Spare tyre and hi-po kits for 3 Series

IT WAS only a matter of time before BMW extended the full potential of its turbocharged petrol engine technology, which has now spread from its staple inline six-cylinder to the 4.4-litre V8 that powers both the X6 xDrive50i SUV and 750i limousine.

It was also inevitable that the Bavarian brand would meet with the demands of some customers for an alternative to its now-trademark run-flat ‘safety’ tyres, which are now fitted almost exclusively across the BMW range and have been criticised by people who want the piece of mind of an actual spare wheel.

Now the German luxury giant, which has long been renowned for its extensive (and expensive) options lists, has now come good on both scores – in the shape of two unexpected new genuine dealer-fit accessories.

While BMW is yet to improve on the 300kW/600Nm outputs of its new twin-turbo V8 (that honour will likely be reserved for the next-generation M5), the most exciting development is a so-called BMW Performance Power Kit for the force-fed direct-injection 3.0-litre straight six that powers the entry-level 1 Series and volume-selling 3 Series.

Bringing the 135i coupe and convertible and the 335i sedan, coupe, convertible and wagon (but, so far, not the X6 xDrive35i) into line with BMW’s new $200,000 740i sedan, the official aftermarket kit increases peak power by 15kW, from 225kW to 240kW, and maximum torque from 400Nm to a beefy 450Nm in automatic versions (up 50kW).

Manual versions will be restricted to a still-sufficient 430Nm of max twist, but that’s still up on the 4.0-litre V8 fitted to the now-established E90-based M3 coupe, sedan and convertible range, which of course also produces a heady 309kW.

The factory boost-kit, which was officially revealed at this week’s Geneva motor show, can be retro-fitted or supplied with new vehicles, including two-door 335i coupes and convertibles blessed with a variation of the M3’s seven-speed twin-clutch automated manual transmission.

Either way, the spinning propeller brand says the result is “a significant increase in power and performance clearly confirmed by actual measurements”, with the kitted 335i sedan claimed to accelerate to 100km/h in 5.4 seconds - two-tenths of a second quicker than the standard production car.

BMW says 80-120km/h overtaking is dispensed with half a second sooner too, so expect the tweaked 135i to benefit even more from the “software and hardware” modifications, which include a revised engine management system, a second radiator, an upgraded main radiator and higher-flow ducting.

The surprising new option, which is a clever way of charging for the extra performance instead of building just one high-output version of the N54 twin-turbo six-pack, makes us wonder just how far the company’s most powerful six-cylinder engine can be developed for next-generation of models.

Indeed, the only bad news is no pricing has yet been revealed for the kit (fuel consumption details for which not been confirmed either), which won’t be available in Australia until around September.

Meantime, BMW Australia has rethought its hitherto-unbending policy of fitting run-flat tyres to its entire BMW and Mini vehicle range – except for all M models and at least the entry-level 520d – by introducing the option of a space-saving temporary spare wheel and tyre for its top-selling 3 Series sedan.

Priced at $820 as a steel item or $1025 for a light-alloy version, the ‘emergency replacement wheel’ is available as a dealer-fitted accessory, with the 15-minute fitment process costing extra (depending on your BMW dealer’s hourly rates) for new or used cars.

Now available nationally and designed locally to fit flush under the boot floor, the space-saver kit comprises a flip-up floor panel with luggage net and wheel brace and jack, plus a regular space-saver temporary spare.

“BMW recognises that some drivers like to have the physical security of an emergency spare wheel in the boot,” says the only brand to fit run-flat tyres as standard in Australia, in a major about-face on the policy it pioneered globally to reduce weight and cost, and which is mimicked in Europe by its German rivals.

BMW says that like run-flat tyres, which have a maximum recommended range of 250km and have been criticised for their inferior but improving ride quality compared to conventional tyres, the 3 Series sedan’s accessory space-saver is limited to 80km/h.

BMW says the new space-saver arrangement, which is in response to a “small number of customers”, remains unavailable for all of its other run-flat-shod models – at least for now. It points out that run-flats “obviate the need to change a punctured wheel at the roadside or when the driver is within easy reach of a BMW dealer or tyre shop”.

The move follows a similar but more generous concession from Holden, which from this month’s production will replace – at no cost – the space-saver fitted as standard in Commodore sedans and wagons with either a full-size spare wheel (previously a $350 option) or a tyre inflation kit for small punctures, following widespread condemnation of the lack of a traditional spare tyre for the VE.

Read more:

Commodore gets new spare options