Forza Magazine 458 Technical Write Up

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01-29-2010, 10:10 AM

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Forza Magazine 458 Technical Write Up

Super-8
Zooming in on the tech behind Ferrari's hottest V8-powered car since the F40.
Story by Frank Markus

Powertrain:
The heart of any Ferrari is its red-headed engine, and the 458’s, clearly visible beneath a glass cover, is designated F136-FB. It’s an evolution of the F430’s basic architecture, with the same deck height and 104mm bore centers, although the block and most of what’s bolted into and onto it are new. Ferrari’s newest V8 grows just 4 percent in displacement, to 4,499cc (the 458 nomenclature is a return to the good old days of mashing up the deciliter engine displacement with the cylinder count), yet cranks out an impressive 11 percent more power and 15 percent more torque than the race-ready 430 Scuderia.

This translates into 565 hp at 9,000 rpm and 398 lb-ft at 6,000 rpm. Nearly 80 percent of the latter is available from just 3,250 rpm, while the pony count climbs by 5 at 200 mph thanks to positive ram pressure generated as air crams into the inlets just aft of each rear window.

The aforementioned direct injection serves as the foundation for this output boost, cooling the intake charge sufficiently to allow a compression ratio jump from 11.9:1 to 12.5:1. Ferrari uses two separate injections at full throttle below 3,000 rpm, the second of which, comprising 20-30 percent of the total, occurs late enough to create a rich mix near the spark plug; this helps boost torque by up to 6 percent.

The 458’s intake manifold incorporates three butterfly valves that connect the left and right bank plenums. These can be opened or closed in four different combinations to alter the manifold’s resonant frequency; while no air travels through these valves, opening them changes the way the sonic shock waves formed by the closing intake valves are reflected back toward the valves, providing three different “sweet spots” at which the reflected wave can help stuff additional air into the cylinder. This is called resonance supercharging, and it boosts torque by up to 30 lb-ft between 2,500 and 6,750 rpm.

The rest of the improvements take small bites out of the engine’s friction (via superfinished cam lobes, Graphal-coated pistons with thinner compression rings, and DLC-coated valve tappets), parasitic losses (a new variable-displacement oil pump conserves 6 hp at 9,000 rpm) and even minor inefficiencies like windage and oil-splash in the crankcase (which are reduced with a new dry-sump system that scavenges the two middle crank throws independently of the fore and aft throws, preventing 6 lb-ft of torque loss at 2,500 rpm). Altogether, these improvements contribute to a 13-percent drop in fuel consumption and a claimed best-in-class CO2 rating.
Spent gases are expelled through three tailpipes in the middle of the rear fascia (just like the F40). Why three? The center one services the twin mufflers during idle, cruising and light-throttle operation, while the outer two serve the bypass valves, which open under wide-open running to reduce backpressure from 7.3 to 5 psi. The exhaust system is lightened by removal of the pre-catalysts and the use of a thinner housing for the remaining cat.

The sole transmission choice is a paddle-shifted seven-speed dual-clutch Getrag transaxle. It is similar to the unit found in the California, but enhanced by a more compact, faster-acting E-Diff3 electronic differential and all-new gearing tailored to the 458’s 9,000-rpm rev-limit. Top speed is achieved in seventh gear.

Will the faithful lament the lack of a three-pedal option? Maybe, but the simple truth is that a stick shift would slow the car down too much, and Ferrari is in the business of going fast. Between launch control, E-Diff3 and instantaneous shifts with no torque interruption, the 458 is said to hit 60 mph from a standstill in less than 3.4 seconds.

Chassis and Suspension:
As you’d expect, the 458’s chassis has also been improved over the F430’s. Dimensionally, the wheelbase stretches 1.9 inches for greater stability, while shrunken overhangs reduce the polar moment of inertia to help the car rotate more eagerly. New aluminum alloys and bonding techniques boost the larger body’s structural rigidity by 20 percent in torsion and 8 percent in bending without adding weight. The 458 tips the scales at 3,247 pounds, about 50 lbs. more than its predecessor.

