Downsizing and reducing cylinder count, accompanied by turbocharging for improved efficiency is how most car manufacturers are meeting increasingly stringent emissions and economy regulations.
However, in replacing their naturally aspirated 4.2 litre V8 with an all-new bi-turbo V6 Audi threw their traditional RS4 and RS5 customers a bit of a curved ball. While it is agreed that the silk ripping aural signature of the new 2.9 TFSI V6 cannot match the NASCAR grade theatre of the higher revving, naturally aspirated bent crank V8 that went before, there is an instantly recognisable and appreciated upside - the new (EA 839) twin-turbo engine has the same number of horses, but significantly more twist on tap.
And since it weighs 182kg without ancillaries, the reduction of 31kg over the naturally aspirated V8 in the nose benefits handling and reduces destabilising weight transfer under hard braking.
On paper, the 450hp from 5,700 to 6,700rpm and 600Nm from 1,900 to 5,000rpm of the bi-turbo V6 plays 450hp at 8,250rpm and 430Nm of torque between 4,000 and 6,000rpm of the old V8. In practice this extra 179Nm at lower revs underpins the superior tractability and low and mid-range grunt of the new turbocharged V6.
For aftermarket tuners like MTM these output numbers are just the starting point. With the scope for tuning a forced aspirated motor being so much greater in terms of potential gains and bang for your buck, it is a no brainer that the chips should fall on the side of the bi-turbo V6.
“Using our M-Cantronic add-on ECU we achieved an easy and reliable 532hp,” says MTM boss Roland Mayer. “A bespoke ECU upgrade adds a further 20hp, taking the stable to 552 horses, and still within the performance envelope of the factory turbochargers.”
However, the stock turbochargers fall short of the airflow volume required by the Stage 2 conversion that MTM is working on now, so the engineers are experimenting with pair of larger turbochargers between the engine’s Vee. This will be augmented by a 100% more efficient water-cooled intercooler system that MTM calls its Thermodynamic Package.