Audi/Bentley 90° twin-turbocharged V8 racing engine

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Audi/Bentley twin-turbo V8 racing engine
Overview
ManufacturerAudi/Bentley (Volkswagen Group)
Production1999-2005
Layout
Configuration90° V-8
Displacement3.6–4.0 L (220–244 cu in)
Cylinder bore85–87 mm (3.35–3.43 in)
Piston stroke79.2–84 mm (3.12–3.31 in)
Valvetrain32-valve, DOHC, four-valves per cylinder
Combustion
TurbochargerHoneywell Turbo Technologies twin-turbochargers
Fuel systemGasoline direct fuel injection
ManagementBosch MS 2.8/2.9
Fuel typeShell racing gasoline
Oil systemDry sump (Shell Racing oil SR)
Output
Power output520–860 hp (388–641 kW)
Torque output516–752 lb⋅ft (700–1,020 N⋅m)

The Audi/Bentley 90° twin-turbocharged V8 racing engine is a 3.6-liter and 4.0-liter, twin-turbocharged, four-stroke, 90-degree, V8 racing engine, used in the Audi R8C, Audi R8R, Audi R8 and Bentley Speed 8 Le Mans Prototype race cars, between 1999 and 2005.[1][2][3][4][5][6][7]

Audi R8C/R8R engine[edit]

The R8C and R8R both use 3.6-liter, twin-turbocharged V8 engines, producing between 600–640 hp (447–477 kW), and between 516–561 lb⋅ft (700–761 N⋅m) of torque, while using two 32.4 mm (1.28 in) air restrictors, and pushing 1.67 bar (24.2 psi) of absolute boost pressure. While the R8R has a large number of vents placed on the nose, most of the intakes and air exits on the R8C are placed on the sides.

The R8R was estimated to boast around 610 hp (450 kW) from its V8 engine, allowing it to hit 335 km/h (208 mph) in 1999 at Le Mans (the original claims were that the car could go 350 km/h (217 mph)).[8][9][10]

Audi R8 engine[edit]

The R8 is powered by a 3.6 L Audi V8 with Fuel Stratified Injection (FSI), which is a variation on the concept of gasoline direct injection developed by VW; it maximizes both power and fuel economy at the same time. FSI technology can be found in products available to the public, across all brands in the Volkswagen Group.

The power supplied by the R8, officially listed at about 610 hp (455 kW) in 2000, 2001, and 2002, 550 hp (410.1 kW) in 2003 and 2004, and 520 hp (388 kW) in 2005, is sent to the rear wheels via a Ricardo six-speed sequential transmission with an electropneumatic paddle shift. Unofficially, the works team Audi R8 for Le Mans (2000, 2001, and 2002) is said to have had around 670 hp (500 kW) instead of the quoted 610 hp. The numbers were quoted at speed, and were due to the car making 50 extra horsepower due to twin ram-air intakes at speeds over 150 mph (240 km/h). Official torque numbers were quoted for this version of the engine at 516 lb⋅ft (700 N⋅m) at 6500 rpm (2004/2005), but the 2002/2003-spec engine produced more torque; with 553 lb⋅ft (750 N⋅m) at 5500 rpm, with boost pressure set at 1.67 bar (24.2 psi) absolute. The equation for horsepower (torque divided by 5250, multiplied by rpm) for these numbers produces a horsepower rating of 638 horsepower (476 kW) at the same 6500 rpm (516/5250*6500=638).[11][12]

Restrictor changes for 2003 brought the power down to 550 bhp for anyone still racing with the R8, but the maximum torque hardly changed.

For 2005, The ACO still felt that the R8 needed to be kept in check, so they reduced the restrictor size on the R8's engine, due to the car not meeting new hybrid regulations, and stipulated the car shall carry ballast weight in an attempt to make the races more competitive. The R8 was restricted even further to only 520 bhp.

