New platform underpins Mazda future

Mazda has lifted the lid on its new product toybox to display the new platform that will underpin its mainstream models through the next decade.

Unnamed as yet, the new platform boasts substantial weight reductions and significant increases in torsional and crash strength. It will underpin the lion's share of the Japanese marque’s model range rolling out under a host of new models.

Its debut date has not been officially confirmed, however, it is most likely to premiere under the new 6 C-D class model range in 2013.

Mazda currently uses a number of different platforms, variously sourced internally or via its partnership with Ford. The new platform is exclusive to Mazda and will eventually be used to anchor the 3, 6, small and medium-sized CX crossovers, and Mazda's various peoplemover models. It's likely that the Mazda2 and CX-9 will eventually get their own new platforms, however there is no clear timetable on these developments.

Mazda revealed the platform at the same technical workshop at which it highlighted its new SKY range of petrol and diesel engine technologies. The workshop took place in Berlin, Germany late last week.

The new platform features MacPherson strut front suspension in place of the double wishbone front-end on the current 6. The lightweight multilink rear suspension is an all-new design. The platform is all-wheel drive friendly and uses fabricated pressed steel front and rear subframes that are at the same time stiffer, lighter and cheaper to manufacture than the existing structures used under current Mazda models.

The new body design uses multiple load paths and body side, B-pillar and rear bulkhead ring structures to provide what Mazda claims will be five-star crash safety. At the front end of the structure top, mid and lower load paths spread frontal crash forces across the structure.

This force distribution strategy is repeated for side and rear impact structures.

Mazda used a body-in-white (BIW) from what's almost certainly the next generation Mazda6 to show off the new structure in Berlin.

It claims to have stripped more than 50kg from the midsize sedan's chassis while at the same time doubling its torsional strength. The structure remains all-steel (no aluminium is used to control costs), but Mazda says it is stronger than the current E90 3 Series and lighter.

Mazda has benchmarked the structure's crash and overall performance against BMW, Audi and Mercedes product as well as Japanese competitors.

The maker says it has upgraded the materials used in the structure. In the case of the BIW around 80 per cent is now high strength or ultra high strength steel. In previous generation Mazda models the ratio was around 60 per cent.

The new structure's B-pillar is fashioned from hot formed steel for a reduction in weight and section size in conjunction with an increase in strength. Epoxy bonding and higher spot weld counts also contribute to the structure's added strength.

The new suspension design features higher rear suspension trailing arm mountings which provide pro-squat geometry for more stable braking. A degree of passive rear wheel steering is built into the design.

At the pointy end, the steering gear is now fully electrically assisted. Mazda boffins are still tuning the system but are confident it will be the match or better of any existing setups.

As part of the Berlin reveal the Carsales Network joined a small international contingent allowed to drive development mules built on the new platform and powered by preproduction versions of the SKY petrol and diesel powertrains.

The demo cars wore crudely modified current model Mazda6 bodywork and interiors but were quite 'polished' on the road.

These Technical Prove-out Vehicles (TPV) capitalised upon the better inherent stability of the new chassis and featured sharper (ie: faster) ratio steering than the current 6. Details like final steering ratios and assistance levels will be fine tuned over the next year or so, Mazda Europe engineers advised.

Better suspension geometry has also allowed Mazda to reduce spring and damper rates in comparison to the last generation 6 for better ride without sacrificing handling. In the case of the TPVs driven the end result certainly seemed to ring true with the engineers' claims. Though our 47km test route was largely limited to autobahn the cars demonstrated good body control and a cosseting ride -- even on a badly surfaced section of highway.

Dimensions have grown compared to the current 6 -- at least in the case of the TPV. The wheelbase has been stretched 50mm with the majority of the stretch ahead of the firewall, most logically to help improve front/rear weight distribution. This is a tactic Audi employed in its redesign of the A4 family. Front and rear track have increased 18 and 25mm respectively.

Insiders say the new Mazda6 will also be 50mm longer overall but front and rear overhangs will be drastically trimmed. Expect the car to be around 15mm wider. Mazda's international Design Workshop which commences in Milan today (Monday, August 30) should yield some clues to the styling on the new car.

Unlike the current generation 6 which features a 'stretched' version for some markets it's likely that Mazda will return to a single body size with the next-gen car. Currently Mazda builds a larger 6 for the North American market but worldwide marketing head for Mazda Masahiro Moro says the experiment has not been a success.

Moro told the Carsales Network the larger car has not yielded enough extra sales to encourage Mazda to build a US-specific model in the next generation.

"The medium car market in the USA is now characterised by more than one size of medium car... With this generation we moved to the larger end... Buyers of the new 6 say they like the [larger] trunk but we should not design our cars from the back to the front.

"Mazda is different [from other medium car brands]. We need to retain our Zoom Zoom feel and this means we will design the new model properly -- from the front, back."

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