Audi's Renn Sport Special : Audi RS 5 [review]

Car Specifications
Engine: 
4163cc, Normal Aspiration
Cylinder Layout: 
V8, 32 valves, DOHC, Variable cam timing
Top Speed: 
250 km/h limited) 280 km/h (optional extra)
Transmission: 
7 gear S-Tronic (double clutch)
0-100km/h: 
4.6 seconds
Power: 
450 bhp at 8250 rpm
Torque: 
430 Nm at 4000 to 6000 rpm

Motor Prime drives the RS 5 around the Ascari Race Circuit

Kudos to Audi because they have stayed with a normal aspirated high revving V8 whereas BMW has decided on the turbocharging route for their M-cars. While its true that turbocharging is the efficient way to go for lower consumption with higher power but Audi has managed that with the new RS 5 lowering consumption by nearly 20 per cent yet offering 450 bhp which is 30 bhp more than the RS 4.

The engine is a tweaked version of the wonderful V8 that is also found in the excellent R8 coupe and RS 4. For now the R8 will not get the new engine tweaks that give it 30 bhp more making this RS 5 something pretty special.

Audi claims despite the hike in power it is actually more fuel efficient delivering 252 gm/km and 10.8 L/100 km in the combined mode. Compare that to the 329 gm/km and 13.7 L/100 km of the lighter and less powerful RS 4. Oddly enough compression ratio has been lowered a tad from 12.5 to 12.3 to 1 so how did they get the power lift?

Careful examination revealed Audi has resorted to the time-honoured way of making power by revving higher so instead of peaking at 7800 rpm power peaks at the former rev limit of 8250 rpm thanks to an extended torque curve which extends 430 Nm up to 6000 rpm some 500 rpm higher.

Consequently the RS5 does not really feel brawnier through the rev range but it just keeps spinning eagerly to the 8500 rpm limit. The 7-speed S-Tronic (or DSG in Audi-speak) equipped RS 5 gets to 100 km/h a tick earlier at 4.6 seconds vs 4.8 seconds for the 6-speed manual RS 4. The reason for this is the increase in kerb weight.

  See the Launch Control feature engaged HERE  

The RS 5 tips the scales at 1725-kg which is 75-kg more than the 1650-kg RS 4. Where the RS 5 gains an advantage is the 0-200 km/h where it widens the lead 15.5 vs 16.6 seconds. In mitigation the RS 5 contains a fair bit more equipment like the Active Rear differential, beefier brakes, wheels and tyres. Besides the RS 5 sits on a wheelbase of 2751mm which is considerably longer and thus bigger than the RS 4.

Of course we would have liked to have seen significant weight reduction but the RS 5 is obviously more of an extreme GT rather than a hardcore sports car much like the current cohort of similar cars like the BMW M3, Mercedes-Benz C 63 AMG and Lexus IS-F. This leaves room for a specialized hardcore version should the Audi boffins see the niche potential.

Like all high powered Audis, the RS 5 utilises all wheel drive quattro. In this case the all wheel drive system has two active differentials, a clever center diff that has a nominal f:r 40:60 torque split but can shuffle up to 70 per cent of torque to the front or 85 per cent to the rear depending on the driver's needs.

It is the optional Sport Rear Differential that provides the most entertainment in the RS 5. It can channel 100 per cent to either of the rear wheels. Audi test drivers claim it is worth a few seconds a lap as it reduces power-on understeer in a AWD car.

By vectoring torque to the outside rear wheel it steers the car more toward neutrality and indeed in Dynamic mode the ESP will allow some tail out fun. One can feel this when powering out early in corners as the RS 5 seems to point into the apex a bit more with power.

And being all wheel drive, it could be hurled into the slower corners with near abandon, assured that full power application does not provoke a wayward tail and now with the Active rear differential with less understeer as well. In the front axle there is no active differential but by using the ESP and ABS, a light braking on the inner wheel produces the same vectoring effect.

For the first time the optional Ceramic brakes were combined with steel rears and this proved to be quite a good combo countering known disadvantages of one with advantages of the other. The progressive low speed characteristics of the steel items reduced the grabby response of the CCB ones in front and the vast temperature resistance of the front CCB discs would prevent the fade of the rear steel items.

Moreover the CCB items in the front only weigh a remarkable 4-kg despite their large 380mm diameter. The standard 365mm steel items feature an advanced floating rotor design, pinned to an aluminum hub.

The AWD proved a boon on the fast open roads surrounding the track as it ensured safe dissemination of that prodigious power to the oftentimes slippery road surfaces of the serpentine mountain roads. We found that by customizing the car's set up via the MMI controls, we could enjoy the RS 5 a little better.

See our Winding Impressions HERE

In Comfort mode, the active rear differential is deactivated, the engine and gear-shift map is distinctly pedestrian, aiming for high levels of comfort and smoothness in town driving. If you have the optional Dynamic Ride Control (DRC) with variable damping, the suspension is rather supple in the Comfort map. The steering is light but remains direct. Comfort is however a mode you rather not select for fast driving.