Bentley Speed 8/EXP Speed 8 engine[edit]

The engine from the Audi R8, a 3.6-liter V8, with (Honeywell Turbo Technologies) turbocharger,[13] was used as the initial powerplant for the Bentley in 2001. It produced 637 hp (475 kW) and over 479 lb⋅ft (649 N⋅m) of torque, via two 33.1 mm (1.30 in) intake restrictor, with boost pressure limited to 1.87 bar (27.1 psi) by regulations.[14][15][16][17]

Following its initial year of competition, the Audi-sourced V8 was modified to better suit the EXP Speed 8. This saw the engine expand to 4.0 liters, producing between 600–650 hp (450–480 kW), and 590 lb⋅ft (800 N⋅m) of torque, using two 30.7 mm (1.21 in) intake restrictor plates, with boost pressure still being limited to 1.87 bar (27.1 psi) by regulations. This would ultimately lead to Bentley redesigning the car for 2003, leading to the change of name to simply Speed. Without the intake restrictor plates (completely unrestricted), and with boost pressure set at around 1.9 bar (28 psi), the 4.0-liter engine is reportedly capable of producing up to 860 hp (640 kW), and about 750 lb⋅ft (1,020 N⋅m) of torque.[18][19][20][21][22][23][24]

Applications[edit]

References[edit]

  1. ^ "2000 - 2002 Audi R8 - Images, Specifications and Information". Ultimatecarpage.com.
  2. ^ "Audi R8 405 Brochure" (PDF). taylorandcrawley.com. Retrieved 17 September 2023.
  3. ^ "You can now buy one of the most dominant cars in Le Mans history". CAR Magazine.
  4. ^ "Audi R8 group LMP900 (2000) - Racing Cars". tech-racingcars.wikidot.com.
  5. ^ "2000 Audi R8 | Audi". 20 April 2016.
  6. ^ "Find of the Day: Audi R8 LMP900 Endurance Racer". 14 April 2020.
  7. ^ "Last Stop at Le Mans for the Audi R8". www.audiworld.com.
  8. ^ "1999 Audi R8R - Images, Specifications and Information". Ultimatecarpage.com.
  9. ^ "Mulsanne's Corner: 1999 Audi R8R". www.mulsannescorner.com.
  10. ^ "1999 Audi R8R | Audi". 21 April 2016.
  11. ^ "Mulsanne's Corner: 2001-2005 Audi R8". www.mulsannescorner.com.
  12. ^ "Mulsanne's Corner: 2000 Audi R8". www.mulsannescorner.com.
  13. ^ Honeywell Turbo Technologies. "Honeywell Turbo Technologies » Honeywell Turbos Boost 14th Consecutive Victory at 24 Hours of Le Mans". honeywell.com. Archived from the original on 10 July 2018. Retrieved 2 February 2014.
  14. ^ "2003 Bentley Speed 8 | Bentley". 5 April 2016.
  15. ^ "2003 Bentley Speed 8 - Images, Specifications and Information". Ultimatecarpage.com.
  16. ^ "Bentley Speed 8 specs, lap times, performance data". FastestLaps.com.
  17. ^ Neil, Dan (1 July 2003). "Bentley Speed 8". Car and Driver.
  18. ^ "Mulsanne's Corner: 2003 Bentley Speed 8". www.mulsannescorner.com.
  19. ^ "2002 Bentley EXP Speed 8". Autodius.
  20. ^ "Bentley Speed 8 - 2003 Le Mans Winning Car". SnapLap. 16 November 2016.
  21. ^ "Bentley EXP Speed 8 group GTP (2001) - Racing Cars". tech-racingcars.wikidot.com.
  22. ^ "Bentley EXP Speed 8 (2002)". NetCarShow.com.
  23. ^ "Hero Racecars - 2001 Bentley Speed 8 LMP1 Winner Laid Bedrock for Modern Flying B". 18 November 2014.
  24. ^ "Mulsanne's Corner: 2001-2002 Bentley EXP Speed 8". www.mulsannescorner.com.
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