Next MX-5 to run rotary power?
This Superlight showcar proves Mazda can trim the MX-5 design to a neat 1 000kg. With rotary-hybrid power it should offer 118kW performance and 5l/100km economy too.
The world’s most popular roadster may become the first production car to boast rotary-hybrid power.
Design goals for the new MX-5 (due in 2012) are quite lofty. Mazda hopes to trim the roadster’s kerb weight to an even 1 000kg (down from 1 095kg) and ensure 5l/100km fuel economy without sacrificing any of the current MX-5’s performance credentials.
When Mazda debuts its fourth generation MX-5 Japanese insiders predict it to feature the company’s characteristic rotary engine configuration. In order to achieve the design targets in terms of mass and economy, the rotary engine will need some help in the form of a lithium-ion battery pack.
Part of the MX-5’s appeal has always been its tactile responses and harmonious dynamics, attributable to low mass and impeccably geared powertrains. In an attempt to keep mass as low as possible (as near to the design target of 1 000kg) Mazda realises a reduction from the current car’s 2l in-line four engine capacity to a 1.3l rotary would save an appreciable amount of weight.
Smaller engine, similar power
Downsizing the engine capacity will not inhibit performance though, as the forced-induction rotary is expected to tally a similar power output to the current MX-5's 118kW. The issue is achieving an economy target of 5l/100km, as rotary engines feature notoriously severe fuel consumption. To this end a lithium-ion battery pack and electric motor are rumoured to be part of the drivetrain upgrade in order to ensure the requisite economy.
Hybrid drivetrains tend to be heavy though, which would work against one of the fourth-generation MX-5’s most fundamental design targets - keeping mass as low as possible. At last year's Frankfurt motorshow Mazda showed off its Superlight concept, which managed to tally a kerb weight of only 1 000kg – illustrating material and construction technology is available to package the next MX-5 at a similar licensing mass.
A recent patent filed by Mazda, for electric motor technology mounted in a wheel hub, strongly supports the conjecture around the next MX-5 taking over the mantle as Mazda’s sole rotary-powered vehicle - after the current RX-8 is discontinued next year.
Do you think the new MX-5 will be a rotary of four-cylinder turbo? Debate it here...