Parathetw ta ekshs:
'2.5-litre to 3-litre
Mazda RENESIS Rotary (RX-8)
“This extremely small engine gives the driver
a feeling that no other machine can match”
Lasse Swärd, Dagens Nyheter
It is surely all rotary engine inventor Felix Wankel could have wished for: Mazda now has four Awards’ trophies, this latest triumph adding to the three that the engine won last year, including taking the overall title of International Engine of the Year 2003.
Wankel’s work was certainly pioneering, the three faces of the rotor acting like pistons, circulating within the housing and producing a pumping action. The concept makes for a compact powerplant (it measures just 338mm deep), and Mazda has added trick refinement and performance-boosting features such as a side-intake, side-exhaust layout, with the exhaust ports moved to the sides of the rotor chamber. The configuration means the size of the ports can be freely set and an expanded air intake port area achieved.
The design makes Mazda’s unit a 1.3-litre at rest, but the RENESIS qualifies for this 2.5-litre to 3-litre category as when on the move, it is the equivalent of a 2.6-litre and is classified as such in some countries.
It’s a setup that provides an engine that revs to 9,000rpm, and in high-power form (a low-power version is also available) produces 228bhp. But fuel economy does not suffer: as fitted inside the RX-8, RENESIS has the potential to return a wholly acceptable 8.3L/100km (34mpg). Oh, and an inherent benefit of the rotary design is smoothness – this unit spins freely to its redline.
But it’s not just about performance: the RENESIS is clean too. It already meets the 2005 EURO IV emission levels, while a three-stage induction system featuring shutter valves at the intake ports, allows for improved filling efficiency.
The Mazda’s victory is taken with a 10 point advantage over the BMW 3-litre diesel, with 37 of the 56 judges awarding points in favour of this unique engine.
Results
points
Mazda RENESIS (RX-8) 252
BMW Diesel 3-litre (330d, X3, 530d, X5, 730d) 242
BMW 3-litre (Z4, 330i, X3, 530i, X5, 730i) 189
Subaru 3-litre (Legacy, Outback) 133
Audi Diesel 3-litre (A6, A8) 70
Mercedes-AMG Diesel 3-litre (C-Class) 68 '