Under-the-skin improvements include new lower control arms front and rear, and a rear multilink setup that improves both longitudinal compliance and lateral stiffness for quieter, more comfortable bump absorption and better cornering responsiveness. Magnetorheological shocks assess ride control every millisecond (down from 5 milliseconds in the 599 GTB Fiorano) and can adjust their damping rate in just 8 milliseconds. A 35-percent reduction in the dampers’ internal friction helps absorb small bumps in the road surface, while a “bumpy road” setting (first seen on the 430 Scuderia) softens the shocks to help keep the wheels in contact with uneven pavement when the steering wheel-mounted manettino is set to Sport mode or better. These lightning-quick dampers better control body roll and allow the use of smaller anti-roll bars, which helps improve general suspension compliance, and stiffer springs without exacting a ride penalty.

The standard carbon-ceramic brakes feature a “Prefill” system that pulls the pads away from the discs during acceleration and cruising for improved efficiency. When the driver lifts off the throttle, the system brings the pads back into contact so that there’s no dead brake-pedal travel or response lag. Stopping distances are said to drop by five feet from 62 mph and by 39 feet from 124 mph relative to the F430.

The F1-Trac stability-control system now has authority over the suspension settings, E-Diff3 and these ultra-powerful brakes, which allows correction without resorting to heavy-handed brake or throttle intervention. As a result, Ferrari claims corner-exit acceleration in Race mode is 32 percent better than before.

Aerodynamics:
Compared to the F430, the 458’s slinky, wind-tunnel-honed shape seduces the air into providing more downforce (up to 794 pounds at 200 mph) with less drag. Naturally, that downforce is split 41/59 percent front/rear, roughly matching the car’s static weight distribution so that dynamic balance doesn’t change at speed.

Among the 458’s coolest aero tricks are the SMC “aerolastic” wings in the front fascia inlets. These normally direct air up onto the radiators, but at 124 mph their outer edges begin deflecting downward by up to 0.8 inch to reduce drag. The little vents just inboard of the headlights connect to the ones just outboard, and direct slower-moving air into the stream heading over the fender humps, a traditionally high-lift area. This slow air flow reduces lift substantially.

In back, Ferrari’s patented base-bleed system (developed on the FXX) vents both high-pressure air from the rear wheelhouses and engine-compartment cooling air through the screens inboard of the taillights. This helps detach the vortices that otherwise try to suck the car backwards. Air flowing over the rear fenders and through the transmission and clutch oil coolers slows down enough to contribute notable rear downforce, working in conjuction with the rear diffuser.

Interior:
The 458’s interior gets its own share of techie upgrades, though these require a bit of orientation for the driver. Most noticeably, column stalks are out: Turn-signal, high-beam and wiper control happens via buttons on the multi-function steering wheel. The radio, Bluetooth phone and navigation system are controlled by a mouse-knob and a screen to the right of the tachometer; a virtual speedometer appears on this screen when the navigation is off. To the left of the tach is another screen that displays temperature gauges, lap times, the settings of the myriad electronic driving aids or the temperature status of the tires, brakes and engine.

All of this engineering work combines into one very fast car. Ferrari claims the 458 can lap the Fiorano test track in 1 minute 25 seconds, the same as the track-ready 430 Scuderia and the exotic Enzo. This raises a question: Has an edict been issued forbidding any vehicle to outrun the Enzo until its hyper-exotic replacement arrives? The factory reps shrugged off such conspiracy theories, pointing out that the Enzo’s incredible five pounds per horsepower was offset by comparatively crude vehicle-dynamic controls, tires, suspension and so on, while the Scuderia wore competition-spec Pirelli P Zero Corsa tires. For its part, the 458 leverages copious power and abundant electrickery to achieve the same results on more pedestrian Michelin Pilot Sport rubber.

History likely won’t associate the 458 with the 158 F1 or F40, but that doesn’t mean the new car isn’t every bit as thrilling to drive as either of its famous ancestors. We’ll give you a quick taste of the experience now, but our full test drive will have to wait for an upcoming issue.