind the Typhoon’s four-spoke steering wheel

There’s grip aplenty, though, and even over Bristol’s gnarled and broken street surfaces the Syclone rides acceptably well.

But chassis dynamics were never going to define the Syclone – at least not in the USA.

As a pure marketing tool it was solid gold for GMC; the Porsche and Ferrari comparisons alone were headline-grabbers.

And in 1991, its only build year, 2995 Syclones were sold, despite a meagre 500lb payload meaning it was hardly functional as a working pick-up and low ground-clearance preventing any form of off-roading.

GMC unexpectedly took the fight to Porsche and Ferrari

But GMC evidently wished to amortise its investment costs with PAS still further, so in 1992 the company turned its second ‘concept truck’ into a production reality.

The Typhoon, based on the aforementioned GMC Jimmy/Chevrolet Blazer, was essentially a Syclone from the B-pillars forward and used the same PAS-developed powertrain.

But while a Syclone was something of a one-trick pony, the Typhoon was a fully fledged carrier of four people, with sumptuous leather trim and a full exterior colour range, while sacrificing very little in outright performance (0-60mph was up by just 0.7 secs to 5.3).

The 223lb-lighter Syclone (left) is faster to 60mph by 0.7 secs

Weighing in at 3822lb – 223lb more than the Syclone – the Typhoon introduced an 8in-shorter, 100.5in wheelbase, making it more manoeuvrable around town and, in theory, a more alert handler.

It also gained an electronic load-levelling system, meaning a 900lb payload – ironically 400lb up on that of the pick-up-bodied Syclone.

The white example keeping the Syclone company today is also owned by Marcus.

Exported to Japan early in its life (only 84 Typhoons were exported from new, all of which were destined for Saudi Arabia), it still wears non-standard turn signals on its wings and a black scuttle panel that should be body-coloured.

A shorter wheelbase makes the Typhoon more manoeuvrable around town

Inside, other than some minor control redesigns, a four-spoke steering wheel and internally adjustable door mirrors, the Typhoon’s front cabin is much the same as that of the Syclone.

But occupants over six-feet tall would have had the luxury of a few more inches of seat travel instead of hitting a bulkhead.

Being a two-door body, entry to the rear is a little compromised and, thanks to the leather-trimmed storage bins at either end of the bench, there’s only room for two passengers.

But that added usability clearly boosted the go-faster GMC’s appeal, with 4697 sold during its 1992-’93 production years, an increase of more than 50% over the Syclone.

‘The concept was initially rejected, but when GMC got wind of the project it immediately saw potential’

Drive the Typhoon straight after its pick-up sibling and you feel the extra bulk playing its part.

It’s still hot-rod quick, but lacks the outright lairiness of the Syclone.

There’s less aural drama, too, perhaps thanks to its generously insulated rear cabin.

But one characteristic instantly stands out versus driving the Syclone, and it tells a far bigger story about GMC outsourcing both vehicles’ development.

The Typhoon better fulfils its aesthetic brief

At almost any speed in Marcus’ Typhoon, engine vibration fizzes through all control surfaces, as if a vital filter is missing. Which it is.

When the rubber engine mounts disintegrated, rather than replace them – which is an engine-out task – Marcus opted to do without them completely, leaving the engine solid-mounted to the chassis.

As he explains, the lightning-quick PAS turnaround of the Syclone/Typhoon programme left little time for thorough development, which would have exposed the effects of significantly increased heat-soak – as well as additional torque stress – from the turbo’s installation in the engine bay, in turn causing accelerated wear of the rubber mounts.

In other words, replacing the bushes would become an ongoing major task, and one that you can’t blame him for wanting to avoid.

Wheelspin is notable by its absence in the Syclone, despite the potent performance, and it rides well over broken surfaces

It would be easy to part company with these hooligan trucks having had your view tainted by some flawed chassis dynamics and a lack of development that would contribute to issues further down the line.

But they should be celebrated, partly because their existence showed that get-the-job-done pragmatism was alive and well, even in a global conglomerate, and more importantly, they demonstrated that GM suits were still brave enough to enliven one of their brands with such a radical – yet not hugely profitable – model.

Images: Luc Lacey

Thanks to: Marcus Hawker and Mark Edwards

Factfiles

GMC Syclone

• Sold/number built 1991/2995
• Construction steel body, separate steel chassis
• Engine all-iron, ohv 4300cc V6, with turbocharger, intercooler and multi-point fuel injection
• Max power 280bhp @ 4200rpm
• Max torque 350lb ft @ 3600rpm
• Transmission four-speed automatic, 4WD
• Suspension: front independent, by wishbones, torsion bars, anti-roll bar rear live axle, semi-elliptic leaf springs; telescopic dampers f/r
• Steering power-assisted recirculating ball
• Brakes discs front, drums rear
• Length 15ft ½in (4585mm)
• Width 5ft 4¾in (1646mm)
• Height 5ft 1¼in (1557mm)
• Wheelbase 9ft ¼in (2751mm)
• Weight 3599lb (1632kg)
• 0-60mph 4.6 secs
• Top speed 124mph
• Mpg 14
• Price new $25,970
• Price now £15-25,000*

GMC Typhoon

• Sold/number built 1992-‘93/4697
• Construction steel body, separate steel chassis
• Engine all-iron, ohv 4300cc V6, with turbocharger, intercooler and multi-point fuel injection
• Max power 280bhp @ 4200rpm
• Max torque 350lb ft @ 3600rpm
• Transmission four-speed automatic, 4WD
• Suspension: front independent, by wishbones, torsion bars, anti-roll bar rear live axle, semi-elliptic leaf springs; telescopic dampers f/r
• Steering power-assisted recirculating ball
• Brakes discs front, drums rear
• Length 14ft 2¼in (4674mm)
• Width 5ft 4¾in (1646mm)
• Height 5ft (1524mm)
• Wheelbase 8ft 4½in (2552mm)
• Weight 3822lb (1734kg)
• 0-60mph 5.3 secs
• Top speed 126mph
• Mpg 14
• Price new $29,530
• Price now £12-18,000*
   

_{*Prices correct at date of original publication}

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