Moments later we hear the calmer sound of a printer producing a graph, whose scales must start at 223hp and 401lb ft to enable the peak outputs to fit on a sheet of A4. This is impressive proof of Viezu’s work, although “making Ford Transits go slower” in order to reduce their running costs is the usual fare of this Warwickshire-based engine management specialist, says CEO Paul Busby. “It’s not the most glamorous work,” he adds, “but it’s more profitable.” But Busby and Viezu have a distant history of tuning Jaguars and have recently rekindled the activity to spectacular effect. The company also offers more rampant XKs and Land Rovers, too, all sharing the same JLR V8.
In the days of the E-Type, it would have taken an extensive dissection of an engine to achieve power gains on this scale, with special components required to extricate the extra power. This F-Type, subtly named Predator, shares only a freer exhaust with these 20th century techniques, and mostly only for aural reasons.
To unleash the V8’s inner beast, you must undam the hidden torrent of extra power not by plunging in with a socket set but by manipulating the algorithms that make up the engine’s electronic marching orders. Viezu technical director Simon White explains that “the engine is actually more powerful” than in the form in which it is sold.
“We look at the parameters within the ECU for power and torque and see where it is being held back,” he says. “We try to limit the changes to the ECU and change more of the maps for the supercharger. We’re trying to get several parameters to work together and not stress the engine.”
To maintain reliability, Viezu doesn’t touch the temperature control maps (“They’re there for a reason”), although the intercooler is upgraded. “There are thousands of maps,” says White, “but we change only 50-60. There’s no change below 60% of total power on part-throttle. We try to retain a manufacturer feel to the driveability. It’s on a wide-open throttle that we make the changes.”
If you can sense this Jaguar straining when it’s lashed to a dyno, that’s nothing to the strain you feel with a wide-open throttle on the road as the F-Type tenses to deal with 687lb ft deluging through its driveline. And there’s a thrilling strain for the driver, too, as you try to find places where you might momentarily apply full throttle. It may be four-wheel drive, but the torque seems to compress the Jag’s spasming body as its rear wheels seemingly attempt to sledgehammer past the fronts. The last time I felt this sensation was aboard a Lamborghini Aventador. The word ‘quick’ barely begins to describe the experience.
And certainly not the noise. The Predator’s semi-free-flow exhaust sounds like King Kong with a headache even in Normal mode, while in Dynamic it’s like a small war on wheels.
This F-Type has been modified in other ways, too, not least with a set of gold 20in alloys with a slightly different offset, an assortment of carbonfibre add-ons, a 20mm lower ride height and stiffer suspension bushes of the polybush variety. The ride is much firmer at low to medium speeds, but the difference starts to tell at higher speeds on B-roads, the ride turning choppy enough to give the bump-stops some work and the Jag frequently needing more of a steer to keep it line – which is not necessarily what you need in a car this blastingly fast.
On smoother roads, these issues melt away as briskly as the oncoming scenery. Like so many cars this uproariously rapid, the Predator is a device whose capabilities you will only gradually uncover.
As is its potential value for money. The wheels, the carbonfibre and the suspension modifications are not essential (we’d avoid the lowering and polybushing), which means that a 641bhp all-wheel-drive F-Type can be yours for £99,788, or a lot less if you add the £8108 to the price of a used V8 R. Which is probably the best option if you want a less expensive, more spectacular route to F-Type SVR-plus performance.