Transcript Slide 1
Insight into aerodynamic improvements for the S2 Lotus Exige By Simon Farren Presented at US Distributor Sector 111 11th April 2009 Why can Improvements be made? Manufacturers Vehicles have to meet certain criteria for type approval: • Approach Ramp angles • Heights above ground for lamps (Minimum ride heights) • Edge radius have to meet minimum requirements Manufacturers also try to optimise drag to improve fuel economy or top speed figures. Vehicle Styling, practicality and packaging plays an important part in design. Cost constraints Wind tunnel testing S2 Exige Specs Tested The ride heights on both cars were set to 120mm front and rear. The Frontal areas: Standard Exige = 18.30 Sq ft Modified Reverie wide arch Exige = 18.73 Sq ft Std Exige This had an aftermarket exhaust fitted with above diffuser exit, and a new diffuser with no Centre exhaust hole. Reverie modified Exige Reverie Wide Arch kit +40mm front & Rear. 7.5x17” Et18 (fitted with 20mm spacers) Team dynamics front wheels with 215/40R17 Toyo T1-r tyres. 9.0x18” Et25 (fitted with 20mm spacers) Team dynamics front wheels with 245/35R18 Toyo T1-r tyres. Reverie 225mm chord adjustable (plan view curved) clamshell mounted rear wing. Fitted with Reverie Wide arch Exige s2 front spoiler. Fitted with reverie bolt on front S2 Elise / Exige Canards. Simulated with New Reverie Wider S2 Elise /Exige Rear Mid Floor (Tests 7,8,9 only). Simulated with New Reverie Horizontal S2 Elise / Exige Side Sill extensions (Tests 8 & 9 only). Simulated with New Reverie wide 3 element rear diffuser , running under rear wishbones (Tests 8 & 9 only). Note regrettably this car had a stage 2 exhaust with tip exits in the centre rear diffuser tunnel. Rear diffuser smoke flow visualization Rear wing smoke flow visualization Front spoiler fences / canards Side Skirts Key aerodynamic Improvements Taped static pressure bubble on top of front splitter Maximised under floor area Improved rear diffuser vanes to control air flowing in from sides Side tunnels in diffuser working as floor under wishbones Exhaust out of diffuser so centre tunnel working Fitted efficient adjustable rear wing Reduced leakage of air under floor to low pressure Tuned aero balance front to rear to match CoG Better lift / drag ratio with increased down force Positive arch louvers (not fitted in test) Allow High pressure out Table of coefficients 10N = 2.248 lbs Table of aerodynamic forces 10N = 2.248 lbs Table of aerodynamic forces 10N = 2.248 lbs Reverie positive louvers Reverie wide wheel arch kit Reverie aerodynamic parts on track Recent Customer Developed Parts Supercharged Rst-V6 550hp Evo Rear Wing, Diffuser, Floor, Splitter