At the other extreme is the Dynamic mode which sharpens engine response, and provides aggressive gear-shift mapping also stiffens the suspension damping to the point it is nearly but not unbearably firm. It does offer supreme body control which is appreciated on the fast open road. (only with optional DRC or active suspension)

However the power assistance of the steering is reduced to the point the steering is pretty heavy. While it does feel he-man meaty and satisfying in an old school way it has a certain disconnect between sharpness and response of the chassis.

Fortunately you can set it up via the MMI and by leaving everything else on Dynamic and putting the steering on auto proved to be the right compromise and it feels proportional and modern. The active steering system alters the assistance and steering ratios to suit the particular driving mode selected.

At low speeds the system favours low effort and high maneuverability and at high speeds it increases effort and reduces steering sensitivity to reduce high speed nervousness. It even adds a touch of countersteer at the limit to maintain a broad region of neutrality. The auto setting offers the ideal compromise between the two extremes.

The suspension system compromises of uprated dampers and springs which sit the RS 5 20mm lower than the standard A5. The front and rear sway bars are thicker and with the DRC that links the dampers in a diagonal fashion together acts like an active anti-roll system. Also to get the added sharpness in response the bushings have been substituted with stiffer ones.

With the current set up the RS 5 can satisfy some of the hardcore owners as it acquits itself around the Ascari Race Circuit near Marbella, Spain. While it is not really a hardcore machine like a GT3 RS it does not embarrass itself around the track putting down power earlier and more effectively allowing the RS 5 to leap out of corners as all four contact patches are put to full use. The high revving nature of the engine where the power is available at the last two thousand revs suits the race track where one is always shifting at the rev limit to get maximum performance.

Here Dynamic mode makes a hero out of ordinary drivers allowing mere mortals to reach and stay at the edge of the performance envelop with relative ease. Thing is being so deceptively simple should not a reason not to attend advanced driving courses of which Audi has many to offer.

On the open road is probably where the RS 5  is in its element, bearing down on vast ribbons of tarmac with consummate ease. Perhaps the best bit about the RS 5 is its prodigous overtaking power. Shift down two or three gears and hit the throttle, the RS 5 leaps forward and sustains the acceleration with a massive swath of power accompanied by the most delightful and sonorous engine note, burbling excitingly with every gear change. We kept swapping gears just to hear this effect, its just so intoxicating and habit forming.

The difference between the sport exhaust and standard one is just in the intensity of the exhaust note and while it is noticeably louder it is still too polite for the hardcore among you. It does not raise the power output and is there to circumvent the new stricter EU noise pollution laws. Also optional is the possibility to raise the limited top speed to 280 km/h should 250 km/h be too slow for you.

There is no indication Audi will offer the RS treatment to the A4, A4 Avant and A5 Sportback range though there is the potential thanks to the common design. There is not doubt the RS 5 is pitched squarely at the BMW's 420 bhp M3 coupe both in concept and performance.

Pros:

  • Superb 450 bhp V8 that spins to 8500 rpm
  • Excellent 7-Speed S-Tronic gearbox
  • Excellent suspension set up even with standard non DRC system
  • Great Sports seats
  • Surprisingly effective CCB-Steel brake combo
  • Very refined overall
  • Effortless performance
  • More kit than M3
  •  

Cons:

  • At 1725-kg it has put on a fair bit of weight
  • Leaning toward refinement rather than hardcore
  • Wide appeal means not as focused
  • More expensive than M3

Fast Facts : Audi RS 5
ENGINE
CAPACITY : 4163cc
CYLINDER LAYOUT : V8 Normal Aspiration
VALVES : 32 valves, Variable valve timing, DOHC
BORE X STROKE : 84.5 x 92.8mm
COMPRESSION RATIO : 12.3:1
MAXIMUM POWER : 450 bhp at 8250 rpm
MAXIMUM TORQUE : 430 Nm at 4000-6000 rpm

TRANSMISSION
TYPE : 7-Speed S-Tronic
DRIVEN WHEELS : AWD

PERFORMANCE
TOP SPEED : 250 km/h (limited, option for 280 km/h)
0-100KM/H : 4.6 seconds

SUSPENSION
FRONT : 5-link wishbone type suspension
REAR : Trapezoidal-link rear suspension

BRAKES
FRONT : 365mm Floating rotor (380mm CCB option)
REAR : 324mm Floating rotor

TYRES
TYPE : Pirelli P-Zero
SIZE : 265/35 R 19 (std) 275/30 R 20 (option)

SAFETY
AIRBAGS : 8
TRACTION CONTROL : ESP

MEASUREMENTS
LENGTH : 4649mm
WIDTH : 1860mm
HEIGHT : 1366mm
WHEELBASE : 2751mm
KERB WEIGHT : 1725-kg
TURNING CIRCLE : 11.6m

PRICE in 2010 :$tba

Summary
Obviously the great debate between RWD and AWD rages on and this will no doubt perpetuate the debate. Over unknown roads it is always better to be in the more surefooted AWD machine and is where the RS5 excels. The last RS4 had already drawn blood and now the latest RS5 with its advanced active AWD and sport differential might be just enough to give this round to AWD. - mp at the Ascari Race Circuit, Marbella, Spain
Photos: 
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