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Prodrive P2: Ahead Of The Curve

Posted in Concept Cars, Emissions, Fast Cars, Subaru by Geoff | September 20th, 2008 | Leave a Reply |

Prodrive P2 Prototype
Prodrive P2 Prototype

Regardless of whether you have an appreciation of it’s outward design (especially the “P” badge on front), the P2 prototype from Prodrive is meant to be a demonstration of the considerable technical prowess of the company behind six World Rally Championship titles with Subaru, five British Touring Car Championships, the 2003 GTS class winner at Le Mans with its Ferrari 550 GTS Maranello and the managers of Aston Martin Racing.  The P2 serves as the embodiment of technologies and materials that are currently available and often under-utilized in mainstream auto manufacturing.  The P2 is a fully working two-seater sports car prototype that features Prodrive’s latest technology and which was entirely designed, engineered and built in just nine months.  Even more impressive than all that, is that the P2 was built using the tiny Subaru R1 as a starting point. 

According to Prodrive, the P2 uses a modified two-liter flat-four Subaru Impreza STi engine and Subaru all wheel drivetrain, and incorporates two innovative technologies to enhance performance; ALS and ATD.  ALS is derived from the same system found on the Prodrive-designed Subaru World Rally Car, but modified for use on the road.  Essentially, ALS (Anti-Lag System) keeps the turbo on full boost at low engine speeds and gives the car immediate throttle response and improved performance by using more of the engine’s torque throughout the rev range. 

Turbo-charged engines tend to run with a rich fuel mixture and, as a result, some of this fuel remains unburnt and ends up in the exhaust.  At low engine speeds, when turbo-lag is experienced, the anti-lag system can introduce ambient air into the red hot exhaust manifold causing this fuel to spontaneously combust. This increases the manifold pressure,spinning the turbo back onto boost.  In tests, it has been shown to double engine torque at low revs, enabling a test car to accelerate from 30 to 50 mph in the same time in third gear as it would without the system in second gear.

As well as enhancing the performance of turbo-charged cars, it could also provide a solution to the downsizing of engines in cars and therefore improve fuel economy by about 25 percent and reduce emissions.  According to Prodrive, with an anti-lag system, you could in theory replace a normally aspirated, two liter engine with a turbo-charged one liter.  The ATD system, (Active Torque Dynamics) uses active center and rear differentials to control the torque split between the front and rear of the car and across the rear axle for optimal car handling characteristics by helping to correct over or understeer.  For example, should the car begin to understeer while on power,then more torque will be pushed to the rear wheels, while if it began to oversteer then drive is sent to the front of the car, balancing it in all situations. The principle of ATD is to keep a vehicle going where the driver wants it to go, by modulating the torque at the road wheels using active differentials rather than applying the brakes, as is the case with stability systems such as ESP.

P2 Prototype
P2 Prototype

The philosophy (right or wrong ) behind the external design of the car was practical performance.  Weighing just 1100 kg and with a power to weight ratio of more than 350 bhp/tonne, P2 is expected to reach 60 mph in under four seconds and has a top speed of nearly 174 mph.

Rear of P2
Rear of P2

The P2 is not currently in production, though Prodrive is in talks with several automakers about integrating at least some of these technologies into their vehicles.

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