Audi's new baby R4 supercar

Audi’s £25k mid-engined R4 is destined for production in 2014/15, after chairman Rupert Stadler decided to press ahead with a plan to share platforms with new entry-level Porsche and Volkswagen two-seaters.

Previewed by the E-tron Spyder concept, the new sports car project has been the subject of intensive planning between Audi, Porsche and VW. Recent reports in the German media have even suggested the R4 had been placed on hold, amid concerns it was too close to the established TT.

But Audi officials have confirmed to Autocar that the svelte-looking R4 has received the official green light, and will form a significant part of the company’s future sports car programme.

“We have not abandoned plans for a roadster along the lines of the E-tron Spyder,” a source revealed to Autocar. “We have reached a stage where we are moving forward and are now in the process of progressing the business case further, but it won’t go on sale until after the third-generation TT.”

While the exact launch timing remains secret, confirmation that the R4 will follow the TT into showrooms suggests that sales will start towards the end of 2014. “We have to make sure there is space in the line-up without causing a conflict with existing models,” said our insider. “It will definitely happen.”

That timing should see the R4 lining up alongside the larger, second-generation R8 supercar, with which it will also share styling themes, inspired by the E-tron Spyder concept.

Read more on the Audi R4's VW and Porsche sister roadsters

Until Stadler made the key decision, the sticking point for the R4 programme had been its proposed construction. Plans initially called for a relatively simple and cost-effective steel unitary body arrangement with component sets taken from the Volkswagen Golf.

Engineers also considered basing it around a more complex aluminium spaceframe design; that would have been expensive, but would have provided added engineering integrity. However, the decision to bring Porsche into the project in early 2010 has seen a further evolution in the plan.

Insiders now suggest the production version of the R4 will share major elements of its front-end structure with the third-generation Boxster – itself closely related to the 911. The R4’s rear structure, however, will be “radically different”, according to one Audi source.

Read Autocar's VW BlueSport concept review

Engineering efforts are concentrating initially on two petrol engines, a similar strategy to that used on the R8. As with all models based on the Group’s new MMB platform, they will be mounted transversely behind the cabin and deliver power to the rear wheels, a layout that allows significant parts sharing with front-drive engine and gearbox modules.