McLaren has gone public about its intentions to launch a new sports car aimed squarely at the Porsche 911 Turbo.

Known internally as P13, the new model will be McLaren’s core sports car. It will cost about £120,000 and be equipped with a 3.8-litre V8 with about 450bhp. The target is for total sales of up to 2500 units per year when it goes on sale in 2015.

Speaking to Autocar at the recent Geneva motor show, McLaren chief Ron Dennis confirmed the P13’s existence as the smallest model below the 12C supercar and P1 hypercar as part of a three-strong line-up.

Dennis said the positioning of the car was very much up for discussion. However, several senior company sources that have worked on the project for almost a decade confirmed to Autocar that the 911 Turbo was the model very much in the sights of the P13.

This is based around McLaren’s view that there is very little available in the market for high-performance sports cars that cost between £100,000 and £150,000.

For instance, the standard Porsche 911 range, Audi R8 and Aston Martin Vantage all come in below £100,000 and have accessible performance, yet the next rung of supercars – such as the Lamborghini Gallardo, Mercedes SLS, Ferrari 458 Italia and the 12C itself – are all deep into the £150,000 and above bracket, with a harder, more-focused edge to match.

McLaren’s thinking is that there is a huge gap in the performance car market for something that mixes that harder edge while maintaining everyday usability – something that only the 911 Turbo can claim to have at present. Performance cars in that £120,000 or so bracket – the Aston Martin DB9 and Bentley Continental GT – are more GTs than sports cars.

One insider said: “The truth is, if you have £120,000 to spend on a sports car you’d still end up going for a Porsche 911, even though you can get one for £70,000. There is nothing else out there between £100,000 and £150,000.”

McLaren is now finalising the specification for the new sports car to fit that £120,000 brief. At the core of the P13 will be the firm’s carbonfibre MonoCell chassis, seen on the 12C and adapted into the MonoCage on the P1 that adds a roll bar and air scoop over the cabin.

The carbonfibre structure was always intended for use on a smaller, more affordable entry-level model right from McLaren Automotive’s rebirth a decade ago. As such, there are no cost concerns on offering the technology at a lower price point than on the £176,000 12C. The investment has already been made in ramping up the technology for a larger-volume, lower-priced model.

The MonoCell is able to underpin coupé and convertible bodystyles with no major structural changes to increase stiffness. As such, the P13 is expected to launch first as a coupé in 2015, with a convertible version following a year later, a similar gap between launches as with the 12C coupé and convertible models.

At the heart of the mid-engined, rear-drive P13 will be a version of McLaren’s now familiar twin-turbocharged 3.8-litre engine, detuned to around 450bhp. The engine produces 616bhp in the 12C and 727bhp in its more focused application in the P1, where it is also hooked up to an electric motor for added boost. Drive in the P13 will be sent to the rear wheels through a Graziano seven-speed dual-clutch, adapted from the 12C and P1.

Insiders are remaining tight-lipped on performance figures, but a 0-62mph time of sub 4.0sec would be a clear target for the P13, as will a top speed close to, but not exceeding, 200mph.

The new four-wheel-drive 911 Turbo is targeting a 0-62mph time closer to 3.0sec and a top speed in excess of 200mph, but McLaren has made its intentions clear with the P1 that it is more interested in making honed driver’s cars rather than models with headline-grabbing performance figures.

McLaren insiders have so far also remained coy on the looks of the new P13, but it is understood to lean more heavily on the P1 than on the MP4-12C. Insiders have admitted that the look of the 12C was “too much about technology and less about beauty”, something that will be the opposite when the finished form of the P13 is revealed.

Despite using the MonoCell chassis and same fundamental engine and suspension layout as the 12C, the P13 will have slightly more compact dimensions thanks to tighter packaging of its components, but this will be emphasised further by its cleaner styling.

McLaren is targeting sales of around 2500 units per year of the P13, which should push its annual volumes close to 4000 units per year, including the production of the 12C coupé and Spider.

The two model ranges, as well as the P1, are all able to be built on the same production line at the McLaren Technology Centre in Woking .